1、 Recommendation ITU-R P.1239-3(02/2012)ITU-R reference ionospheric characteristicsP SeriesRadiowave propagationii Rec. ITU-R P.1239-3 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocomm
2、unication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radi
3、ocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing de
4、clarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Recommendations (Also available online at htt
5、p:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowa
6、ve propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standa
7、rds emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2012 ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, withou
8、t written permission of ITU. Rec. ITU-R P.1239-3 1RECOMMENDATION ITU-R P.1239-3 ITU-R reference ionospheric characteristics (Question ITU-R 212/3) (1997-2007-2009-2012) Scope This Recommendation provides models and numerical maps of the monthly median characteristics of the ionosphere, and informati
9、on regarding the statistical variability. The ITU Radiocommunication Assembly, considering a) that long-term reference ionospheric data and prediction methods are needed for radio-circuit design, service planning and frequency band selection, recommends 1 that for the prediction of ionospheric chara
10、cteristics, use should be made of the formulations contained in Annex 1. Annex 1 Ionospheric characteristics 1 Introduction Expressions are provided for the evaluation of the monthly median of foF2, M(3000)F2, foE, foF1, hF and hF,F2 and of the monthly median, upper decile and lower decile of foEs a
11、nd fbEs. Also included are representations of the percentage of occurrence of spread-F. These formulations yield values for any location, month and time-of-day for different solar epochs. In the case of foE and foF1, empirical formulae in terms of solar-zenith angle are presented. For the other iono
12、spheric characteristics a numerical mapping technique based on orthogonal Fourier functions is applied. 2 Mapping functions The general form of the numerical map function, (, , T) is the Fourier time series: (, , T ) = a0(, ) + j = 1Haj(, ) cos j T + bj (, ) sin j T (1) where: : ionospheric characte
13、ristic to be mapped : geographic latitude (90 90) 2 Rec. ITU-R P.1239-3 : East geographic longitude (0 360) ( in degrees East of the Greenwich meridian) T : universal time (UTC) expressed as an angle (180 T 180) H : maximum number of harmonics used to represent the diurnal variation. The Fourier coe
14、fficients, aj(, ) and bj(, ), vary with the geographic coordinates, and are represented by series of the form: aj (, ) = k = 0KU2j,kGk (, ), j = 0, 1, 2, . . . , H (2a) bj (, ) = k = 0KU2j 1,kGk (, ), j = 1, 2, . . ., H (2b) The particular choice of the functions, Gk(, ) is determined by specifying
15、the integers k (k0, k1, k2, . . . , ki, . . . , km; km= K), where i is the order in longitude. Therefore, a numerical map can be written more explicitly in the form: (, , T ) = k = 0KU0k Gk(, ) + j = 1Hcos j T k = 0KU2j,kGk(, ) + sin j T k = 0KU2j 1,kGk(, ) (3) U2j,kand U2j1,kin equations (2a), (2b)
16、 and (3), can be written as Us,k, where s is either 2j or 2j 1. In the numerical mapping technique, the modified magnetic dip: X = arc tan Icos (4) has been used, where I is the magnetic dip and is the geographic latitude. Since X is a function of both geographic latitude and longitude, the formal e
17、xpression of (, , T), equation (3), is unchanged. Table 1 shows the geographic functions, Gk(, ). A model of the Earths magnetic field for epoch 1960 based on a sixth-order spherical-harmonic analysis is employed in order to determine modified magnetic dip and gyrofrequency required in the evaluatio
18、n of the numerical maps. The 1960 epoch must be used, rather than some other epoch of interest because it is that which is used in generating the values of the numerical coefficients. Rec. ITU-R P.1239-3 3TABLE 1 Geographic coordinate functions Gk(, ) (X is a function of and , m is the maximum order
19、 in longitude) q0= k0; qi (i = 1, m) = ki ki 1 22k Main latitude variation k First order longitude k Second order longitude . . . k mth order longitude 0 1 k0+ 1 cos cos k1+ 1 cos2 cos 2 . . . km1+ 1 cosm cos m 1 sin X k0+ 2 cos sin k1+ 2 cos2 sin 2 . . . km1+ 2 cosm sin m 2 sin2X k0+ 3 sin X cos co
20、s k1+ 3 sin X cos2 cos 2 . . . km1+ 3 sin X cosm cos m . k0+ 4 sin X cos sin k1+ 4 sin X cos2 sin 2 . . . km1+ 4 sin X cosm sin m . . . . . . . . . . . . k0sinq0X k1 1 sinq1X cos cos k2 1 sinq2X cos2 cos 2 . . . km 1 sinqmX cosm cos m k1sinq1X cos sin k2sinq2X cos2 sin 2 . . . kmsinqmX cosm sin m Th
21、e magnetic induction Fx, Fyand Fz(Gauss) along the geographic North, East and vertically downwards directions respectively, is given by: Fx = n = 16m = 0nxmngmncos m + hmnsin m Rn + 2(5a) Fy= n = 16m = 0nymngmnsin m hmncos m Rn + 2(5b) Fz= n = 16m = 0nzmngmncos m + hmnsin m Rn + 2(5c) where: x mn= d
22、d (Pn, m(cos ) (6a) y mn= m Pn, m(cos )sin (6b) z mn= (n + 1) Pn, m (cos ) (6c) with: 4 Rec. ITU-R P.1239-3 : northern co-latitude (= 90 ), where is the geographic latitude (degrees) (North positive, _90 90) Pn,m(cos ) : associated Legendre function defined as: Pn,m (cos ) = sinm cosn m (n m) (n m 1
23、)2(2n 1) cosn m 2 + (n m) (n m 1) (n m 2) (n m 3)(2) (4) (2n 1) (2n 3)cosn m 4 + . . . (7) gm,nand hm,n: numerical coefficients for the field model (Gauss) R : height-dependent scaling factor given as: R = 6 371.26 371.2 + hr(8) where: hr: height at which the field is evaluated (taken as 300 km). Th
24、e total magnetic field, F, is given as: F = F 2x+ F 2y+ F 2z(9) The magnetic dip, I, and gyrofrequency, fH(MHz) are determined from: I = tan 1FzF 2x+ F 2y(10) and fH= 2.8 F (11) 3 Prediction of foF2 and M(3000)F2 3.1 Monthly median values The F2-layer numerical maps are based on vertical incidence s
25、oundings of the ionosphere at a large number of ground stations all over the world. The sets of numerical coefficients defining the diurnal and geographical variations of the monthly median of foF2 and M(3000)F2 are based on a linear relationship with solar activity1. The coefficients are the values
26、 of Us,k(see equations (2) and (3) that define the function (, , T), of the numerical map of the given characteristic for the indicated month and level of solar activity. The coefficients are available for each month of the year, and for two levels of solar activity, R12= 0 and R12= 100. R12is the t
27、welve-month running mean value of the monthly sunspot numbers and is used as an index of the level of solar activity. For some applications it may be more appropriate to use grid-point tables for the ionospheric characteristics rather than implementing equation (1). Computer programs to calculate gr
28、id-point tables for foF2 and M(3000)F2 are available on the Radiocommunication Study Group 3 website in 2 alternative software procedures. Output grid point tables for foF2 and M(3000)F2, from one of the programs mentioned above, are also available on the Radiocommunication Study Group 3 website. 1S
29、everal different sets of coefficients have been available. The recommended set is that approved at the CCIR Plenary Assembly, Oslo, 1966. Rec. ITU-R P.1239-3 5For the evaluation of parameters between grid points the bi-linear interpolation procedure given in Recommendation ITU-R P.1144 (Annex 1) sho
30、uld be used. For most purposes it is adequate to assume a linear relationship with R12for both foF2 and M(3000)F2. However, the relationship between foF2 and R12becomes non-linear at a level of solar activity which is a function of geographic location, time of day and season. The most noticeable dep
31、arture from linearity is for values of R12above approximately 160. For values of R12greater than 160, the error is reduced by assuming that higher values are effectively 160. The relationship of M(3000)F2 with R12is also taken to be linear over the range of values up to R12= 160. For higher values o
32、f R12, M(3000)F2 is taken to be the value obtained for R12= 160. 3.2 Variability factors The decile factors for describing the daily variations within a month for foF2 are given in Tables 2 and 3. The tables are for the local time and geographic latitude at the control point. Tables are given for th
33、ree ranges of sunspot number, R12, and for the three seasons: Winter: November-February in the Northern Hemisphere and May-August in the Southern Hemisphere Equinox: March, April, September and October Summer: May-August in the Northern Hemisphere and November-February in the Southern Hemisphere. A
34、bilinear interpolation process may be used between tabulated points. 4 Prediction of foE The method for predicting the monthly median foE is based on all published data over the years 1944-1973 from 55 ionospheric stations. foE (MHz) is given by: (foE)4= A B C D (12) where: A : solar activity factor
35、, given as: A = 1 + 0.0094 ( 66) (13) : monthly mean 10.7 cm solar radio flux expressed in units of 1022W m2Hz1. Forprediction purposes, it is appropriate to approximate by an estimate of 12, the twelve-monthly smoothed value (see Recommendation ITU-R P.371) B : seasonal factor, given as: B = cosmN
36、(14) where: N = for | | 12, p = 1.20. 2nd Case: 73 100 Lat. Local time (h) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 90 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 0.68 85 0.65 0.65 0.67 0.69 0.69 0.
37、69 0.70 0.71 0.71 0.71 0.69 0.68 0.68 0.68 0.67 0.66 0.66 0.66 0.68 0.70 0.70 0.70 0.68 0.65 80 0.62 0.62 0.66 0.70 0.70 0.70 0.72 0.74 0.74 0.74 0.70 0.67 0.67 0.67 0.66 0.64 0.64 0.64 0.68 0.73 0.73 0.73 0.68 0.62 75 0.66 0.66 0.69 0.72 0.72 0.72 0.74 0.76 0.76 0.76 0.73 0.70 0.70 0.70 0.69 0.68 0
38、.68 0.68 0.72 0.76 0.76 0.76 0.71 0.66 70 0.69 0.69 0.72 0.74 0.74 0.74 0.76 0.77 0.77 0.77 0.74 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.75 0.78 0.78 0.78 0.74 0.69 65 0.73 0.73 0.74 0.76 0.76 0.76 0.78 0.79 0.79 0.79 0.78 0.76 0.76 0.76 0.76 0.76 0.76 0.76 0.78 0.80 0.80 0.80 0.76 0.73 60 0.77 0.77 0.
39、78 0.78 0.78 0.78 0.80 0.81 0.81 0.81 0.80 0.80 0.80 0.80 0.80 0.79 0.79 0.79 0.80 0.82 0.82 0.82 0.80 0.77 55 0.80 0.80 0.80 0.79 0.79 0.79 0.80 0.82 0.82 0.82 0.83 0.84 0.84 0.84 0.83 0.82 0.82 0.82 0.83 0.84 0.84 0.84 0.82 0.80 50 0.83 0.83 0.82 0.80 0.80 0.80 0.82 0.84 0.84 0.84 0.86 0.87 0.87 0
40、.87 0.86 0.84 0.84 0.84 0.85 0.86 0.86 0.86 0.84 0.83 45 0.84 0.84 0.82 0.80 0.80 0.80 0.83 0.86 0.86 0.86 0.87 0.88 0.88 0.88 0.87 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.85 0.84 40 0.86 0.86 0.84 0.81 0.81 0.81 0.84 0.87 0.87 0.87 0.88 0.90 0.90 0.90 0.88 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.86 0.86
41、35 0.84 0.84 0.81 0.78 0.78 0.78 0.83 0.88 0.88 0.88 0.89 0.90 0.90 0.90 0.89 0.88 0.88 0.88 0.87 0.86 0.86 0.86 0.85 0.84 30 0.83 0.83 0.80 0.76 0.76 0.76 0.82 0.89 0.89 0.89 0.90 0.90 0.90 0.90 0.89 0.88 0.88 0.88 0.87 0.86 0.86 0.86 0.84 0.83 25 0.80 0.80 0.76 0.73 0.73 0.73 0.81 0.89 0.89 0.89 0
42、.90 0.90 0.90 0.90 0.89 0.88 0.88 0.88 0.86 0.84 0.84 0.84 0.82 0.80 20 0.78 0.78 0.74 0.70 0.70 0.70 0.80 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.86 0.83 0.83 0.83 0.80 0.78 15 0.80 0.80 0.76 0.73 0.73 0.73 0.81 0.89 0.89 0.89 0.90 0.90 0.90 0.90 0.90 0.89 0.89 0.89 0.86 0.84 0.84
43、0.84 0.82 0.80 10 0.83 0.83 0.80 0.76 0.76 0.76 0.82 0.89 0.89 0.89 0.90 0.90 0.90 0.90 0.90 0.89 0.89 0.89 0.86 0.84 0.84 0.84 0.84 0.83 5 0.83 0.83 0.80 0.76 0.76 0.76 0.82 0.89 0.89 0.89 0.90 0.90 0.90 0.90 0.90 0.89 0.89 0.89 0.86 0.84 0.84 0.84 0.84 0.83 0 0.82 0.82 0.80 0.78 0.78 0.78 0.82 0.8
44、8 0.88 0.88 0.89 0.90 0.90 0.90 0.88 0.87 0.87 0.87 0.84 0.81 0.81 0.81 0.82 0.82 Rec. ITU-R P.1239-3 13 TABLE 2 (continued) d) foF2 variability: lower decile, equinox, R12100 Lat. Local time (h) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 90 0.69 0.69 0.69 0.69 0.69 0.69
45、 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 85 0.68 0.68 0.68 0.68 0.68 0.68 0.70 0.72 0.72 0.72 0.70 0.68 0.68 0.68 0.68 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.69 0.68 80 0.66 0.66 0.66 0.67 0.67 0.67 0.71 0.75 0.75 0.75 0.70 0.66 0.66 0.66 0.68 0.70 0.7
46、0 0.70 0.71 0.72 0.72 0.72 0.69 0.66 75 0.66 0.66 0.68 0.69 0.69 0.69 0.72 0.74 0.74 0.74 0.71 0.68 0.68 0.68 0.69 0.70 0.70 0.70 0.71 0.72 0.72 0.72 0.69 0.66 70 0.67 0.67 0.69 0.71 0.71 0.71 0.72 0.73 0.73 0.73 0.72 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.71 0.72 0.72 0.72 0.70 0.67 65 0.68 0.68 0.70
47、 0.73 0.73 0.73 0.72 0.72 0.72 0.72 0.71 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.71 0.72 0.72 0.72 0.70 0.68 60 0.69 0.69 0.72 0.75 0.75 0.75 0.73 0.71 0.71 0.71 0.71 0.71 0.71 0.71 0.71 0.71 0.71 0.71 0.72 0.72 0.72 0.72 0.70 0.69 55 0.70 0.70 0.73 0.76 0.76 0.76 0.73 0.70 0.70 0.70 0.71 0.72 0.72 0.7
48、2 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.71 0.70 50 0.71 0.71 0.74 0.78 0.78 0.78 0.74 0.70 0.70 0.70 0.72 0.72 0.72 0.72 0.74 0.74 0.74 0.74 0.74 0.73 0.73 0.73 0.72 0.71 45 0.75 0.75 0.78 0.80 0.80 0.80 0.76 0.72 0.72 0.72 0.74 0.75 0.75 0.75 0.76 0.77 0.77 0.77 0.78 0.78 0.78 0.78 0.77 0.75 40 0.79 0.79 0.80 0.82 0.82 0.82 0.78 0.75 0.75 0.75 0.76 0.78 0.78 0.78 0.79 0.80 0.80 0.80 0.82 0.84 0.84 0.84 0.82 0.79 35 0.80 0.80 0.81 0.82 0.82 0.82 0.82 0.81 0.81 0.81 0.82 0.82 0.82 0.82 0.83 0.84 0.84 0.84 0.84 0.85
