ukssdc_d_20052007.bib

@COMMENT{{{This file has been generated by bib2bib 1.74}}
@COMMENT{{{Command line: /soft/ukssdc/share/bib2bib -c 'exists ukssdc_d' -c 'year = 2005 or year = 2006 or year = 2007' -s author -ob ukssdc_d_20052007.bib ukssdc.bib}}

@ARTICLE{araujo-pradere2005:_variability,
  AUTHOR = {Araujo-Pradere, E.A. and Fuller-Rowell, T.J. and Codrescu, 
                  M.V.},
  TITLE = {Characteristics of the ionospheric variability as a function 
                  of season, latitude, local time, and geomagnetic activity},
  JOURNAL = {Radio Science},
  YEAR = {2005},
  VOLUME = {40},
  NUMBER = {5},
  UKSSDC_D = {},
  UKSSDC_I = {},
  URL = {http://dx.doi.org/10.1029/2004RS003179},
  ABSTRACT = {An
	ionospheric F-2 critical frequency database has been  assembled to
	  determine the variability of the F region as a function of local
	    time, latitude, season, and geomagnetic activity. The database
	comprises observations from 75 ionosonde stations covering a range
	      of geomagnetic latitude and includes 43 storm intervals. The
	  database was previously used to develop the Storm-Time Empirical
	       Ionospheric Correction Model (STORM). The mean and standard
	  deviation have been evaluated by sorting the data by local time,
		 season (five intervals centered on equinox, solstice, and
      intermediate intervals), latitude (four regions each 20 degrees wide
	   in geomagnetic latitude), and up to eight levels of geomagnetic
	  activity. The geomagnetic activity index was based on a weighted
      integral of the previous 33 hours of ap and is the same as that used
	   by the STORM model. The database covers a full solar cycle, but
	  insufficient information was available to sort by solar activity
	    without compromising the estimates of variability on the other
       sorting parameters. About half the data were contained in the first
	level of geomagnetic activity, between 0 and 500 units of filtered
	ap corresponding to Kp <= 2, and half above that level. When local
	 time dependence was included in the binning, sufficient data were
      available to sort into two levels of geomagnetic activity, quiet (Kp
       <= 2(+)) and disturbed (Kp > 3(-)). For all latitudes and levels of
       geomagnetic activity, the lowest variability was typically found in
	   summer (10-15%), and the largest variability occurred in winter
		(15-40%), with equinox (10-30%) lying between the solstice
	   extremes. The exception was low latitudes at equinox, which had
	    surprising low variability (10%), possibly because of the weak
	     interhemispheric flow at this time of year. At middle and low
	    latitudes, the variability tended to increase with geomagnetic
	    activity in winter and equinox but remained fairly constant in
	  summer. At high latitudes, the surprising result was that in all
	   seasons, and in winter in particular, the variability tended to
	  decrease, probably because of the increased upwelling of neutral
		    molecular species and stronger chemical control of the
	      ionosphere. The data have also been used to build a table of
	 estimated variability suitable for inclusion in the International
       Reference Ionosphere or any other climatological model. For periods
       where data were scarce or nonexistent, an estimated variability was
	      provided on the basis of expectations of the consequences o
	     physical processes. This was necessary to fill in the table o
	  values in order to develop a module suitable for inclusion in th
				    International Reference Ionosphere.}
}

@ARTICLE{austin:_whatever_happened_to_40_metres,
  AUTHOR = {Austin, B.A.},
  TITLE = {Whatever Happened to 40 Metres?},
  JOURNAL = {Mercury, the Journal of the Royal Signals Amateur Radio
                  Society},
  YEAR = {2005},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_FIRST = {}
}

@ARTICLE{belahaki2005,
  AUTHOR = {Belehaki, A. and Cander, Lj. and Zolesi, B. and Bremer, J. and Juren, C. and Stanislawska, I. and Dialetis, D. and Hatzopoulos, M.},
  TITLE = {DIAS Project: The establishment of a European digital upper 
                  atmosphere server},
  JOURNAL = {Journal of Atmospheric and Solar-Terrestrial Physics},
  YEAR = {2005},
  VOLUME = {67},
  NUMBER = {12},
  PAGES = {1092--1099},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_OTHER = {},
  ABSTRACT = {The main objective of DIAS (European Digital Upper Atmosphere Server) project is to develop a pan-European digital data collection on the state of the upper atmosphere, based on real-time information and historical data collections provided by most operating ionospheric stations in Europe. A DIAS system will distribute information required by various groups of users for the specification of upper atmospheric conditions over Europe suitable for nowcasting and forecasting purposes. The successful operation of the DIAS system will lead to the development of new European added-value products and services, to the effective use of observational data in operational applications and consequently to the expansion of the relevant European market.},
  KEYWORDS = {Ionosphere; Upper atmosphere; Ionospheric monitoring; Ionospheric nowcasting; Ionospheric forecasting; Digital libraries},
  URL = {http://dx.doi.org/10.1016/j.jastp.2005.02.021}
}

@ARTICLE{bencze05,
  AUTHOR = {Bencze, P.},
  TITLE = {On the long-term change of ionospheric parameters},
  JOURNAL = {jastp},
  YEAR = 2005,
  VOLUME = 67,
  NUMBER = 14,
  PAGES = {1298--1306},
  MONTH = {September},
  UKSSDC_D = {},
  UKSSDC_I = {},
  URL = {http://dx.doi.org/10.1016/j.jastp.2005.06.020},
  ABSTRACT = {Independent of the possible sources (solar activity, geomagnetic activity, greenhouse effect, etc.) of a global change in the upper atmosphere, it is the sign of a long-term trend of temperature that might reveal the cause of a global change.

Long-term change of temperature in the F region of the ionosphere has been studied and is assumed to be expressed in terms of thickness of the bottornside F2 layer characterized by the difference between height of the maximum electron density of the F2 layer hmF2 and altitude of the lower boundary of the F region represented by h'F. Using the difference of two ionospheric parameters has the advantage that it reduces the effect of changes resulting from alteration of equipment and scaling personnel. In this study, in summer only night values of the difference hmF2-h'F and in winter both day and night values have been taken into account considering that h'F might indicate the lower boundary of the F region in these periods. The study of the behaviour of hmF2-h'F taking separately the stations and determining yearly the mean measure (trend) of the variation of hmF2-h'F with solar and geomagnetic activities found that this difference increases significantly with enhanced solar activity, but trends of the solar activity effect exerted on this difference themselves do not practically change with increasing sunspot number. Further, hmF2-h'F decreases only insignificantly with growing geomagnetic activity. Trends of the geomagnetic activity effect related to hmF2-h'F change only insignificantly with increasing Ap; however, trends of the geomagnetic activity effect decreased with increasing latitude.

As a result of this investigation it has been found that hmF2-h'F regarded as thickness of the bottornside F2 layer shows an effect of the change of solar activity during the last three solar cycles, indicating temperature change in the upper atmosphere to be expected on the basis of changing solar activity. Furthermore, though a long-term variation of solar activity considering only years around solar activity minima is relatively small, the difference hmF2-h'F indicates a trend opposing the change of solar activity; that is, it decreases slightly during the first three 20, 21, 22 solar cycle minima (1964-1986), but decreases more abruptly according to the change of solar activity towards the minimum of solar cycle 23 (1986-1996), thus also indicating variation of temperature in the F region. However, this variation cannot be explained by the change of solar and geomagnetic activities alone, but assumes some other source (e.g. greenhouse gases) too. (c) 2005 Elsevier Ltd. All rights reserved.}
}

@ARTICLE{blanch2005,
  AUTHOR = {Blanch, E. and Altadill, D. and Boska, J. and Buresova, D. 
                  and Hernandez-Pajares, M.},
  TITLE = {November 2003 event: Effects on the Earth's ionosphere 
                  observed from ground-based ionosonde and GPS data},
  JOURNAL = {Annales Geophysicae},
  YEAR = {2005},
  VOLUME = {23},
  NUMBER = {9},
  PAGES = {3027--3034},
  UKSSDC_D = {},
  UKSSDC_I = {},
  URL = {http://overview.sref.org/1432-0576/ag/2005-23-3027},
  ABSTRACT = {Intense late-cycle solar activity during October and November
                  2003 produced two strong geomagnetic storms: 28 October-5 
                  November 2003 (October) and 1923 November 2003 (November); 
                  both reached intense geomagnetic activity levels, K-p = 9, 
                  and K-p = 8+, respectively. The October 2003 geomagnetic 
                  storm was stronger, but the effects on the Earth's ionosphere
                  in the mid-latitude European sector were more important 
                  during the November 2003 storm. The aim of this paper is to 
                  discuss two significant effects observed on the ionosphere 
                  over the mid-latitude European sector produced by the 
                  November 2003 geomagnetic storm, using, data from ground 
                  ionosonde at Chilton (51.5 degrees N; 359.4 degrees E), 
                  Pruhonice (50.0 degrees N; 14.6 degrees E) and El Arenosillo 
                  (37.1 degrees N; 353.3 degrees E), jointly with GPS data. 
                  These effects are the presence of well developed anomalous 
                  storm E, layers observed at latitudes as low as 37 degrees N 
                  and the presence of two thin belts: one having enhanced 
                  electron content and other, depressed electron content. Both 
                  reside over the mid-latitude European evening sector.}
}

@ARTICLE{2006JATP...68.2075B,
  AUTHOR = {Bremer, J. and Cander, L.R. and Mielich, J. and Stamper, R.},
  TITLE = {{Derivation and test of ionospheric activity indices from real-time ionosonde observations in the European region}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2006,
  MONTH = DEC,
  VOLUME = 68,
  PAGES = {2075-2090},
  DOI = {10.1016/j.jastp.2006.07.003},
  ADSURL = {http://adsabs.harvard.edu/abs/2006JATP...68.2075B},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {New ionospheric activity indices are derived from automatically
       scaled online data from several European ionosonde stations. These indices
       are used to distinguish between normal ionospheric conditions expected from
       prevailing solar activity and ionospheric disturbances caused by specific
       solar and atmospheric events (flares, coronal mass ejections, atmospheric
       waves, etc.). The most reliable indices are derived from the maximum
       electron density of the ionospheric F 2-layer expressed by the maximum
       critical frequency foF 2. Similar indices derived from ionospheric M(3000)F
       2 values show a markedly lower variability indicating that the changes of
       the altitude of the F 2-layer maximum are proportionally smaller than those
       estimated from the maximum electron density in the F 2-layer. By using the
       ionospheric activity indices for several stations the ionospheric
       disturbance level over a substantial part of Europe (34N60N; 5W40E)
       can now be displayed online.  },
  UK_OTHER = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{butcher2005,
  AUTHOR = {Butcher, N.},
  TITLE = {Daily ionospheric forecasting service (DIFS) III},
  JOURNAL = {Annales Geophysicae},
  YEAR = {2005},
  VOLUME = {23},
  NUMBER = {12},
  PAGES = {3591--3598},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_FIRST = {},
  URL = {http://overview.sref.org/1432-0576/ag/2005-23-3591},
  ABSTRACT = {The daily variability of the ionosphere can greatly affect HF
                  or SATCOM communications. HF skywave operators plan frequency
                  schedules months in advance, however, they also require daily
                  knowledge of the ionospheric conditions in order to modify 
                  assignments. SATCOM operators also require daily information 
                  about the levels of scintillation, which are variations in 
                  phase, amplitude, polarisation and angle of arrival that can 
                  cause severe degradation of the received signal.

                  Using a number of ionosonde measurements and geomagnetic and 
                  solar values, a Daily Ionospheric Forecasting Service (DIFS) 
                  has been developed, which provides HF and SATCOM operators 
                  with daily forecasts of predicted ionospheric conditions. The
                  system uses in-house algorithms and an externally developed 
                  Global Ionospheric Scintillation Model (GISM) to generate HF 
                  and SATCOM forecasts. HF forecasts consist of a past summary 
                  and a forecast section, primarily displaying observed values 
                  and predicted categories for the Maximum Usable Frequency 
                  (MUF), as well as an Ionospheric Correction factor (ICF) that
                  can be fed into the ionospheric propagation prediction tool, 
                  WinHF. SATCOM forecasts give predictions of global 
                  scintillation levels, for the polar, mid and equatorial 
                  latitude regions. Thorough analysis was carried out on DIFS 
                  and the results conclude that the service gives good 
                  accuracy, with user feedback also confirming this, as well.}
}

@ARTICLE{2005JATP...67.1118C,
  AUTHOR = {Cander, L.R. and Mihajlovic, S.J.},
  TITLE = {{Ionospheric spatial and temporal variations during the 29 31 October 2003 storm}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2005,
  MONTH = AUG,
  VOLUME = 67,
  PAGES = {1118-1128},
  DOI = {10.1016/j.jastp.2005.02.020},
  ADSURL = {http://adsabs.harvard.edu/abs/2005JATP...67.1118C},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {A prominent large-scale ionospheric disturbance was observed in
        the European mid-latitude sector during the recent extreme space weather
        event in October 2003. Measurements of the horizontal component of the
        geomagnetic field H, the critical frequency of the F2 layer foF2, and the
        vertical total electron content (TEC) from the European network of
        observational sites are used to describe the temporal and spatial storm
        evolution process. It is found that the ionospheric F region storm
        morphology was dominated by negative disturbances over high mid-latitudes
        and positive disturbance at low mid-latitudes during the initial phase and
        by overall negative disturbances during the main phase. Although a good
        agreement between the two independent measurements was detected by
        comparing the storm-time behaviour of foF2 and TEC during the main phase of
        the storm, some irregularities have been recognised in TEC variations at
        high mid-latitudes. The relative merit of real-time observational
        solar-terrestrial data for accurate specification of the geomagnetically
        disturbed ionospheric F region during the extreme space weather conditions
        is discussed.  },
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2005JATP...67.1053R,
  AUTHOR = {Cander, L.R. and Zolesi, B.},
  TITLE = {{Space weather and RF communications: Monitoring and modelling}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2005,
  MONTH = AUG,
  VOLUME = 67,
  PAGES = {1053-1053},
  DOI = {10.1016/j.jastp.2005.05.001},
  ADSURL = {http://adsabs.harvard.edu/abs/2005JATP...67.1053R},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{clilverd05:_recon,
  AUTHOR = {Clilverd, M.A. and Clarke, E. and Ulich, T. and Linthe, J. and Rishbeth, H.},
  TITLE = {Reconstructing the long-term aa index},
  JOURNAL = {Journal of Geophysical Research},
  YEAR = 2005,
  VOLUME = 110,
  NUMBER = {A7},
  MONTH = JUL,
  ABSTRACT = {The robustness of the aa geomagnetic index is of critical
              importance to the debate about the previously reported doubling
              of the solar coronal magnetic field in the last 100 years,
              inferred from an increasing trend in this index. To test the
              trend in aa, we have reconstructed the aa index using two
              long-running European stations (Sodankyla from 1914 and Niemegk
              from 1890) to provide data for the northern component of the
              index that are independent of data from the UK observatories
              used in the "official'' aa index. Both the fully
              "reconstructed'' aa series, based on Sodankyla ( 67 degrees N, L
              = 5.2 R-E) and Niemegk ( 52 degrees N, L = 2.3 R-E) data in
              combination with the official aa Southern Hemisphere data,
              confirm the increasing trend in the index. The Niemegk-based
              index shows little solar cycle variation in its deviation from
              the official index, probably because of the midlatitude location
              of the station. The high-latitude station, Sodankyla, is more
              affected by active geomagnetic conditions during solar maximum
              because of the proximity of the auroral oval to the
              station. Nevertheless, its index also clearly confirms the
              increasing trend in the aa index and hence supports the idea of
              a long-term increase in solar coronal magnetic field
              strength. As an added test, we reconstructed the aa index from a
              single site using data from two long-running UK stations,
              Eskdalemuir and Lerwick, applying a technique known as
              interhourly variation (IHV) proposed by Svalgaard et al. (
              2004). The resulting series is designed to be primarily
              sensitive to solar wind conditions. Both the reconstructed
              aa(IHV) also showed an increasing trend with time and high
              consistency with the official aa index. Overall, we conclude
              that the robustness of the trend in the aa index supports the
              idea of a long-term increase in solar coronal magnetic field
              strength.},
  UKSSDC_D = {},
  UK_FIRST = {}
}

@ARTICLE{davis2005,
  AUTHOR = {Davis, C.J. and Johnson, C.G.},
  TITLE = {Lightning-induced intensification of the ionospheric sporadic E layer},
  JOURNAL = {Nature},
  PAGES = {799--801},
  YEAR = {2005},
  VOLUME = {435},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_FIRST = {},
  ABSTRACT = {A connection between thunderstorms and the ionosphere has
                  been hypothesized since the mid-1920s(1). Several mechanisms
                  have been proposed to explain this connection(2-7), and
                  evidence from modelling(8) as well as various types of
                  measurements(9-14) demonstrate that lightning can interact
                  with the lower ionosphere. It has been proposed, on the
                  basis of a few observed events(15), that the ionospheric
                  'sporadic E' layer - transient, localized patches of
                  relatively high electron density in the mid-ionosphere E
                  layer, which significantly affect radio-wave propagation -
                  can be modulated by thunderstorms, but a more formal
                  statistical analysis is still needed. Here we identify a
                  statistically significant intensification and descent in
                  altitude of the mid-latitude sporadic E layer directly above
                  thunderstorms. Because no ionospheric response to
                  low-pressure systems without lightning is detected, we
                  conclude that this localized intensification of the sporadic
                  E layer can be attributed to lightning. We suggest that the
                  co-location of lightning and ionospheric enhancement can be
                  explained by either vertically propagating gravity waves
                  that transfer energy from the site of lightning into the
                  ionosphere, or vertical electrical discharge, or by a
                  combination of these two mechanisms.}
}

@ARTICLE{2007JATP...69..621E,
  AUTHOR = {Echer, E.},
  TITLE = {{On the quasi-biennial oscillation (QBO) signal in the foF2 ionospheric parameter}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2007,
  MONTH = APR,
  VOLUME = 69,
  PAGES = {621-627},
  DOI = {10.1016/j.jastp.2006.11.001},
  ADSURL = {http://adsabs.harvard.edu/abs/2007JATP...69..621E},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006JATP...68.1871E,
  AUTHOR = {Elias, A.G. and Ortiz de Adler, N.},
  TITLE = {{Earth magnetic field and geomagnetic activity effects on long-term trends in the F2 layer at mid-high latitudes}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2006,
  MONTH = DEC,
  VOLUME = 68,
  PAGES = {1871-1878},
  DOI = {10.1016/j.jastp.2006.02.008},
  ADSURL = {http://adsabs.harvard.edu/abs/2006JATP...68.1871E},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2007AnGeo..25..495F,
  AUTHOR = {Finch, I. and Lockwood, M.},
  TITLE = {{Solar wind-magnetosphere coupling functions on timescales of 1 day to 1 year}},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2007,
  MONTH = MAR,
  VOLUME = 25,
  PAGES = {495-506},
  ADSURL = {http://adsabs.harvard.edu/abs/2007AnGeo..25..495F},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {There are no direct observational methods for determining the
        total rate at which energy is extracted from the solar wind by the
        magnetosphere. In the absence of such a direct measurement, alternative
        means of estimating the energy available to drive the magnetospheric system
        have been developed using different ionospheric and magnetospheric indices
        as proxies for energy consumption and dissipation and thus the input. The
        so-called coupling functions are constructed from the parameters of the
        interplanetary medium, as either theoretical or empirical estimates of
        energy transfer, and the effectiveness of these coupling functions has been
        evaluated in terms of their correlation with the chosen index. A number of
        coupling functions have been studied in the past with various criteria
        governing event selection and timescale. The present paper contains an
        exhaustive survey of the correlation between geomagnetic activity and the
        near-Earth solar wind and two of the planetary indices at a wide variety of
        timescales. Various combinations of interplanetary parameters are evaluated
        with careful allowance for the effects of data gaps in the interplanetary
        data. We show that the theoretical coupling, P, function first proposed by
        Vasyliunas et al. is superior at all timescales from 1-day to 1-year.},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006RaSc...41S6012F,
  AUTHOR = {Fotiadis, D.N. and Kouris, S.S.},
  TITLE = {Capturing the morphology of long-duration negative ionospheric
            disturbances using an empirical pattern recognition method},
  JOURNAL = {Radio Science},
  YEAR = 2006,
  MONTH = DEC,
  VOLUME = 41,
  PAGES = {6012-+},
  DOI = {10.1029/2005RS003395},
  ADSURL = {http://adsabs.harvard.edu/abs/2006RaSc...41S6012F},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {On the basis of an ionospheric definition of disturbed
       conditions independent of any causative mechanism, a feature-guided pattern
       recognition method reveals the dominant morphology of long-duration negative
       foF2 disturbances. A catalogue of negative disturbances lasting more than
       24 hours is compiled from hourly foF2 data from 75 ionosonde stations and
       three solar cycles. Disturbances in each month and station are handled
       separately, and four local time intervals of disturbance commencement are
       considered. A median disturbance profile is produced only when a minimum
       occurrence probability holds. The time window under morphological
       investigation is selected such that nonsystematic features, precursor
       phenomena, and poststorm effects are not included in analysis. The
       disturbance patterns, first grouped according to major characteristic
       features and then fitted with simple mathematic functions, are described by
       a range of the normalized deviation of hourly foF2 to its corresponding
       monthly median and are provided to radio users along with their distribution
       in space and time. The present model is a nonconditional stand-alone model
       which may, in the event of an ionospheric disturbance at a certain location,
       predict its further development.},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{fraser05:_new_zealan,
  AUTHOR = {Fraser, G.J.},
  TITLE = {The antecedents and subsequent development of scientific radar in New Zealand},
  JOURNAL = {jastp},
  YEAR = 2005,
  VOLUME = 67,
  NUMBER = 15,
  PAGES = {1411--1418},
  MONTH = {October},
  UKSSDC_D = {},
  URL = {http://dx.doi.org/10.1016/j.jastp.2005.07.010},
  ABSTRACT = {In New Zealand after World War 2 radar techniques were used in various investigations in geophysics and astronomy. Much local expertise had become available from defence laboratories, which had been set up in 1939 and eventually merged into the Radio Development Laboratory, disbanded in 1946. Wartime radar development had in turn been founded on pre-war research in radio propagation and ionospheric research which included the use of pulse ionosondes. Frequent support for the pre-war radio research in both Britain and New Zealand was given by Ernest Rutherford who, throughout his life, retained the interest from his own early researches in radio wave propagation. This paper is a brief survey of events from Rutherford's early experiments in 1894 to present-day research programmes.}
}

@ARTICLE{2006RaSc...41S6S08G,
  AUTHOR = {Garner, T.W. and Bust, G.S. and Gaussiran, T.L. and 
        Straus, P.R.},
  TITLE = {Variations in the midlatitude and equatorial ionosphere during the October 2003 magnetic storm},
  JOURNAL = {Radio Science},
  YEAR = 2006,
  MONTH = DEC,
  VOLUME = 41,
  PAGES = {6-+},
  DOI = {10.1029/2005RS003399},
  ADSURL = {http://adsabs.harvard.edu/abs/2006RaSc...41S6S08G},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {The October 2003 geomagnetic storm (often called the Halloween
        storm) was one of the largest storms (as measured by Dst) yet recorded. The
        storm-induced synoptic-scale changes in the ionosphere's plasma content and
        density can be viewed through space weather maps created by objective
        analysis algorithms. For this study, these maps, which specify the electron
        density in altitude, latitude, and longitude, are created by the
        ionospheric data assimilation three dimensional (IDA3D), a
        three-dimensional variation algorithm of the ionospheric electron density.
        These maps, representing the average conditions in the ionosphere over a 15
        min sampling time, show how dramatically the ionosphere changed during the
        Halloween storm. Following the southward turning of the interplanetary
        magnetic field, the dayside electron content is significantly reduced in
        the equatorial ionosphere between +/-18$\deg$ magnetic latitude and is enhanced
        poleward of this latitude. This is the expected behavior when the
        equatorial fountain is enhanced by a strong penetration electric field. In
        addition, the electron content is significantly increased in the dayside
        midlatitude ionosphere, which corresponds to a storm-enhanced density (SED)
        plume. Above 40$\deg$ magnetic latitude, the dayside plasma content is
        significantly reduced in the regions adjacent to the SED structure, which
        enhances the electron content gradient. Electron density maps in the
        altitude-magnetic latitude plane show an increase in the topside electron
        densities within an SED plume.},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{gulyaeva05:_night,
  AUTHOR = {Gulyaeva, T. and Stanislawska, W.},
  TITLE = {Night-day imprints of ionospheric slab thickness during geomagnetic storm},
  JOURNAL = {Journal of Atmospheric and Solar-Terrestrial Physics},
  YEAR = 2005,
  VOLUME = 67,
  NUMBER = 14,
  PAGES = {1307--1314},
  MONTH = {September},
  UKSSDC_D = {},
  UKSSDC_I = {},
  URL = {http://dx.doi.org/10.1016/j.jastp.2005.07.006},
  ABSTRACT = {Spatial maps of the ionosphere-plasmasphere slab thickness (T) were generated as a ratio of the total electron content (TEC) to the F-region peak electron density (NmF2) at 1 degrees spaced grid points from the instantaneous maps of TEC and foF2 at latitudes 35 degrees to 70 degrees N, and longitudes -10 degrees to 40 degrees E. Data of 23 observatories are used for the construction of TEC and foF2 maps with Kriging technique from independent networks of GPS-TEC and ionosonde observations at solar minimum (1995-1996) and maximum (2002) under quiet and disturbed magnetic conditions. The net-weight factor (omega) is introduced as a ratio of disturbance to quietness representing area mean TEC,foF2 and tau for a particular day and time normalized by relevant monthly median value. Analysis of w evolution for TEC, foF2 and T maps have revealed that TEC and foF2 depletion is accompanied by positive increment of slab thickness for more than 48 hrs during the magnetic storm at solar maximum but T enhancement is shorter and delayed by 12 to 24 hrs regarding the storm onset at solar minimum. The slab thickness positive increment at the main,phase of geomagnetic storm has been associated with relevant increase of the real thickness of the topside ionosphere. To estimate-the upper boundary of the ionosphere the International Reference Ionosphere expanded towards the plasmasphere (IRI*) is modified to assimilate the ionosonde F2 layer peak and the GPS-T.EC observations. Slab thickness is decomposed in three parts (the bottomside and topside ionosphere, and the plasmasphere). Eliminating the plasmasphere part from the total slab thickness, we obtain the ratio of bottomside slab thickness to the real thickness below the F2 layer peak. Assuming that this ratio is also valid above the F2 layer peak, we obtain the topside boundary of the ionosphere varying from 500 km by day to 2300km by night. (c) 2005 Elsevier Ltd. All rights reserved.}
}

@ARTICLE{2007JATP...69..528G,
  AUTHOR = {Gulyaeva, T.L.},
  TITLE = {{Variable coupling between the bottomside and topside thickness of the ionosphere}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2007,
  MONTH = APR,
  VOLUME = 69,
  PAGES = {528-536},
  DOI = {10.1016/j.jastp.2006.10.015},
  ADSURL = {http://adsabs.harvard.edu/abs/2007JATP...69..528G},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006GeoRL..3307811J,
  AUTHOR = {Johnson, C.G. and Davis, C.J.},
  TITLE = {{The location of lightning affecting the ionospheric sporadic-E layer as evidence for multiple enhancement mechanisms}},
  JOURNAL = {Geophysical Research Letters},
  YEAR = 2006,
  MONTH = APR,
  VOLUME = 33,
  PAGES = {7811-+},
  DOI = {10.1029/2005GL025294},
  ADSURL = {http://adsabs.harvard.edu/abs/2006GeoRL..3307811J},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {We present a study of the geographic location of lightning
        affecting the ionospheric sporadic-E (Es) layer over the ionospheric
        monitoring station at Chilton, UK. Data from the UK Met Office's Arrival
        Time Difference (ATD) lightning detection system were used to locate
        lightning strokes in the vicinity of the ionospheric monitoring station. A
        superposed epoch study of this data has previously revealed an enhancement
        in the Es layer caused by lightning within 200km of Chilton. In the current
        paper, we use the same data to investigate the location of the lightning
        strokes which have the largest effect on the Es layer above Chilton. We
        find that there are several locations where the effect of lightning on the
        ionosphere is most significant statistically, each producing different
        ionospheric responses. We interpret this as evidence that there is more
        than one mechanism combining to produce the previously observed enhancement
        in the ionosphere.},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006JATP...68..877K,
  AUTHOR = {Kane, R.P.},
  TITLE = {{Are the double-peaks in solar indices during solar maxima of cycle 23 reflected in ionospheric foF2?}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2006,
  MONTH = MAY,
  VOLUME = 68,
  PAGES = {877-880},
  DOI = {10.1016/j.jastp.2006.02.003},
  ADSURL = {http://adsabs.harvard.edu/abs/2006JATP...68..877K},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{lastovicka2005,
  AUTHOR = {Lastovicka, J.},
  TITLE = {On the role of solar and geomagnetic activity in long-term
                  trends in the atmosphere-ionosphere system},
  JOURNAL = {Journal of Atmospheric and Solar-Terrestrial Physics},
  YEAR = {2005},
  VOLUME = {67},
  NUMBER = {1--2},
  PAGES = {83--92},
  UKSSDC_D = {},
  UKSSDC_I = {},
  ABSTRACT = {The long-term continuous increase of greenhouse gas
                  concentration in the atmosphere and other anthropogenic
                  influences represent serious threat for human
                  civilization. Therefore, it is necessary to determine the
                  long-term trends and changes in the atmosphere-ionosphere
                  system. The observed long-term trends in the 20th century
                  might be. however, influenced by contribution of Sun's
                  origin, and the process of determination of anthropoger c
                  trends from observational data may be "spoilt" by the
                  11-year solar cycle. The role of solar/geomagnetic activity
                  in long-term trends in various regions of the
                  atmosphere/ionosphere system is briefly reviewed for the
                  first time. The ways; of avoiding or at least diminishing
                  the effect of solar cycle on trend determination are
                  mentioned. As for the possible solar and geomagnetic
                  activity responsibility for part of the observed long-term
                  trends. the two main conclusions are as follows: (i) The
                  role of solar and geomagnetic activity in the observed
                  long-term trends decreases with decreasing altitude from the
                  F-region ionosphere down to the troposphere. (ii) In the
                  20th century the role of solar and geomagnetic activity in
                  the observed long-term trends/changes was decreasing from
                  its beginning towards its end.}
}

@ARTICLE{lockwood07:_recen,
  AUTHOR = {Lockwood, M. and Fr\"ohlich, C.},
  TITLE = {Recent oppositely directed trends in solar climate forcings and the
           global mean surface air temperature},
  JOURNAL = {Proc. R. Soc. A},
  YEAR = 2007,
  VOLUME = 463,
  NUMBER = 2086,
  PAGES = {2447--2460},
  ABSTRACT = {There is considerable evidence for solar influence on the
              Earth's pre-industrial climate and the Sun may well have been a
              factor in post-industrial climate change in the first half of
              the last century. Here we show that over the past 20 years, all
              the trends in the Sun that could have had an influence on the
              Earth's climate have been in the opposite direction to that
              required to explain the observed rise in global mean
              temperatures.},
  URL = {http://dx.doi.org/10.1098/rspa.2007.1880/},
  UKSSDC_D = {},
  UK_FIRST = {}
}

@ARTICLE{2006JGRA..11102306L,
  AUTHOR = {Lockwood, M. and Lanchester, B.S. and Morley, S.K. and 
    Throp, K. and Milan, S.E. and Lester, M. and Frey, H.U.  },
  TITLE = {{Modeling the observed proton aurora and ionospheric convection responses to changes in the IMF clock angle: 2. Persistence of ionospheric convection}},
  JOURNAL = {Journal of Geophysical Research (Space Physics)},
  YEAR = 2006,
  MONTH = FEB,
  VOLUME = 111,
  NUMBER = {A10},
  PAGES = {2306-+},
  DOI = {10.1029/2003JA010307},
  ADSURL = {http://adsabs.harvard.edu/abs/2006JGRA..11102306L},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {We apply a numerical model of time-dependent ionospheric
       convection to two directly driven reconnection pulses during a 15-min
       interval of southward IMF on 26 November 2000. The model requires an input
       magnetopause reconnection rate variation, which is here derived from the
       observed variation in the upstream IMF clock angle, $\theta$. The
       reconnection rate is mapped to an ionospheric merging gap, the MLT extent of
       which is inferred from the Doppler-shifted Lyman- emission on newly opened
       field lines, as observed by the FUV instrument on the IMAGE spacecraft. The
       model is used to reproduce a variety of features observed during this event:
       SuperDARN observations of the ionospheric convection pattern and transpolar
       voltage; FUV observations of the growth of patches of newly opened flux; FUV
       and in situ observations of the location of the Open-Closed field line
       Boundary (OCB) and a cusp ion step. We adopt a clock angle dependence of the
       magnetopause reconnection electric field, mapped to the ionosphere, of the
       form Enosin4($\theta$/2) and estimate the peak value, Eno, by matching
       observed and modeled variations of both the latitude, OCB, of the dayside
       OCB (as inferred from the equatorward edge of cusp proton emissions seen by
       FUV) and the transpolar voltage PC (as derived using the mapped potential
       technique from SuperDARN HF radar data). This analysis also yields the time
       constant OCB with which the open-closed boundary relaxes back toward its
       equilibrium configuration. For the case studied here, we find OCB = 9.7 +/-
       1.3 min, consistent with previous inferences from the observed response of
       ionospheric flow to southward turnings of the IMF. The analysis confirms
       quantitatively the concepts of ionospheric flow excitation on which the
       model is based and explains some otherwise anomalous features of the cusp
       precipitation morphology.  },
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006JGRA..11109109L,
  AUTHOR = {Lockwood, M. and Rouillard, A.P. and Finch, I. and Stamper, R.},
  TITLE = {{Comment on ``The IDV index: Its derivation and use in inferring long-term variations of the interplanetary magnetic field strength'' by Leif Svalgaard and Edward W. Cliver}},
  JOURNAL = {Journal of Geophysical Research (Space Physics)},
  YEAR = 2006,
  MONTH = SEP,
  VOLUME = 111,
  NUMBER = {A10},
  PAGES = {9109-+},
  DOI = {10.1029/2006JA011640},
  ADSURL = {http://adsabs.harvard.edu/abs/2006JGRA..11109109L},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UKSSDC_W = {}
}

@ARTICLE{materassi2005,
  AUTHOR = {Materassi, M. and Mitchell, C.N.},
  TITLE = {A simulation study into constructing of the sample space for 
                  ionospheric imaging},
  JOURNAL = {Journal of Atmospheric and Solar-Terrestrial Physics},
  YEAR = {2005},
  VOLUME = {67},
  NUMBER = {12},
  PAGES = {1085--1091},
  ABSTRACT = {Ionospheric imaging usually involves solving an underdetermined inversion problem. The inversion is performed involving additional constraints to enforce realistic profiles in the vertical. One way to incorporate those vertical profile constraints is to perform the inversion using Empirical Orthogonal Functions (EOFs). The need of defining a sample space spanned by EOFs to obtain ionospheric images yields the possibility to employ ionosonde measurements in ionospheric tomography based on stochastic inversion of GPS data. Here we present a simulation study based on an existing network of GPS ground receivers and ionosondes across Europe. The locations of the transmitters used in the simulation are actual satellite positions. Simulated GPS data, constructed assuming that the ionosphere is the international reference ionosphere, are inverted via the Multi Instrument Data Analysis System. The sample space of this stochastic inversion is constructed employing ionosonde measurements simulated from the same model ionosphere. Such use of ionosonde data to construct the sample space produces better results than without ionosonde data.},
  KEYWORDS = {Electromagnetic methods; Ionosphere; Radio propagation; Remote sensing; Radio tomography; Data inversion},
  URL = {http://dx.doi.org/10.1016/j.jastp.2005.02.019},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_OTHER = {}
}

@ARTICLE{mendillo06_flares_mars,
  AUTHOR = {Mendillo, M. and Withers, P. and Hinson, D. and Rishbeth, H. and Reinisch, B.},
  TITLE = {Effects of solar flares on the ionosphere of Mars},
  JOURNAL = {Science},
  YEAR = 2006,
  MONTH = FEB,
  VOLUME = 311,
  PAGES = {1135--1138},
  ABSTRACT = {All planetary atmospheres respond to the enhanced x-rays and ultraviolet (UV) light emitted from the Sun during a flare. Yet only on Earth are observations so continuous that the consequences of these essentially unpredictable events can be measured reliably. Here, we report observations of solar flares, causing up to 200% enhancements to the ionosphere of Mars, as recorded by the Mars Global Surveyor in April 2001. Modeling the attitude dependence of these effects requires that relative enhancements in the soft x-ray fluxes far exceed those in the UV.},
  URL = {http://dx.doi.org/10.1126/science.1122099},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_OTHER = {}
}

@ARTICLE{2006AnGeo..24.2533M,
  AUTHOR = {Mikhailov, A.V.},
  TITLE = {{Ionospheric long-term trends: can the geomagnetic control and the greenhouse hypotheses be reconciled?}},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2006,
  MONTH = OCT,
  VOLUME = 24,
  PAGES = {2533-2541},
  ADSURL = {http://adsabs.harvard.edu/abs/2006AnGeo..24.2533M},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {The ionospheric F2-layer parameter long-term trends are
        considered from the geomagnetic control concept and the greenhouse
        hypothesis points of view. It is stressed that long-term geomagnetic
        activity variations are crucial for ionosphere long-term trends, as they
        determine the basic natural pattern of foF2 and hmF2 long-term variations.
        The geomagnetic activity effects should be removed from the analyzed data
        to obtain real trends in ionospheric parameters, but this is not usually
        done. Only a thermosphere cooling, which is accepted as an explanation for
        the neutral density decrease, cannot be reconciled with negative foF2
        trends revealed for the same period. A more pronounced decrease of the O/N2
        ratio is required which is not provided by empirical thermospheric models.
        Thermospheric cooling practically cannot be seen in foF2 trends, due to a
        weak NmF2 dependence on neutral temperature; therefore, foF2 trends are
        mainly controlled by geomagnetic activity long-term variations. Long-term
        hmF2 variations are also controlled by geomagnetic activity variations, as
        both parameters, NmF2 and hmF2 are related by the F2-layer formation
        mechanism. But hmF2 is very sensitive to neutral temperature changes, so
        strongly damped hmF2 long-term variations observed at Slough after 1972 may
        be considered as a direct manifestation of the thermosphere cooling.
        Earlier revealed negative hmF2 trends in western Europe, where magnetic
        declination D<0 and positive trends at the eastern stations (D>0), can be
        related to westward thermospheric wind whose role has been enhanced due to
        a competition between the thermosphere cooling (CO2 increase) and its
        heating under increasing geomagnetic activity after the end of the 1960s.},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006AnGeo..24..961M,
  AUTHOR = {Morley, S.K. and Lockwood, M.},
  TITLE = {A numerical model of the ionospheric signatures of time-varying magnetic reconnection: III. Quasi-instantaneous convection responses in the Cowley-Lockwood paradigm},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2006,
  MONTH = MAY,
  VOLUME = 24,
  PAGES = {961-972},
  ADSURL = {http://adsabs.harvard.edu/abs/2006AnGeo..24..961M},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {Using a numerical implementation of the cowlock92 model of flow
        excitation in the magnetosphere-ionosphere (MI) system, we show that both
        an expanding (on a ~12-min timescale) and a quasi-instantaneous response in
        ionospheric convection to the onset of magnetopause reconnection can be
        accommodated by the Cowley-Lockwood conceptual framework. This model has a
        key feature of time dependence, necessarily considering the history of the
        coupled MI system. We show that a residual flow, driven by prior
        magnetopause reconnection, can produce a quasi-instantaneous global
        ionospheric convection response; perturbations from an equilibrium state
        may also be present from tail reconnection, which will superpose
        constructively to give a similar effect. On the other hand, when the MI
        system is relatively free of pre-existing flow, we can most clearly see the
        expanding nature of the response. As the open-closed field line boundary
        will frequently be in motion from such prior reconnection (both at the
        dayside magnetopause and in the cross-tail current sheet), it is expected
        that there will usually be some level of combined response to dayside
        reconnection.},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_FIRST = {}
}

@ARTICLE{2006AnGeo..24..901N,
  AUTHOR = {Nygr{\'e}n, T. and Aikio, A.T. and Voiculescu, M. and 
        Ruohoniemi, J.M.},
  TITLE = {{IMF effect on sporadic-E layers at two northern polar cap sites: Part II   Electric field}},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2006,
  MONTH = MAY,
  VOLUME = 24,
  PAGES = {901-913},
  ADSURL = {http://adsabs.harvard.edu/abs/2006AnGeo..24..901N},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {This paper is the second in a series on a study of the link
        between IMF and sporadic-E layers within the polar cap. In Paper I
        (Voiculescu et al., 2006), an analysis of the sporadic-E data from Thule
        and Longyearbyen was presented. Here we concentrate on the electric field
        mechanism of sporadic-E generation. By means of model calculations we show
        that the mechanism is effective even at Thule, where the direction of the
        geomagnetic field departs from vertical only by 4. The model calculations
        also lead to a revision of the electric field theory. Previously, a thin
        layer was assumed to grow at a convergent null in the vertical ion
        velocity, which is formed when the electric field points in the NW sector.
        Our calculations indicate that in the dynamic process of vertical plasma
        compression, a layer is generated at altitudes of high vertical convergence
        rather than at a null. Consequently, the layer generation is less sensitive
        than previously assumed to fluctuations of the electric field direction
        within the NW sector. The observed diurnal variations of sporadic-E
        occurrence at Longyearbyen and Thule are compared with the diurnal
        variations of the electric field, calculated using a representative range
        of IMF values by means of the statistical APL model. The results indicate
        that the main features of Es occurrence can be explained by the convection
        pattern controlled by the IMF. Electric fields calculated from the IMF
        observations are also used for producing distributions of sporadic-E
        occurrence as a function of electric field direction at the two sites. A
        marked difference between the distributions at Thule and Longyearbyen is
        found. A model estimate of the occurrence probability as a function of
        electric field direction is developed and a reasonable agreement between
        the model and the experimental occurrence is found. The calculation
        explains the differences between the distributions at the two sites in
        terms of the polar cap convection pattern. The conclusion is that the
        electric field is the major cause for sporadic-E generation and,
        consequently, IMF has a clear control on the occurrence of sporadic E
        within the polar cap.},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{oliveros2005,
  AUTHOR = {Oliveros, B.M. and Hernandez R.D.M. and Saurez L.P.},
  TITLE = {On the onset and meridional propagation of the ionospheric 
                  F2-region response to geomagnetic storms},
  JOURNAL = {Journal of Atmospheric and Solar-Terrestrial Physics},
  YEAR = {2005},
  VOLUME = {67},
  NUMBER = {17--18},
  PAGES = {1706--1714},
  UKSSDC_D = {},
  UKSSDC_I = {},
  URL = {http://dx.doi.org/10.1016/j.jastp.2004.12.013},
  ABSTRACT = {The meridional propagation velocities of the ionospheric 
                  F2-region response to 268 geomagnetic storms are calculated. 
                  Ionospheric vertical sounding data of I h time resolution 
                  from several stations located in a longitude sector 
                  approximately centred along the great circle that contains 
                  both the geomagnetic poles and the geographic poles are used.

                  Most meridional propagation velocities from high to low 
                  latitudes are less than 600 m/s. The smaller velocities are 
                  typical of global neutral meridional wind circulation and the
                  larger are representative of traveling atmospheric 
                  disturbances.

                  Simultaneous disturbances at several locations are more 
                  frequent during positive phases than during negative phases. 
                  Negative phase meridional propagation velocities associated 
                  with meridional neutral winds are less frequent in the 
                  southern hemisphere when compared with corresponding 
                  velocities observed in the northern hemisphere. This may be 
                  related to the fact that the distance between the geomagnetic
                  pole and the equator is smaller in the northern hemisphere.

                  Most negative phase onsets are within the 06-10 LT interval. 
                  For middle geomagnetic latitudes a "forbidden time interval" 
                  between 11 and 14 LT is present. The positive phase onsets 
                  show the "dusk effect". (c) 2005 Elsevier Ltd. All rights 
                  reserved.}
}

@ARTICLE{2007RaSc...42S3004O,
  AUTHOR = {Orus, R. and Cander, L.R. and Hernandez-Pajares, M.},
  TITLE = {{Testing regional vertical total electron content maps over Europe during the 17-21 January 2005 sudden space weather event}},
  JOURNAL = {Radio Science},
  YEAR = 2007,
  MONTH = MAY,
  VOLUME = 42,
  PAGES = {3004-+},
  DOI = {10.1029/2006RS003515},
  ADSURL = {http://adsabs.harvard.edu/abs/2007RaSc...42S3004O},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {The intense level of solar activity recorded from 16 to 23 January 2005 led to
       a series of events with different signatures at the Earth's ionospheric
       distances. Measurements of the critical frequency of the F 2 layer f o F 2 and
       the vertical total electron content (VTEC) are used to describe the temporal
       and spatial electron density distributions during this space weather event,
       which gives an excellent opportunity to test regional VTEC maps over Europe
       under such disturbed solar-terrestrial conditions. In this context, the tests
       used to validate the International GNSS Service (IGS) VTEC maps have been
       applied to assess the accuracy of the European Rutherford Appleton Laboratory
       (RAL) VTEC maps. Thus the self-consistency test and the Jason altimeter test
       have been used to compare such performances with the IGS and Universitat
       Politecnica de Catalunya global ionospheric maps. The results show
       discrepancies between the RAL maps and the IGS ones, which leads to significant
       RMS and bias values of several total electron content units. Moreover, in this
       work a kriging technique to improve the accuracy of any regional VTEC map is also considered, with relative improvements of the RAL VTEC maps up to more
       than 20% at the peak of the storm.},
  UK_OTHER = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{peitrella05,
  AUTHOR = {Pietrella, M. and Perrone, L.},
  TITLE = {Instantaneous space-weighted ionospheric regional model for
                  instantaneous mapping of the critical frequency of the F2
                  layer in the European region},
  JOURNAL = {Radio Science},
  YEAR = {2005},
  VOLUME = {40},
  NUMBER = {1},
  UKSSDC_D = {},
  UKSSDC_I = {},
  URL = {http://dx.doi.org/10.1029/2003RS003008},
  ABSTRACT = {An instantaneous space-weighted ionospheric regional model
                  (ISWIRM) for the regional now-casting of the critical
                  frequency of the F2 layer ( foF2) has been developed. The
                  geographical area of applicability of the model is ranged
                  between 35degreesN - 70degreesN and 5degreesW -
                  40degreesE. Inside this region the hourly values of foF2 are
                  obtained, correcting the monthly medians values of foF2
                  predicted by the space-weighted ionospheric local model (
                  SWILM) on the basis of hourly observations of foF2 coming
                  from four reference stations ( Rome, Chilton, Lycksele, and
                  Loparskaya ( or Sodankyla)). The performance of the model,
                  evaluated at four testing stations ( Tortosa, Juliusruh,
                  Uppsala, and Kiruna) during some periods characterized by
                  strong solar and geomagnetic activity, can be considered
                  satisfactory, given that the hourly values of the residuals
                  are almost always below 1 MHz. A comparison between ISWIRM's
                  performance using manually validated and autoscaled data of
                  foF2 and SWILM's performance was made for two disturbed
                  periods. One example of instantaneous ionospheric mapping of
                  foF2 relative to the selected disturbed periods is also
                  shown.}
}

@ARTICLE{2006JATP...68..469R,
  AUTHOR = {Rishbeth, H.},
  TITLE = {{F-region links with the lower atmosphere?}},
  JOURNAL = {Journal of Atmospheric and Terrestrial Physics},
  YEAR = 2006,
  MONTH = FEB,
  VOLUME = 68,
  PAGES = {469-478},
  DOI = {10.1016/j.jastp.2005.03.017},
  ADSURL = {http://adsabs.harvard.edu/abs/2006JATP...68..469R},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006AnGeo..24.3293R,
  AUTHOR = {Rishbeth, H. and M{\"u}ller-Wodarg, I.C.F.},
  TITLE = {{Why is there more ionosphere in January than in July? The annual asymmetry in the F2-layer}},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2006,
  MONTH = DEC,
  VOLUME = 24,
  PAGES = {3293-3311},
  ADSURL = {http://adsabs.harvard.edu/abs/2006AnGeo..24.3293R},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {Adding together the northern and southern hemisphere values for
        pairs of stations, the combined peak electron density NmF2 is greater in
        December-January than in June-July. The same applies to the total
        height-integrated electron content. This "F2-layer annual asymmetry"
        between northern and southern solstices is typically 30%, and thus greatly
        exceeds the 7% asymmetry in ion production due to the annual variation of
        Sun-Earth distance. Though it was noticed in ionospheric data almost
        seventy years ago, the asymmetry is still unexplained.

        Using ionosonde data and also values derived from the International
        Reference Ionosphere, we show that the asymmetry exists at noon and at
        midnight, at all latitudes from equatorial to sub-auroral, and tends to
        be greater at solar minimum than solar maximum. We find a similar
        asymmetry in neutral composition in the MSIS model of the thermosphere.
        Numerical computations with the Coupled
        Thermosphere-Ionosphere-Plasmasphere (CTIP) model give a much smaller
        annual asymmetry in electron density and neutral composition than is
        observed. Including mesospheric tides in the model makes little
        difference. After considering possible explanations, which do not
        account for the asymmetry, we are left with the conclusion that
        dynamical influences of the lower atmosphere (below about 30 km), not
        included in our computations, are the most likely cause of the
        asymmetry.},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2007JGRA..11205103R,
  AUTHOR = {Rouillard, A.P. and Lockwood, M. and Finch, I.},
  TITLE = {{Centennial changes in the solar wind speed and in the open solar flux}},
  JOURNAL = {Journal of Geophysical Research (Space Physics)},
  YEAR = 2007,
  MONTH = MAY,
  VOLUME = 112,
  NUMBER = {A11},
  PAGES = {5103-+},
  DOI = {10.1029/2006JA012130},
  ADSURL = {http://adsabs.harvard.edu/abs/2007JGRA..11205103R},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {We use combinations of geomagnetic indices, based on both
        variation range and hourly means, to derive the solar wind flow speed, the
        interplanetary magnetic field strength at 1 AU and the total open solar
        flux between 1895 and the present. We analyze the effects of the regression
        procedure and geomagnetic indices used by adopting four analysis methods.
        These give a mean interplanetary magnetic field strength increase of 45.1
        +/- 4.5% between 1903 and 1956, associated with a 14.4 +/- 0.7% rise in the
        solar wind speed. We use averaging timescales of 1 and 2 days to allow for
        the difference between the magnetic fluxes threading the coronal source
        surface and the heliocentric sphere at 1 AU. The largest uncertainties
        originate from the choice of regression procedure: the average of all eight
        estimates of the rise in open solar flux is 73.0 +/- 5.0%, but the best
        procedure, giving the narrowest and most symmetric distribution of fit
        residuals, yields 87.3 +/- 3.9%.},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006AnGeo..24.2347S,
  AUTHOR = {Senior, A. and Kosch, M.J. and Yeoman, T.K. and Rietveld, M.T. and McCrea, I.W.},
  TITLE = {{Effects of high-latitude atmospheric gravity wave disturbances on artificial HF radar backscatter}},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2006,
  MONTH = SEP,
  VOLUME = 24,
  PAGES = {2347-2361},
  ADSURL = {http://adsabs.harvard.edu/abs/2006AnGeo..24.2347S},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {Observations of HF radar backscatter from artificial
    field-aligned irregularities in an ionosphere perturbed by travelling
    disturbances due to atmospheric gravity waves are presented. Some features
    of the spatio-temporal structure of the artificial radar backscatter can be
    explained in terms of the distortion of the ionosphere resulting from the
    travelling disturbances. The distorted ionosphere can allow the HF pump
    wave to access upper-hybrid resonance at larger distances from the
    transmitter than are normally observed and can also prevent the pump wave
    reaching this resonance at close distances. The variation in altitude of
    the irregularities sometimes results in a significant variation in the
    elevation angle of arrival of the backscattered signal at the radar
    implying that the radar "sees" a target moving in altitude. We suggest that
    this may be evidence of off-orthogonal scattering from the irregularities.  },
  UK_OTHER = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006JGRA..11109110S,
  AUTHOR = {Svalgaard, L. and Cliver, E.W.},
  TITLE = {{Reply to the comment by M. Lockwood et al. on ``The IDV index: Its derivation and use in inferring long-term variations of the interplanetary magnetic field''}},
  JOURNAL = {Journal of Geophysical Research (Space Physics)},
  YEAR = 2006,
  MONTH = SEP,
  VOLUME = 111,
  NUMBER = {A10},
  PAGES = {9110-+},
  DOI = {10.1029/2006JA011678},
  ADSURL = {http://adsabs.harvard.edu/abs/2006JGRA..11109110S},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{tsagouri2005,
  AUTHOR = {Tsagouri, I. and Zolesi, B. and Belehaki, A. and 
                  Cander, Lj.},
  TITLE = {Evaluation of the performance of the real-time updated 
                  simplified ionospheric regional model for the European area},
  JOURNAL = {Journal of Atmospheric and Solar-Terrestrial Physics},
  VOLUME = {67},
  NUMBER = {12},
  PAGES = {1137--1146},
  YEAR = {2005},
  UKSSDC_D = {},
  UKSSDC_I = {},
  UK_OTHER = {},
  ABSTRACT = {The increasing demand for upper-atmosphere nowcasting services for operational applications reveals the need for a realistic mapping of the ionosphere over Europe in real-time and especially during storm periods. To meet this need, a real-time updating method of simplified ionospheric regional model (SIRM) with autoscaled ionospheric characteristics observed by four European Digital Portable Sounders (DPS) ionosondes was recently developed. SIRM belongs to the group of ionospheric models for the standard vertical incidence (VI) ionospheric characteristics such as the critical frequency of the ionospheric F2 layer foF2 and the propagation factor M(3000)F2, which oversimplify a number of the ionospheric phenomena of real significance for radio communications applications showing satisfactory performance for median ionospheric condition description in restricted area of mid-latitudes. As a step forward, the rapid conversion of real-time data from four European digisondes to the driving parameters of the SIRM was introduced as the real-time SIRM updating (SIRMUP). In SIRMUP approach, the values of the ionospheric characteristics from first-guess model parameters at measurement points are combined with real-time measurements. The reliability of the real-time SIRM update method has already been tested in terms of the foF2 for various ionospheric conditions and the simulation results were very promising. In this paper, the simulation tests are continued in order to investigate the efficiency of the SIRMUP method in mapping the propagation conditions over Europe as they are expressed by the propagation factor M(3000)F2. In general, the results demonstrate that SIRMUP procedure has the potential to be used in real time for nowcasting the standard ionospheric characteristics over Europe, for operational applications.},
  KEYWORDS = {Ionospheric radio-propagation; Ionospheric mapping; Ionospheric modelling; Mid-latitude ionosphere},
  URL = {http://dx.doi.org/10.1016/j.jastp.2005.01.012}
}

@ARTICLE{2006AnGeo..24..887V,
  AUTHOR = {Voiculescu, M. and Aikio, A.T. and Nygr{\'e}n, T. and 
        Ruohoniemi, J.M.},
  TITLE = {{IMF effect on sporadic-E layers at two northern polar cap sites: Part I   Statistical study}},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2006,
  MONTH = MAY,
  VOLUME = 24,
  PAGES = {887-900},
  ADSURL = {http://adsabs.harvard.edu/abs/2006AnGeo..24..887V},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {n this paper we investigate the relationship between polar cap
        sporadic-E layers and the direction of the interplanetary magnetic field
        (IMF) using a 2-year database from Longyearbyen (75.2 CGM Lat, Svalbard)
        and Thule (85.4 CGM Lat, Greenland). It is found that the MLT distributions
        of sporadic-E occurrence are different at the two stations, but both are
        related to the IMF orientation. This relationship, however, changes from
        the centre of the polar cap to its border. Layers are more frequent during
        positive By at both stations. This effect is particularly strong in the
        central polar cap at Thule, where a weak effect associated with Bz is also
        observed, with positive Bz correlating with a higher occurrence of Es.
        Close to the polar cap boundary, at Longyearbyen, the By effect is weaker
        than at Thule. On the other hand, Bz plays there an equally important role
        as By, with negative Bz correlating with the Es occurrence. Since Es layers
        can be created by electric fields at high latitudes, a possible explanation
        for the observations is that the layers are produced by the polar cap
        electric field controlled by the IMF. Using electric field estimates
        calculated by means of the statistical APL convection model from IMF
        observations, we find that the diurnal distributions of sporadic-E
        occurrence can generally be explained in terms of the electric field
        mechanism. However, other factors must be considered to explain why more
        layers occur during positive than during negative By and why the Bz
        dependence of layer occurrence in the central polar cap is different from
        that at the polar cap boundary.},
  UKSSDC_D = {},
  UKSSDC_I = {}
}

@ARTICLE{2006AnGeo..24.2743W,
  AUTHOR = {Willis, D.M. and Henwood, R. and Stephenson, F.R.},
  TITLE = {{The presence of large sunspots near the central solar meridian at the times of modern Japanese auroral observations}},
  JOURNAL = {Annales Geophysicae},
  YEAR = 2006,
  MONTH = OCT,
  VOLUME = 24,
  PAGES = {2743-2758},
  ADSURL = {http://adsabs.harvard.edu/abs/2006AnGeo..24.2743W},
  ADSNOTE = {Provided by the Smithsonian/NASA Astrophysics Data System},
  ABSTRACT = {The validity of a technique developed by the authors to
        identify historical occurrences of intense geomagnetic storms, which is
        based on finding approximately coincident observations of sunspots and
        aurorae recorded in East Asian histories, is corroborated using more modern
        sunspot and auroral observations. Scientific observations of aurorae in
        Japan during the interval 1957-2004 are used to identify geomagnetic storms
        that are sufficiently intense to produce auroral displays at low
        geomagnetic latitudes. By examining white-light images of the Sun obtained
        by the Royal Greenwich Observatory, the Big Bear Solar Observatory, the
        Debrecen Heliophysical Observatory and the Solar and Heliospheric
        Observatory spacecraft, it is found that a sunspot large enough to be seen
        with the unaided eye by an "experienced" observer was located reasonably
        close to the central solar meridian immediately before all but one of the
        30 distinct Japanese auroral events, which represents a 97% success rate.
        Even an "average" observer would probably have been able to see a sunspot
        with the unaided eye before 24 of these 30 events, which represents an 80%
        success rate. This corroboration of the validity of the technique used to
        identify historical occurences of intense geomagnetic storms is important
        because early unaided-eye observations of sunspots and aurorae provide the
        only possible means of identifying individual historical geomagnetic storms
        during the greater part of the past two millennia.},
  UK_FIRST = {},
  UKSSDC_D = {},
  UKSSDC_I = {}
}


This file has been generated by bibtex2html 1.74