INTERNATIONAL ISO WD STANDARD Working draft ______________________________________________________________ Space environment (natural and artificial) Earth's ionosphere and plasmasphere. Model of distribution of density, temperature and effective collision frequency of electrons WORKING DRAFT ______________________________________________________________ Reference No. ISO ISO WD PREFACE International Standard Organization (ISO) is an association of national standard organizations (ISO participant committees). International Standards are developed by ISO Technical Commit- tees. Each of the participant committees is entitled to at- tend sessions of any of Technical Committees when subjects of interest to the former are discussed. The governmental, non-governmental, and international organizations co-opera- ting with ISO are also entitled to attend the sessions. The draft of International Standards approved by Technical Committees are sent to all of the participant committees for consideration pending approval of the ISO Council. International Standard "Space environment (natural and artifi- cial). Earth's ionosphere and plasmasphere. Model of distribu- tion of density, temperature and effective collision frequency of electrons" has been developed by ISO/TC20 Technical Commit- tee on Aircraft and Spacecraft, ISO/TC20/SC14 Subcommittee on Space Systems and Operations, and ISO/TC20/SC14/WG4 Working Group on Space Environment (Natural and Artificial). In the present International Standard the appendixes A and B are of informative nature only. ISO WD CONTENTS 1. Scope of application.................................. 1 2. Definitions and notations............................. 2 3. General statement..................................... 4 Appendix A. Structure of information presented in the tables................................................... 7 Appendix B. Bibliography................................. 9 ISO WD Space environment (natural and artificial) Earth's ionosphere and plasmasphere. Model of distribution of density, temperature and effective collision frequency of electrons 1. SCOPE OF APPLICATION The present International Standard defines the model of dist- ribution of the mean monthly values of density, temperature and effective collision frequency of electrons in the Earth's ionosphere and plasmasphere in the height interval from 65 km to 20000 km at any longitudes, at geographic latitudes from 80 north latitude to 80 south latitude, for any time of the day, different days in a year and various solar activity le- vels. The present International Standard is employed to estimate the effect of charged particles on technical devices in the Earth's environment and to define the mean ionospheric opera- tional conditions of available and designed means of radio communication, radio navigation and other radiotechnical means in the ranges of medium and heigher frequencies. The present Standard shall not use to define parameters of the Earth's ionosphere and plasmasphere to the periods of iono- spheric storms or to the periods, when the index of geomagne- tic activity Kp>3. 1 ISO WD 2. DEFINITIONS AND NOTATIONS The present International Standard uses terms, notations and theirs definitions given in table 1. Table 1 - Terms, notations and theirs definitions 旼컴컴컴컴컴컴컴컴쩡컴컴컴컴컴쩡컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Term � Notation � Definition � 쳐컴컴컴컴컴컴컴컴탠컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Earth's iono- � � Region of the Earth's atmosphe- � � sphere � � re in the height interval from � � � � 30 km to 1000 km containing � � � � partially ionized cold plasma � � Ionospheric � � Continuous ionospheric distur- � � storm � � bance � � Ionospheric � � Disturbance in ionization dis- � � disturbance � � tribution in the ionospheric � � � � layers which exceeds usual � � � � changes in mean characteristics � � � � of ionization for given geophy- � � � � sical conditions � � Earth's plasma-� � Region of magnetosphere contai- � � sphere � � ning low energy plasma partic- � � � � les with energy less 1 eV, with � � � � density equal or more 10 m � � Plasmapause � � Outward boundary of the plasma- � � � � sphere formed by geomagnetic � � � � field lines where plasma densi- � � � � ty falls no less than by 10 ti- � � � � mes � � Solar activity � � A series of processes occurring � � � � in the Sun's atmosphere affec- � � � � ting the interplanetary space � � � � and, in particular, the Earth; � � � � the level of solar activity is � � � � characterized by indexes � � Wolf number � W � An international relative num- � � � � ber of sunspots determined on � 2 ISO WD The end of the table 1 旼컴컴컴컴컴컴컴컴쩡컴컴컴컴컴쩡컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Term � Notation � Definition � 쳐컴컴컴컴컴컴컴컴탠컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � � � every day; the most commonly � � � � used index of solar activity � � Mean smoothed � Wm � A 12-months-running mean month- � � the Wolf number � � ly number of sunspots � � Planetary 3-hour� Kp � Index characterizing the dis- � � index of geomag-� � turbance in the Earth's magne- � � netic activity � � tic field over the 3-hour in- � � � � terval; the index is expressed � � � � in numbers from 0 to 9 (Kp sca- � � � � le is uneven quasilogarithmic) � � Density of elec-� Ne � � � trons � � � � Temperature of � Te � � � electrons � � � � Effective colli-� Nu � Total frequency of collisions � � sion frequency� � of electrons with neutral par- � � of electrons � � ticles and ions calculated by � � � � the formulae of gas - kinetic � � � � theory � � Medium frequen-� � Radio frequencies from 300 MHz � � cies � � to 3000 MHz � � Corrected geoma-� �' � Geomagnetic latitude in calcu- � � gnetic latitude � � lating which higher spherical � � � � harmonic expansion terms of geo-� � � � magnetic field are used along- � � � � side with dipoles � 읕컴컴컴컴컴컴컴컴좔컴컴컴컴컴좔컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 3 ISO WD 3. GENERAL STATEMENTS 3.1. The model of distribution of density, temperature and effective collision frequency of electrons presented in the present International Standard is developed by generalization of the particular empirical (physico-statistical) models of distribution of ionosphere and plasmasphere parameters, developed by statistical processing of experimental data. The models of distribution of Ne and Te are developed directly using experimental data.The model of distribution of Nu is calculated, values of Nu are calculated with the models of Ne, Te and neutral atmosphere parameters by the formulae of gas-kinetic theory. Note - In the present International Standard values of Nu are calculated with Ne, Te from this Standard and neutral atmo- sphere parameters from the Groves model [1] and Jacchia model [2]. See appendix B. 3.2. To determine parameters of the ionosphere and the plasma- sphere at fixed heights for a selected geographic point it is necessary to present: - the geographic latitude in degrees (the north latitude is given with plus, the south latitude is given with minus); - the geographic longitude (eastern) in degrees; - the date, (number, month) according to which the day number in a year is determined; - the local time in hours; - mean smoothed the Wolf number. Note - Duration of year is taken 365 days. 3.3. Mean values of Ne, Te and Nu are presented at some fixed heights as the tables in a file param.tbl. 4 ISO WD 3.4. The tables are calculated for the following input data: - geographic latitudes 80; 60; 40; 20; 10; 0 degrees for the north hemisphere and -10; -20; -40; -60; -80 degrees for the south hemisphere; - geographic longitudes 30; 150 and 270 degrees; - March, June, September, December (the parameter values are refered to 15 number of each month, i.e. to the day num- bers in a year 74, 166, 258 and 349, respectively); - local time 0; 2; 4; 6; 8; 12; 14; 16; 18; 20; 22 h; - Wm = 10; 100; 150; - Kp = 3. 3.5. If present coordinates of a selected point and heliogeo- physical conditions do not coincide with the data presented in 3.4 the Ne, Te and Nu values are found by linear interpola- ting the Te, common logarithms of Ne and Nu with respect to height, time, coordinates, day number in a year and solar ac- tivity. 3.6. The errors of Ne, Te and Nu values established by Standard are determined as mean square deviations of relative differences of these values and the experimental mean-monhtly values for given heliogeophysical conditions. 3.7. The electron density error is: - no more than factor 2 at heights from 65 km to 75 km; - no more than 20% in the daytime and no more than 50% at night at heights from 75 km to 100 km; - no more than 10% in the daytime and no more than 30% at night at heights from 100 km to 200 km; - no more than 15% at low and middle latitudes (퀠'� < 60 ) and no more than factor 2 at high latitudes (퀠'� > 60 ) at heights from 200 km to 3000 km; - no more than 30% at heights from 3000 km to 15000 km; 5 ISO WD - no more than 50% at heights from 15000 km to 20000 km. 3.8. For the electron temperature the error is no more than 10% in the daytime and no more than 15% at night. 3.9. For the effective collision frequency of electrons the error is no more than 20% below 110 km and is determined by the errors of Ne, Te (see 3.7, 3.8) and neutral particle den- sity (see [2]) above 110 km. 6 ISO WD Appendix A (informative) STRUCTURE OF INFORMATION PRESENTED IN THE TABLES 1. Information presented in the each table about mean values of Ne, Te and Nu includes: - information line (first); - mean values of one of parameters for conditions given in the information line. 2. An information line includes the following: - table number; - parameter name; - number of the heights for which each parameter was cal- culated; - mean smoothed Wolf number; - month; - geographical coordinates (latitude and longitude in degrees). The information line was written in the FORMAT (4X,I4,2X,A3,1X,I2,1X,I5,I4,2I5). 3. Mean parameter values are presented as follows. Each line contains 13 numbers. First of them is a height in kilometers, for which the calculations are performed, other 12 numbers are calculated values of a parameter shown in the information line for 0; 2; 4; 6; 8; 10; 12; 14; 16; 18; 20; 22 hours local ti- me. Ne is given in m , Te in Kelvin, Nu in s . Zero parame- ter values mean that under given conditions the model not yield values of this parameter. The values of Ne and Nu were written in the FORMAT (2X,0PI6,12(1X,1PE8.2)), the values of Te were written in the FORMAT (2X,13(I6,1X)). At latitudes where the mean plasmapause height is below 20000 7 ISO WD km, the tables of Ne are limited by a plasmapause height from above or 1000 km. Tables of Te and Nu are limited from above by 1000 km or a plasmapause height (according to Ne) and 4000 km, if the plasmapause height is exceed 4000 km. 4. Tables of Ne, Te and Nu are grouped according to input data. First, values of Ne, Te and Nu are presented for conditions given in 3.4 at Wm=10 (tables from 1 to 396) then at Wm=100 (tables from 397 to 792) and Wm=150 (tables from 793 to 1188). Within one activity for the month and geographical latitudes chosen the values are given of all three parameters for every longitude. Then the values of all parameters are presented for the next latitude in the same order. Information for other months is presented similarly. The order of input data varia- tion corresponds to the order given in 3.4. Any questions, suggestions and remarks on the developed draft of International Standard are welcome. Please address to Yu. K. Chasovitin SPA "Typhoon", Lenin Str., 82, 249020, Obninsk, Kaluga Region, Russia. E-mail: typhoon@meteo.ru Fax: (08439) 4-09-10 8 ISO WD Appendix B (informative) BIBLIOGRAPHY [1] G.V. Groves. Seasonal and Latitudinal Models of Atmosphe- ric Temperature, Pressure and Density, 25 to 110 km. Air Force Cambridge Res. Labs. L.G. Hanscom Field, Mass., U.S.A., 1970. [2] L.G. Jacchia. Termosphere Temperature, Density and Compo- sition: New Models 1977, SAO-Special Report, Cambridge, Mass., U.S.A., 1977.