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FRITZ,

S6D

SGD

R.

Be

1976

1975-1976

1976a

1976b

ATS-6 Radio Beacon Content Measurements at Boulder,
July 1975 ~ May 1975 (Report UAG-58, World Data
Center A for Solar-Terrestrial Physics, Boulder,
Colorado, USA 80303), 61 pp.

Solar-Geophysical Data, 374-384 Part I, 7, October
1975 - August 1976 (U.S. Department of Commerce,
Boulder, Colorado, USA 80303).

Solar-Geophysical Data, 385 Part 1, 6, September
1976 (U.S. Department of Commerce, Boulder,
Colorado, USA 80303).

Solar-Geophysical Data, 380 Part I, 12, April 1976
(U.S. Department of Commerce, Boulder, Colorado,
USA 80303).



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Oct.
1975

Jan.
1976

Feb.

April

Table 4. (Continued)

ATS6 to Ootacamund Total Slant Path Electron Content 10!/_TM* -- Part 11.
UNIVERSAL TIME
ui cet aT 1 1 19 0 4 4

4.8767 4.0357 2.8363 ------ 2.2989 ~ 2.2302 2.0923 1.7201 0.6446
4.6284, eee oo siete. =+ Pen
4.4906 3.8705 2.9329 2.2849 1.7753 1.9266 1.8579 1.9679 1.8440 0.6033
4.6702 4.3253 ------ 2.9194 2.8363 2.2715 1.8166 1.4717 1.3339 0.7964
4.5871 3.9257 2.5885 1.6853 1.5622 - weeeee aaae 0.8790

3.0887 3.0707 2.9742 2.5685 2.2989 1.8992 0 0.7551

3.7878 2.6572 2.0092 1.3339 1.0995 0.9482 -

3.0433, 2.0923 1.2787 0.9756 0.6446 0.5481 0.5207 0.3968

3.1538 - -

3.9944 2 -

3.029% 2.2715
2.5641 2.3168
2.5229 2.2461
2.5366 1.6986

2.8251 2.4267 2.1382
2.3992 2.3992 2.2481 -
2.2756 2.0558 2.0283 1.6986
2.7701 2.2304
3.0586 2.0146 1.3552

5201

3.2235 2.6602 2.0833 2.2893
2.9075 2.0283 1.7124 1.6437

1.9322
1.2728
2.9350 2.2619 1.9596 1.3690 1.0667
1
1

2.0146 1.5750 1.6300
2.756 2.4OK 2.4130 1.9871

10118 0.8057
+5201 1.6025

3.5532 2.6740 2.2207 2 1.3415 0.9568
3.3059 2.5503 2.2344 1 1.3552 1.1766
3.3608 3.04%9 2.3168 2.0695 1.3003 0.9706 0.8195
3.1685 2.6465 2.0970 2.0833 1 1.3827 1.1354
2.9625 2.9213 2.3718 2.4267 1 1.6025 1.3003

3.3059 2.5916 2.0009 1.8910 1.8635 1.3140 0.8740
2.9350 2.7152 2.1245 2.2069 1.8360 1.1217 0.8195
3.2922 2.8388 2.4542 2.2619 1.9459 1.3827 1.2316
3.0037 2.4958 1.9059 1.4926 ~----~ -iti--
3.0174 2.5366 2.0970 1.8223 1.3964 1.1354 0.8740

4646 2.1471 1.9679 +2926 0.9482

2.1263 2 1.9132 1

2.8503 2.6850 1.9958 1.5822 1.4857 1.2513 1.1134
2.9198 2.6711 2.1471 1.3891 1.6509 1.4717 1.5270
3.6774 3.2086 2.3954 1.9545 1,7061 1.4996 1.2787
3.2917 3.0433 2.8229 2.2302 -

3.0847 2.7403 1.9958 1.1960 1.1547 1.2787 1.4031
3.4430 2.9055 2.4093 2.3128 2.0092 1.6374 1.2239
3.5674 3.1951 2.6298 1.9679 1.6788 1.6096 1.2926
3.6774 3.3051 2.6985 2.4367 2.0231 1.7753 1.0860
3.3877 3.3051 2.8363 2.1610

2.8916 2.8503 2.2989 1.9679

ean--- 3.4982 3.2364 2.0506

3.7187 3.3330 2.6159 1.9818

3.8013 3.9391 2.8090 2.0784

4.1462 3.6361 2.7676 2.2575

4.0357 3.6634 3.0986 2, 46N6

4.1322 3.7052 2.7950 1.9679

4.1875 3.4982 2.8090 2.2436

Wlug06 3.8848 3.4430 2.8916

0371 1.5957

2
1.3617 1.1687
0.9895 1.4031

2.2989
1.8166

2.3817
WLT9UT neenee ~ 1.6235 1.2651
W215 weeeee = 2.4919 1.4994
W13116 w----- = siee--
Y.1737 3.2088 2.9193 2.4230 1.7338

1.
oO.
0.
1

24165

1134
9064
+0860
+9343

0.8239
1.0583

0.7370
0.7096

0.7508

0.630

0.8881
0.7783
0.8607

0.7645

0.5894
0.7825
1.9138
121821

0.8790
oO. 7412
0.9203
0.8651

1.9818
1.6378
2.0788

313891

1.2787
1.4304

0.6409
0.4623

0.7783
0.5310

0.7920
0.5310
0.6546

0.6546

0.5207
0.6586
0.9064
0.9895

0.7551
0.8930
0.7685

1.4031
1.1960

2.0510
1.2373
1.7618

3752

0.9462
1,108

1.2787
o.7272

+8377

0.6033

0.9756
0.7138

1.3617
0.8103
0.9343
0.9616

0.6999
0.7551

1.1273

0.6238
0.5585
0.4623

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37


CONTENTS

Page
ABSTRACT. eee ec eceeeceeec eee cece cece cee eeeeneeeennees 1
1. THE ATS-6 EXPERIMENT AT OOTACAMUND 1

2, DESCRIPTION OF DATA PROCESSING 2
2.1 Digital Data.. 3
2.2 Chart Data . 4
2.3 Discussion of Errors... 5
3. SUMMARY OF SOLAR AND GEOMAGNETIC ACTIVITY 5
4. SUMMARY OF Ny DATA..... 8
5. ACKNOWLEDGMENTS 8
6. REFERENCES... eee eee cece cette eect eee ee vn neeeeeeeteeieeeeees 8
7. 10
8. 16
9. DAILY Ny PLOTS OF DIGITALLY RECORDED DATA, OCT 1975 - JAN 1976............. 23
10. DAILY Ny PLOTS OF CHART RECORDED DATA, OCT 1975 - JUL 1976.........-00-0--. 31
FIGURES

Figure
1, ATS~6-to-Ootacamund Ray Pathe... cece ccecce cece eeeuecteeerveceeees 2
2. Definition of the ATS-6 Reference Orientation for Roll, Pitch and Yaw.. 4
3. Provisional Hourly Equatorial Dst Index for Oct 1975 - Feb 1976. 6
4. Provisional Hourly Equatorial Dst Index for Mar - Jul 1976. 7
5. Seminannual Variations in Nz at Two Selected Times : 7

TABLES

Table
1. Data on the ATS-6-to-Ootacamund Path.... 3
2. Daily 2800-MHz Solar Flux Adjusted to 1 AU........ wees : 6
3. Hourly Ny Subsamples Digitally Recorded, 2 Oct 1975 - 28 Jan 1976... 16
4. Hourly Ny Subsamples Chart Recorded, 21 Oct 1975 - 13 Apr 1976..... 18
5. Hourly Ny Subsamples Chart Recorded, 14 Apr - 28 Jun 1976... 20
6. Hourly Nz Subsamples Chart Recorded, 29 Jun - 22 Jul 1976... 22

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8. TABLES OF HOURLY SUBSAMPLES

Table 3. Hourly Np Subsamples Digitally Recorded

2 Oct 1975 - 28 Jan 1976

APSE to Ootacamund Total Slant Path Electron Content 10!%m7? —- part Iq.

6968

7566
Neus
7547
4620
2831

= 1837
12966

4176
4105
5256

154
4562
5763
7238
5536

+3646

4697
4909
6457
6095
9507

5 ay
6920
sunt

+5584
26807

4080
4369
475
4186
3uT2

3236

12807
+3905

5290
3713

2703
eee

4268
4755

UNIVERSAL 9IH)

i 3 i ~ 6 8 2 1
1.1950 1.9781 2.83N5 6462 +3840 5.3136
0.8979 1.7823 2.7125 +2963 +2202 6.2708
1.0127 2.0215 2.9363 +5869 4072 6.6059
0.964% 1.8580 3.008) +0961 +2967 5.4771
0.8116 1.5894 2.5907 +2866 0637 5.9878
0.6115 1.8756 2.3518 +9332 0907
0.9249 1.9289 2.6908 771) +5200
0.8506 1.61N0 2.a73y 3, 4.0791 +5426 848g
0.9673 1.9911 2.0662 4.1466 4.5917 4.8092 4.9380 +2265
0.9167 1.8566 2.5606 4.NoBO B.RBey 5.1285 s5TNS
0.9963 1.8802 2.7516 3.7676 4.5310 4.6621 4.5720 4.8705 5.1796

2.0948 3.7840 4.7677 5.6589

1.3990 3.2u10 Wl 2923 6221 4.9896 ~

1.6670 3.4064 4.0700 4 4.7784 5.3719 5.5403

1.7282 3.1918 Wl tHe W 4.6626 bleBEN 5.2877
1.0247 1.8638 3.5400 &. 1683 1973 .U268 5. 0N55
0.8140 1.5687 2.9387 3.8605 +6265 5.0590 5.3782
1.0362 1.6863 3.3191 4.2021 +9862 5.6738 5.N795
0.7585 1.7321 3.3682 4.1366 952 5.0981 5.2722
O.5EHo 1.2508 3.2196 3.5988 : -
O.519" 1.2514

4.0478

1.0836 ------ 2 3
0.7701 1.8421 2 3.
o.9124 2 - 3
1.0030 1 2 =
0.8232 1 weree- 3k

3 3 :
= 3.2603 3.6196 4.0671
2.2 2.6653 3.0992 3.6741
2 3.3023 3.5381 3.7218
- 3.4286 3.5868 3.8158
0.8574 - 3. 5195
1.0918 2 3. 3.6962
0.8719 - 3. 3.9769
0.6201 2. 3. : 4.4225
0.6394 - 3.2179 3.4778 2.9378
0.7552 1 2. 4.2658
0.6398 4 2. 3.0968
0.8280 1 2.
0.7807 4 :
0.6846 1. a. 3.8915
0.6u28 1.2044 ~ 2.9126 3.0915 3.0901
0.7320 1.0582 1.9600 2.4b10 2.6175 =
0.5931 1.2557 > 2.9015 3.3249 3.5525
0.6727 19,1202 1.6236 2.3349 2.7109 2.8929
0.7962 1.2084 1.6044 2.1382 2.5519 3.0877
0.5001 1.3951 2.7454 2.7443 3.u387
0.5083 1.34K9 2.1044 2.6783 2.8760 3.0067
0.5406 1 2.8591 2.9203 3.2319
o.iN7 4, -
O.4109 1. 3
0.4046 1, 1279
0.3535 1.0590
o.bi47 1.0918
0.5256 1.0064
0.0475 0. 9huT
0.3974 1, 1086
0.4817 1.0080
0.4523 0.9939
0.4422 1.0276
0.5189 1.1786 3.2372

16

5.2543
5.6555
5.8397
5.6690
5.8687



Table 6.

Hourly Np Subsamples Chart Recorded
29 June - 22 Jul 1976

UNIVERSAL TIME
5 6

ATS6 to Ootacamund Total Slant Path Electron Content 10h"? -- Part I.

0 4 3 2 8 9 10 uu
0.2171 0.6033 1.2787 1.9545 2.5606 2.7676 2.7537 2.7537 2.7950 2.7537 2.5885
0.1485 0.5481 1.4031 1.9405 2.2436 2.7263 2.6298 2.6850 2.8229 2.7403 2.6850
0.1898 0.6307 1.1273 1.4996 2.2302 2.7950 2.9881 2.9881 2.5885 2.8229 2.9055
0.2450 0.5207 0.9756 1.3200 1.8714 2.5193 2.7403 2.8642 2.9329 2.8363 2.8781
0.2311 0.6307 1.2100 1.7061 2.1709 2.7403 2.9468 3.0707 3.2364 3.1951 2.6229
0.3002 0.7138 1.2513 1.5957 1.9958 2.5193 2.7263 3.0887 2.8503 3.0160 2.8503
0.2850 0.6307 1.2787 1.8579 2.5193 2.5885 2.9194 3.0433 3.0833 3.0020 2.9194
0.2850 0.6586 1.3891 1.8653 2.6985 2.9607 2.6985 2.6711 2.8503 3.2917 4.1399
0.2171 0.6307 1.4031 1.9958 2.4226 2.8229 2.7676 2.8503 2.6229 2.9055 2.7676
0.2724 0.6307 1.378 1.8853 2.2715 2.7537 3.1120 3.0707 2.9607 2.8781 2.8503
oo2--- - 2.6437 3.087 3.2499 3.4295 3.4708 3.2086 3.2086
0.7272 1.5544 2.289 2,572 2.7950 2.9468 3.1812 2.9198 2.7537 2.5885
0.5759 1.3752 1.7201 2,0092 2.9881 3.0160 2.8916 2.9881 3.2364 3.0707
0.6446 1.2100 1.7335 2.1871 si---- 2.703 2.8503 2.9198 3.0020
0.6999 1.1547 1.6648 2.2649 2.7537 2.5885 2.6711 2.8642 3.0986 2.6437
seere wece-- 2.0871 2.8642 2.9607 2.8229 2.7950 3.0707 2.2436
0.3002 0.6725 1.2513 1.6922 2.2436 2.9068 2.9468 2.9055 2.7263 2.8229 2.7816
0.2171 0.6307 1.1821 1.9818 2.5193 3.2364 3.1951 3.2364 3.2917 3.3191 -----~
0.1885 0.4515 1.0169 1.7201 2.2849 218642 2.9329 2.8642 3.029% 2.8642 2.7816
0.2171 0.6033 1.2239 1.5622 2.1749 2.5059 2.5606 2.6298 2.5606 2.5332 2.4919
0.1898 0.4515 0.962 1.2239 1.7753 2.4919 2.5606 2.5059 2.5059 2.7537 2.9881
0.2724 0.5481 0.9616 1.3200 2.0510 2.7537 2.7676 -----—
0.2863 0.6033 0.9616 eres sieee-  -2---- enone
0.3550 0.6725 1.1821 1.6922 2.2989 2.7263 2.7403 2.8229 2.7403 2.7263 2.74Q3
ATS6 to Ootacamund Total Slant Path Electron Content 10!a"? —- part 11.
UNIVERSAL TIME
1 ret cr 1 4 18 19 0 1
2.6437 - 0.3629 0.3002 0. 211 0.1624
2.9055 0.5207 0.5881 -
2.9861 0.8651 0.4655 0.4102 0.3968 0.4242 0.2311 0.2589
2.7403 - 0.5207 0.4381 0.3968 0.3968 0.3002 0.2450
2.6711 0.7551 0.7551 0.5068 0.479% 0.4102 0.3002
2.6711 0.5346 0.4794 0.4102 0.2863 0.2171 0.2450
2.7816 0.4794 0.4381 0.4102 0.4381 0.2171 0.2450
2.8229 0.5081 0.4794 0.3968 0.3002 0.2171 0.2171
2.3680 - 0 0.2171 0.2171 0.2728
3.0020 - ~ ateeee ateeee
3.2364 0.9343 0.4515 0.3968 0.3002 0.3415 0.3002
2.3680 0.7551 0.5346 0.4794 0.4515 0.3415 0.3002
2.6159 0.7551 0.4242 0.3002 0.2311 0.2171 0.2171
2.5059 0.9895 0.5346 0.4655 0.3689 0.3002 0.3550
2.3128 - wlleee -
1.8027 - 0 0.3968 0.3550 0.3002
2.7124 oroua2 0 - ~ - 0.2450
2.7124 0 0.6307 0.5207 0.3276 0.2863 0.2311 0.1898
2.7537 ° 0.6033 0.4102 0.2724 0.2589 0.1071 0.1898
- 0.4655 0.3968 0.3002 0.3002 0.1211 0.1898
2.5472 - 0.9064 0 0.6033 0.4515 0.3415 0.3689 0.1898 0.2450
- 0.7964 0 0.6033 0.6033 0.5207 0.3689 0.3550 0.3002
- ° 0.8103 0.6307 0.5207, 0.3829 0.3002 0.3550

2.5059

1.0029

22



Table 4. Hourly Ny Subsamples Chart Recorded
21 Oct 1975 - 13 Apr 1976

ATS6 to Ootacanund Total Slant Path Electron Content 107m"? -- Part 1.

UNIVERSAL TIME
A 4 4 tk tt

oct. 1.5957 2.2575 3.1399 4.0496 4.5871 4.7115 4.8628 4.8628 5.0285
1975 1.7061 2.5332 319118 wieeet penne
ponen ~ seesee 5.0972
1.761% 2.0923 2.9068 4.2018 4.7389 5.3455 5.6899 ------
- 419733, 419320 4.9459
Nove 2.1789 2 4 4.9320 5.0420 5.4281 5.8278 5.4834
1.7888 2 3 l2ueT W13118 411049 4.0083 414906
17201 2 3 wlan = - atee--
: 4.4632 5.2N90 S.4¥21 5.4008 5.6212 5.6212 5.8691
1.9132 3.0298 3.6561 4.1601 4.2979 4, 4.5184 4.7250
1.6922 2.3954 310707 3.7600 - 418767 -2----
Dee. 11N651 2 218663 3.5119 .o202 4 413499 4.2675
1.4788 2 3.1823 3.5257 3.8416 3.9378 411713 4.2538 412263
115887 2 3.3471 3.6356 3.9241 43362 4.3087 4.3499 4 .4OND
8 +0037 3.4833 3.6081 4.0614 4.1026 4.4598 4.5010
n 11823. 3.4707 3.6905 - 411988 4.2263
12 1.4788 sor74 313196 3.4295 3 3.9281 4.0202
13 1.5750 18526 3.1410 3.37K6 3 3.6356 316631
1 116162 11960 3.3608 3.4570 3 410065 318966
" - - = 3.4295 3.4433 4.1301 3.8966
22 : 1 2.6465 3.0037 ~---- 412675,
23 1.451% 2.2344 219213 313471 3.4707 3.6356
2u 1.2053 1.7948 2.3031 2.5641 2.7427 3.0311 2.9213
27 1.4102 2.4kON 218526 3.3273 3.2097 322k
28 0 ° 1.3827 2.3718 3.0311 3.2788 3.4570 3.8966 \
310. ° 1.3277 2.4542 2.7289 219350 3.3059 411576 317730
Jan, 1 Ot ° 1.1629 2.0186 28800 2.9899 3.2784 3.7455 317730
38 0. 1.1492 2.1794 310174 2.9762 3.017% 3.2922 313059
11 0.3528 0.5447 1.0805 2.2893 311136 3.88N5 3.9103 3.7592 3.8008
16 - - - 3.3746
a 1.9459 2.7976 3.1136 3.44330 317508
22 2.7289 218800 3.4021 3.2647
23 210558 2.5091 3.0586 3.2372
2h pnenee
29 0.4760 0.4623 1.0867 1.7536 2.5641 2.9625 3. 7
Feb. 3 0 O.2724 0.8651 1.5130 1.9679 2.4919 2.7950 3.0087 3.6361 3.4017 3.3877 2.8781
io 0.3276 0.8238 1.2926 1.8992 2.3954 2.4646 2.3128 2.7403 3.0847 2.8781 2.7537
5 0 O.¥r02 1.0169 1.7201 2.2849 2.7803 2.7537 2.6159 219055 3.08N7 3.2777 312899
§ 0.W2u2 0.3968 0.9895 1.5409 2.0510 2.4919 2.9868 3.2777 315398 316634 3.7526 3.8708
7 0.5620 0.5346 1.0995 078% 2.4780 2.9194 3.4843 3.8013 3.6361 3.3051 3.1812
9 +0510 2.5332 2.8363 2.8916 310847 3.3330 3.2638 3.1538
10 70923 2.6572 3.0847 3.2086 316221 3.5988 3.4017 3.4136
n +2989 2.9881 2.9881 312364 3.4156 3.3051
12 +2436 2.9881 3.4295 3.3191 3.3877 3.5395
13 2.6159 3.4843 3.5674 3.5678 3.9809 4.2019
14 217950 3.5674 3.3330 3.8978 3.6634
15 2.8363 313191 3 ooee
16 2.1537 3.3330. 3.4982 3.6221 3.7052 3.7739
"7 2.7537 3.5674 3.6634 3.7326 316087 3.8013
18 0.2863 0.3968 1.2513 2.1197 3.0020 3.4017 3.4708 4.0083 ¥.u771 4.1322
19 0.5481 0.4381 1.0562 1.7335 2.6985 3.4982 3.6221 315678 3.7526 4lo2ze
20 0.5346 0.5068 1.2513 2.0784 2.8363 315678 3.8152 3.9118 3.9670 4.2018
21 - 1.0029 4.7888 2.6298 3.2638 3.7739 410083 317326 3.6361
22 - 2.6159 3.1260 3.3464 ~- 319257 louse 4l1462
23 0.3415 0 1.0169 1.7061 3.5674 3.7326 3.8152 3.8978
24 01102 0 111408 119958 3.4843 3.6638 318844 40770
25 0182k2 0 111960 1.9958 3.5256 3.4295,
26 - - 3.4982 3.7052 3.8705
ar ° 1 3.5674 3.7878 -2---=
26 - 1.1687 2.0784 3.6361 3.9809 4.0770 4.1735 4.2979
29 0.3276 0 1.1138 2.0231 3.8292 3.9948 411875 &l2701 4.0357
arta) - 1.330 210370 ou57 6.5724 412978 4.3529 4.4357
2 : 1.8578 3.2363 5.4833 5.9245 5.6350 512076 5.1311
9 - 1.3891 2.3803 4i7527 Wlu3s7 413116 17251 5. 12u9
10 - 1.3064 1.9819 4.835% 4.9733 4.9733 5.2490 5.5109
n 0.6309 1.4167 2.3265 3.1812 ------ 4.2702 44219418354 Slouz2 4.9457
12 0.7688 1.4994 2.4230 3.3466 3.5672 3.8429 4.0497 4.2427 4.4357 4.8216 4.8630
3 0.7550 1.5408 2.5333 3.6637 4.2289 4.5735 417665 4.9857 5.0698 5.4033 5.2490

18



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1
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rs |
ATS 6 1976 Ootacamund |
6b May J t
Hourly means, uf |
chart data. xe) |
ur ON, Ur oN, 3 5 4
000.34 «= «12 5 oe
Ol 0.84 13 Q 4
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04 «2.89 16 &
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poitiiitiritiiits j
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TTT j
ATS 6 1976 Ootacamund 1
gh June '
Hourly means,
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ur oN, Ur Ny sk 7 j

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Ol 0.83 13
02 1.48 14
03 2.02 15
04 2.56 16
05 2.90 17
06 3.11 18
07 (3.20 19
08 3.28 20

Total Siont-Path Electron Content 10" mTM
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2.3 Discussion of Errors

The absolute accuracy (e.g., the accuracy of a measurement with respect to zero)
of the calibration value 228° is difficult to determine. The estimated calibration
accuracy is #10°. Intercomparison of $44; to $4, indicates an overall accuracy of
+4° [Davies et al.,'1979]. At night ¢q;] is less sensitive than $141 to factors af-
fecting calibration values. The estimated absolute error applies to both the chart
and digital data.

The relative error (e.g., the accuracy between any two measurements) of the
digital data is not the same as the chart data relative error. Intercomparisons of
$a, and 14, digital data indicated a mean relative error in the digital data of
1%. At night the worst-case relative error approximated 3%; a small number of days
showed a 6% worst-case error.

Chart data were compared with digital data during 3 months of overlapping rec-
ords. With respect to simultaneous digital measurements (from Oct 1975 to Jan 1976)
of Nz, the chart data had a 2% mean relative error. At night the worst-case relative
error approximated 8%; a small number of days showed a 14% worst-case error. These
errors should be added to the digital relative error to obtain the best approximation
of chart data relative error.

Since the chart data have not been corrected for ATS-6 pointing maneuvers, a
number of days show sudden changes in Nz concurrently with ATS-6 pointing changes.
This is particularly true during summer nights when Ny is relatively low. During
winter nights pointing effects generally are within the relative error.

The pitch corrections suggested by Donnelly et al. [1979] are sometimes insuffi-
cient to compensate for sudden Ny changes in the chart data. There is some evidence,
albeit inconclusive due to insufficient data, that roll (or some combination of pitch
and roll) maneuvers are responsible for significant relative Nz changes at night in
the chart data. For example, see 23 May or 24 May 1976 on page 43 , where Ny abrupt-
ly changes at 2100 and 2300 UT. Pitch corrections would amount at most, in this
specific case, to a 3% change in Nt. Yet it is apparent tha Ny changes by roughly
30%. This effect has not been observed in the digital data.

3. SUMMARY OF SOLAR AND GEOMAGNETIC ACTIVITY

For Nz comparisons, the daily solar flux at 2800 MHz (Table 2) and the provi-
sional hourly equatorial Dst values (Figures 3 & 4) are reproduced from the prompt
section of Solar-Geophysical Data [1975-1976]. The Dst index (in UT) represents
magnetic field variations at the magnetic Equator on the Earth's surface.

An important feature of the Phase II data is that these measurements were taken
when solar activity was, for the most part, at a minimum. For Nz comparisons,
effects of solar activity should be considered. As an example, compare 28 March with
1 April 1976 in Table 2 and in the daily Nz plots on page 38 . On 28 March the solar
radio flux was relatively high because a prominent active region on the visible solar
disk had flared at an X1 level at 1900 UT [SGD, 1976]. Three days later, on 1 April,
avery large enhancement in Nz occurred (e.g., Ny = 6.6 x 10°’ m-*; the April mean Ny
= 4.5 x 1017 m-2) about the same time that the Dst index decreased about 200 nT.

Figure 5 clearly indicates a semiannual variation in Ny. Two arbitrary times
were chosen, 0500 and 1700 LT, that approximate the times of diurnal minimum and
maximum. During these times Ny was subsampled and plotted against the date. Unfor-
tunately, data during September 1975 and March 1976 were not available to provide
measurements around the equinoxes. Nevertheless, Figure 5 indicates Ny is generally
greater near the autumnal equinox than near the vernal equinox.

Similarly, the effects of a solstice are apparent in Ny during January and July,
Nz generally being greater during the winter solstice than during the summer sol-
stice. Also note that Ny is greater during the equinox months than during the
solstice months. It is not clear whether all these relationships agree with the
semiannual variations of the solar zenith angle for a receiver located 11° north of
the Equator.



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Faraday Rotation, 145, was measured concurrently with modulation phase, but it
is not included in this report because its accurate measurement requires several
corrections discussed by Davies et al. [1979]. Figure 1 illustrates the ray path
geometry and Table 1 gives some pertinent information. With this geometry D149 is
very sensitive to certain effects such as satellite orbital inclination, pitch and
yam mereuvers, errors in the calibration of equipment, and inaccuracies in the geo-
magnetic field models used [Donnelly et al., 1979].

40°

North

8

Ss

Latitude,

, yo a _ _Yotacamun¢

36° 45° 55° 65° 15° 85° 95°
Longitude, East

Fig. 1. ATS-6-to-Ootacamund Ray Path

2. DESCRIPTION OF DATA PROCESSING

The data are presented here in two groups, depending on the recording device
used. The digital data were recorded from October 1975 to January 1976 (the record-
ing device is briefly described in the next section); these data are presented as
2-min subsamples. The paper chart data were recorded from October 1975 to July 1976
and are presented as 15-min subsamples.

The digital data have high time resolution, high accuracy and have corrections
for the effects of satellite maneuvers. Because of the labor required, the chart
data are not corrected for satellite maneuvers. For many days between October and
January observations exist concurrently in both chart and digital form. Comparisons
between concurrent chart and digital data show good agreement. Only the digital data
are presented for those days of concurrent records.

Data are not available during the equinox period of March 1976 because of power
limitations resulting from the eclipse of ATS-6. On a number of days either the

2



ATS-6 RADIO BEACON ELECTRON CONTENT MEASUREMENTS
AT OOTACAMUND, INDIA
OCTOBER 1975 - JULY 1976

by

S$.0. Bouwer, K. Davies, R.F. Donnelly, R.N. Grubb, J.E. Jones and J.H. Taylor
Space Environment Laboratory
NOAA Environmental Research Laboratories
Boulder, Colorado USA 80303

and

R.G. Rastogi, M.R. Deshpande, H. Chandra and G. Sethia
Physical Research Laboratory
Ahmedabad 380009, India

ABSTRACT

We present an atlas of total slant-path columnar electron content data measured
between the ATS-6 satellite and Ootacamund, India, a site near the magnetic Equator.
Although these measurements were taken during a solar minimum, we summarize ‘the
general level of flare and geomagnetic activity that occurred during the observation
period. These total content (Nr) data were derived from the modulation phase (group
delay) of a carrier signal transmitted from the geastationary satellite's Radio
Beacon Experiment. Sudden changes in satellite pitch angle and possibly in roll,
absolute calibration, and some sporadic noise contributed an error of about +4° to
our results. This atlas contains two data sets: (1) Ny as 2-min subsamples digital-
ly recorded between 2 October 1975 and 28 January 1976 corrected for ATS-6 pitch
maneuvers and (2) Ny as 15-min subsamples chart recorded between 21 October 1975 and
22 duly 1976 but uncorrected for changes in satellite orientation.

1. THE ATS-6 EXPERIMENT AT OOTACUMUND

This report summarizes measurements of the total slant-path electron content,
NT, made between the ATS-6 satellite and Ootacamund, India (N11 £77). These measure-
ments were made during Phase II of the radio beacon experiment, when ATS-6 was
positioned at an equatorial location of E35 from August 1975 to August 1976. The
experiment at Ootacamund was a joint undertaking between the National Oceanic and
Atmospheric Administration of the United States and the Physical Research Laboratory,
Ahmedabad, India.

The radio beacon aboard ATS-6 transmits on carrier frequencies of 40.016, 140.56
and 360.144 MHz with amplitude modulations of 1.0004 and 0.10004 MHz for the measure-
ment of modulation phase (also called group delay), Faraday rotation and amplitude
[Davies et al., 1975]. This report presents results based on the modulation phase
measurements from 2 October 1975 to 22 July 1976. The equipment and calibration pro-
cedures used during Phase II were essentially the same as those used during Phase I
at Boulder [Davies et al., 1975; Fritz, 1976].

The most important results from Ootacamund are based on the modulation phase
measurements, $14); the measurement and interpretation of #4, is insensitive to the
geomagnetic field and therefore can be made at an equatorial station with high ac-
curacy. Ny can be expressed as

. 14,
Ny -f Nads = -4.82 x 10°"igys (1)

where the integral is of the electron density Ne from the ground station to the
satellite. The constant multiplying factor is specific to the ATS-6 Phase II data.



75° E Local Time

8 12 16 20
i
ATS 6 1976 Ootacamund

% 6b July |
Hourly means, we
chart data. Q
Ur ON, Ur OY, L 4

T T eo

2
000.25 = «12 §
01 0.61 = 13 ab |
02 1.20 14 &
03° 6421.70 «15 3
04 «2.25 16 é
05° 2.47 «17
06 «2.79 «18 5
07 2.8719 t
08 2.92 20 5
09 «2.90 21 o
10 2.96 22 3
112.8323 &

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14



Important to the determination of the absolute value of $141 was the orientation
of the transmitting antenna on board ATS-6. A comparison between calculated values
of $14, and both $49.1 and 4, (less sensitive channels to satellite maneuvers) indi-
cated that the 141-MHz modulation phase responded significantly to satellite
maneuvers, Upon examination of NASA satellite telemetry data we found that satellite
Maneuvers were usually sudden changes, followed by long periods of fixed pointing
[Donnelly et al.s 1979].

Tests for ATS-6 roll, pitch and yaw indicated ¢. 41 Was predominantly sensitive
to pitch (see Figure 2). According to Davies et al. [1979], this sensitivity result-
ed from the electrical phase of the transmission varying with pitch angle. During
significant sudden pitch changes, data were deleted, and the appropriate correction
was added to $14) during periods of fixed pointing.

Zz Orbital
Earth's North
Center
OF
- Y
Yaw y aw East

~
Along Earth Radia?

A Antenna
Vector

Fig. 2. Definition of the ATS-6 reference orientation for roll, pitch and yaw.

2.2 Chart Data

The charts provide the exclusive source of data between February and July
1976. March is not included because of extensive off-times of the beacon. From
4 May to 22 duly there are no data available from 1300 to 1600 UT because another
experiment had priority.

The chart data use relation (2) with p=0. The effect of not correcting for
pitch in the chart data is discussed (with other errors) in the following section.
Also, there exists some residual sporadic noise that has not been removed. Except at
night, when Nr is at a minimum, there errors are of minor importance.

4

i
|
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Table 5. Hourly Np Subsamples Chart Recorded
14 Apr - 28 Jun 1976
ATS6 to Ootacamund Total Slant Path Electron Content 10!/nTM? -- part 1.
UNIVERSAL TIME
on 3 6 2 10 uu
sprit. 18 1.8992 3.0020 ~ 4.8216
19% 15. o. 1.4167 2.1060 3.1123 4.1324 4.4081 4.6562 4. 79%1 7527
16 0. o. 116235 3.0020 3.4845, 4.3667 5.0008
17 On °. 1.8B56 2.3679 3.087 - Perey) 424908
18 0. 0.647 1.5270 2.2576 2.8779 3.5672 4.2013 4.3667 4.4908 wlurT0
19 0.7550 1.5270 2.3954 3.1536 3.6085 3.9394 4.0910 4.1599 4.2013
20 0.8101 1.5545 2.3954 3.1123 3.6637 4.0221 412013, - 427251
2 1.5821 2.3679 3.1123 3.4569 3.6223 3.9807 4.1737 42 au92
22 v.7062 2.782 3.2226 3.8642 1328 413392 L251 5.6763
23 0.6723 1.506 2.2774 2.9869 3.6223 4.0910 4.3116 4.5459 4.9003
zu oo. 0.6723 1.6510 2.5057 3.3191 3.7050 3.9256 4.1599 4.2289 4 -
25 o. 0.6723 1.6924 2.4368 3.2639 3.8153 4.0635 W.2427 wl¥z19 4. 4.9733
20 0. 0.6047 1.45N5 2.5333 3.1674 3.2915 3.6637 3.9945 410359 4 wletbt
May roo 0.7272 1.6645 2.4919 3.0433 3.2636 3.5121 3.6634 3.8431 4. 43806
2 0. 0.6999 1.3065 2.1471 3.0573 3.7326 4.3527 13393 21601 3.9257 4.1062
40 0.6238 1.7061 2.6159 4.2840 4.0909 4.2566 4.9459 5.0837 5.1251
woo 0.6307 1.4996 2.5059 3.2086 3.5808 3.884% 4.6563 5.0972 5.0146 4.7528
6 - - 2.8642 3.3743 3.5808 4.1875 4.4358 u.N632 4.6563
1.3339 1.8774 2.8229 3.2364 3.3191 3.5256 4.0909 4.2014 wu. 2427
5 9.6999 1.2373 1.9132 2.5885 2.9329 3.3191 3.7739 4.4322 411875 4.0909
9 0.7551 1.4031 1.9818 2.6985 3.1538 3.3877 3.567% 3.6913 3.8013 3.7739
10 - - 2.2436 3.0160 3.0986 3.2364 3.4843 3.7739 3.884 3.7739
n ° 1 2.3680 2.6503 3.0573 3.3464 3.4708 3.6638 319531 k.2701
te 0. - 2.5193 3.1812 3.5674 3.8152 4.0909 4.3527 .5u58 4.5458
1y 0.3002 0.9064 1.8579 2.6717 3.3051 3.5674 3.8978 4.1735 4.2701 4.2701 4M. ko79
14 0.9895 1.7614 2.6298 3.0707 3.4982 3.7326 3.9257 4.0635 4.2427 4.3606
15 1.0169 1.7753 2.4646 3.1260 3.5256 3.6913 3.6361 3.6361 3.7739 3.9257
16 0.9756 1.5409 2.1471 2.6572 3.1260 3.8152 3.9531 3.9257 318152 3.8978
7 V.113H 1.7061 2.4646 3.2086 3.7326 3.6361 3.5534 3.7878 4.0083 0222
18 0.928 1.0169 1.7335 2.4228 3.1120 3.6634 3.8705 3.9670 0.1735 4.21NB 4.0357 3.8431
19 0.3829 0.9064 1.6509 2.2036 2.7263 3.0707 3.2499 3.3191 3.5674 3.8013 3.9809 3.9118
20 0.3415 0.8790 1.4165 1.9818 2.8363 3.3464 316634 3.9257 4.6010 4.6976 4.5184 4,358
21 0.3002 0.9068 1.8027 2.3680 2.6985 3.3191 3.884% 3.9809 4.0909 W.2427 4.4358 4.4558
2> 0.1698 0.7685 1.U717 2.1889 3.0020 3.6087 3.7187 3.7739 3.8152 3.7878 3.5608
24 0.3002 0.8103 1.4717 2.2715 3.0986 3.5534 3.8844 3.9531 3.8978 319809 3.8152
©, 3002 0.8103 1.430% 2.0510 2.5606 2.919% 3.1399 3.2364 3.2917 3.5674 3.598
0.2589 0.7272 1.3752 1.8714 2.7950 3.3877 3.5256 3.5808 3.7187 3.7052 3.5674
0.3968 0.8236 1.7061 2.4228 2.8503 2.9881 3.0160 3.1951 3.2777 313877 3.3877
0.6033 1.2926 2.0923 2.8229 3.1399 3.2777 3.5256 3.5808 3.4843 3.4708
0.8238 1.5544 2.0092 2.5885 3.1673 3.7326 3.6361 3.7739 3.7739 3.5256
0 0.3276 0.8235 1.2513 2.3128 2.8229 3.0160 3.4843 3.8152 4.0357 4.0083 3.8431 3.8849
31 0.3829 0.6651 1.7610 2.1610 2.5746 3.0020 3.4843 3.6361 3.8705 %.0083 4.1322 3.7878
June 7 0.7964 1.5683 1.7753 2.3680 2.9681 3.4156 3.4569 3.4569 3.4156 3.4708 3.5256
2 - - 2.4228 2.7537 3.0160 3.2638 3.4156 = 3.6634 3.2364
5 0.2589 0 1 1.8710 2.5606 2.8503 3.2638 3.2499 3.3464 3 3.1673 3.2086
¥ 0.1898 0.6307 1.9818 2.6985 2.7950 3.1399 3.6087 3.3051 3.4982 3.2364 3.2638
5 - 2.0923 2.4919 2.8781 3.2899 3.4708 3.5808 3.4708 3.6634
6 0.5386 1.0029 2.1610 2.6850 2.8503 3.2777 3. 3.5948 3.8978 3.7326 3.7326
7 oO.¥i02 0.9064 2.0784 2.6850 3.1260 3.4569 3.2086 3.0573 3.346% 3.3191 2.9863
8 0.4381 0.9756 2.1610 2.8229 2.9881 3.2899 3.2917 3.8569 315674 3.6913 3.5256
9 0.5759 1.0582 2.5072 3.0707 3.236" 3.1812 3.3330 3.2499 3.4569 2.9607
10 0.102 0.9064 2.2849 2.7537 2.9607 3.3793 3.3191 3.0707 3.2364 3.0887
n — 2.0510 2.4367 2.7816 3.0020 3.4295 3.4843 3.6361 3.9609
12 0.2589 0.8377 2.3128 - 3.4156 3.6087 3.4708 3.6913 3.9809 3.4569
13 0.2585 0.7272 1.9958 2. 3.4569 3.5256 3.4708 3.4156 3.4156 3.3743 3.2368
140.2311 0.8103 1.7753 2.5332 2.8363 3.1538 3.1951 +3191 3.0847 3.0707
15 0.3829 0.8516 2.0231 2.2849 2.8916 3. - >
16 o.7a72 1.9405 2.6985 3.0986 2.9607 3.1399 +4982 3.3877 3.1673
17 0.2311 0.7138 1.6648 2.0510 2.5746 2.7263 2.8363 11260 2.9468 3.1812
18 0.3968 0.9383 1.9132 2.3954 2.6850 3.0573 3.1399, 15256 3.6913 3.5946
19 0.3276 0.8790 1.6648 2.9055 3.1120 3.0707 - :
20 0.2450 0.7272 1.9132 2.7537 2.8503 2.8916 +7676 2.9468 3.0020
21 0.3415 0.7964 2.0231 3.0020 3.1538 10707 3.236% 3.2086
22 0.3968 0.9343 2.1610 2.7816 3.0020 3.1120 :4295 3.3877 3.0433
23 0.5207 1.0029 2.17N9 2.8781 2.8229 2.8602 11260 3.0573 3.0573
24 0.479% 0.9343 2.0510 2.6298 2.6985 2.8503 +0847 2.9742 3.0020
25 0.2589 0.6999 1.9818 2.6437 - cence
27 0.2850 0.7272 2.0923 2.7816 2.8363 3.0847 1399 3.1673 2.9607
28 0.3002 0.6103 1.9132 2.6711 2.8229 2.7403 19468 2.9742 2.9881
20



REPORT UAG-74

WORLD DATA CENTER A
for
Solar-Terrestrial Physics

ATS-6 RADIO BEACON ELECTRON CONTENT
MEASUREMENTS AT OOTACAMUND, INDIA
OCTOBER 1975-JULY 1976

Sy
zZ p2
Thi

March 1980

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APR ISTE

va 16

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Fig. 4.

eee boots op mI eee = al

FA TPevor

Tine

[| pe

ined A ye rT

Fe a ee A Li ran loot
CTP HO NR RTE CTR HHT RAH oT we HN

Graph of the provisional hourly equatorial Dst index for March - duly 1976
in nT units. This index represents magnetic field variations at the di-
pole Equator on the Earth's surface averaged over local time. Note that
both the 100-nT vertical interval, placed on the last day of each month,
and the zero-reference level change from month to month.

T t T T Tt T Tt TT
_ 12:00 UT, 17:00 LT

Total Slant-Path Content 10 !

Total Slant-Poth Content 10 |? m~@

t i
“wri 20 JUN 1020S UL

Date

APRIO 20
1976

Fig. 5. Semiannual variations in Ny at two selected times.

7



Table 2.

ke 175 |

JAW 1976

Fea 1916

Fig. 3.

weer ee
er wis
ia NY
pote LE

AoW 1975

Daily 2800-MHz Solar Flux in Units of 10-22 wWm-2 Hz-1 Measured Near 1700 UT
and Adjusted to 1 AU. Table adapted from Solar-Geophysical Data [1976a].

P8180

mean | sees | rsa | rant

Teco

PR fA fn

__. L Lat ee rod
THEIR Po tR eee BA ww wT

Graph of the provisional hourly equatorial Dst index for October 1975
through February 1976 in nT units. This index represents magnetic field
variations at the dipole Equator on the Earth's surface averaged over
local time. Note that both the 100-nT vertical interval, placed on the
last day of each month, and the zero-reference level change from month to
month.



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26


Table 1. Data on the ATS-6-to-Ootacamund path

Satellite Location
Geographic: NO.0 £35.0
Distance from Earth's center: 42,167 km

Receiver Location

Geographic: N11.38 £76.66
Distance from Earth's center: 6380. km
Length of Ray Path 37,746 km
Azimuth of ATS-6 at Ootacamund 257.5°
Elevation of ATS-6 at Ootacamund 40.5°
Daily Latitude Excursion of ATS-6 0.7°

transmitter or the receiving equipment failed to operate, or computer processing
difficulties arose. Nevertheless, the two groups provide data for at least 20 days
out of every month (except March). Also, off-times of the transmitter and short
periods of satellite maneuvers interrupted observations during an individual day.
For example, in the first figure of the daily plots of Ny on page 23 , the 2 October
data show off-times from 0330 to 0630 UT, 0745 to 0800 UT, 1100 to 1600 UT and from
2000 to 2200 UT. At no point in the data processing was interpolation used to bridge
these gaps. A dash (-) in the data lists that follow indicates the occurrence of
such gaps.

2.1 Digital Data

The receiving equipment was installed at Ootacamund in September 1975. Due to
shipping damage, the computer that served as a real-time digital recorder in Boulder
during Phase I did not record data at Ootacamund. Instead, a digital recorder orig-
inally intended for the occasional recording of scintillation data was provided by
Dr. E. Fremouw, formerly of SRI International. This substitute recorder provided
data every 0.1 $ and was returned to SRI at the end of January 1976.

Tapes of these high-density data were then processed in Boulder on a large batch
computer and a versatile BASIC minicomputer with graphic, storage, data communica-

tion, and user-interrupt features. Cycle ambiguities were resolved, sporadic noise
was removed, and corrections were made for equipment calibrations and satellite mo-
tions. The final data are sampled every 2 min and they provide excellent time

resolution. These 2-min data are archived and available from World Data Center A for
Solar-Terrestrial Physics, Environmental Data and Information Service, NOAA, Boulder,
Colorado 80303.

Cycle ambiguities in @yq, were removed by inspection--a technique that used the
graphics/user-interaction capability of our BASIC minicomputer and the relation

°
bia = Pig + 228° + 360°n + p, (2)
where p is the satellite pitch angle and n denotes some integer. The satellite pitch

angle is a correction specific to the Ootacamund data.

3



oe.
1975

Rov.

Jan.

1976

Table 3. (Continued)

ATS6 to Ootecamund Total Slant Path Electron Content 10''mTM? -- Part IT.
UNIVERSAL TIME
1 14 Le 16 1 18 19 0 1 3
2.2558 2.2775 2.2052 1.9901 -
- 2.6763 2.1117 1.6699 1.6101 -
5.4043 2.4005 2.5770 2.0673 1.5065 1.2268 -
5.2331 cise-- 019273 017421 =
5.6883 2.0027 1.3261
- 2.5948 - - - -
5 - = 2.3952 2.0032 1.8074 1.5817 1 0
5 4.7542 3.6181 3.2825 2.8065 2.7275 1.9800 1.4785 1.1896 0. oO.
9515 4.7133 3.7483 3.1523 3.1238 = - - ° o.
4.4963) 4.24U5 3.6475 2.7492 2.4873 2. 2. 2.3113 2.0601 1.1954 0.8656
4.5527) = - 2.4593 1.9762 - 2.3552 .9514 0.7894
5.4515 =. 3 2.4357 2.0562 2. - 0469 0.6664
4.6467 3 2 1 1. 1.7813 .9534 0.6843
4.82220 ~. - 2 2 1.6290 .0107 0.9186
5.1960 4 3 2 2 1.7972 .58120 1.0927
4.8664 4 3.0997 2 2.0779
4las6o 8. 3.2131 2. 1.1500
4.63330 4 3.4759 2. 1.8903
4.6906 4. 3.2516 2. V.5THS
3.7903 3 312974 1 1.8556
4.38200 3 2.9285 2 - = 5372 0.3458
N.7277) We 2.9637 2 1 1 9784 0.6823
413805 3 312164 2. 1.73781 17547 015251
4liu22 3 2.9425 3 - - 11819 0.8318
4.7538 3 3.0033 2 1 1 9886 0.8945
w.55u1 2 2.0708 2 - - ~ 1.1679 1. 0.6780
wAN2NG =. 2.9695 -. 2.2hi4 2. 1.7799 1.4322 1.2384 0.8285 0.6380
wleugh 3 218586 2 2.4953 - 1 o.Ta31
4.6158 4, 3.6196 3 2.0562 1.4322 1.2615 1.1247 0.9702 0.7214 0.6336
4.8656 4 3.8809 - 1.6449 91,2702 1.1549 1.0122 )
4.2055 3.6823 3.587 3.5376 2.2124 1.493H 1.1120 8309
4.0970 3.6721 3.1128 2.9531 2.6517 2.0620 5118
412378 314373 2.8606 -
H.MHO3 3.4624 2.9845 2.52 62301
4lu316 313968 2.3935 ~ 14684
2.8499 1.3801 1 0.9992 0.9731 0.897% 0.7826
- 1.3041 1. 1 4.1284 1.0035 0.9543
2 v2iT1 oO ° 017103 0.5849 0.5695
2 T4177 1.5778 1 1.3049 0.9567 0.5628
2.4960 - - 0.4904
LMS TH oO 0.7947 0.7339 0.5276
4347 101% 0.9572 0.7831 0.7311 0.6862 0.6317
leiiso

27151

3.3360

+7691

0018
1986
0197
+0665
+2878

8384
+0751
4190
+0105,

+6304 1.4269 1.1896 0.9413

2.9213 2.2071 1 1
3.N987 2.5823 = 2.
2.9N30 2.3899 2 1 -
3.3100 2.5862 2.0244 1.4674 1.3391 1.6381 +8285
3.3134 2.7757 2.4396 2.0017 1.0529 9953
3.0293 2.6161 2.3706 - =
3.0708 2.4820 2.4121 1 1. 1.0025
2.8326 2.3571 1.8498 1 1.0117 0.8236
3.3669 2.792 ~ 4.8734 1.5721 1.3112 6944
2.661% 2.3200 1.8108 ~----~ sercce 1122

1.9559 1.7982 1.4949 1, 1665 +8569
2.5119 2.0268 1.6087 1.2615 0.9080 +7494
2.7656 2.3547 2.0692 1.3729 0.7590
2.6281 2. 2.0224 1.2586 0.6u1e

- 2.0808 1.4279 1.1159 0.8960 0.7291 0.6790

2.3624 1.7606 1.9332 1.5388 1.1299 1.0450 0.9090 0.8815 0.9432
3.0u14 2.0355 1.4685 1.4140 1.3965 1.1809 0.9471 0.8781 0.8309
2.8369 2.1580 1.9834 2.2563 1.7852 1.5074 1.3010 0.9939 0.8796
2.7N58 2.1705 1.6368 1.8799 1.4660 1.6130 1.3831 1.4631 1.197%

17

0.6322

0.5232

0.7865

0.4909

+5873
+6785
6491
2un6t
2 6u8t

+7981
6510
0.6385
0.8690

0.5719



UAG-48A

UAG-49

UAG-50

UAG-51

UAG-52

UAG-53

UAG-54

UAG-55

UAG-56

VAG-57

UAG-58

UAG-59

UAG-60

UAG-61

UAG-62

UAG-63

UAG-64

UAG-65

UAG-66

UAG-67

UAG- 68

UAG-69

UAG-70

UAG-71

UAG-72

UAG-73

"synoptic Observations of the Solar Corona during Carrington Rotations 1580-1596 (11 October 1971 - 15 January 1973)",
[Reissue with quality images] by R. A, Howard, M. J. Koomen, D. J. Michels, R. Tousey, C. R. Detwiler, D. E.
Roberts, R. T. Seal and J. D. Whitney, E. 0. Hulbert Center for Space Research, NRL, Washington, D. C. 20375
and R. T. and S. F. Hansen, C. J. Garcia and E. Yasukawa, High Altitude Observatory, NCAR, Boulder, Colorado
80303, February 1976, 200 pages, price $4.27.

“Catalog of Standard Geomagnetic Variation Data", prepared by Environmental Data Service, NOAA, Boulder, Colorado,
August 1975, 125 pages, price $1.85.

“High-Latitude Supplement to the URSI Handbook on Ionogram Interpretation and Reduction”, by W. R. Piggott, British
Antarctic Survey, c/o SRC, Appleton Laboratory, Ditton Park, Slough, England, October 1975, 292 pages, price $4.00.

"Synoptic Maps of Solar Coronal Hole Boundaries Derived from He II 304A Spectroheliograms from the Manned Skylab
Missions", by J. D. Bohlin and D. M. Rubenstein, E. 0. Hulbert Center for Space Research, Naval Research Lab-
oratory, Washington, D. C. 20375 U.S.A., November 1975, 30 pages, price 54 cents.

“Experimental Comprehensive Solar Flare Indices for Certain Flares, 1970-1974", compiled by Helen W. Dodson and
. Ruth Hedeman, McMath-Hulbert Observatory, The University of Michigan, 895 Lake Angelus Road North, Pontiac,
Michigan 48055 U.S.A., November 1975, 27 pages, price 60 cents.

"Description and Catalog of Ionospheric F-Region Data, Jicamarca Radar Observatory (November 1966 - April 1969)", by
W. L. Clark and T. E. Van Zandt, Aeronomy Laboratory, NOAA, Boulder, Colorado 80302 and J. P. McClure, University
of Texas at Dallas, Dallas, Texas 75230, April 1976, 10 pages, price 33 cents.

“Catalog of Ionosphere Vertical Soundings Data", prepared by Environmental Data Service, NOAA, Boulder, Colorado
80302, April 1976, 130 pages, price $2.10.

“Equivalent Ionospheric Current Representations by a New Method, Illustrated for 8-9 November 1969 Magnetic Disturb-
ances”, by Y. Kamide, Cooperative Institute for Research in Environmental Sciences, University of Colorado,
Boulder, Colorado 80302 and Geophysical Institute, University of Alaska, Fairbanks, Alaska 99701, H. W. Kroehl,
Data Studies Division, NOAA/EDS/NGSDC, Boulder, Colorado 80302, M. Kanamitsu, Advanced Study Program, National
Center for Atmospheric Research, Boulder, Colorado 80303, J. H. Allen, Data Studies Division, NOAA/EDS/NGSOC,
Boulder, Colorado 80302, and S.-1. Akasofu, Geophysical Institute, University of Alaska, Fairbanks, Alaska
99701, April 1976, 91 pages, price $1.60.

"Iso-intensity Contours of Ground Magnetic H Perturbations for the December 16-18, 1971 Geomagnetic Storm", by
- Kamide, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder,
Colorado 80302 and Geophysical Institute, University of Alaska, Fairbanks, Alaska 99701 (currently Guest worker
at Data Studies Division, NOAA/EDS/NGSDC, Boulder, Colorado 80302), April 1976, 37 pages, price $1.39.

“Manual on Ionospheric Absorption Measurements", edited by K. Rawer, Institut fiir Physikalische Weltraumforschung,
Freiburg, G.F.R., June 1976, 202 pages, price $4.27.

"ATS6 Radio Beacon Electron Content Measurements at Boulder, July 1974 - May 1975", by R. B. Fritz, Space Environment.
Laboratory (currently with Wave Propagation Laboratory), NOAA, Boulder, Colorado 80302 USA, September 1976,
61 pages, price $1.04,

"Auroral Electrojet Magnetic Activity Indices AE(11) for 1974", by Joe Haskell Allen, Carl C. Abston and Leslie D.
Morris, National Geophysical and Solar-Terrestrial Data Center, Environmental Data Service, December 1976,
144 pages, price $2.16.

"Geomagnetic Data for January 1976 (AE(7) Indices and Stacked Magnetograms)" by J. H. Allen, C. C. Abston and
L. D. Morris, NGSDC/EDS/NOAA, July 1977, 57 pages, price $1.07. :

“Collected Data Reports for STIP Interval II 20 March - 5 May 1976", edited by Helen E. Coffey and John A.
McKinnon, National Geophysical and Solar-Terrestrial Data Center, Environmental Data Service, August 1977,
313 pages, price $2.95.

"Geomagnetic Data For February 1976 (AE(7) Indices and Stacked Magnetograms)" by J. H. Allen, C. C. Abston and
L. D. Morris, NGSDC/EDS/NOAA, September 1977, 55 pages, price $1.11.

"Geomagnetic Data for March 1976 (AE(7) Indices and Stacked Magnetograms)" by J. H. Allen, C. C. Abston and
1D. Horris, NGSDC/EDS/NOAA, September 1977, 5? pages, price S111.

eomagnetic Data for April 1976 (AE(8) Indices and Stacked Magnetograms)” by J. H. Allen, C. C. Abston and
L. D. Morris, NGSDC/EDS/NOAA, February 1978, 55 pages, price $1.00.

"The Information Explosion and Its Consequences for Data Acquisition, Documentation, and Processing” by G. K. Hartmann,
Max-Planck-Institut fiir Aeronomie, 0-341] Katlenburg-Lindau 3, GFR, May 1978, 36 pages, price 75 cents.

"synoptic Radio Maps of the Sun at 3.3mm 1970-1973" by Earle B. Mayfield, Space Science Lab., and Fred 1. Shimabukuro
Electronics Res. Lab., The Ivan A. Getting Laboratories, The Aerospace Corp., £1 Segundo, California 90245,
May 1978, 30 pages, price 75 cents.

“Ionospheric D-Region Profile Data Base, A Collection of Computer-Accessible Experimental Profiles of the D and Lower

§ Regions", by L. F. McNamara, Ionospheric Prediction Service, Sydney, Australia, August 1978, 30 pages, price
cents.

"A Comparative Study of Methods of Electron Density Profile Analysis", by L. F. McNamara, Ionospheric Prediction
Service, Sydney, Australia, September 1978, 56 pages, price $1.41.

"Selected Disturbed D-Region Electron Density Profiles. Their relation to the undisturbed D region", by L. F.
McNamara, Ionospheric Prediction Service, Sydney, Australia, October 1978, 50 pages, price $1.29.

"Annotated Atlas of Hx Synoptic Charts for Solar Cycle 20 (1964-1974) Carrington Solar Rotations 1487-1616", by
Patrick S. McIntosh, Space Environment Laboratory, ERL/NOAA, February 1979, 327 pages, price $3.50.

"Magnetic Potential Plots Over the Northern Hemisphere for 26-28 March 1976", by A.D. Richmond, SEL/ERL/NOAA, H.W.
Kroehl, NGSDC/EDIS/NOAA, M.A. Henning, Lockheed Missiles and Space Co., Aurora, CO, and Y. Kamide, Kyoto
Sangyo Univ., Kyoto, Japan, April 1979, 115 pages, price $1.50.

“Energy Release in Solar Flares, Proceedings of the Workshop on Energy Release in Flares, 26 February-1 March 1979,
Cambridge, Massachusetts, U.S.A.", edited by David M. Rust, American Science and Engineering, Inc.,
Cambridge, MA and A. Gordon Emslie, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, July 1979,

68 pages, price $1.50.

“Auroral Electrojet Magnetic Activity Indices AE(11-12) for January-June 1975", by J. H. Allen, C. C. Abston,
E. Salazar and J. A. McKinnon, NGSOC/EDIS/NOAA, August 1979, 114 pages, price $1.75.



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23


UAG Series of Reports

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Boulder, CO 80303, USA. The annual subscription price is $25.20 ($17.30 additional for foreign mailing). In years when the
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UAG-1 ""IQSY Night Airglow Data", price $1.75.

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UAG-23 “U.R.S.I. Handbook of Ionogram Interpretation and Reduction, Second Edition, November 1972", edited by W. R. Piggott
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UAG-29 “Auroral Electrojet Magnetic Activity Indices AE (11) for 1968", price 75 cents.

UAG-30 “Catalogue of Data on Solar-Terrestrial Physics”, price $1.75.

UAG-31 “Auroral Electrojet Magnetic Activity Indices AE (11) for 1969",
UAG-32 “Synoptic Radio Maps of the Sun at 3.3 mm for the Years 1967-1969
UAG-33 “Auroral Electrojet Magnetic Activity Indices AE (10) for 1967", price 75 cents.

UAG-34 ibsorption Data for the IGY/IGC and IQSY", price $2.00.

UAG-35 “Catalogue of Digital Geomagnetic Variation Data at World Data Center A for Solar-Terrestrial Physics", price 20 cents.

UAG-36 "An Atlas of Extreme Ultraviolet Flashes of Solar Flares Observed Via Sudden Frequency Deviations During the ATM-SKYLAB
Missions", price 55 cents.

UAG-37 “Auroral Electrojet Magnetic Activity Indices AE (10) for 1966", price 75 cents.

UAG-38 "Master Station List for Solar-Terrestrial Physics Data at WOC-A for Solar-Terrestrial Physics”, price $1.60.

UAG-39 "Auroral Electrojet Magnetic Activity Indices AE (11) for 1971", by Joe Haskell Allen, Carl C. Abston and Leslie D.
Morris, National Geophysical and Solar-Terrestrial Data Center, Environmental Data Service, February 1975,
144 pages, price $2.05.

UAG-40 "H-Alpha Synoptic Charts of Solar Activity For the Period of Skylab Observations, May, 1973-March, 1974", by Patrick
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UAG-41 “H-Alpha Synoptic Charts of Solar Activity During the First Year of Solar Cycle 20, October, 1964 - August, 1965",
by Patrick S. McIntosh, NOAA Environmental Research Laboratories, and Jerome T. Nolte, American Science and
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UAG-42 "Observations of Jupiter's Sporadic Radio Emission in the Range 7.6-89 “Hz 19 December 1971 through 21 March 1975",
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Colorado, Boulder, Colorado 80302, April 1975, 49 pages, price $1.15.

UAG-43 “Catalog of Observation Times of Ground-Based Skylab-Coordinated Solar Observing Programs", compiled by Helen E&.
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‘ice 75 cents.
price 35 cents.

UAC-44 "Synoptic Maps of Solar 9.1 cm Microwave Emission from June 1962 to-August 1973", by Werner Graf and Ronald N,
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price $2.85.

UAG-45 "Auroral Electrojet Magnetic Activity Indices AE (11) for 1972", by Joe Haskell Allen, Carl C. Abston and Leslie
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144 pages, price $2.10.

UAG-46 "Interplanetary Magnetic Field Data 1963-1974", by Joseph H. King, National Space Science Data Center, NASA Goddard
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UAG-47 "Auroral Electrojet Magnetic Activity Indices AE (11) for 1973", by Joe Haskell Allen, Carl C, Abston and Leslie
D. Morris, National Geophysical and Solar-Terrestrial Data Center, Environmental Oata Service, June 1975,
144 pages, price $2.10.





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7. PLOTS AND TABLES OF MONTHLY MEANS

75°E Local Time

8 12 16 20 24 4 f
st Ln J |
ATS 6 1975 Ootacamund
October f

Hourly means,
digital data.

UT

00
ol
02
03
04
05
06
o7
08
09
10
ll

Np

UUUARERONEOO
PUUHSCURERUY.CH
FOOSSSOUGANN

12
13
14
15
16
17
18
19
20
21

23

Hourly means,
digital data.

UT

0.52

00
ol
02
03
04
05
06
07
08
09
10
11

Np

0.80
1.69
2.54
3.37
3.84
4,09
4.38
4.54
4.74
4.69
4.68

4.36

12
13
14
15
16
17
18
19
20
21
22
23

3.71
3.05
2.80
2.48
1.89
1.51
1.37
1.16
1.08
0.85
0.67

Total Slant -Path Electron Content 107 mTM@

Total Slant-Path Electron Content 10!7 m=?

Universal Time
75° E Local Time
8 14 16 20 a] 4
Ls A SL 0
ATS6 1975 Ootacamund
November

6 4
5k iia 4

=

ow

pita ta

potori tid

4 8

1
12 16 20

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10

I
}
7
}
;
|
;





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chart data.

UT Np ut

00 (0.41 12

3.56

Ol 0.39 13
02 «1.08 14
03 «1.80 15
04 «2.48 16
05 3.05 7
06 3.26 18
07) 3.42 19
08 3.66 20
09° 3.72 21
10 3.71 22
Il 3.66 23

Hourly means,
chart data.

Ur ON, Ur
00. 0.47 «12
01 0.73 «13
020042155 (14
03° «2.45 15
04 «3.20 «16
05° 3.72017
06 «4.0318
07 «4.4019
08 «4.67 20
09 4.73 21
10 4.84 22
lL 4.7923

3.24
2.63
2.08
1.78
1.69
1.52
1.41
1.26
1.09
0.81
0.58

DADUEGRUSEOOU
FRRESSGGGREGS

CODCOREE NEWS

Total Slant-Path Electron Content 10!” m@

Total Slant-Path Electron Content 10'7 m*

75° E Local Time

8 2 16 20 24 4
TT T TTT T TTT T TTT T TT TT TTT T
ATS 6 1976 Ootacamund

February

rit ptr ta rr teri ti
4 8 12 16 20
Universal Time
75° E Local Time
8 12 16 20 24 4
TTT TT
ATS 6 1976 Ootacamund

April

io

stiritiiitiin

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Universal Time

12



WORLD DATA CENTER A
for
Solar-Terrestrial Physics

REPORT UAG-74 |

ATS-6 RADIO BEACON ELECTRON CONTENT MEASUREMENTS
AT OOTACAMUND, INDIA
OCTOBER 1975-JULY 1976

by

S.D. Bouwer, K. Davies, R.F. Donnelly, R.N. Grubb, J.E. Jones and JH. Taylor |
Space Environment Laboratory

NOAA Environmental Research Laboratories |
Boulder, Colorado USA 80303

and

R.G. Rastogi, M.R. Deshpande, H. Chandra and G. Sethia |

Physical Research Laboratory
Ahmedabad 380009, India ly
|
| |

March 1980

ZG
Published by World Data Center A for Ahi

Solar-Terrestrial Physics, NOAA, Boulder, Colorado

Remittance and correspondence regarding subscriptions should be sent to the National Geophysical and
Solar—Terrestrial Data Center, NOAA, Boulder, CO 80303.

and printed by t

U.S. DEPARTMENT OF COMMERCE |

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION |
ENVIRONMENTAL DATA AND INFORMATION SERVICE |

Boulder, Colorado, USA 80303 f

t

SUBSCRIPTION PRICE: $25.20 a year; $17.30 additional for foreign mailing; single copy price varies.* |
Checks and money orders should be made payable to the Department of Commerce, NOAA/NGSDC. }
|

*Price this issue $2.50


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April
1976

May

June

Table 5. (Continued)
ATS6 to Otacamund Total Slant Path Electron Content 10'7m* -- Part It.
UNIVERSAL TIME
1 a Tt 4 16 1 18 19 0 1 a

W.8492 4.3667 3.9807 3.1398 2.7539 2.4506

4.3116 4.1462 3.2363 2.4506 1.7338 1.4305

4.6838 4.3805 3.4845 2.5195 1.6786 1.4305 1.0563 0.9480

2. 2.1473 1.4856 1.1410 0.8653 0.7274

4.5459 4.1462 3.0571 2.3954 1.4998 1.3478 1.1810 0.5620

4.0221 3.167% 2.6436 1.9681 1.6373 1.4167 0.7274 0.6447

3:8842 3.1536 2.4506 2.2025 1.5621 1.3476 0.7550

WleKg2 4.0221 3.6637 3.2363 2.4919 2.0370

4.3392 3.9532 3.1123 2.3265 1.6510 1.2099

weeeee - - 1.0996 0.8239 -----~ -

4.6492 4.3392 3.3197 1.8440 1.4305 1.0583 0.7550 0.6034 0.5482 0.4655 0.4793

¥og10 3.9532 2. 1.3202 0.8515 0. -

¥log0g 3.346 2 0.8790 0.6033 0.5068 0.4102 0.3829 0.3829 0.3550 0.2724

4.3393 3.8844 2. 1.1134 0.9343 0.7138 0.6307 0.4926 0.4102 0.3968 0.3689

4.3806 2.7950 1. 0.906% 0.6033 0.5759 0.4928 0.3829 0.3002 0.3002 0.2589 0.1898

4.2701 1.4996 1.1408 0.6377 0.5346 0.3689

alurTy - - :

3.5674 0 0.5759 0.5207 0.4361

3.9809 - 0.6446 0.6033 0.4928

3.5674 aenn-- 0.5620 0.5068 0.4515 -

3.7052 1.2373 0.9068 0.7272 0.6307 0.5068 0.4515 0.4102 0.3829

Wlozee 1.6788 1.1134 0.8790 0.7685 0.6446 0.4928 0.4102 0.3415

3.9944 1.1547 0.7685 0.7412 0.4102 0.3415 0.2589 0.2171 0.3002

3.8013 - - -

3.7739 1.3617 1.1273 0.9756 0.8516 0.6725 0.5068 0.3968

3.4982 1.182) 1.0582 0.9616 0.7685 0.6446 0.4928 0.5306

3.8431 1.5270 1.1h08 1.0582 0.9343 0.8103 -

3.156 0.9616 0.8516 0.796% 0.7551 0.6725 oO.

3.7326 1.2239 - - -

3.5906 1.1960 0.9895 0.8930 0.6725 0.4928 0.3689 0.3002

3.7878 1.2787 0.9756 0.8651 0.5346 0.4102 0.3415 0.3002

Uloaze 0.9482 0.7272 0.5207 -

3.5674 0.9N82 0.7825 0.589% 0.5068 0.¥102 0.2724 0.3415

3.2368 0.6999 0.5620 0.5068 0.3829 0.1698 0.2728

3.3877 7551 0.5346 0.479% 0.3968 0.2171 0.2589

3.2917 8790 = 0.4928 3968 0.3829

2.5606 6307 0

3.8705 0169 0. ~ -

3.4430 +8238 0.6999 0.5068 0.4102 0.3550 0.2726

3.9944 1.0562 0.9064 0.6446 0.5481 0.4102 0.4102 0.3968 0.3829

3.3191 aiese - -

3.6087 ~ - : =

2.6437 0 0.4381 0.3968 0.3415 0.2728 0.2589

3.0986 0.6307 0.5068 0.3968 0.4282 0.2724 0.2450

3.1951 0.7551 0.4102 0.3415 0.2724 0.2450 0.2450

3.6634 0.8516 0.8516 0.7272 0.7412 0.5068 0.5346

3.1812 9756 0.8651 0.7685 0.5068 0.3276 0.272% 0.3689

2.8229 8516 0.8516 0.796 0.5620 0.3968 0.3550 0.4581

3.1673 9064 0.7625 0.7551 0.7138 0.6307 0.6033 0.6033

2.9194 8516 0.7272 0.6999 0.5894

2.6711 - -

3.8152 9895 0 0 0.5620

3.0707 6725 0 0.5759 0.4515

3.1538 6033 0.5759 0.4515 0.3550

3.2066 0.7138 0.6307 0.5759 0.5068 0

3.1951 1551 0.7272 0 0.4102 0.2803

3.1260 9343 0.8651 0.6586 0.5346 0.5346 0.3550 0.4381

3.3191 +8651 0.7138 0.5759 0.3550 0.2450 0.2450 0.2863
0.6586 0.5346 0.3002 0.2863 0 0.
0.7685 0.7551 0.5620 0.5207 0 o
0.9064 0.7272 0.5620 0.5207 0 0
0.8790 0.7964 0.6033 0.4794 0 0
0.8516 0.7272 0.5346 0.6033 0 °
0.5759 0.4102 0.1698 0.
0.8651 0.7551 : o. °
0.5620 0.5759 0.4794 0.3689 0.2724 0.

21



WORLD DATA CENTER A
National Academy of Sciences
2101 Constitution Avenue, N.W.
Washington, D.C., U.S.A., 20418

World Data Center A consists of the Coordination Office
and seven Subcenters:

World Data Center A
Coordination Office
National Academy of Sciences
2101 Constitution Avenue, N.W.
Washington, D.C., U.S.A., 20418
[Telephone: (202) 389-6478]

Glaciology [Snow and Ice]: Rotation of the Earth:
World Data Center A: Glaciology World Data Center A: Rotation
[Snow and Ice] of the Earth
Inst. of Arctic & Alpine Research U.S. Naval Observatory
University of Colorado Washington, D.C., U.S.A. 20390
Boulder, Colorado, U.S.A. 80309 . [Telephone: (202) 254-4023]

[Telephone: (303) 492-5171]
Solar—Terrestrial Physics (Solar and

Meteorology (and Nuclear Radiation): Interplanetary Phenomena, Lonospheric
Phenomena, Flare-Associated Events,
World Data Center A: Meteorology Geomagnetic Variations, Magnetospheric
National Climatic Center and Interplanetary Magnetic Phenomena,
Federal Building Aurora, Cosmic Rays, Airglow):
Asheville, North Carolina, U.S.A. 28801
[Telephone: (704) 258-2850] World Data Center A
for Solar-Terrestrial Physics
Oceanography : Environmental Data and Information
Service, NOAA
World Data Center A: Oceanography Boulder, Colorado, U.S.A. 80303
National Oceanic and Atmospheric [Telephone: (303) 499-1000, Ext. 6467]
Administration
Washington, D.C., U.S.A. 20235 Solid-Earth Geophysics (Seismology,
[Telephone: (202) 634-7249] Tsunamis, Gravimetry, Earth Tides,
Recent Movements of the Earth's
Rockets and Satellites: Crust, Magnetic Measurements,
Paleomagnetism and Archeomagnetism,
World Data Center A: Rockets and Volcanology, Geothermics):
Satellites
Goddard Space Flight Center World Data Center A
Code 601 for Solid-Earth Geophysics
Greenbelt, Maryland, U.S.A. 20771 Environmental Data and Information
[Telephone: (301) 344-6695] Service, NOAA

Boulder, Colorado, U.S.A. 80303
[Telephone: (303) 499-1000, Ext. 6521]

NOTES:

1. World Data Centers conduct international exchange of geophysical observations
in accordance with the principles set forth by the International Council of Scientific
Unions. WDC-A is established in the United States under the auspices of the National
Academy of Sciences.

2. Communications regarding data interchange matters in general and World Data
Center A as a whole should be addressed to: World Data Center A, Coordination Office
(see address above).

3. Inquiries and communications concerning data in specific disciplines should
be addressed to the appropriate subcenter listed above.



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The nine figures in section 7 with their accompanying tables are plots of the
mean hourly Ny values averaged over the month. The means of October 1975 through
January 1976 were calculated exclusively from the digital data. These figures have
roughly the same scale as the daily plots in sections 9 and 10. Thus, by superimpos-
ing tracing-paper duplicates of the monthly average profiles onto the daily plots,
one can easily make day-to-day comparisons. Dashed lines in the monthly plots en-
close a standard deviation above and below the mean.

Tables 3-6 in section 8 provide the hourly subsamples for each day plotted in
sections 9 and 10. Table 3 is exclusively digital data; Tables 4, 5 and 6 exclusive-
ly chart data.

4, SUMMARY OF Ny DATA

Sections 9 and 10 contain diurnal plots: solid-line curves denote graphs gener-
ated from the digital data; dotted-line curves denote graphs composed from chart
recorded data. Three special features in the diurnal plots deserve note.

(a) A local maximum can occur 4 h before the main diurnal maximum. See 19 October
on page 24 , where a local maximum appears before the daily peak at 1500 LT.

(b) Two local maxima each having roughly the same Ny; value can emerge. See
10 January on page 30 at 1200 and 1600 LT. This splitting of the peak Ny seems
to occur more frequently near a solstice than near an equinox.

(c) One or more local maxima can develop during the evening hours. See, for
example, the 31 October profile and its three distinct nighttime peaks
illustrated on page 25

5. ACKNOWLEDGMENTS

The bulk of the digital data processing was accomplished with the invaluable
assistance of Janet E. Falcon, Thomas B. Gray, William M. Retallack and Richard W.
White, of the NOAA Space Environment Laboratory Analysis Group. We thank Robert
Hetzel for his assistance in processing the ATS-6 pointing data and 40-MHz Faraday
rotation data, and Mr. J. Thron for developing corrections for the ATS-6 location.
We extend a special thanks to Edward Green for his assistance in software development
and data entry.

6. REFERENCES

DAVIES, K., 1975 "Some Early Results of the ATS-6 Radio Beacon
R.B. FRITZ, Experiment," Radio Set., 10, Nos. 8-9, 785-799.
R.N. GRUBB and

J.E. JONES

DAVIES, K., 1979 "ATS-6 Satellite Radio Beacon Measurements at
R.F. DONNELLY, Ootacamund, India," Radio Sei., 14, No. 1, 85-95.
R.N. GRUBB,

P.v.S. RAMA RAO,

R.G. RASTOGI,

M.R. DESHPANDE,

H
H
G

CHANDRA,
.0. VATS and

SETHIA
DONNELLY, R.F., 1979 ATS-6 Radio Beacon Pointing Data, October 1975 -
R. HETZEL and January 1976 (NOAA Tech. Memo ERL SEL-53, Space
Jd. FALCON Environment Laboratory, Boulder, Colorado, USA

80303), 94 pp.
8



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Hourly means,
digital data.

UT Np UT
00 0.53 12
Ol 0.67 13
02 1.44 14
03 2.01 15
04 2.76 16
05 (3.21 17
06 3.52 18
07 (3.65 19
08 3.90 20
09 «3.95 21
10 3.94 22
lL 3.95 23

Hourly means,
digital data.

3.17

UT Ny ur
00 «(0.40 12
Ol 0.45 13
02 «1.09 14
03 1.80 15
04 2.55 16
05 2.85 v7
06 3.05 18
07 = (3.33 19
08 «3.48 20
09 «3.47 21
10 3.45 22
ll 3.29 23

3.80
3.16
2.51
2.22
1.98
1.74
1.39
1.23
1.03
0.94
0.79
0.61

Total Slant -Path Electron Content 10"? m*

-2

2.80
2.23
1.89
1.62
1.23
1.09
0.94
0.89
0.77
0.63
0.50

17
Total Slant-Path Electron Content 10° m

75° E Local Time

8 4 16 20 24 4
i
ATSE6 1975 Ootacamund
December
6 4
5 4

Universal Time

75° E Local Time

8 12 16 20 24 4
as |
ATS6 1976 Ootacamund

January
6 4
Sr 4

Universal Time

ll

i
|

i]
I
|

|