F — 543
FOR MARCH 1994 VOL. 46   NNO. 3
COMMUNICATIONS RESEARCH LABORATORY MINISTRY OF POSTS AND TELECOMMUNICATIONS TOKYO, JAPAN
This  Series contains  data on ionosphere ( I ) ,  solar radio emission (S) and radio propagation (P) obtained at the follow- ing stations under the Communications Research Laboratory, Ministry of Posts and Telecommunications of Japan.
A. IONOSPHERE
lonospheic observations are carried out at the above  four stations  in Japan by means of vertical  sounding  using  iono- sondes. The ionosonde produces ionograms, which are record- ed digitally on computer storage medium as well as graphical- ly  on 35 mm  photographic  film. The digitally-recorded  iono- grams are collected from each station by the central computer and reduced to numerical values and Summary Plots  by the automatic processing system. The  ionograms obtained at Kokubunji are manually scaled as well by experienced specialists to supplement automatically-scaled parameters.
A1.  Automatic Scaling
Digital   ionograms are automatically scaled by  the pattern recognition method.  The following five  factors of  ionospheric characteristics are  published  for the present.  The  reliability of these factors has been ascertained by comparison of the automatically-scaled  parameters  with the  manually-scaled values of large amounts of test ionograms. The  published data  consist of tabulations of hourly  values of  three factors ( foF2, fEs, fmin ) and  monthly  medians of two factors ( h´Es,  h´F ) , daily Summary Plots and monthly medians plot of foF2. a.  Characteristics of lonosphere
b.  Descriptive Letters The following descriptive letters are used in the tables. Impossible measurement because of the presence A of  a lower thin layer,for example Es ( for foF2 ). B Impossible measurement because  of absorption in the vicinity of fmin. C Impossible  measurement because of  any failure in observation. G Impossible automatic scaling because of  too small ionization density of the layer ( for fEs ). N Impossible automatic scaling because of  complex echoes. Blank  No digital record because of trouble in the auto- matic data  processing  system,  but existence  of  film record.
c.  Definitions of the CNT,MED,UQ and LQ
Median count (CNT) is the number of numericalvalues from which the median has been computed. In addition to numerical values, the count may include a descriptivel etter G. Median ( MED ) is defined as the middle value when the numerical  values  are  arranged  in  order of  magnitude, or the average of  the two middle values if there is an even number of values. Upper quartile ( UQ ) is  the median value  of  the upper half of the values  when they are ranked  according  to  magnitude; the  lower quartile ( LQ ) is the median value  of  the lower half. If  CNT is  less than 10,  there are blank spaces left. d. Reliability of Automatic Scaling The results of the comparison between automatically- scaled  values  and  manually-scaled  ones showed  that hourly values  of  foF2 , fEs  and  fmin  were scaled within a difference of 1 MHz from about 90 , 90 and 99% , respectively of the test ionograms.
e.  Summary Plot
Daily  Summary  Plots which are made  from  quarter-hourly digital  ionograms are published  to present general ionosphere conditions. The upper and middle parts of a Summary Plot show  the diurnal  variation of  the frequency  range of the echoes reflected from the Fand E regions, respectively. The two solid arcing lines indicate the predicted values of fxE  and  foE  calculated  by  the method described in the CCIR report 340.  The lower part shows the diurnal  variation of the virtual height where the echo traces become horizontal.
A2.  Manual Scaling
The  published  data consist of  tabulations of  hourly values of the ionospheric characteristics and figures of daily f-plot. All symbols and terminology in the tables or figures of ionospheric data are used  in accordance with the "URSI Hand- book of  Ionogram  Interpretation and Reduction ( Second Edi- tion ) 1972 " and  its revision of  chapters  I-4,  published in July 1978. a.  Characteristics of lonosphere

b. Symbols
( i )  Descriptive Letters The following I etters are  entered after, or used to replaced a numerical value on the monthly tabulation sheets, if necessary. Measurement influenced by, or impossible because A of,  the presence of  a lower thin layer,for example Es. B Measurement influenced by, or impossible because of, absorption in the vicinity of fmin. C Measurement influenced by, or impossible because of, any non-ionospheric reason. D Measurement influenced by, or impossible because of, the  upper limit of the normal frequency range in use. u Measurement influenced by, or impossible because of, the lower limit of the normal frequency  range  in use. L Measurement influenced by, or impossible because of,  the presence of  spread echoes. G Measurement influenced or impossible because the ionization  density  of  the layer  is  too  small to  enable it to be made accurately. H Measurement influenced by, or impossible because of,  the presence of a stratification. K Presence of particle E layer. Measurement influenced or impossible because the L trace  has no sufficiently definite cusp between layers. Interpretation of  measurement  questionable because M the  ordinary  and  extraordinary components  are  not distinguishable. N Conditions are such that  the measurement  cannot be interpreted. Measurement  refers to  the  ordinary  component. o P Man-made perturbations of  the observed parameter; or spur type spread F present. a Range spread present. Measurement influenced by, or impossible because R of,  attenuation in the vicinity of a critical frequency. s Measurement influenced by, or impossible because of, interference or atmospherics. T Value determined by  a sequence  of observations, the actual observation being inconsistent or doubtful. > Forked trace which may  influence the measurement. W Measurement influenced or impossible because the echo lies outside the height range recorded. X Measurement  refers to  the  extraordinary component. Y Lacuna phenomena, severe layer tilt. z Third magneto-electronic   component   present. (ii)  Qualifying Letters The following  letters are entered in the first  column before a numerical value on the monthly tabulation sheets, if necessary. Less than. Used only  when fbEs is deduced from A foEs because total blanketing of higher layer is present. D Greater than. E Less than. l Missing value has been replaced by an interpolated value. J Ordinary component characteristic deduced from the extraordinary  component. M Mode interpretation uncertain. o Extraordinary  component  characteristic  deduced from the  ordinary component. ( Used for x-character- istics only. ) T Value determined  by a sequence of  observations, the actual  observation being inconsistent  or doubtful. U Uncertain or  doubtful numerical value. Measurement deduced from the third magneto- Z electronic component. ( iii )  Description of Types of Es When more than one type of Es trace are present on the ionogram, the  type  for  the  trace used to  determine  foEs must be written first. The  number of multiple trace  is indicated after the type letter. The types are: f An  Es  trace which shows no appreciable increase of height  with frequency. - A flat Es trace at or below the normal E layer minimum virtual height or below the particle E layer minimum virtual  height. C An  Es trace showing  a relatively symmetrical cusp at or below  foE.  ( Usually a daytime type. ) h An Es trace showing a discontinuity in height with the  normal  E  layer trace  at  or above  foE. The cusp  is not symmetrical, the low frequency end of the Estrace lying clearly above the high frequency end of the normnal  E  trace. ( Usually a daytime type. ) An Es trace which is  diffuse and  non-blanketing प over a wide frequency range. An  Es  trace showing  an  increase in virtual height at r the  high  frequency  end  similar to  group retardation. An Es trace having a well-defined flat or gradually a rising lower edge with stratified and diffuse traces present above it. A diffuse Es trace which rises steadily with fre- quency and usually emerges from another type Es trace. A weak diffuse trace at heights below 95 km as- d sociated with high absorption and large fmin. The designation 'n' is used to denote an Es trace which cannot be classified into one of the standard types. k The  designation  'k'  is used  to show  the presence of particle E. When foEs > foE (particle E) the Es type precedes k. c. Definitions of the CNT, MED, UQ and LQ Median count ( CND)  is  the  number of values from which the median has  been computed. In addition to numerical values, the  count  may  include  certain  descriptive  letters. Median ( MED) is the middle value when the numerical values are arranged  in order of  magnitude, or the average of the two middle values if there is an even number of  values. Upper quartile ( UQ ) is the median value of the upper half of  the values when they are ranked according  to  magnitude; the lower quartile ( LQ ) is  the median value of  the lower half.
B. SOLAR
RADIO
Solar radio observations at 200, 500 and 2800 MHz are carried  out  at Hiraiso. The observation equipment consists of two parabolic antennas, one with 10-meter diameter for 200 MHz  measurements  and  one  with 2-meter diameter for  500 and 2800 MHz  measurements, Observations are continuously carried out almost  from sunrise to sunset.
B1.  Daily Data at Hiraiso
The three-hourly  mean and daily mean values of  the solar radio emission intensities are tabulated separately for 200 and 500 MHz measurements. The intensities are expressed by the
flux density in 10 22 Wm 2 Hz 1 unit. The table for 200 MHz measurements also presents the variability  indices  defined by  the  number of  impulsive  radio bursts within the  three-hour intervals as follows: 0 quiet or no burst, 1 a   few bursts,
EMISSION
22 many burs!s, 3 very many bursts. The daily variability index is defined as the daily mean of three-hourly indices. The following symbols are used in the tables, when inter- ference  or  radio  bursts prevented  measuring  the base-level flux  densities or determining the variability indices: Measurement  impossible  because  of  inter- ference. B Measurement impossible because of bursts. Daily  data within parentheses mean that  the observation time does not exceed one third of the period.
B2. Outstanding Occurrences at Hiraiso
The table is a list of outstanding occurrences of solar radio  emission  bursts  observed  at  200, 500 and  2800 MHz during a  month. Listed in the table are the date, frequencies, the type of event, the start time and the time of maximum, both in U.T. ex- pressed in hours, minutes and tenths of a minute, the  duration in  minutes,  the peak and  mean flux  densities  in 10 22  Wm 22 Hz 1 unit, and  the polarization. The type of event is expressed by a combination of a numerical code  and  a  letter symbol  in accordance  with the " Descriptive Text of Solar Geophysical Data, NOAA " as defined  by H. Tanaka  in  the " Instruction  Manual for Monthly Report of Solar Radio Emission, WDC-C2 " in January 1975:
The polarization is expressed by the polarization degree and  sense as follows: R or L W,M or S 0 00 numerical  values, if  necessary. D
u
U
greater than, or later than, less than or earlier than, approximate, or uncertain. B3.  Summary Plots of F 10.7  at Hiraiso The 10.7 cm solar radio flux at Hiraiso is plotted over a one month period. The 10.7 cm flux (F 10.7 ) is determined by adjust- ing  the 10.7 cm radio flux measured at  Hiraiso to the  Pentinc- ton 10.7 cm radio flux. The figure on the right-hand  side  shows the F10.7 index estimated at Hiraiso.
C. RADIO    PROPAGATION
C1.  H.F. Field Strength at Hiraiso
Field strength observation of 15 MHz standard waves transmitted from WWV and WWVH stations which are located respectively  at  Fort Collins,  Colorado and  Kauai,  Hawaii, is carried  out  at  Hiraiso.  In order to  avoid interference among the same frequency waves, the  upper sideband  of  WWV  or WWVH with the audio tone  600 Hz is picked up by the use of a  narrow band-pass filter with 80 Hz bandwidth.Particulars of the transmitters and the receiver are summarized in the follow- ing table. The tabulated field strength expressed in dB above one microvolt per meter is the average of quasi-peak values of the incident upper sideband field intensity for 45 seconds after the universal time indicated on the table. Abbreviated symbols are as follows:
C S innuenced by,  or impossible  because of,  any artificial accident, influenced  by,  or   impossible  because  of, interferences or atmospherics.
C2.  Radio Propagation Quality Figures at Hiraiso
The  tabulated six-hourly quality figures are calculated for standard  waves   WWV   transmitted  from   Fort Collins  and WWVH transmitted from Kauai. Quality figures expressing radio propagation conditions range  over five grades as follows: very poor(very disturbed), 1 2 poor(disturbed), 3 rather poor(unstable), 4 normal, 5 good. Whole day quality figure ranged in grades of  1o, 1+, 2-, 20, 2+, 3-, 30, 3+, 4-, 40, 4+, 5-, 50  stands for an average of six-hourly quality figures of the two circuits.  Abbreviated symbols are as follows: C artificial accident, s propagational accident, U inaccurate.
right- or left-handed polarization, weak,moderate or strong polarization, almost zero or unable to detect polarization due to small increase of flux, polarization degree of less than 1 percent. One of the following symbols may be attached after The  column of conditions presents a record of  the forecast of  radio  propagation  conditions  which is applicable to forth- coming 12 hours and broadcast six times par hour from JJY ( Japan Standard Wave ) staion. The conditions are denoted as follows: normal, N U unstable. W disturbed. Data on geomagnetic storms which are often correlated with  radio  propagation  disturbances are  tabulated  based on reports from observation at Kakioka Magnetic Observatory, Japan  Meteorological  Agency. Time ( U.T. ) is  expressed  in hours  and  minutes ( or tenths  of  an hour ) ,  and   range   in nanotesla. When they are uncertain quantitatively, / 's are used to replace the numerical values. Continuation of  a geomagnetic storm is denoted by ---.
C3.  Phase Variation in OMEGA Radio Waves at Inubo
The phase values of eight OMEGA radio signals as received at Inubo are depicted for an interval of one month, along with the phase deviation defined as a deviation from a value averaged over the six quietest day within the month. Par- ticulars  of  the received signals are given  in  the  table  below. In  each of  the  four  panels of the  figure, the phase ( φ ) is shown in the lower part and the phase deviation ( Δ φ ) is shown  in  the  upper part. The phase data are sampled  every 30 min, so the curves of the phase and phase deviation are composed  of 48 data points per day. The phase delay is measured as a positive value. The  polar cap phase anomaly ( PCPA ) caused by the solar protons are well detected on the Norway signal. The start, end and  maximum times of  the  PCPA are listed in  the  table next to the figure, where the times are expressed as  day / hour & minute in U.T.. The maximum phase deviation in the list is  defined as a phase advance ( negative values in the figure ) in degrees.
C4.  Sudden Ionospheric Disturbances
a.  Short  Wave  Fade-out ( SWF) at Hiraiso The  table  of  short  wave  fade-out ( SWF) is prepared from the record of  field intensities measured at  Hiraiso. Drop-out  intensities of the 10 MHz, the 20 MHz, and the 25 MHz waves are respectively distinguished by marks ', '' from those of  the 15 MHz wave for WWV and  WWVH. and Values of start, duration, type, and importance are obtained from data of the circuit whose drop-out intensity in dB is underlined as xx. When these quantities could not be deter- mined accurately, they are accompanied by one of the follow- ing symbols. D greater than, E less than, uncertain or doubtful. U Types of fade-out are as follows: sudden drop-out and gradual recovery, S slow  drop-out taking 5  to 15  minutes and SL gradual recovery, gradual  and  irregular in  both  drop-out and G recovery. Importance of fade-out is scaled according to its amplitude into nine ascending grades as 1-, 1, 1+, 2-, 2, 2+, 3-, 3, 3+. Correspondence of solar optical and X-ray flares, and solar radio burst to SWF is  marked by X, being determined with data from interchange messages  of  IUWDS and obser- vations at Hiraiso. In table ( a ) SWF, date indicates the day to which the start-time of the event belongs. b.  Sudden Phase Anomaly ( SPA ) at  Inubo Data  of sudden phase anomaly ( SPA ) are prepared from the records  of  phase measurement of  VLF radio  waves  re- ceived at Inubo. The transmitting stations are listed in the following table. Phase  advance  is shown in unit of degree at its maximum stage.  No transmission  or  no reception during  the period  is indicated by -, an indistinguishable record is spaced out, and  a  multi-peak event is marked by *. The most remarkable or distinct phase advance is underlined and listed in the column of Time. In table ( b ) SPA, date indicates the day to which the start-time of the event belongs. The following letters may be attached to the value, if necessary. greater than, D m less than, uncertain or doubtful. U
HOURLY VALUES of FES AT WAKKANAI MAR.1994 6
7
8 HOURLY VALUES OF FES MAR.1994 AT KOKUBUNJI
HOURLY VALUES of FOF2 AT Y A M A G A W A
HOURLY VALUES of FES AT Y A M A G A W A MAR.1994
HOURLY VALUES of FES AT OK I N A W A
F XE
F OE (E(P); PREDICTED VALUE FOR I 43 MONTHLY, MEDIANS, of H'F, and H'ES MAR.1994 135E MEAN TIMECUTC+9HD AUTOMATIC SCALING STATION WAKKANAI - LAT. 45.4N LON. 141.7E
MONTHLY MEDIANS OF H'F AND H'ES 135E MEAN TIMECUTC+9H) MAR.1994 AUTOMATIC SCALING S T A T I O N . Y A M A G A W A LAT. 31.2N LON. 130.6E
H ' E S oolo 1 lo 2 lo 3 lo 4 lo 5 lo 6 lo 7 lo 8 lo 9 l1 0 l1 1 1 1 2 l1 3 l1 4 l1 5 l1 6 l1 7 l1 8 l1 9 l20 l2 1 l22 l23 CNT 14 14 13 16 .15 12 .12 _25 29 28 26 23 _25_22 20 18 14 19 _21_22 19 14 14 17 ME01061105110711061105110611051145114914311341121111811121113111311131113110711051109110811021107 U  010911071109110911081131107115516817114311311125112313111191191131111911311311151107112 97 99 L  011031101110511031101103110011091113112211911171114111311113111111011071101 97101102
I ONOSPHERIC  DATA  STATION KOKUBUNJI MAR.1994 FXI (0.1MHZ)      135*E MEAN TIME (G.M.T. + 9HD I ONOSPHERIC  DATA  STATION KOKUBUNJI
I ONOSPHERIC  DATA  STATION KOKUBUNJI MAR.1994 FOF1 (0.01MHZ) - 135 E MEAN TIME CG.M.T. + 9HD
IONOSPHERIC DATA  STATION KOKUBUNJI MAR.1994  FOE (0.01MHZ)    135*E MEAN TIME (G.M.T. + 9H)
I ONOSPHERIC. DATA  STATION KOKUBUNJI
I ONOSPHERIC -DATA  STATION KOKUBUNJI MAR.1994  FBES (0.1MHZ) 135* E MEAN TIME CG.M.T. + 9H)
IONOSPHERIC  DATA  STATION KOKUBUNJI I ONOSPHERIC  DATA STATION  KOKUBUNJI MAR.1994'M(3000)F2 (0.01)  135*E MEAN TIME (G.M.T. + 9H)
IONOSPHERIC  DATA  STATION KOKUBUNJI MAR.1994 MC3000F1 (0.01)  135*E MEAN TIME CG.M.T. + 9HD I ONOSPHERIC  DATA  STATION KOKUBUNJI MAR,1994 H'F2 (KM) 135*E MEAN TIME CG.M.T. + 9HD
I ONOSPHERIC  DATA  STATION  KOKUBUNJI 135'E MEAN TIME CG.M.T. + 9HD MAR.1994 H'F CKM)
IONOSPHERIC  DATA  STATION KOKUBUNJI MAR.1994  H'E (KM)
IONOSPHERIC  DATA  STATION KOKUBUNJI MAR.1994 H'ES CKMD      135'E MEAN TIME (G.M.T. + 9H)
I ONOSPHERIC  DATA  STATION KOKUBUNJI MAR.1994 TYPES OF ES  . 135* E MEAN TIME CG.M.T. + 9HD
! ' . CONTO SYNDOL.5 !!! B. Solar Radio Emission B1. Daily Data at Hiraiso 200 MHz Not available until system improvement is completed. B. Solar Radio Emission B1. Daily Data at Hiraiso 500 M H z
Hiraiso March 1994
Note: A vertical grid space corresponds to a 100 sfu. Elevation angle range N F 10.7 89.7 90.0 95.3 105.3 94.0 92.9 97.0 91.2. 90.3 90.6 89.6 84.1 89.7 91.4 88.1 84.4 84.9 85.6 87.2 85.6 88.3 88.8 90.4 92.2 91.8 87.0 89.1 88.5 86.1 88.2 88.2 C1. H.F. 'FIELD STRENGTH ', '( UPPER SIDE-BAND OF WWV ) MAR   1994 4.5 N BANDUIDTH 80 HZ " " " RECEIVING ANTENNA ROD FREQUENCY  15 NHZ MEASURED  AT  HIRAISO
24 24 24 24 24 23 25 25 25 25 25 25 25 25 24 25 25 24 24　23　24　24　24　24 CNT -25 -25 -27 -28 -28 -14 -8 -27 -27 -27 - 27 -6    -8 -7  -7  -6 -27 -27 -27 -27 -27 -28 MED - 8 -27 -27 -27 -12 -3 -27 ES -26 -27 -27 -27 -27 4 4 -3 -18 -12 -20 U D 2 -1   -1 -55 - L D C1.  H.F.  FIELD  STRENGTH    ( UPPER  SIDE-BAND  OF  WWVH ) MAR 1994 FREQUENCY , 15 MHZ BANDWIDTH  80 HZ RECEIVING  ANTENNA  ROD 4.5 N
C2. Radio Propagation Quality Figures at Hiraiso
C3. Phase Variation in OMEGA Radio Waves at Inubo NORWAY - 13. 6 kHz 100 ww 0 400 a . 2 8 g 10 -1 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 (deg.) NORTH DAKOTA - 13. 6 kHz 180 Δ φ 8 Win -100 -200 400 $ 200 a - 2 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 (d e g . ) 100 B -100 see -200 400 200 & a . 2 8 e 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 21 28 29 (d e g . ) JAPAN - 13.6 kHz ! 0 0 a -You can -100 -200 400 Δ φ $ 200 \\\ 8 B 5 6 7 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 25 26 27 20 I n u b o Matrich 1994 (d o g . ) △ φ -100 -200 φ   200 Δ Φ I n u b o (d e g . ) HAWAII - 13. 100 Δ Φ 8 - 1 8 0 -200 400 Φ 200 C d d (d e g . ) 13.6 kHs LA REUNION 100 c - 100 - 200 400る200 e 24 20 21 22 23 17 18 15 16 10 ! 3 1.4 111 12 Δ Φ (d e g . ) AUSTRALIA -1 3, 6 kHz 100 8 -100 -200 400 φ 200 8 15 16 △ φ (d e g . ) ARGENTINA 100 8 - 1 0 0 -200 480る200 a l 3 2 s 7 8 s 8 g 10 11 As for LIBERIA-13.6kHz, no record during 24 January 0820 UT Note : - 2 March 1500 UT, due to the maintenance of transmitter. Polar Cap Phase Anomaly (PCPA) on Norway-Inubo Circuit NONE .
(a) Short Wave Fade-out (SWF) at Hiraiso
CO:Colorade(WWV) HA:Hawaii(WWVH) AUS:Australia MOS:Moscow BBC:London * Optical and X-ray Flares
IONOSPHERIC  DATA  IN JAPAN   FOR   MARCH   1994 F-543  Vol.46  No.3  (Not for Sale)
電離層月報（1994年3月）第46巻第3号(非売品) 1994年7月25日  印刷1994年7月30日-発行郵政治省通信総合合研究所所〒184 東京都小金井市賃井北町４丁目２一１ ☎ (0423)  (21)  1  2  1  1 (代) Queries about "lonospheric  Data in Japan" should be forwarded to " Communications Research Laboratory, Ministry of Posts and Telecommunications, 2-1 Nukui-Kitanachi 4-chome, Koganei-shi, Tokyo 184 JAPAN.