
Total disturbed days observation	31

ESF days	20	Irregularity in Digisonde only	2
 NSF days	10	Irregularity in Digisonde and GNSS only	1
No data	1	Irregularity in Digisonde and Radar only	4
		Irregularity in Digisonde, GNSS and Radar	10
		Insufficient data	3
Total  quiet days observation	44

ESF days	40	Irregularity in Digisonde only	4
 NSF days	1	Irregularity in Digisonde and GPS only	2
No data	3	Irregularity in Digisonde and Radar only	7
		Irregularity in Digisonde, GPS and Radar	27
		No sufficient data	0
Threshold criterion data :

AE&VE MSA-HSA (Disturbed)
Date and DOY	DOY	foF2 at 18:45 IST	foF2 just before spread F	h'F at 18:45 IST	h'F just before spread F	Maximum altitude of  spread	Duration in digisonde	Ap	F10.7	Storm phase
		(MHz)	(MHz)	(km)	(km)	(km)	(hr)			
No cascade										
30-08-2024,243	243	11.061	8.909	298.4	405.9	477.6	1.25	24	218.3	MP
01-04-2022	91	11.892	11.743	299.7	332.9	415.2	1.5	--	146.4	MP
31-08-2024,244	244	11.023	10.442	305	432.4	473.6	1.88	--	235.9	RP
13-09-2024,257	257	10.907	10.651	335.5	390	448.4	1.88	--	188.1	RP

Date and DOY	DOY	foF2 at 18:45 IST	foF2 just before spread F	h'F at 18:45 IST	h'F just before spread F	Maximum altitude of  spread	Duration digisonde	F10.7	Storm phase
		(MHz)	(MHz)	(km)	(km)	(km)	(hr)		
Cascading at least up to GPS									
06-10-2024,280	280	10.899	10.078	393.9	464.3	575.8	5.38	264.2	SSC
10-10-2024,284	284	9.28	8.336	382	459	597	4	215.6	MP
15-2-2014, 46	46	10.3	10.279	301	368.7	730	5.75	158.1	SSC
23-04-2023	113	10.817	9.572	289.1	417.8	524	2.63	136.7	MP
13-08-2024,226	226	10.576	9.304	307.7	428.5	620.9	4.25	266.7	RP
14-09-2024,258	258	10.419	9.242	326.2	443.1	603.7	3.63	174.4	RP
19-09-2024,263	263	12.571	10.504	324.9	428.5	571.8	3.5	162.6	RP
23-08-2015,235	235	10.8	9.109	261.2	325	446	1.86	136.1	RP
01-10-2015, 274	274	9.448	9.149	319.6	376.7	595.7	7	120	RP
25-04-2023	115	10.737	10.459	277.1	350.1	525.4	5.75	132.3	RP
28-02-2014	59	11.247	9.501	299.7	421.8	670	7.73	167.5	RP

WS & SS MSA-HSA (Disturbed)
Date and DOY	DOY	foF2 at 18:45 IST	foF2 just before spread F	h'F at 18:45 IST	h'F just before spread F	Maximum altitude of  spread	Duration in digisonde	F10.7	Storm phase
		(MHz)	(MHz)	(km)	(km)	(km)	(hr)		
No cascade
10-11-2024,315	315	9.703	8.724	359.4	412.5	520	2.46	226	RP
02-01-2025,2	2	10.715	10.582	310.3	328.9	417.8	3	205.4	RP
22-11-2023, 326	326	11.486	11.495	312.5	317.5	421.8	1.9	184.8	RP
06-01-2025,6	6	7.944	7.778	319.6	371.4	435.1	1.5	166.2	RP
10-6-2024, 162	162	12.3	10.35	300	344.8	415	0.75	183.3	MP
12-05-2024, 133	133	10.5	9.72	260	366.1	440	3.25	226.4	RP
15-5-2024,136 	136	10.12	9.03	310	390	554	2.13	220.8	RP
16-5-2024, 137	137	11.34	10.89	307.5	396.6	470	2.25	211.9	RP
14-05-2024,135	135	--	10.4	--	375.4	500	1.75	224.6	RP

Date and DOY	DOY	foF2 at 18:45 IST	foF2 just before spread F	h'F at 18:45 IST	h'F just before spread F	Maximum altitude of  spread	Duration digisonde	F10.7	Storm phase
		(MHz)	(MHz)	(km)	(km)	(km)	(hr)		
Cascading at least up to GPS
3-12-2023, 337	337	8.19	8.19	350	350	598.4	6.6	135.2	RP
1-11-2015, 305	305	9.152	8.646	332.9	351.5	540	2	122.4	RP
01-01-2025,1	1	10.474	10.011	356.8	433.8	631.5	3	211.9	MP
25-11-2023, 329	329	--	8.37	--	362.5	613	2.1	171.9	MP
21-11-2023, 325	325	--	8.13	--	310	550	6.6	167.3	MP
14-12-2015,348	348	8.74	7.343	286.4	386	626.2	10.16	120.2	MP
10-05-2024, 131	131	11.04	10.56	295	410	526	1.89	227.9	MP
17-05-2024, 138	138	12.788	11.758	292.5	375	552	10.25	208.7	MP										
WS & SS (MSA-HSA Quiet)
Date	DOY	F10.7	h'F just before spread F	Maximum altitude of spread (km)	Duration in digisonde (hr)
					
No cascade					
04-07-2023	185	172.8	297	377	1.75
09-07-2023	190	185.2	285.6	346	1.25
12-07-2023	193	199.7	299.5	349	2
04-12-2023	338	133.9	362	500	10.36
07-12-2023	341	130.6	352	473	7.39
11-12-2023	345	122.1	351	497	6.5
21-12-2023	355	187.4	375.4	429.8	2.3
Date	DOY	F10.7	h'F just before spread F	Maximum altitude spread (km)	Duration in   Digisonde (Hr)
					
Cascading at least up to GPS				
10-07-2023	191	196.9	305.5	438	10
23-11-2023	327	168.6	323.6	616.9	9
27-11-2023	331	144.5	341	562	8.89
29-11-2023	333	138.2	349.7	493	9.86
30-11-2023	334	135.1	326	534	10
13-12-2023	347	130.7	305	454	10.61
19-12-2023	353	173.5	345	547	9.61
28-11-2023	332	247.8	339	521	9.25
24-01-2025	24	198.2	441.7	620	5.13
25-01-2025	25	176.2	425.8	621	5.88
26-01-2025	26	165.4	309	639.5	5.88
27-01-2025	27	157.6	420.5	664.7	8.86									
AE&VE (MSA-HSA Quiet)
Date	DOY	h'F just before spread F	Maximum altitude of spread (km)	Duration in digisonde (hr)	duration GNSS		F10.7
							
No Cascade							
03-04-2022	93	366	449	1.5	NA	--	140.2
25-09-2022	268	348	419	1.89	NA	--	135.5
Date	DOY	h'F just before spread F	Max alt spread	Duration Digisond	duration GNSS	F10.7
						
Cascading at least up to GPS					
05-04-2022	95	378	477	5	4.17	122.5
16-09-2022	259	343	538	7.25	6.39	132.5
20-09-2022	263	320	457	6	5.12	138.4
21-09-2022	264	330.4	516	5.5	4.94	138
12-04-2023	102	406.7	577	11	6.47	154.7
13-04-2023	103	348	564	9.25	7.85	160.4
14-04-2023	104	355.8	554	8.75	6.08	172.3
15-04-2023	105	419.4	640	5.89	5.05	176.9
16-04-2023	106	391.4	564	7.5	7.31	179.1
17-04-2023	107	386.4	587	12	9.26	167.8
20-04-2023	110	376	531	11.25	8.06	148.4
01-04-2014	91	399.2	594.4	4.25	2.46	153.1
02-04-2014	92	415.2	723	5.36	4.36	154.6
03-04-2014	93	400.6	666.1	8.61	6.5	153
04-04-2014	94	364.7	638.2	6.63	5.33	157
06-04-2014	96	376.7	590.4	5.25	4.5	141.2
08-04-2014	98	404.6	524	5.25	0.9	132.4
09-04-2014	99	367.4	597	5.25	4.6	131
11-03-2024	71	432.4	565.2	3.11	2.7	125.1
maximum altitude of ESF spread with post sunset h’F for magnetically disturbed equinoctial  and solsticial  periods
WS-SS (Disturbed)

Date and DOY	DOY	foF2 at 18:45 IST	foF2 just before spread F	h'F at 18:45 IST	h'F just before spread F	Maximum altitude of  spread	Duration in digisonde	F10.7	Storm phase
		(MHz)	(MHz)	(km)	(km)	(km)	(hr)		
Both cascade and no cascade									
									
01-01-2025,1	1	10.474	10.011	356.8	433.8	631.5	3	211.9	MP
02-01-2025,2	2	10.715	10.582	310.3	328.9	417.8	3	205.4	RP
06-01-2025,6	6	7.944	7.778	319.6	371.4	435.1	1.5	166.2	RP
10-05-2024, 131	131	11.04	10.56	295	410	526	1.89	227.9	MP
12-05-2024, 133	133	10.5	9.72	260	366.1	440	3.25	226.4	RP
15-5-2024,136 	136	10.12	9.03	310	390	554	2.13	220.8	RP
16-5-2024, 137	137	11.34	10.89	307.5	396.6	470	2.25	211.9	RP
17-05-2024, 138	138	12.788	11.758	292.5	375	552	10.25	208.7	MP
10-6-2024, 162	162	12.3	10.35	300	344.8	415	0.75	183.3	MP
1-11-2015, 305	305	9.152	8.646	332.9	351.5	540	2	122.4	RP
05-11-2021,309	309	10.612	10.241	266.5	273.1	311.6	2	91.2	MP
05-11-2015,309	309	8.14	8.054	323.6	343.5	437.7	3.36	108.1	MP
07-11-2015, 311	311	9.092	8.95	318.3	323.6	423.1	1.5	112.9	RP
10-11-2024,315	315	9.703	8.724	359.4	412.5	520	2.46	226	RP
21-11-2023, 325	325	--	8.13	--	310	550	6.6	167.3	MP
22-11-2023, 326	326	11.486	11.495	312.5	317.5	421.8	1.9	184.8	RP
25-11-2023, 329	329	--	8.37	--	362.5	613	2.1	171.9	MP
3-12-2023, 337	337	8.19	8.19	350	350	598.4	6.6	135.2	RP
06-12-2015, 340	340	7.386	7.386	306.3	306.3	404.6	1.5	99.3	RP
14-12-2015,348	348	8.74	7.343	286.4	386	626.2	10.16	120.2	MP
15-12-2015, 349	349	7.98	7.489	305	355.4	558.5	8.36	115.2	RP
20-12-2015, 354	354	8.149	7.831	326.2	356.8	516.1	2.25	112.8	MP
21-12-2015, 355	355	11.458	10.703	297	307.7	489.5	1.6	117.8	RP

AE-VE (Disturbed)
Date and DOY	DOY	foF2 at 18:45 IST	foF2 just before spread F	h'F at 18:45 IST	h'F just before spread F	Maximum altitude of  spread	Duration in digisonde	F10.7	Storm phase
		(MHz)	(MHz)	(km)	(km)	(km)	(hr)		
Both cascade and no cascade									
16-02-2016,47	47	8.997	7.137	297	347.5	602.3	2.5	101.5	MP
17-02-2016,48	48	10.283	9.203	286.4	334.2	532	3.13	97.5	RP
18-02-2016, 49	49	10.986	10.498	270.5	324.9	498.8	5	92.7	RP
18-02-2020,49	49	7.57	7.49	253.2	302.3	437.7	5.25	69.4	MP
28-02-2014	59	11.247	9.501	299.7	421.8	670	7.73	167.5	RP
07-03-2016,67	67	11.242	10.143	270.5	372.7	513	3.63	92.8	RP
01-04-2022	91	11.892	11.743	299.7	332.9	415.2	1.5	146.4	MP
21-04-2017, 111	111	9.375	8.312	265.2	327.6	451	1.5	83.1	RP
23-04-2023	113	10.817	9.572	289.1	417.8	524	2.63	136.7	MP
25-04-2023	115	10.737	10.459	277.1	350.1	525.4	5.75	132.3	RP
13-08-2024,226	226	10.576	9.304	307.7	428.5	620.9	4.25	266.7	RP
23-08-2015,235	235	10.8	9.109	261.2	325	446	1.86	136.1	RP
30-08-2024,243	243	11.061	8.909	298.4	405.9	477.6	1.25	218.3	MP
01-09-2016, 245	245	10	9.443	265.2	290.4	376.7	1.1	96.9	RP
13-09-2024,257	257	10.907	10.651	335.5	390	448.4	1.88	188.1	RP
14-09-2024,258	258	10.419	9.242	326.2	443.1	603.7	3.63	174.4	RP
19-09-2024,263	263	12.571	10.504	324.9	428.5	571.8	3.5	162.6	RP
27-09-2016, 271	271	9.88	8.937	274.5	311.6	466.9	4.1	85.9	RP
28-09-2016, 272	272	11.595	11.346	258.5	267.8	319.6	0.75	84.8	MP
01-10-2015, 274	274	9.448	9.149	319.6	376.7	595.7	7	120	RP
05-10-2015,278	278	10.8	10.03	289	291.7	330.2	0.63	82.6	RP
06-10-2015,279	279	9.349	9.1	297	354.1	390	1	81.3	MP
06-10-2024,280	280	10.899	10.078	393.9	464.3	575.8	5.38	264.2	SSC
09-10-2015, 282	282	9.46	7.84	257.2	302.3	350.1	1	81	MP
10-10-2024,284	284	9.28	8.336	382	459	597	4	215.6	MP
12-10-2015, 285	285	10.412	10.343	293.1	306.3	435.1	1.61	88.7	MP
13-10-2016, 287	287		9.889		315.6	520	3	94.8	MP
25-10-2016, 299	299	9.195	8.886	305	334.2	593.1	2.36	76.9	MP

Disturbed period Radar statistics

Type of irregularity		recovery phase		ssc/main phase			BT-TS	TS	BT/BS				Mp - cascaded 	Mp - non cascaded	Rp - cascaded 	Rp - non cascaded 
Bottom type- Top side 	5	Bottom type- Top side irregularities	4	Bottom type- Top side irregularities	1	Main phase	1	3	0	BT-TS	5	BT-TS	1	0	2	2
Top side 	5	Top side irregularities	2	Top side irregularities	3	Recovery phase	4	2	4	TS	5	TS	2	1	1	1
Bottom type/ Bottom side 	4	Bottom type/ Bottom side irregularities	4	Bottom type/ Bottom side irregularities	0	--	--	--	--	BT/BS	4	BT/BS	0	0	0	4

Quiet period Radar statistics

Type of irregularities observed in Radar		cascaded irregularities	Non cascaded irregularities
Bottom type- Top side irregularities	12	12	0
Top side irregularities	13	13	0
Bottom type/Bottom side irregularities	9	8	1

The mean electron density gradient scale length for disturbed periods of various seasons
VE	L		AE	L		SS	L		WS	L			N total	Mean	Standard Deviation	SE of mean	Sum	Minimum	Median	Maximum
DISTURBED																																							
15_02_2014	22.18189		06_10_2024	18.30006		10_05_2024	21.62735		01_01_2025	36.60013		VE	5	26.56282	8.71628	3.89804	132.81409	18.57734	22.18189	40.48196
23_04_2023	22.18189		10_10_2024	40.48196		16/05/2024	29.39101		14_12_2015	3.60456		AE	10	27.14509	8.41871	2.66223	271.45093	10.81367	29.39101	40.48196
28/02/2014	40.48196		01_10_2015	21.90462		15/05/2024	47.69107		21_11_2023	30.22283		SS	6	22.55159	14.41148	5.88346	135.30955	7.20912	18.16143	47.69107
25/04/2023	18.57734		13_08_2024	32.99557		14/05/2024	14.6955		25_11_2023	20.79553		WS	10	22.95826	10.16737	3.21521	229.58261	3.60456	22.45917	36.8774
01_04_2022	29.39101		14_09_2024	29.39101		12/05/2024	7.20912		01_11_2015	18.30006										
			19_09_2024	29.39101		10_06_2024	14.6955		03/01/2025	36.8774										
			23_08_2015	10.81367					02_01_2025	14.6955										
			30_08_2024	32.99557					06_01_2025	25.78645										
			13_09_2024	25.50918					10_11_2024	18.57734										
			31_08_2024	29.66828					22_11_2023	24.12281	
The mean post sunset neutral density threshold for cascading at least up to GNSS and/ or Radar scale sizes during disturbed periods of equinoxes (VE & AE) and  solstices  (SS & WS)	

Date	doy	h'F just before ESF	Mean Neutral density from 17 IST to 19/20 IST		Date	doy	h'F just before ESF	Mean Neutral density from 17 IST to 19/20 IST
								
cascade					no cascade			
06_10_2024	280	464.3	1.6863E8		01_04_2022	91	332.9	5.0243E8
10_10_2024	284	459	1.9483E8		30_08_2024	243	405.9	2.3542E8
15_02_2014	46	368.7	2.7347E8		13_09_2024	257	390	3.4487E8
23_04_2023	113	417.8	1.6327E8		31_08_2024	244	432.4	1.8423E8
01_10_2015	274	376.7	1.4123E8		18/03/2015	77	300	6.9016E8
13_08_2024	226	428.5	1.6883E8					
14_09_2024	258	443.1	1.6597E8					
19_09_2024	263	428.5	1.9527E8					
23_08_2015	235	325	2.5865E8					
17/03/2015	76	560	1.648E7					
28/02/2014	59	421.8	1.3595E8					
25/04/2023	115	350.1	3.379E8	

Date	doy	h'F just before ESF	Mean Neutral density from 17 IST to 19/20 IST		Date	doy	h'F just before ESF	Mean Neutral density from 17 IST to 19/20 IST
								
cascade					no cascade			
								
01_01_2025	1	433.8	1.8453E8		16/05/2024	137	396.6	2.48386E8
14_12_2015	348	386	1.106E8		15/05/2024	136	390	2.5445E8
21_11_2023	325	310	6.3255E8		14/05/2024	135	375.4	2.981E8
25_11_2023	329	362.5	3.305E8		12/05/2024	133	366.1	3.987E8
01_11_2015	305	351.5	2.1083E8		03/01/2025	3	331.5	5.3562E8
10_05_2024	131	410	2.7195E8		10_06_2024	162	344.8	3.4848E8
					02_01_2025	2	328.9	5.9207E8
					06_01_2025	6	371.4	3.0487E8
					10_11_2024	315	412.5	2.7863E8
					22_11_2023	326	317.5	5.909E8
The mean post sunset neutral density threshold for cascading at least up to GNSS and/ or Radar scale sizes during quiet periods of equinoxes (VE & AE) and  solstices  (SS & WS)
	
Date	DOY	F10.7	h'F	post sunset mean neutral density at h'F(/CC)	h'F at 2.5 MHz just before ESF	h'F at 3 MHz just before ESF
AEVE					km	km
Cascade						
05-04-2022	95	122.5	378	1.636E8	378	388.6 
16-09-2022	259	132.5	343	2.6763E8	343	354
20-09-2022	263	138.4	320	4.1305E8	320	328.9
21-09-2022	264	138	330.4	3.3763E8	330.4	340.8
12-04-2023	102	154.7	406.7	1.5377E8	406.7	420.5
13-04-2023	103	160.4	348	3.8107E8	348	355.4
14-04-2023	104	172.3	355.8	3.4473E8	355.8	368.7
15-04-2023	105	176.9	419.4	1.4933E8	419.4	437.7
16-04-2023	106	179.1	391.4	2.1413E8	391.4	403.2
17-04-2023	107	167.8	386.4	2.3193E8	386.4	397.9
20-04-2023	110	148.4	376	2.392E8	376	387.3
01-04-2014	91	153.1	399.2	1.6972E8	399.2	412.5
02-04-2014	92	154.6	415.2	1.3843E8	415.2	425.8
03-04-2014	93	153	400.6	1.7517E8	400.6	413
04-04-2014	94	157	364.7	2.8923E8	364.7	372.7
06-04-2014	96	141.2	376.7	2.1612E8	376.7	393.9
08-04-2014	98	132.4	404.6	1.4907E8	404.6	415.2
09-04-2014	99	131	367.4	2.5007E8	367.4	379.3
11-03-2024	71	125.1	432.4	1.0481E8	432.4	444.4
						
Date	DOY	F10.7	h'F	post sunset mean neutral density at h'F(/CC)	h'F at 2.5 MHz just before ESF	h'F at 3 MHz just before ESF
					km	km
NO Cascade						
						
03-04-2022	93	140.2	366	2.1002E8	366	376.7
25-09-2022	268	135.5	348	2.643E8	348	359.4		
Date	DOY	F10.7	h'F	Mean post sunset neutral density at h'F cm-3	h'F at 2.5 MHz just before ESF	h'F at 3 MHz just before ESF
WSSS					km	km
Cascade						
10-07-2023	191	196.9	305.5	4.601E8	305.5	311.6
23-11-2023	327	168.6	323.6	5.111E8	323.6	331.5
27-11-2023	331	144.5	341	3.8735E8	341	351.5
29-11-2023	333	138.2	349.7	4.005E8	349.7	359.4
30-11-2023	334	135.1	326	4.6005E8	326	336.9
13-12-2023	347	130.7	305	5.845E8	305	314.3
19-12-2023	353	173.5	345	3.429E8	345	356.8
28-11-2023	332	247.8	339	4.034E8	339	352.8
24-01-2025	24	198.2	441.7	1.2867E8	441.7	457.7
25-01-2025	25	176.2	425.8	1.4135E8	425.8	440.4
26-01-2025	26	165.4	309	6.7387E8	309	318.3
27-01-2025	27	157.6	420.5	1.4348E8	420.5	432.4	
Date	DOY	F10.7	h'F	Mean post sunset neutral density at h'F cm-3	h'F at 2.5 MHz just before ESF	h'F at 3 MHz just before ESF
					km	km
NO Cascade						
04-07-2023	185	172.8	297	5.2237E8	297	306.3
09-07-2023	190	185.2	285.6	5.8868E8	285.6	295.7
12-07-2023	193	199.7	299.5	5.3723E8	299.5	307.7
The mean electron density gradient scale length for quiet periods of various seasons
SS	L		WS	L		VE	L		AE	L			N total	Mean	Standard Deviation	SE of mean	Sum	Minimum	Median	Maximum
QUIET																				
CAS+NOCAS 																				
10-07-2023	16.91369		23-11-2023	21.90462		05-04-2022	29.39101		16-09-2022	30.5001		VE	17	33.32177	7.53452	1.82739	566.47012	20.51825	32.71829	50.74108
04-07-2023	25.78645		27-11-2023	29.11374		12-04-2023	38.26377		20-09-2022	24.67736		AE	4	28.90578	3.04054	1.52027	115.62312	24.67736	29.66828	31.6092
09-07-2023	28.00464		29-11-2023	26.89555		13-04-2023	20.51825		21-09-2022	28.83646		SS	4	23.36031	4.80985	2.40493	93.44123	16.91369	24.26145	28.00464
12-07-2023	22.73644		30-11-2023	30.22283		14-04-2023	35.7683		25-09-2022	31.6092		WS	15	30.85132	6.36908	1.64449	462.76977	21.90462	29.39101	44.36379
			13-12-2023	25.78645		15-04-2023	50.74108													
			19-12-2023	32.71829		16-04-2023	32.71829													
			28-11-2023	38.26377		17-04-2023	31.88647													
			24-01-2025	44.36379		20-04-2023	31.33193													
			25-01-2025	40.48196		01-04-2014	36.8774													
			26-01-2025	25.78645		02-04-2014	29.39101													
			27-01-2025	32.99557		03-04-2014	34.38194													
			04-12-2023	26.06373		04-04-2014	22.18189													
			07-12-2023	24.40008		06-04-2014	47.69107													
			11-12-2023	34.38194		08-04-2014	29.39101													
			21-12-2023	29.39101		09-04-2014	32.99557													
						11-03-2024	33.27284													
						03-04-2022	29.66828	
The mean electron density gradient scale length during main phase and recovery phase events of  equinoxes and  solstices
Solstice				Equinox		
Main phase	21.25765	4.72867	--	Main phase	27.58873	3.38361
Recovery phase	23.73463	3.7648	--	Recovery phase	26.52585	2.87558																					