ukssdc_w.bib

@comment{{This file has been generated by bib2bib 1.93}}

@comment{{Command line: /soft/ukssdc/share/bib2bib -c 'exists ukssdc_w' -s author -ob ukssdc_w.bib ukssdc.bib}}

@article{aruliah1996,
  author = {Aruliah, A.L. and Farmer, A.D. and Fuller-Rowell, T.J. and
                  Wild, M.N. and Hapgood, M. and Rees, D.},
  title = {An equinoctial asymmetry in the high-latitude thermosphere
                  and ionosphere},
  journal = {Journal of Geophysical Research},
  pages = {15713--15722},
  year = {1996},
  month = jul,
  volume = {101},
  number = {A7},
  abstract = {A large equinoctial asymmetry has been observed in
                  thermospheric winds and ion velocities at high latitude
                  sites in northern Scandinavia. Throughout the solar cycle,
                  average nighttime thermospheric meridional winds are larger
                  in spring than autumn despite similar levels of solar
                  insolation. The average ion velocities are also larger in
                  spring than autumn at solar maximum, but at solar minimum
                  this position is reversed. Numerical simulations of the
                  thermosphere and ionosphere have not predicted such
                  asymmetries because they generally assume forcing functions
                  that are symmetric about the solstices. The proposed
                  explanation lies in the annual and diurnal variation in
                  solar wind-magnetosphere coupling caused by changes in the
                  orientation of the geomagnetic pole, and hence the
                  magnetosphere, with respect to the average orientation of
                  the IMF (the Russell-McPherron effect). This causes a
                  12-hour phase difference between the times of maximum solar
                  wind-magnetosphere coupling at the two equinoxes. In
                  addition, the orientation of the geomagnetic axis with
                  respect to the average IMF is such that $ > 0$
                  for the March equinox and $ < 0$ for
                  September. This results in a further source of asymmetry of
                  forcing of the high-latitude ionosphere as the result of
                  electric fields associated with the four sign combinations
                  of $B_{y}$ and $B_{z}$. Several predictions arise from the
                  explanation given: for example, a high-latitude station
                  measuring thermospheric neutral winds in Alaska,
                  $180^{\circ}$ in longitude from Kiruna, might be expected to
                  see nighttime thermospheric winds that are larger in the
                  autumn than in the spring.},
  url = {http://www.agu.org/pubs/crossref/1996/95JA01102.shtml},
  ukssdc_w = {},
  ukssdc_d = {}
}

@article{aruliah97:_model_high_latit_equin_asymm,
  author = {Aruliah, A.L. and Schoendorf, J. and Aylward, A.D. and Wild,
                  M.N.},
  title = {Modelling the High-Latitude Equinoctial Asymmetry},
  journal = {Journal of Geophysical Research},
  pages = {27207--27216},
  year = {1997},
  volume = {102},
  number = {A12},
  abstract = {Fabry-Perot Interferometer measurements of neutral winds and
                  European Incoherent SCATter radar measurements of plasma
                  velocities have shown a significant equinoctial asymmetry in
                  the average behavior of the thermosphere and ionosphere
                  above northern Scandinavia. Existing standard models of the
                  upper atmosphere use forcing functions that are symmetric
                  about the solstices, therefore these observations are
                  unexpected. It is suggested that the asymmetry arises from
                  the diurnal variation in the cross polar cap potential
                  difference (CPCPD) because there is a 12 hour phase
                  difference between the variations at the March and September
                  equinoxes. The variation in the CPCPD is caused by an annual
                  and diurnal variation in the orientation of the
                  magnetosphere with respect to the interplanetary magnetic
                  field. This is known as the Russell-McPherron(R-M)
                  effect. The plausibility of this explanation of the
                  equinoctial asymmetry in thermospheric winds is supported by
                  investigation of the effect of their geomagnetic history,
                  i.e., the repercussions on the winds of the activity levels
                  in the few hours prior to the observation. The consequences
                  of the R-M effect have been simulated in the University
                  College London/Sheffield/Space Environment Laboratory
                  coupled thermosphere-ionosphere model by imposing a
                  diurnally varying high-latitude electric field pattern. The
                  results are used to test the predictions, given in an
                  earlier paper, of the average behavior expected at other
                  high-latitude sites. A corollary to the study is that the
                  evidence presented here implies that the auroral oval may be
                  smaller at solar minimum, which is also unexpected.},
  ukssdc_w = {},
  ukssdc_d = {}
}

@article{davis1997,
  author = {Davis, C. J. and Wild, M. N. and Lockwood, M. and Tulunay, Y. K.},
  affiliation = {Rutherford Appletpn Laboratory Chilton Didcot OX11 OQX
                  United Kingdom},
  title = {Ionospheric and geomagnetic responses to changes in {IMF}
                  ${B}_{z}$: a superposed epoch study},
  journal = {Annales Geophysicae},
  publisher = {Springer Berlin / Heidelberg},
  issn = {0992-7689},
  keyword = {Earth and Environmental Science},
  pages = {217-230},
  volume = 15,
  issue = 2,
  url = {http://dx.doi.org/10.1007/s00585-997-0217-9},
  doi = {10.1007/s00585-997-0217-9},
  abstract = {Superposed epoch studies have been carried out in order to
                  determine the ionospheric response at mid-latitudes to
                  southward turnings of the interplanetary magnetic field
                  (IMF). This is compared with the geomagnetic response, as
                  seen in the indices ${K}_{p}$, ${AE}$ and $Dst$. The solar
                  wind, IMF and geomagnetic data used were hourly averages
                  from the years 1967--1989 and thus cover a full 22-year
                  cycle in the solar magnetic field. These data were divided
                  into subsets, determined by the magnitudes of the southward
                  turnings and the concomitant increase in solar wind
                  pressure. The superposed epoch studies were carried out
                  using the time of the southward turning as time zero. The
                  response of the mid-latitude ionosphere is studied by
                  looking at the F-layer critical frequencies, $f_{o}F2$, from
                  hourly soundings by the Slough ionosonde and their deviation
                  from the monthly median values, ${\delta}f_{o}F2$. For the
                  southward turnings with a change in $B_{z}$ of
                  ${\delta}B_{z}>11.5$ nT accompanied by a solar wind dynamic
                  pressure $P$ exceeding 5 nPa, the F region critical
                  frequency, $f_{o}F2$, shows a marked decrease, reaching a
                  minimum value about 20 h after the southward turning. This
                  recovers to pre-event values over the subsequent 24 h, on
                  average. The $Dst$ index shows the classic storm-time
                  decrease to about -60 nT. Four days later, the index has
                  still to fully recover and is at about -25 nT. Both the
                  $K_{p}$ and $AE$ indices show rises before the southward
                  turnings, when the IMF is strongly northward but the solar
                  wind dynamic pressure is enhanced. The average $AE$ index
                  does register a clear isolated pulse (averaging 650 nT for 2
                  h, compared with a background peak level of near 450 nT at
                  these times) showing enhanced energy deposition at high
                  latitudes in substorms but, like $K_{p}$, remains somewhat
                  enhanced for several days, even after the average IMF has
                  returned to zero after 1 day. This $AE$ background decays
                  away over several days as the $Dst$ index recovers,
                  indicating that there is some contamination of the currents
                  observed at the $AE$ stations by the continuing enhanced
                  equatorial ring current. For data averaged over all seasons,
                  the critical frequencies are depressed at Slough by 1.3 MHz,
                  which is close to the lower decile of the overall
                  distribution of ${\delta}f_{o}F2$ values. Taking 30-day
                  periods around summer and winter solstice, the largest
                  depression is 1.6 and 1.2 MHz, respectively. This seasonal
                  dependence is confirmed by a similar study for a Southern
                  Hemisphere station, Argentine Island, giving peak
                  depressions of 1.8 MHz and 0.5 MHz for summer and
                  winter. For the subset of turnings where
                  ${\delta}B_{z}>11.5$ nT and $P<= 5$ nPa, the response of the
                  geomagnetic indices is similar but smaller, while the change
                  in ${\delta}f_{o}F2$ has all but disappeared. This confirms
                  that the energy deposited at high latitudes, which leads to
                  the geomagnetic and ionospheric disturbances following a
                  southward turning of the IMF, increases with the energy
                  density (dynamic pressure) of the solar wind flow. The
                  magnitude of all responses are shown to depend on
                  ${\delta}B_{z}$. At Slough, the peak depression always
                  occurs when Slough rotates into the noon sector. The largest
                  ionospheric response is for southward turnings seen between
                  15--21 UT.},
  uk_first = {},
  ukssdc_w = {},
  ukssdc_d = {},
  ukssdc_i = {},
  pdf = {http://www.ann-geophys.net/15/217/1997/angeo-15-217-1997.pdf},
  year = 1997
}

@incollection{hapgood1993,
  author = {Hapgood, M.A.},
  editor = {Heck, A. and Murtagh, F.},
  title = {Multi-step queries: the need for a correlation environment},
  booktitle = {Adding Intelligence to Information Retrieval: the Case of
                  Astronomy and Related Space Sciences},
  year = {1993},
  month = jan,
  publisher = {Kluwer},
  address = {Dordrecht},
  ukssdc_w = {},
  uk_first = {}
}

@article{hapgood1991,
  author = {Hapgood, M.A. and Lockwood, M. and Bowe, G.A. and Willis,
                  D.M. and Tulunay, Y.K.},
  title = {Variability of the interplanetary medium at 1 a.u. over 24
                  years: 1963--1986},
  journal = {Planetary and Space Science},
  pages = {411--423},
  year = {1991},
  month = mar,
  volume = {39},
  number = {3},
  abstract = {A survey is presented of hourly averages of observations of
                  the interplanetary medium, made by satellites close to the
                  Earth (i.e. at 1 a.u.) in the years 1963-1986. This survey
                  therefore covers two complete solar cycles (numbers 20 and
                  21). The distributions and solar-cycle variations of IMF
                  field strength, $B$, and its northward component (in GSM
                  coordinates), $B_{z}$, and of the solar-wind density, n,
                  speed, $\upsilon$, and dynamic pressure, P, are
                  discussed. Because of their importance to the terrestrial
                  magnetosphere/ionosphere, particular attention is given to
                  $B_{z}$ and P. The solar-cycle variation in the magnitude
                  and variability of $B_{z}$, previously reported for cycle
                  20, is also found for cycle 21. However, the solar-wind data
                  show a number of differences between cycles 20 and 21. The
                  average dynamic pressure is found to show a solar-cycle
                  variation and a systematic increase over the period of the
                  survey. The minimum of dynamic pressure at sunspot maximum
                  is mainly due to reduced solar-wind densities in cycle 20,
                  but lower solar-wind speed in cycle 21 is a more significant
                  factor. The distribution of the duration of periods of
                  stable polarity of the IMF $B_{z}$ component shows that the
                  magnetosphere could achieve steady state for only a small
                  fraction of the time and there is some evidence for a
                  solar-cycle variation in this fraction. It is also found
                  that the polarity changes in the IMF $B_{z}$ fall into two
                  classes: one with an associated change in solar-wind dynamic
                  pressure, the other without such a change. However, in only
                  20\% of cases does the dynamic pressure change exceed 50\%.},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@techreport{rs1982,
  author = {Hewish, A. and others},
  title = {Synoptic data for Solar-Terrestrial Monitoring},
  institution = {The Royal Society},
  year = {1992},
  month = sep,
  address = {London},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@article{king1973,
  author = {King, J.W.},
  title = {Solar radiation changes and the weather},
  journal = {Nature},
  pages = {443--446},
  year = {1973},
  month = oct,
  volume = {245},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@article{liu1983,
  author = {Liu, C. and Smith, P.A. and King, J.W.},
  title = {A new solar index which leads to improved foF2 predictions
                  using the CCIR Atlas},
  journal = {Telecommunications Journal},
  pages = {408--414},
  year = {1983},
  volume = {50},
  number = {VIII},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_other = {}
}

@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{lockwood1999,
  author = {Lockwood, M. and Stamper, R.},
  title = {Long-term drift of the coronal source magnetic flux and the
                  total solar irradiance},
  journal = {Geophysical Research Letters},
  pages = {2461-2464},
  year = 1999,
  month = {august},
  volume = 26,
  number = 16,
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {},
  abstract = {We test the method of Lockwood et al. [1999] for deriving
                  the coronal source flux from the geomagnetic aa index and
                  show it to be accurate to within 12\% for annual means and
                  4.5\% for averages over a sunspot cycle. Using data from
                  four solar constant monitors during 1981--1995, we find a
                  linear relationship between this magnetic flux and the total
                  solar irradiance. From this correlation, we show that the
                  131\% rise in the mean coronal source field over the
                  interval 1901--1995 corresponds to a rise in the average
                  total solar irradiance of $\Delta I = 1.65 \pm 0.23
                  Wm^{-2}$.},
  url = {grlcover.html}
}

@article{lockwood1999:_doubling_coronal_mag_field,
  author = {Lockwood, M. and Stamper, R. and Wild, M.},
  title = {A Doubling of the Sun's Coronal Magnetic Field during the
                  Last 100 Years},
  journal = {Nature},
  volume = 399,
  pages = {437--439},
  year = 1999,
  month = {june},
  abstract = {The solar wind is an extended ionized gas of very high
                  electrical conductivity, and therefore drags some magnetic
                  flux out of the Sun to fill the heliosphere with a weak
                  interplanetary magnetic field,. Magnetic reconnection -- the
                  merging of oppositely directed magnetic fields -- between
                  the interplanetary field and the Earth's magnetic field
                  allows energy from the solar wind to enter the near-Earth
                  environment. The Sun's properties, such as its luminosity,
                  are related to its magnetic field, although the connections
                  are still not well understood,. Moreover, changes in the
                  heliospheric magnetic field have been linked with changes in
                  total cloud cover over the Earth, which may influence global
                  climate. Here we show that measurements of the near-Earth
                  interplanetary magnetic field reveal that the total magnetic
                  flux leaving the Sun has risen by a factor of 1.4 since
                  1964: surrogate measurements of the interplanetary magnetic
                  field indicate that the increase since 1901 has been by a
                  factor of 2.3. This increase may be related to chaotic
                  changes in the dynamo that generates the solar magnetic
                  field. We do not yet know quantitatively how such changes
                  will influence the global environment.},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {},
  pdf = {http://www.nature.com/nature/journal/v399/n6735/pdf/399437a0.pdf},
  url = {http://www.nature.com/nature/journal/v399/n6735/abs/399437a0.html},
  doi = {10.1038/20867}
}

@techreport{lockwood95:_groun_based_measur_suppor_clust,
  author = {Lockwood, M. and Stamper, R. and Wild, M.N. and Opgenoorth,
                  H.J.},
  title = {Ground-Based Measurements in Support of CLUSTER: An On-Line
                  Planning Procedure},
  institution = {DRAL},
  year = {1995},
  month = feb,
  number = {RAL-95-018},
  ukssdc_d = {},
  ukssdc_w = {},
  uk_first = {}
}

@article{lockwood99:_onset_expan_enhan_ionos_convec,
  author = {Lockwood, M. and Wild, M.N. and Cowley, S.W.H.},
  title = {The Onset and Expansion of Enhanced Ionospheric Convection
                  Following a Southward Turning of the IMF},
  journal = {Journal of Geophysical Research},
  year = {1999},
  note = {submitted},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@inproceedings{lockwood99:_predic,
  author = {Lockwood, M. and Wild, M.N. and Stamper, R. and Grande, M.},
  title = {Predicting solar disturbance effects on navigation systems},
  booktitle = {Journal of Navigation},
  pages = {203--216},
  year = {1999},
  volume = {52},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@incollection{opgenoorth97:_new_famil_geomag_distur_indic,
  author = {Opgenoorth, H.J. and Persson, M.A.L. and Lockwood, M. and
                  Stamper, R. and Wild, M.N. and Pellinen, R. and Pulkkinen,
                  T. and Kauristie, K. and Hughes, T. and Kamide, Y.},
  editor = {Lockwood, M. and Wild, M.N. and Opgenoorth, H.J.},
  title = {A New Family of Geomagnetic Disturbance Indices},
  booktitle = {Satellite - Ground Based Coordination Sourcebook},
  pages = {49--62},
  year = {1997},
  publisher = {ESA},
  volume = {SP-1198},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_other = {}
}

@article{pulkkinen01:_sun_g_connec_time_scales,
  author = {Pulkkinen, T.I. and Nevanlinna, H. and Pulkkinen, P.J. and
                  Lockwood M.},
  title = {The Sun-Earth Connection in Time Scales from Years to Decades and Centuries},
  journal = {Space Science Reviews},
  year = 2001,
  volume = 95,
  number = {1-2},
  pages = {625--637},
  month = jan,
  uk_other = {},
  ukssdc_d = {},
  ukssdc_w = {},
  abstract = {The Sun--Earth connection is studied using long-term
                  measurements from the Sun and from the Earth. The auroral
                  activity is shown to correlate to high accuracy with the
                  smoothed sunspot numbers. Similarly, both geomagnetic
                  activity and global surface temperature anomaly can be
                  linked to cyclic changes in the solar activity. The
                  interlinked variations in the solar magnetic activity and in
                  the solar irradiance cause effects that can be observed both
                  in the Earth's biosphere and in the electromagnetic
                  environment. The long-term data sets suggest that the
                  increase in geomagnetic activity and surface temperatures
                  are related (at least partially) to longer-term solar
                  variations, which probably include an increasing trend
                  superposed with a cyclic behavior with a period of about 90
                  years.}
}

@unpublished{saunders1993,
  author = {Saunders, M.A. and Lockwood, M. and Wild, M.N.},
  title = {The semi-annual variation in great geomagnetic storms},
  year = {1993},
  month = mar,
  note = {Submitted to Annales Geophysicae},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@article{stamper1996,
  author = {Stamper, R.},
  title = {Improved prediction of I_{F2} and I_{G} indices using neural
                  networks},
  journal = {IEEE Proc.-Microw. Antennas Propag.},
  pages = {341--346},
  year = {1996},
  month = aug,
  volume = {143},
  number = {4},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@article{stamper98:_solar_causes_long_term_increas_geomag_activ,
  author = {Stamper, R. and Lockwood, M. and Wild, M.N. and Clark,
                  T.D.G.},
  title = {Solar Causes of the Long-Term Increase in Geomagnetic
                  Activity},
  journal = {Journal of Geophysical Research},
  pages = {28325--28342},
  year = {1999},
  month = dec,
  volume = {104},
  number = {A12},
  ukssdc_w = {},
  ukssdc_d = {},
  ukssdc_i = {},
  uk_first = {},
  abstract = {We analyze the causes of the century-long increase in
                  geomagnetic activity, quantified by annual means of the {\it
                  aa} index, using observations of interplanetary space,
                  galactic cosmic rays, the ionosphere, and the auroral
                  electrojet, made during the last three solar cycles. The
                  effects of changes in ionospheric conductivity, the Earth's
                  dipole tilt, and magnetic moment are shown to be small; only
                  changes in near-Earth interplanetary space make a
                  significant contribution to the long-term increase in
                  activity. We study the effects of the interplanetary medium
                  by applying dimensional analysis to generate the optimum
                  solar wind-magnetosphere energy coupling function, having an
                  unprecedentedly high correlation coefficient of
                  0.97. Analysis of the terms of the coupling function shows
                  that the largest contributions to the drift in activity over
                  solar cycles 20--22 originate from rises in the average
                  interplanetary magnetic field (IMF) strength, solar wind
                  concentration, and speed; average IMF orientation has grown
                  somewhat less propitious for causing geomagnetic
                  activity. The combination of these factors explains almost
                  all of the 39\% rise in {\it aa} observed over the last
                  three solar cycles. Whereas the IMF strength varies
                  approximately in phase with sunspot numbers, neither its
                  orientation nor the solar wind density shows any coherent
                  solar cycle variation. The solar wind speed peaks strongly
                  in the declining phase of even-numbered cycles and can be
                  identified as the chief cause of the phase shift between the
                  sunspot numbers and the {\it aa} index. The rise in the IMF
                  magnitude, the largest single contributor to the drift in
                  geomagnetic activity, is shown to be caused by a rise in the
                  solar coronal magnetic field, consistent with a rise in the
                  coronal source field, modeled from photospheric
                  observations, and an observed decay in cosmic ray fluxes.}
}

@incollection{stamper97:_on_line_direc_groun_based_stp_obser,
  author = {Stamper, R. and Wild, M. and Lockwood, M.},
  editor = {Lockwood, M. and Wild, M.N. and Opgenoorth, H.J.},
  title = {An On-Line Directory of Ground-Based STP Observatories},
  booktitle = {Satellite - Ground Based Coordination Sourcebook},
  pages = {367--407},
  year = {1997},
  publisher = {ESA},
  volume = {SP-1198},
  ukssdc_d = {},
  ukssdc_w = {},
  uk_first = {}
}

@article{szuszczewicz1997,
  author = {Szuszczewicz, E.P. and Blanchard, P. and Wilkinson, P. and
                  Crowley, G. and Fuller-Rowell, T. and Richards, P. and Abdu,
                  M. and Bullett, T. and Hanbaba, R. and Lebreton, J.P. and
                  Lester, M. and Lockwood, M. and Millward, G. and Wild,
                  M. and Pulinets, S. and Reddy, B.M. and Stanislawska, I. and
                  Vannaroni, G. and Zolesi, B.},
  title = {The First Realtime Worldwide Ionospheric Prediction Network:
                  An Advance in Support of Spaceborne Experimentation, On-Line
                  Model Validation, and Space Weather},
  journal = {Geophysical Research Letters},
  pages = {449-452},
  year = {1998},
  month = {feb},
  volume = {25},
  number = {4},
  abstract = {We report on the first realtime ionospheric predictions
                  network and its capabilities to ingest a global database and
                  forecast F-layer characteristics and ``in situ'' electron
                  densities along the track of an orbiting spacecraft. A
                  global network of ionosonde stations reported
                  around-the-clock observations of F-region heights and
                  densities, and an on-line library of models provided
                  forecasting capabilities. Each model was tested against the
                  incoming data; relative accuracies were intercompared to
                  determine the best overall fit to the prevailing conditions;
                  and the best-fit model was used to predict ionospheric
                  conditions on an orbit-to-orbit basis for the 12-hour period
                  following a twice-daily model test and validation
                  procedure. It was found that the best-fit model often
                  provided averaged (i.e., climatologically-based) accuracies
                  better than 5\% in predicting the heights and critical
                  frequencies of the F-region peaks in the latitudinal domain
                  of the TSS-1R flight path. There was a sharp contrast,
                  however, in model-measurement comparisons involving
                  predictions of actual, unaveraged, along-track densities at
                  the 295 km orbital altitude of TSS-1R. In this case, extrema
                  in the first-principle models varied by as much as an order
                  of magnitude in density predictions, and the best-fit models
                  were found to disagree with the ``in situ'' observations of
                  Ne by as much as 140\%. The discrepancies are interpreted as
                  a manifestation of difficulties in accurately and
                  self-consistently modeling the external controls of solar
                  and magnetospheric inputs and the spatial and temporal
                  variabilities in electric fields, thermospheric winds,
                  plasmaspheric fluxes, and chemistry.},
  ukssdc_w = {},
  ukssdc_d = {},
  ukssdc_i = {},
  uk_other = {}
}

@incollection{wild97:_clust_groun_based_data_centr,
  author = {Wild, M.N. and Lockwood, M.},
  editor = {Lockwood, M. and Wild, M.N. and Opgenoorth, H.J.},
  title = {Cluster-Ground Based Data Centre},
  booktitle = {Satellite - Ground Based Coordination Sourcebook},
  pages = {361--366},
  year = {1997},
  publisher = {ESA},
  volume = {SP-1198},
  ukssdc_w = {},
  uk_first = {}
}

@article{willis1996,
  author = {Willis, D.M. and Davda, V.N. and Stephenson, F.Richard},
  title = {Comparison between Oriental and Occidental Sunspot
                  Observations},
  journal = {Quarterly Journal of the Royal Astronomical Society},
  pages = {189--229},
  year = {1996},
  month = {jun},
  volume = {37},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}

@article{willis09:_presen_of_large_sunsp_near,
  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 major geomagnetic storms},
  journal = {Annales Geophysicae},
  year = 2009,
  volume = 27,
  pages = {185--197},
  number = {1},
  url = {http://www.ann-geophys.net/27/185/2009/},
  month = jan,
  abstract = {A further study is made of 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. Previously, the
                  validity of this technique was corroborated using scientific
                  observations of aurorae in Japan during the interval
                  1957--2004 and contemporaneous 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. The
                  present investigation utilises a list of major geomagnetic
                  storms in the interval 1868--2008, which is based on the
                  magnitude of the AA* magnetic index, and reconstructed solar
                  images based on the sunspot observations acquired by the
                  Royal Greenwich Observatory during the shorter interval
                  1874--1976. 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 for
                  almost 90\% of these major geomagnetic storms. Even an
                  "average" observer would easily achieve a corresponding
                  success rate of 70\% and this success rate increases to
                  about 80\% if a minority of ambiguous situations are
                  interpreted favourably. The use of information on major
                  geomagnetic storms, rather than modern auroral observations
                  from Japan, provides a less direct corroboration of the
                  technique for identifying historical occurrences of intense
                  geomagnetic storms, if only because major geomagnetic storms
                  do not necessarily produce auroral displays over East
                  Asia. Nevertheless, the present study provides further
                  corroboration of the validity of the original technique for
                  identifying intense geomagnetic storms. This additional
                  corroboration of the original technique is important because
                  early unaided-eye observations of sunspots and aurorae
                  provide the only possible means of identifying individual
                  geomagnetic storms during the greater part of the past two
                  millennia.},
  uk_first = {},
  ukssdc_d = {},
  ukssdc_w = {}
}

@article{willis07:_sporadic_aurorae,
  user = {r.henwood@rl.ac.uk},
  author = {Willis, D.M. and Stephenson, F. R. and Huiping Fang},
  title = {Sporadic aurorae observed in East Asia},
  journal = {Annales Geophysicae},
  volume = {25},
  number = {2},
  pages = {417-436},
  year = {2007},
  month = mar,
  url = {http://www.ann-geophys.net/25/417/2007/angeo-25-417-2007.html},
  pdf = {http://www.ann-geophys.net/25/417/2007/angeo-25-417-2007.pdf},
  ukssdc_w = {},
  ukssdc_d = {},
  abstract = {All the accessible auroral observations recorded in Chinese
                  and Japanese histories during the interval AD 1840--1911 are
                  investigated in detail. Most of these auroral records have
                  never been translated into a Western language before. The
                  East Asian auroral reports provide information on the date
                  and approximate location of each auroral observation,
                  together with limited scientific information on the
                  characteristics of the auroral luminosity such as colour,
                  duration, extent, position in the sky and approximate time
                  of occurrence. The full translations of the original Chinese
                  and Japanese auroral records are presented in an appendix,
                  which contains bibliographic details of the various
                  historical sources. (There are no known reliable Korean
                  observations during this interval.) A second appendix
                  discusses a few implausible "auroral" records, which have
                  been rejected. The salient scientific properties of all
                  exactly dated and reliable East Asian auroral observations
                  in the interval AD 1840--1911 are summarised succinctly. By
                  comparing the relevant scientific information on exactly
                  dated auroral observations with the lists of great
                  geomagnetic storms compiled by the Royal Greenwich
                  Observatory, and also the tabulated values of the Ak
                  (Helsinki) and aa (Greenwich and Melbourne) magnetic
                  indices, it is found that 5 of the great geomagnetic storms
                  (aa>150 or Ak>50) during either the second half of the
                  nineteenth century or the first decade of the twentieth
                  century are clearly identified by extensive auroral displays
                  observed in China or Japan. Indeed, two of these great
                  storms produced auroral displays observed in both countries
                  on the same night.  Conversely, at least 29 (69\%) of the 42
                  Chinese and Japanese auroral observations occurred at times
                  of weak-to-moderate geomagnetic activity (aa or
                  Ak$\leq$50). It is shown that these latter auroral displays
                  are very similar to the more numerous (about 50) examples of
                  sporadic aurorae observed in the United States during the
                  interval AD 1880--1940. The localised nature and spatial
                  structure of some sporadic aurorae observed in East Asia is
                  indicated by the use of descriptive terms such as
                  "lightning", "rainbow", "streak" and "grid".}
}

@article{willis79:_statis,
  author = {Willis, D.M. and Tulunay, Y.K.},
  title = {Statistics of the largest sunspot and facular areas per
                  solar cycle},
  journal = {Solar Physics},
  pages = {237--246},
  year = {1979},
  volume = {64},
  abstract = {The paper uses the statistics of extreme values to
                  investigate the statistical properties of the largest areas
                  of sunspots and photospheric faculae per solar cycle. The
                  largest values of the synodic-solar-rotation mean areas of
                  umbrae, whole spots and faculae, which have been recorded
                  for nine solar cycles are shown to comply with the general
                  form of the extreme value probability function. Empirical
                  expressions are derived for the three extreme value
                  populations from which the characteristic statistic
                  parameters, namely the mode, median, mean and standard
                  deviation, can be calculated for each population. It is
                  found that extreme areas of umbrae and whole spots have a
                  diversion comparable to that found by Siscoe for the extreme
                  values of sunspot number whereas the extreme areas of
                  faculae have a smaller dispersion which is comparable to
                  that found by Siscoe for the largest geomagnetic storm per
                  solar cycle.},
  ukssdc_w = {},
  ukssdc_d = {},
  uk_first = {}
}