Satellite observations of aberrations of radio signals traversing auroral ionosphere indicating decreasing trend in scintillation activit

Porter, R.

Zonge, K. L.

English

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Produced by the NASA Center for Aerospace Information (CASI) 
https://ntrs.nasa.gov/search.jsp?R=19690023143 2020-03-12T05:04:07+00:00Z
Prepared for
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
GODDARD SPACE FLIGHT CENTER
under
Contract NAS 5-3940
Modification $8
561 9
^ ^	 E
r
a	 -
GEOPHYSICAL INSTITUTE
of the
UNIVERSITY OF ALASKA
ABERRATIONS OF RADIO SIGNALS TRAVERSING THE AURORAL I07ROSPHERE
SIMI-ANNUAL ANALYSIS REPORT
including
Data covering the period
July 1, 1968 through January 31, 1969
I. INTRODUCTION
This report is primarily concerned with a summary of the analysis of
satellite tracking records obtained from Gilmore Creek during the period
of July 1, 1968 through January 31, 1969. These data are presented main-
ly to indicate the decreasing trend in scintillation activity as observed
through satellite records. A more detailed analys'3 will be given in the
eontract annual report when a full year's data will be available.
Il, ANALYSIS OF SATELLITE RECORDS
A. Computer ?rogram Development
A computer program has been developed for the reduction of data obtained
€rom Gilmore Creek Satellite records. A reproduction of this program is
, included in Appendix A. The reduction techniques parallel those used in
manual analysis and described in Sections IIC and IIIC, of report UAG R-
with the simplifications outlined in Section IIIA of the 1967 Annual
Report.(2)
B, Analysis
The records used were the "ten most isturbed" passes selected by Gilmore
Creek STADAN personnel for each of seven months from July 1968 through
January 1969. Seventy records were received and 68 were used for analysis.
No records were discarded due to the lack of sufficient information for
proper analysis.
the average 136 MHz scintillation index for these 68 records is 1.7.
This is a reduction of 402 from last year's average of 2.8. For additional
e60parison, the average scintillation for the 1967 contract year was 2.0
ifs 1.6 for the preceding year.
tigu e I is a computer plot of average 136 MHz scintillation indices for
yzed pass records versus universal time. Figure 2 shows the monthly
1 K
average scintillation indices for the passes analyzed. Comparison of
Figure 1 with the corresponding figure in the 19A8 annual report shows a
dramatic decrease in the number of highly disturbed passes. As described
' in previous reports, scintillation can be experienced in any part of the
sky, but not with uniform probability of severity. Figures 2 and 3 display
the average scintillation index in various sectors of the sky using a format
identical to prior reports. As found in past years, scintillation was more
severe in the geomagnetic northern half of the sky than in the southern half.
The north-to-south ratio for this seven month period is 2.2 as compared with
1.8, 1.8 and 1.9 of the previous three years. A marked reduction over last
year in scintillation activity is evident when Figure 3 is compared with
Figure 2 of the 1968 Annual Report.
C. Conclusion
Comparison of these data for this seven month period with similar
data from the prior year indicates a sharp decrease in the average scintillation
activity. However, since these data are not complete over the period of one
year they should be used only as an indicator when comparing with past
Information.
2
REFERENCES
(1) Fremouw, E. J., "Aberrations of VHF-UHF Signal Traversing the Auroral
Ionosphere", Geophysical Institute Report UAG R-181, University of
Alaska, 1966.
(2) Zonge, K. L. and E. J. Fremouw, "Aberrations of Radio Signals Traversing
the Auroral Ionosphere," Geophysical Institute, University of Alaska,
NASA Contract NAS5-3940, Annual Report, July, 1967.
3
LIST OF FIGURES
Figure 1. Average 136 KHz scintillation indices for analyzed pass
records versus Universal Time.
Figure'2. Monthly average scintillation index for the "10 Most Dic :x ^ed
Passes" per month from Gilmore Creek STADAN.
Figure 3. Seven month average scintillation index for disturbed pasf:s
in 36 sectors of the sky defined in geomagnetic X-Y coord - ates.
Dashed axes represent local geographic coordinates.
Figure 4. Quadrant averages of scintillation index based on Figure 3.
4
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JUL AUG SEP OCT NOV DEC JAN
1968	 1	 0	 1969
Rig. 2. Monthly average scintillation index for the "10 Most
j	 Disturbed Passes" per month from Gilmore Creek STADAN.
6
3
X
W
C
Z
2
02
Q
J
_J
H
2
N
W
Q
S
W
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}
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S
F-
2
O
2
0
GNO DISTURBED
.PASSES
Fig. 3. Seven month average scintillation index for disturbed
passes in 36 sectors of the sky defined in geomagnetic
X-Y coordinates. Dashed axes represent local geographic
coordinates.
7
(R: 
A 3
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APPENDIX A
DOS FORTRAN IV-360/40
C
C	 PROGRAM, MODIFIED APRIL 4,69 *D INCLUDE
C	 19 AVE-SCINTILATION FOR EACH MONTH
C	 2. A SUMMARY OF ALL MONTHS PLOT OF TIME(AVERAGE OF TIME OF PASS)
C	 VS. THE AVERAGE SCINTILATION
C
C	 PROGRAM MODIFIED APRIL 21 # 69 TO INCLUnE A 6X6 TABLE FOR A GROUP OF
C	 MONTHS (SANE GROUP FOR PLOT IN ITEM 2 ABOVE) ANC ALSO FOR AN AVE.
C	 SCINTILLATION FOR THE GROUP.
C
C
C	 FORMAT FOR KEYPUNCHING SCINTILATION INDEXS FOR KEN ZCNGE
C
C
C
G	 CUL 1-10 R.J.+PUNCH DECIMAL	 REV NO. NORM/TIME
C	 COL 12-13 YEAR	 (OUP)
C	 COL 15-16 MOilTH	 (OUP) ***
C	 COL 18-19 DAY	 (OUP.USUALLY)
C	 COL. 21-22 HOUR	 (OUP.1:SUALLY)
C	 COL. 24-25 MIN
C	 COL 28-30 S INDEX FOR GILMORE
C	 COL 32-37 ELEV
	
PUNCH DECIMAL
C	 COL 38-43 AZ	 PUNCH DECIMAL
C	 COL 45-50 RESERVED FOR SATELLITE NUMBER
C	 *** WHEN ALL DATA FOR A MONTH IS PUNCHED PU'UCH A CARL WITH 99 IN
C	 MONTH COLUMNS(COL 15-16)
C
C
C
C	 PLACE A CARD WITH 98 IN COLS 15-16 AFTER THE 99 CARD IF IT IS THE
C	 LAST MONTH OF A GROUP COMBINED TO MAKE A TIME VS AVE. SCINTILATION
C	 PLOT.
C
C	 PLACE A CARD WITH 97 IN COLS 15-16 AFTER THE 98 CARD IF THERE IS
C	 NO MORE DATA TO HANDLE WITH THIS RUN.
C
C	 SPECIAL NOTES
C	 1. PUNCH ONLY THOSE LINES WHERE A S INDEX IS INDICATED.(IGNORE
C	 TOTALS OR AVERAGES)
C	 2. IGNORE ANY PLUS OR MINUS SIGNS ASSOCIATED WITH THE S INDEX
C
DIMENSION NUM(6,6)•TOT16,61*ALAB(80),DATAP(256)tTIMEP(500)9
IAVSCPT(500),NUMG(6,6),TOTG(6.6)
CALL PIOTST IOATAP(256)92561
C
C	 ZERO OUT SUM AREAS
999 IFIRSTcZ
IMCONTsO
Al
V-
IH24=0
RNL=O.
NMON=O.
NGROUP =C
1SINP=C.
TOTMO^u =0.
TOTGRP=0.0
TTIME=O.
NINPAS=C
NPO I NT =0
IDAYL=C
DO 22 M=196
DO 22 L=1r6
NUMG(M,L)=0
22 TOTG(M,L)=0.0
1 DO 2 M=1,6
DO 2 L=1,6
NUM ( Mi, L) =0
2 TOT(M,L)=0.0
C
C	 TITLE COLUMNS FOR DATA LISTING
WRITE (393010)
3010 FDRMATt'1','REV.NO.N0RMITIME	 YEAR MON DAY HOUR MIN S INDEX EL
IEVATION AZIMUTH SAT. NO.	 NEW X
	
NEW Y')
C
C	 READ DATA CARD
C	 1. IF MONTH IS 99 GO TO MONTH END OUTPU T (50) (AFTER GOING TO NEW
C	 REV. SECTION)
C	 2. IF MONTH IS 98 GO TO AVESCIN VS TIME OUTPUT(200)
C	 3. IF MONTH IS 97 JOB IS DONE SO GO TO CALL EXIT(197)
99 REAM 9 1000)REV*NUM,( ALAS(K)9K=8,10)1IY9IMON,IDAY,IHOUR,IMIN,S,EL,
IAZ,(ALA6tK),K=45,50)
1000 FORMAT(F6.Os1X93A1 9 5(1X,I2) , 2X,F3.09IX,2F6 . 191X,6A1)
IF(IMON-99 )3.4993
3 M IMUN-98 )100,2^0,100
100 IF(IMON-97)10191979101
101 IMOUT=IMON
I YOUT= I Y
C
C	 IF IFIRST=O DO NOT TEST FOR NEW DAY OR NEW REV. NUMBER
C	 BUT INSTEAD STORE DAY IN IDAYL AND REVNUM IN RNL AND MAKE IFIRST=1
IF(IFIRST ) 110,1029110
102 IDAYL=IDAY
RNL=REV-UM
IFIRST=1
GO TO 113
C
C	 IF A NEW REV NO. HAS OCCURRED FIND AVE TIME OF PASS AND AVESCIN
110 IFIRNL—REVNUM)300,111,300
C
C	 IF A NEW DAY HAS OCCURRED (WITHIN THE SAME REV.NO.) ADD 24 TO IH24
111 IF(IDAYL-1DAY)112r113,112
112 IH24=24+IH24
IDAYL=IDAY
,_
A2
C
C	 FIND PASS TIME IN HOURS AND DECIMAL
113 AMIN=ININ
AHOUR=IHOUR+IH24
PTIME=AHOUR+(AMIN/60.)
TTIME=TTIME+PTIME
NINPAS=NINPAS+1
NMON=N 90N+ 1
NGROUP=NGROUP+1
TOTMON=TOTMON+S
TOTGRP=TOTGRP+S
TSINP=TSINP+S
C
C	 CONVERT AZ GEOGRAPHIC TO GEOMAGNETIC
400 AZM=AZ-29.
C
CONVERT AZM AND EL TO RADIANS FOR USE IN COMPUTATIONS
AZMR=AZM*.0174533
ELR=EL#.0174533
C
C
	
CONVERT TO X AND Y
F1=COS(ELR)
F2=COS (AZMR )
F3=SIN(ELR)
F4=SIN(AZMR)
YM=ATAN(tFI*F2)/(SQRT(ABS(F1*F1*F4*F4+F3*F3))))*57.2958
XM=ATAN((F1#F4)/F3)$57.2953
C
C
	
PRINT THE DATA FOR CHECKOUT PURPOSES
WRITE(3,3011)REVS^dUM,tALAB(K),K=&,10),IY,IMON,IDAY,IHOUR,IMIN,S,EL,
lAZs(ALAB(K)sK=45,50),XM,YM
3011 FORMAT(' ',5X,F6.0 9 " 13A1,6X, 2(I2,2X),I2,4X,I2,2X,I2,F9.29F10.2,
1F9.2,3X,6A1,lXt2F10.2)
C
	
CHECK DATA TO MAKE SURE BOTH X AND Y ARE LESS THAN 90DEG+OR-
IF(ABS(XM)-90.)4,40,40
4 IF(ABS(YM)-90.)5,40940
40 WRITE(3,3000)EL,AZ,XM,YM
3000 FORMAT( 1 0 0 9 1 THE FOLLOWING COORDINATES ARE OUT OF THIS WORLD.',/,#
lE=':F8.2,3X,'A=',F8.293X,'XMAG=',F8.293X,'YMAG=19FB.2)
GO TO 99
C
	
BOTH X + Y ARE BETWEEN —90 AND +90 SO FIND SUBSCRIPTS AND STORE
5 A=-1.
NX= (120.+XM)/30.
NY= (12C.+YM*A)/30.
NUM(NX,NY)=NUM(NX,NY) +l
NUMG(NX,NY)=NUMG(NX,NY)+1
TOT(NX,NY)=TOT(NX,NY)+S
TOTGtNX,NY)= TOTG(NX,NY)+S
GO TO 99
C
	
A NEW PASS HAS BEEN SENSED
C
	
FIND AVE TIME OF PASS AND AVE SIN. AND ADD ONE TO NUMBER OF POINTS
C
	
ON PLOT
C
300 NPOINT=NPOINT+I
A3
ATT=TTIME/NINPAS
IF(ATT-24)30293021301
301 ATT=ATT-24.
302 -TIMEP(NPOINT)=ATT
AVSCPT(NPOINT)=TSINP/NINPAS
C
C	 WRITE A LINE AT THE END OF EACH REV NUMBER
WRITE(3 1 3100)TIMEP(NPOINT),AVSCPT(NPOINT), NINPAS
3100 FORMAT(' ','AVERAGE TIME OF PASS IN HOURS=',F8.3,'
1TILLATION = 0 9 F7.3,'	 NUMBER IN PASS= 1,I4, ///)
IFIRSI=0
IH24=0
NINPAS=O
TTIME=0.0
TSINP=C.O
RNL=REVNUM
IDAYL=IDAY
AVERAGE SCIN
C
`
C
C
1C
C
IF IMCONT=1 WE ARE HERE BECAUSE AN ENO OF MONTH HAS BEEN SENSED
SO WE WISH TO CONTINUE BY OUTPUTING THE MONTHLY 6X6 TABLE
IF IMCCNT =O WE WISH TO HANDLE AS THE FIRST DATA CARD IN NEW PASS
IF(IMCCNT)50,386,50
386 WRITE(313010)
GO TO 113
C
C	 A SUMMARY PLOT IS DESIRED AS 98 CARD HAS BEEN SENSED
200 NPI=NPCINT+1
NP2=NPOINT+2
TIMEP(`PI)=0.0
TIMEP(NP2)=2.0
AVSCPT(NP1)=0.0
AVSCPT(NP2)=0.4
CALL AXIS(0.0 9 0.0 9 'AVERAGE TIME OF PASS IN HOURS',-29,12.90.090.09
12.0,20.)
CALL AXIS(0.0,0.0,'AVERAGE SCINTILLATION INDEX FOR PASS1936,10.0,
190.00.010.4910.0)
FPN=NPCINT
CALL SYM,BOL(1.0 1 10.0 1 .14 9 9 TOTAL NUMBER OF PASSES (POINTS) PLOTTED=
"90.0,40)
CALL Nl.AMBER(-0.0,-0.0,-0.09FPN,0.0, -1)
C
CALL LINE(TIMEP,AVSCPT,NPOINT,1,-1,3)
C	 GO TO NEW ZERO
CALL PLOT(15.00.0,-3)
C
C	 PRINT CUT THE 6X6 TABLE FOR THE GROUP (TITLE,CALCULATE ETC.)
WRITE(30020)IMOUT,IYOUT
3020 FORMAT('1 1 9 1 TABLE OF SCINTILLATION AVERAGES FOR THE GROUP OF MONTH
1S ENDING WITH MONTH= 1 ,139' YEAR=1913,///)
C
C	 CALCULATE AVERAGES AND PUT IN TOTE ARRAY
00 16 M=196
00 16 L=196
IF(NUMG(M,L))18,17,18
- C.
C ` C
A4
Ca ^,
17 TOTG(M,L)=0.0
GO TO 16
18 B=NUMG(M,L)
TOTG(M,L)=TOTG(M,L)/B
16 CONTINUE
C
C	 TITLE COLS. AND PRINT OUT DATA FOR GROUP
WRITE(3,3003)
WRITE (30004)
:;U 19 J=1,6
LABI=120— (.1*30)
LA82=LA81-30
19 WRITE(3,3005)LABI,LA82,(TOTG(K,J),NUMG(K,J),K=1,6)
C
C	 FIND AVESCIN FOR GROUP ^.ND PRINT IT WITH NO. OF OBSERVATIONS IN
C	 GROUP
AVEGRP=TOTGRF/NGROUP
WRITE(313021),NGROUP,AVEGRP
3021 FORMAT( 1 0 1 1 'NU %'BER OF OBSERVATIONS IN „ROUP=',I5,' 	 AVERAGE SCIN
1TILLATION FOR GROUP=',F10.3)
TOTGRP=C.O
NGROUP=O
GO TO 999
C
THE PLOT IS NOW DONE AND ANOTHER GROUP CAN BE DONE
C
C
C	 AN END OF MONTH HAS BEEN SENSED — OUTPUT (CALCULATE AVERAGES INTO
C
	
TOT ARRAYS)
C
C	 HOWEVER FIRST IT IS NECESSARY TO CONSIDER THAT THIS IS THE END OF
C	 A PASS—
 SO GO BACK AND FIND AVE. TIME, AVE. SCIN. AND PRINT LINE
49 IMCONT=1
GO TO 300
50 WRITE (393001)IYOUT,IMOUT
3001 FORMAT( 1 1 1 9 1 TABLE OF SCINTILLATION AVERAGES FOR YEAR=',I3,' MONTH
1=1,13t///)
IMCONT=C.
00 6 M=1,6
DO 6 L=1,6
IF(NUM(M,L))8,7,8
7 TOT(M,L)=0.0
GO TO 6
8 B-NUM(M,L)
TOT(M,L)=TOT(M,L)/B
6 CONTINUE
G
C	 TITLE THE COLUMNS AND THEN PRINT OUT DATA
WRITE (393003)
3003 FORMAT('0',16X,'-90. TO —60. • ,8X 9 • -60. TO —30.',8X,'-30. TO 0.0 It
18X, 1 0.0 TO +30.',8X 9 '+30. TO +60. 9 ,8X 9 9 +60. TO +90.0)
WRITE(393004)
3004 FORMAT(' 9 ,12X,6(' AVE.SIN.	 NUMBER -'))
00 9 J=1,6
LABI=120—(J#30)
m —
8f
V l
s
A5
'	 LA'82=LAB1-30
9 WRITE(393005)LABlt LAB2,(TOT(K,J),NUM(K,J),K=1,6)
3005 FORMAT( 1 0 1 04,' TO',I496(F10.3,2X,I5,3X))
G
C	 FIND THE AVESCIN FOR MONTH AND PRINT IT WITH NUM. OF OBSERVATIONS
C	 IN MONTH - THEN RESET THESE TOTALS
AVEMON=TOTMON/NMON
WRITE(3,3200)NMON,AVEMON
.3200 FORMAT('0 1 9 'NUMBER OF OBSERVATIONS IN MONTH= 1 9 I4,'	 AVERAGE SCINT
1ILLATION FOR MONTH=11F10.3)
TOTMON=0.0
NMON=0
GO TO 1
197 CALL E X I T
END
A6


Aberrations of radio signals traversing the auroral ionosphere Semiannual analysis report, 1 Jul. 1968 - 31 Jan. 1969

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