Ionosphere and Space Weather | Royal Meteorological Institute

Ionogram Characteristics

Date:

Date/Time (UT)	foF2	foF1	foE	fmin	hmF2	hmF1	hmE	M(3000)	TEC
2023-03-28 00:00:01	5.15			1.65	421.0			2.485	9.228
2023-03-28 00:05:02	5.10			1.50	409.0			2.551	8.196
2023-03-28 00:10:00	5.15			1.65	418.6			2.493	9.285
2023-03-28 00:15:01	5.10			1.65	408.8			2.532	8.475
2023-03-28 00:20:02	5.10			1.50	405.2			2.523	8.067
2023-03-28 00:25:00	5.05			1.65	388.2			2.631	6.617
2023-03-28 00:30:01	5.05			1.25	396.3			2.595	7.549
2023-03-28 00:35:02	5.05			1.65	397.1			2.543	7.542
2023-03-28 00:40:00	5.05			1.65	390.5			2.604	7.281
2023-03-28 00:45:01	5.15			1.65	404.7			2.505	8.648
2023-03-28 00:50:02	5.00			1.65	392.9			2.617	7.658
2023-03-28 00:55:00	5.00			1.50	389.5			2.588	7.319
2023-03-28 01:00:01	4.85			1.70	370.8			2.671	5.358
2023-03-28 01:05:02	5.00			1.65	392.3			2.566	7.572
2023-03-28 01:10:00	4.95			1.60	382.2			2.632	6.820
2023-03-28 01:15:01	4.95			1.65	381.8			2.623	6.854
2023-03-28 01:20:02	5.00			1.65	387.1			2.583	7.394
2023-03-28 01:25:00	4.85			1.75	370.1			2.654	5.727
2023-03-28 01:30:01	4.95			1.65	389.4			2.598	7.721
2023-03-28 01:35:02	4.90			1.65	382.2			2.616	7.029
2023-03-28 01:40:00	4.85			1.60	377.6			2.624	6.537
2023-03-28 01:45:01	4.85			1.70	386.0			2.612	7.337
2023-03-28 01:50:02	4.80			1.60	381.7			2.631	6.861
2023-03-28 01:55:00	4.75			1.65	374.8			2.646	6.161
2023-03-28 02:00:01	4.65			1.65	370.4			2.634	5.700
2023-03-28 02:05:02	4.70			1.50	378.8			2.598	6.346
2023-03-28 02:10:00	4.75			1.65	391.9			2.545	7.279
2023-03-28 02:15:01	4.75			1.25	395.1			2.563	7.853
2023-03-28 02:20:02	4.70			1.50	376.6			2.641	6.239
2023-03-28 02:25:00	4.70			1.60	383.8			2.625	7.084
2023-03-28 02:30:01	4.60			1.20	372.1			2.646	6.109
2023-03-28 02:35:02	4.55			1.80	369.2			2.661	5.643
2023-03-28 02:40:00	4.60			1.65	378.8			2.619	6.545
2023-03-28 02:45:01	4.50			1.20	370.0			2.682	6.165
2023-03-28 02:50:02	4.55			1.50	370.1			2.662	6.168
2023-03-28 02:55:00	4.50			1.70	362.7			2.692	5.639
2023-03-28 03:00:01	4.50			1.65	359.0			2.722	5.578
2023-03-28 03:05:02	4.50			1.50	364.0			2.702	6.177
2023-03-28 03:10:00	4.40			1.65	357.8			2.734	5.781
2023-03-28 03:15:01	4.45			1.75	359.7			2.708	5.802
2023-03-28 03:20:02	4.45			1.60	358.0			2.693	6.042
2023-03-28 03:25:00	4.55			1.60	378.0			2.634	7.559
2023-03-28 03:30:01	4.35			1.75	350.9			2.755	5.488
2023-03-28 03:35:02	4.50			1.60	351.6			2.756	5.971
2023-03-28 03:40:00	4.40			1.65	356.0			2.715	6.228
2023-03-28 03:45:01	4.25			1.65	336.1			2.837	4.846
2023-03-28 03:50:02	4.25			1.65	331.5			2.866	4.742
2023-03-28 03:55:00	4.15			1.50	325.6			2.915	4.647
2023-03-28 04:00:01	4.00			1.20	304.2			2.996	3.468
2023-03-28 04:05:02	3.95			1.50	307.9			2.992	3.562
2023-03-28 04:10:00	4.00			1.50	313.8			2.955	4.069
2023-03-28 04:15:01	3.95			1.20	315.3			2.933	4.430
2023-03-28 04:20:02	3.95			1.50	317.0			2.904	4.378
2023-03-28 04:25:00	3.95			1.50	317.7			2.915	4.538
2023-03-28 04:30:01	3.75			1.40	290.3			3.078	3.014
2023-03-28 04:35:02	3.70			1.50	289.9			3.106	2.998
2023-03-28 04:40:00	3.65			1.60	289.0			3.089	3.029
2023-03-28 04:45:01	3.70			1.35	290.9			3.074	3.446
2023-03-28 04:50:02	3.70			1.50	281.0			3.141	3.031
2023-03-28 04:55:00	3.80			1.65	283.0			3.131	3.341
2023-03-28 05:00:01	3.95			1.25	287.4			3.060	4.069
2023-03-28 05:05:02	4.00			1.60	280.7			3.134	4.076
2023-03-28 05:10:00	4.10			1.80	271.1			3.187	3.846
2023-03-28 05:15:01	4.20			1.40	267.9			3.182	3.974
2023-03-28 05:20:02	4.45			1.70	277.5			3.100	5.465
2023-03-28 05:25:00	4.65			1.65	281.6			3.086	5.969
2023-03-28 05:30:01	4.75			1.65	276.3			3.166	6.130
2023-03-28 05:35:02	4.85			1.80	262.6			3.270	5.337
2023-03-28 05:40:00	4.95			1.65	254.7			3.360	5.343
2023-03-28 05:45:01	5.05		1.55	1.50	249.6		110.0	3.404	5.605
2023-03-28 05:50:02	5.10		1.60	1.50	240.6		110.0	3.467	4.474
2023-03-28 05:55:00	5.30		1.75	1.50	239.1		102.1	3.436	5.460
2023-03-28 06:00:01	5.50		1.90	1.50	242.7		102.6	3.413	6.848
2023-03-28 06:05:02	5.65		2.00	1.50	246.9		103.7	3.389	7.749
2023-03-28 06:10:00	5.70		2.05	1.50	239.5		103.4	3.444	7.437
2023-03-28 06:15:01	5.70		2.10	1.50	225.6		103.9	3.546	5.551
2023-03-28 06:20:02	5.85		2.25	1.50	227.1		106.3	3.505	6.712
2023-03-28 06:25:00	6.00		2.20	1.50	239.0		102.0	3.397	8.533
2023-03-28 06:30:01	6.05		2.35	1.45	240.3		103.5	3.354	9.488
2023-03-28 06:35:02	6.10		2.40	1.60	237.5		105.9	3.296	9.445
2023-03-28 06:40:00	6.25		2.45	1.50	241.4		103.4	3.280	9.740
2023-03-28 06:45:01	6.35		2.50	1.35	236.0		103.7	3.345	8.902
2023-03-28 06:50:02	6.45		2.50	1.50	234.3		103.5	3.403	9.046
2023-03-28 06:55:00	6.55	3.25	2.55	1.50	235.8	157.6	103.6	3.396	9.524
2023-03-28 07:00:01	6.60		2.55	1.40	236.6		103.1	3.357	10.113
2023-03-28 07:05:02	6.75		2.50	1.50	251.0		101.3	3.209	12.748
2023-03-28 07:10:00	6.95	3.05	2.65	1.50			103.3	3.128
2023-03-28 07:15:01	7.15	3.60	2.55	1.35	261.1	161.2	99.8	3.141	14.829
2023-03-28 07:20:02	7.30		2.75	1.50	257.9		104.4	3.200	15.082
2023-03-28 07:25:00	7.40		2.65	1.50	249.9		101.6	3.274	12.862
2023-03-28 07:30:01	7.60		2.70	1.05	255.8		102.0	3.249	15.057
2023-03-28 07:35:02	7.70		2.65	1.50	250.9		99.5	3.252	15.139
2023-03-28 07:40:00	7.75		2.85	1.50	250.0		103.7	3.246	14.815
2023-03-28 07:45:01	7.80		2.80	1.55	251.0		100.2	3.247	15.406
2023-03-28 07:50:02	7.95		2.80	1.65	263.3		99.7	3.201	18.371
2023-03-28 07:55:00	8.05		2.80	1.50	261.7		99.4	3.182	18.741
2023-03-28 08:00:01	8.20		2.85	1.50	258.0		99.9	3.209	18.485
2023-03-28 08:05:02	8.30		2.85	1.50	257.2		99.5	3.204	17.718
2023-03-28 08:10:00	8.40		2.85	1.60	254.7		99.4	3.242	17.228
2023-03-28 08:15:01	8.45	4.30	3.15	1.50	245.2	159.7	102.8	3.315	15.734
2023-03-28 08:20:02	8.55	3.65	2.90	1.75	249.9	142.2	99.4	3.278	16.866
2023-03-28 08:25:00	8.55	3.55	3.20	1.65	251.1	130.5	102.8	3.264	18.043
2023-03-28 08:30:01	8.70		3.20	1.50	267.3		102.9	3.113	23.296
2023-03-28 08:35:02	8.65	3.70	3.05	1.70	264.1	139.5	100.5	3.159	21.942
2023-03-28 08:40:00	8.80	4.10	3.25	1.65	266.0	150.4	102.9	3.102	22.778
2023-03-28 08:45:01	9.00	3.80	3.25	1.70	272.8	141.3	102.9	3.039	24.921
2023-03-28 08:50:02	9.15		3.30	1.85	272.3		102.8	3.023	24.943
2023-03-28 08:55:00	9.30		3.30	1.65	281.5		102.9	3.021	28.352
2023-03-28 09:00:01	9.60		3.25	1.75	272.0		101.9	3.090	23.855
2023-03-28 09:05:02	9.80		3.35	1.75	268.6		102.9	3.177	24.449
2023-03-28 09:10:00	9.90		3.35	1.50	262.5		103.0	3.233	23.546
2023-03-28 09:15:01	9.95		3.15	1.80	257.9		99.3	3.244	22.420
2023-03-28 09:20:02	10.00	5.05	3.30	1.75	258.2	173.9	101.3	3.236	24.162
2023-03-28 09:25:00	10.05	4.95	3.40	1.50	262.4	168.8	103.1	3.239	26.457
2023-03-28 09:30:01	10.20		3.40	1.50	279.4		103.1	3.075	33.458
2023-03-28 09:35:02	10.15		3.20	1.75	274.9		99.4	3.086	30.408
2023-03-28 09:40:00	10.10		3.25	1.90	269.6		99.4	3.092	28.179
2023-03-28 09:45:01	10.10		3.25	1.80	273.6		99.4	3.085	30.582
2023-03-28 09:50:02	10.10		3.25	1.70	267.4		99.5	3.101	28.422
2023-03-28 09:55:00	10.10		3.20	1.80	263.9		98.8	3.109	27.012
2023-03-28 10:00:01	10.25	5.00	3.30	1.75	273.2	164.8	99.5	3.080	30.623
2023-03-28 10:05:02	10.20		3.30	1.80	273.9		99.5	3.065	30.875
2023-03-28 10:10:00	10.15		3.30	1.70	273.1		99.5	3.084	30.890
2023-03-28 10:15:01	10.05	5.10	3.30	1.65	268.1	167.7	99.5	3.100	28.787
2023-03-28 10:20:02	10.00		3.30	1.80	269.4		99.5	3.063	28.866
2023-03-28 10:25:00	9.95		3.35	1.95	277.8		99.4	3.024	32.877
2023-03-28 10:30:01	9.90	4.75	3.35	1.75	274.5	153.6	99.5	3.025	30.850
2023-03-28 10:35:02	9.95	4.95	3.35	1.50	276.0	160.6	99.6	3.022	30.501
2023-03-28 10:40:00	10.00		3.35	1.80	282.9		99.5	2.991	32.433
2023-03-28 10:45:01	10.00		3.35	1.80	280.0		99.5	3.000	31.515
2023-03-28 10:50:02	10.00	4.90	3.30	1.75	279.9	162.4	98.9	2.973	32.548
2023-03-28 10:55:00	10.05	4.75	3.50	1.70	289.3	151.6	99.1	2.921	38.043
2023-03-28 11:00:01	10.05	4.85	3.35	2.20	284.4	158.7	99.3	2.891	34.167
2023-03-28 11:05:02	10.25		3.50	1.50	298.0		99.1	2.859	40.306
2023-03-28 11:10:00	10.30		3.40	2.00	295.7		99.4	2.897	38.103
2023-03-28 11:15:01	10.25		3.40	1.85	283.7		99.5	2.955	33.266
2023-03-28 11:20:02	10.30		3.35	1.85	288.0		98.9	2.933	35.637
2023-03-28 11:25:00	10.25		3.35	1.85	280.6		98.9	2.947	31.655
2023-03-28 11:30:01	10.40		3.35	2.20	291.3		98.7	2.920	36.471
2023-03-28 11:35:02	10.45		3.30	1.95	292.0		98.3	2.933	36.551
2023-03-28 11:40:00	10.45		3.40	1.95	285.9		99.5	2.953	34.141
2023-03-28 11:45:01	10.50		3.40	1.85	289.4		99.5	2.946	36.111
2023-03-28 11:50:02	10.50		3.40	1.65	290.7		99.6	2.947	36.688
2023-03-28 11:55:00	10.50		3.40	1.80	296.8		100.4	2.900	39.715
2023-03-28 12:00:01	10.35		3.40	1.75	293.6		100.4	2.891	37.952
2023-03-28 12:05:02	10.25		3.40	1.85	286.2		100.4	2.931	33.102
2023-03-28 12:10:00	10.40	4.90	3.40	1.75	299.3	155.8	100.4	2.846	38.693
2023-03-28 12:15:01	10.55	4.85	3.35	1.70	304.9	155.8	99.8	2.856	40.850
2023-03-28 12:20:02	10.55	4.90	3.35	1.70	297.4	158.1	99.8	2.878	37.580
2023-03-28 12:25:00	10.65		3.35	1.80	308.6		99.8	2.834	42.321
2023-03-28 12:30:01	10.65		3.35	2.20	307.1		99.3	2.823	41.581
2023-03-28 12:35:02	10.95		3.35	1.85	313.0		99.5	2.761	43.361
2023-03-28 12:40:00	11.05		3.35	2.20	302.9		99.3	2.864	38.156
2023-03-28 12:45:01	11.15		3.35	2.20	300.1		99.3	2.923	38.001
2023-03-28 12:50:02	11.15	5.60	3.25	1.80	293.4	184.5	98.6	2.971	35.868
2023-03-28 12:55:00	11.20	5.30	3.35	1.80	294.5	176.1	100.3	2.952	37.796
2023-03-28 13:00:01	11.30		3.30	1.75	299.7		98.9	2.933	41.011
2023-03-28 13:05:02	11.30	5.45	3.30	1.95	291.6	180.5	99.7	2.970	37.686
2023-03-28 13:10:00	11.20		3.30	1.75	284.9		97.8	2.995	34.119
2023-03-28 13:15:01	11.20		3.30	1.75	289.0		100.3	2.968	36.986
2023-03-28 13:20:02	11.20		3.35	1.85	293.0		100.9	2.943	39.150
2023-03-28 13:25:00	11.15		3.25	1.85	287.5		98.8	2.971	35.608
2023-03-28 13:30:01	11.20		3.30	1.75	291.7		100.3	2.970	38.147
2023-03-28 13:35:02	11.20		3.30	1.70	293.7		100.3	2.958	39.556
2023-03-28 13:40:00	11.15		3.25	1.85	289.1		99.4	2.970	36.800
2023-03-28 13:45:01	11.10		3.30	1.45	286.2		100.9	3.004	36.037
2023-03-28 13:50:02	11.15		3.30	1.65	292.4		100.9	3.003	39.839
2023-03-28 13:55:00	10.95		3.25	2.20	282.4		100.1	3.019	34.535
2023-03-28 14:00:01	10.90		3.20	2.20	289.4		99.1	2.994	38.380
2023-03-28 14:05:02	10.70		3.20	1.95	277.5		99.3	3.023	31.486
2023-03-28 14:10:00	10.70		3.20	2.00	283.2		99.2	2.998	33.982
2023-03-28 14:15:01	10.65		3.10	2.00	286.6		98.5	2.959	35.736
2023-03-28 14:20:02	10.50		3.10	1.85	284.3		98.6	2.972	33.139
2023-03-28 14:25:00	10.45		3.05	1.90	290.1		98.1	2.937	35.138
2023-03-28 14:30:01	10.45		3.05	1.15	288.3		99.0	2.945	33.266
2023-03-28 14:35:02	10.40		3.05	1.95	284.8		99.4	2.981	31.878
2023-03-28 14:40:00	10.20		2.90	1.85	275.0		98.3	3.039	27.024
2023-03-28 14:45:01	10.25		3.00	1.25	285.2		99.4	2.972	32.090
2023-03-28 14:50:02	10.20		2.95	1.75	288.3		99.1	2.949	32.817
2023-03-28 14:55:00	10.25		2.90	1.70	303.5		98.8	2.891	38.514
2023-03-28 15:00:01	10.05		3.10	1.10	282.6		101.4	2.957	29.076
2023-03-28 15:05:02	10.20		2.90	1.95	298.9		98.6	2.913	35.542
2023-03-28 15:10:00	10.05		3.05	1.50	286.2		101.3	2.957	29.670
2023-03-28 15:15:01	10.00		3.00	1.25	286.0		100.6	2.968	29.052
2023-03-28 15:20:02	10.10		2.75	1.75	295.5		98.5	2.942	31.439
2023-03-28 15:25:00	10.05		2.85	1.50	287.4		99.5	2.966	28.888
2023-03-28 15:30:01	10.15		2.90	1.15	295.7		103.0	2.956	32.636
2023-03-28 15:35:02	10.15		2.85	1.65	291.3		102.1	2.972	30.034
2023-03-28 15:40:00	10.10	4.70	2.90	1.60	289.3	178.9	103.9	2.994	29.562
2023-03-28 15:45:01	10.15		2.80	1.65	297.1		102.4	2.960	32.513
2023-03-28 15:50:02	10.15		2.85	1.50	293.9		103.8	2.967	30.799
2023-03-28 15:55:00	10.25		2.80	1.50	296.0		102.8	2.978	31.755
2023-03-28 16:00:01	10.20		2.80	1.55	292.2		103.5	2.989	30.237
2023-03-28 16:05:02	10.25		2.75	1.75	299.0		103.3	2.962	32.760
2023-03-28 16:10:00	10.20		2.70	1.50	290.9		102.6	2.991	28.997
2023-03-28 16:15:01	10.25		2.60	1.45	298.5		101.5	2.974	32.247
2023-03-28 16:20:02	10.25		2.55	1.50	293.2		101.4	2.994	28.750
2023-03-28 16:25:00	10.25		2.50	1.50	287.9		100.7	3.019	27.772
2023-03-28 16:30:01	10.30		2.40	1.50	291.5		100.0	3.024	28.982
2023-03-28 16:35:02	10.30		2.30	1.65	298.3		99.4	2.989	31.114
2023-03-28 16:40:00	10.20		2.30	1.50	289.8		100.1	3.013	28.605
2023-03-28 16:45:01	10.25	2.60	2.15	1.30			99.1	3.014
2023-03-28 16:50:02	10.20		2.45	1.75	279.1		108.1	3.076	22.588
2023-03-28 16:55:00	10.25		2.20	1.50	280.3		103.8	3.097	23.372
2023-03-28 17:00:01	10.30		2.30	1.00	284.3		105.5	3.073	25.619
2023-03-28 17:05:02	10.25		2.15	1.75	287.2		103.9	3.061	26.252
2023-03-28 17:10:00	10.20		2.10	1.70	283.0		103.9	3.076	24.236
2023-03-28 17:15:01	10.25		1.80	1.00	286.9		99.9	3.067	24.232
2023-03-28 17:20:02	10.25		2.00	1.65	289.3		103.6	3.054	26.193
2023-03-28 17:25:00	10.25	2.20	1.90	1.50			103.9	3.071
2023-03-28 17:30:01	10.25		1.50	1.10	278.1		88.8	3.113	21.079
2023-03-28 17:35:02	10.40	2.15	1.75	1.65			110.0	3.101
2023-03-28 17:40:00	10.40		1.75	1.60	284.8		104.0	3.124	25.729
2023-03-28 17:45:01	10.20		1.35	1.00	270.4		88.8	3.189	18.701
2023-03-28 17:50:02	10.25		1.80	1.70	277.2		110.0	3.158	20.990
2023-03-28 17:55:00	10.30			1.90	287.4			3.115	24.371
2023-03-28 18:00:01	10.30		1.25	1.00	286.1		88.6	3.105	24.070
2023-03-28 18:05:02	10.35			1.70	291.3			3.100	24.398
2023-03-28 18:10:00	10.25			1.80	286.8			3.117	23.079
2023-03-28 18:15:01	10.10			1.60	284.1			3.122	21.379
2023-03-28 18:20:02	9.85			1.65	279.1			3.157	18.877
2023-03-28 18:25:00	9.70			1.70	276.8			3.155	17.040
2023-03-28 18:30:01	9.55			1.60	274.3			3.173	15.025
2023-03-28 18:35:02	9.45			1.65	274.5			3.184	14.376
2023-03-28 18:40:00	9.40			1.55	276.9			3.169	14.582
2023-03-28 18:45:01	9.30			1.50	278.0			3.148	14.552
2023-03-28 18:50:02	9.30			1.50	287.0			3.106	17.018
2023-03-28 18:55:00	9.25			1.50	292.3			3.085	17.866
2023-03-28 19:00:01	9.20			1.85	297.8			3.089	19.387
2023-03-28 19:05:02	9.05			1.50	294.0			3.091	17.726
2023-03-28 19:10:00	8.95			1.65	293.4			3.106	16.729
2023-03-28 19:15:01	8.85			1.00	291.7			3.114	16.261
2023-03-28 19:20:02	8.75			1.50	293.8			3.109	16.499
2023-03-28 19:25:00	8.55			1.65	291.1			3.131	15.369
2023-03-28 19:30:01	8.35			1.65	293.8			3.116	15.749
2023-03-28 19:35:02	8.20			1.60	296.3			3.059	15.525
2023-03-28 19:40:00	8.00			1.50	295.8			3.060	14.904
2023-03-28 19:45:01	7.85			1.25	293.7			3.044	14.010
2023-03-28 19:50:02	7.75			1.70	298.0			3.018	13.869
2023-03-28 19:55:00	7.65			1.60	301.6			2.995	14.214
2023-03-28 20:00:01	7.35			1.20	289.9			3.035	11.329
2023-03-28 20:05:02	7.30			1.65	301.8			2.946	12.557
2023-03-28 20:10:00	7.30			1.60	309.7			2.901	13.031
2023-03-28 20:15:01	7.30			1.15	313.2			2.888	13.362
2023-03-28 20:20:02	7.25			1.65	319.8			2.873	13.615
2023-03-28 20:25:00	7.00			1.50	299.7			2.965	9.143
2023-03-28 20:30:01	7.10			1.20	313.3			2.890	11.772
2023-03-28 20:35:02	7.00			1.50	314.3			2.896	11.070
2023-03-28 20:40:00	7.00			1.65	326.9			2.864	12.778
2023-03-28 20:45:01	6.90			1.20	321.3			2.881	11.805
2023-03-28 20:50:02	6.90			1.60	327.4			2.849	12.297
2023-03-28 20:55:00	6.80			1.50	329.0			2.835	12.426
2023-03-28 21:00:01	6.50			1.65	307.1			2.942	7.682
2023-03-28 21:05:02	6.65			1.60	324.9			2.853	10.637
2023-03-28 21:10:00	6.50			1.65	318.1			2.891	8.996
2023-03-28 21:15:01	6.45			1.20	320.2			2.865	9.524
2023-03-28 21:20:02	6.30			1.50	315.5			2.886	8.076
2023-03-28 21:25:00	6.35			1.65	327.5			2.827	9.267
2023-03-28 21:30:01	6.45			1.60	339.0			2.774	10.843
2023-03-28 21:35:02	6.30			1.65	327.7			2.861	8.662
2023-03-28 21:40:00	6.45			1.65	348.1			2.781	11.989
2023-03-28 21:45:01	6.30			1.65	327.8			2.855	8.489
2023-03-28 21:50:02	6.40			1.55	345.3			2.809	11.669
2023-03-28 21:55:00	6.30			1.50	339.4			2.833	10.801
2023-03-28 22:00:01	6.20			1.25	336.2			2.818	10.108
2023-03-28 22:05:02	6.05			1.50	322.8			2.870	7.402

Ionosphere and Space Weather (ISW) section

Ionogram Characteristics