URSI Ionospheric Parameter Codes

The definitions of the parameters have been extracted from UAG23 (URSI Handbook of Ionogram Interpretation and Reduction, November, 1972).
The definitions of the parameters for Codes 70-89, 93-99, and A0-D2 have been included from ulcar.uml.edu

F Layer Parameters

Parameter	Code	Dimension	Description
foF2	00	.1 MHz	F2 layer o-mode (ordinary) critical frequency.
fxF2	01	.1 MHz	F2 layer x-mode (extraordinary) critical frequency.
fzF2	02	.1 MHz	F2 layer z-mode critical frequency.
M3000F2	03	.01	F2 layer M factor (the ratio of the maximum usable frequency divided by the critical frequency).
h'F2	04	km	F2 layer o-mode minimum virtual height.
hpF2	05	km	An estimate of the true height of the F2 layer (measurement of the ordinary mode virtual height at a frequency of 83.4% of the foF2).
h'Ox	06	km	F layer minmum virual height of the x-mode trace at a frequency equal to the foF2.
MUF3000F2	07	.1 MHz	F2 layer maximum usable frequency for 3000km path.
hc	08	km	The height of the maximum obtained by fitting a theorectical h'F curve for the parabola of best fit to the observed ordinary mode trace near foF2 and correcting for under-lying ionizaton.
qc	09	km	EF layer scale height.
foF1	10	.01 MHz	F1 layer o-mode critical frequency.
fxF1	11	.01 MHz	F1 layer x-mode critical frequency
M3000F1	13	.01 MHz	F1 layer M factor (see code 03).
h'F1	14	km	F1 layer o-mode minimum virtual height.
h'F	16	km	F layer o-mode minimum virual height.
MUF3000F1	17	.1 MHz	F1 layer maximum usable frequency(see code 07).

E Layer Parameters

Parameter	Code	Dimension	Description
foE	20	.01 MHz	E layer o-mode critical frequency.
foE2	22	.01 MHz	E2 layer o-mode critical frequency (when it occurs it is between the normal E and F1 layers).
h'E	24	km	E layer o-mode minmum virual height.
h'E2	26	km	E2 layer o-mode minimum virtual height.

Es Layer Parameters

Parameter	Code	Dimension	Description
foEs	30	.1 MHz	Es layer hightest o-mode frequency are which a mainly continuous Es trace is observed.
fxE	31	.1 MHz	Es layer highest x-mode frequency are which a mainly continuous Es trace is observed.
fbEs	32	.1 MHz	The blanketing frequency of layer used to derive foEs.
ftEs	33	.1 MHz	Top frequency of the Es trace (any mode).
h'Es	34	km	The minimim virtual height of the layer used to derive foEs.
Type of Es	36		A characterization of the shape of Es trace.

Other Parameters

Parameter	Code	Dimension	Description
foF1.5	40	.01 MHz	The o-mode critical frequency of the F1.5 intermediate stratification (between F1 and F2).
fmin	42	.1 MHz	The lowest frequency at whcih an o-mode echo is observed on the ionogram.
M3000F1.5	43	.01 MHz	F1.5 layer M factor (see code 03).
h'F1.5	44	km	F1.5 layer o-mode minimum virtual height.
fm2	47	.1 MHz	The fmin for the second order o-mode trace.
hm	48	km	The height of the maximum electron density of the F2 later calculated by the Titheridge method.
fm3	49	.1 MHz	The fmin for the third order o-mode trace.

Spread E/Oblique Parameter

Parameter	Code	Dimension	Description
foI	50	.1 MHz	The highest o-mode frequency of spread F.
fxI	51	.1 MHz	The highest frequency of spread F traces (any mode).
fmI	52	.1 MHz	The lowest o-mode frequency at which spread traces are observed for the F layer.
M30001	53	.01 MHz	M Factor deduces from upper frequency edge of spread traces and fxI (see code 03).
h'I	54	km	Minimum slant range of the spread F trace.
dfs	57	.1 MHz	Frequency range of the spread.

N(h) Titheridge

Parameter	Code	Dimension	Description
fh'F2	60	.1 MHz	Thse frequency at which h'F2 is measured.
fh'F	61	.1 MHz	The frequency at which h'F is measured.
h'mF1	63	km	The maximum virula height in the o-mode F1 cusp.
h1	64	km	True height at f1 Titheridge method.
h2	65	km	True height at f2 Titheridge method.
h3	66	.01 MHz	True height at f3 Titheridge method.
h4	67	.01 MHz	True height at f4 Titheridge method.
h5	68	km	True height at f5 Titheridge method.
H	69	km	Effective scale height at hmF2 Titheridge method.

T.E.C.

Parameter	Code	Dimension	Description
I2000	70	10¹⁶ e/m2	Ionospheric electron content Faraday technique.
I	71	10¹⁶ e/m2	Total electron content to geostationary satellite.
I1000	72	10¹⁶ e/m2	Ionospheric electron content to height 100 km using Digisonde technique.
T	79	10¹⁶ e/m2	Total sub-peak content. Titheridge method.

Other 2

Parameter	Code	Dimension	Description
FMINF	80	.1 MHz	Minimum frequency of E trace (50 kHz increments)Equals fbEs when E present.
FMINE	81	.1 MHz	Minimum frequency of E trace (50 kHz increments).
HOM	82	km	Parabolic E layer peak height.
yE	83	km	Parabolic E layer semi-thickness.
QF	84	km	Average range spread of F trace.
QE	85	km	Average range spread of E trace.
FF	86	.01 MHz	Frequency spread between fxF2 and fxI.
FE	87	.01 MHz	As FF but considered beyond foE.
fMUF3000	88	.01 MHz	MUF (D) /obliquity factor.
h'MUF3000	89	km	Virtual height at fMUF.

N(h)

Parameter	Code	Dimension	Description
hmE (zmE)	90	km	True height of E-layer, ??? method.
hmF1 (zmF1)	91	km	True height of F1 peak, ??? method.
hmF2 (zmF2)	92	km	True height of F2 peak, ??? method.
zhalfNm	93	km	True height at half peak electron density.
yF2	94	km	Parabolic F2 layer semi-thickness.
yF1	95	km	Parabolic F1 layer semi-thickness.

Digisonde profile, F2 layer

Parameter	Code	Dimension	Description
[A0F2]	A0	km	Coefficient A0, truncated to integer km.
<A0F2>	A1	m	A0 - [A0], truncation reminder.
[A1F2]	A2	km	Coefficient A1.
<A1F2>	A3	m	A1 - [A1].
[A2F2]	A4	km	Coefficient A2.
<A2F2>	A5	m	A2 - [A2].
[A3F2]	A6	km	Coefficient A3.
<A3F2>	A7	m	A3 -[A3.]
[A4F2]	A8	km	Coefficient A4.
<A4F2>	A9	m	A4 - [A4].
[fsF2]	AA	MHz	starting frequency of the layer, truncate.
<fsF2>	AB	kHz	fs - [fs].
[fmF2]	AC	MHz	ending frequency fm.
<fmF2>	AD	kHz	fm - [fm].
[hmF2]	AE	km	peak height, truncated.
<hmF2>	AF	m	hm - [hm].
EppF2	AG	0.1 km	error per point an average mismatch of original h'(f) trace and the trace reconstructed from the calculated profiles.

Digisonde profile, F1 layer

Parameter	Code	Dimension	Description
[A0F1]	B0	km	Coefficient A0, truncated to integer km.
<A0F1>	B1	m	A0 - [A0], truncation reminder.
[A1F1]	B2	km	Coefficient A1.
<A1F1>	B3	m	A1 - [A1].
[A2F1]	B4	km	Coefficient A2.
<A2F1>	B5	m	A2 - [A2].
[A3F1]	B6	km	Coefficient A3.
<A3F1>	B7	m	A3 -[A3].
[A4F1]	B8	km	Coefficient A4.
<A4F1>	B9	m	A4 - [A4].
[fsF1]	BA	MHz	starting frequency of the layer, truncate.
<fsF1>	BB	kHz	fs - [fs].
[fmF1]	BC	MHz	ending frequency fm.
<fmF1>	BD	kHz	fm - [fm].
[hmF1]	BE	km	peak height, truncated.
<hmF1>	BF	m	hm - [hm].
EppF1	BG	0.1 km	error per point an average mismatch of original h'(f) trace and the trace reconstructed from the calculated profiles.

Digisonde profile, E layer

Parameter	Code	Dimension	Description
[A0E]	C0	km	Coefficient A0, truncated to integer km.
<A0E>	C1	m	A0 - [A0], truncation reminder.
[A1E]	C2	km	Coefficient A1.
<A1E>	C3	m	A1 - [A1.]
[A2E]	C4	km	Coefficient A2.
<A2E>	C5	m	A2 - [A2].
[W]	C6	km	Valley width [W], truncated.
<W>	C7	m	W - [W].
[D]	C8	km	Valley depth [D], truncated.
<D>	C9	m	D - [D].
[fsE]	CA	MHz	starting frequency.
<fsE>	CB	kHz	fs - [fs].
[fmE]	CC	MHz	ending frequency.
<fmE>	CD	kHz	fm - [fm].
[hmE]	CE	km	peak height, truncated.
<hmE>	CF	m	hm - [hm].
EppE	CG	0.1 km	error per point an average mismatch of original h'(f) trace and the trace reconstructed from the calculated profiles.
Valley ID	CH		Valley Model ID.
B0	D0	km	IRI Thickness parameter.
B1	D1	0.1	IRI Profile Shape parameter.
D1	D2	0.1	IRI Profile Shape parameter, F1 layer.