1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 16698:2013Space environment (naturaland artificial) Methodsfor estimation of futuregeomagnetic activityBS ISO 16698:2013 BRITISH STANDARDNational forewordThis British Stan
2、dard is the UK implementation of ISO 16698:2013.The UK participation in its preparation was entrusted to TechnicalCommittee ACE/68/-/4, Space systems and operations - Spaceenvironment (natural and artificial).A list of organizations represented on this committee can beobtained on request to its secr
3、etary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 73123 5ICS 49.140Compliance with a British Standard cannot conf
4、er immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 June 2013.Amendments issued since publicationDate Text affectedBS ISO 16698:2013 ISO 2013Space environment (natural and artificial) Methods for estimation of
5、future geomagnetic activityEnvironnement spatial (naturel et artificiel) Mthodes destimation de lactivit magntique futureINTERNATIONAL STANDARDISO16698First edition2013-05-01Reference numberISO 16698:2013(E)BS ISO 16698:2013ISO 16698:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT
6、 ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be
7、requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 16698:2013ISO 16698:2013(E) ISO 2013
8、 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Symbols and abbreviated terms . 13 General parameters . 13.1 Geomagnetic field variations 13.2 Quiet level and disturbance fields 23.3 K index (local 3 h range index) 23.4 Kp, Kp, ap, and Ap indices (planetary indices). 23.5
9、aa index (antipodal amplitude index) . 43.6 Dst index (storm time disturbance index) 43.7 ASY and SYM indices (mid-latitude disturbance indices) 53.8 AU, AL, AE, and AO indices (auroral electrojet indices) . 53.9 Time lag in the derivation and temporal resolution (sampling) 64 Classification of pred
10、iction 64.1 Short-term prediction . 64.2 Middle-term prediction . 84.3 Long-term prediction 85 Methods of prediction . 95.1 Prediction based on statistical models. 95.2 Prediction based on physical principle 96 Evaluation of prediction efficiency 96.1 Definition of prediction error . 96.2 Methods of
11、 evaluation 97 Compliance criteria 107.1 Rationale 107.2 Reporting 107.3 Documenting 107.4 Publishing . 107.5 Archiving . 10Annex A (informative) Websites where geomagnetic indices are available .11Annex B (informative) Websites where the space weather predictions and/or “now casting” are presented
12、12Annex C (informative) Definition of various skill scores 13Bibliography .14BS ISO 16698:2013ISO 16698:2013(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is
13、 normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part
14、 in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prep
15、are International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that so
16、me of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 16698 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations.iv ISO 2013
17、All rights reservedBS ISO 16698:2013ISO 16698:2013(E)IntroductionThis International Standard provides guidelines for specifying the process of estimating future geomagnetic activity. Geomagnetic indices describe the variation of the geomagnetic field over a certain time period and provide a measure
18、of the disturbance of the magnetosphere.The accuracy and method of predicting geomagnetic indices depends on the time scale of prediction. This International Standard presents existing works based on three categories of time scale:a) short-term prediction (1 h to a few days);b) middle-term predictio
19、n (a few weeks to a few months);c) long-term prediction (half year to one solar cycle).These are required as input parameters for the magnetospheric magnetic field (ISO 22009), upper atmosphere (ISO 14222), ionosphere, plasmasphere (ISO/TS 16457), magnetosphere charged particles, and other models of
20、 the near-Earth space environment. They also serve as the input parameters for orbital lifetime prediction and worst-case environment analysis of electrostatic charging.Three International Standards deal with the Earths magnetic field, including ISO 16695 on the internal magnetic field, ISO 22009 on
21、 the magnetospheric magnetic field, and this International Standard. ISO 2013 All rights reserved vBS ISO 16698:2013BS ISO 16698:2013Space environment (natural and artificial) Methods for estimation of future geomagnetic activity1 ScopeThis International Standard specifies the methods used for estim
22、ating geomagnetic indices for time intervals ranging from the short-term (hours to a few months) to the long-term (months to years).Geomagnetic indices are used to describe the activity levels of the disturbance of the geomagnetic field. These indices can be used to estimate upper atmospheric and pl
23、asmaspheric densities and many other space environment models. They are also used as the input parameters for orbital lifetime prediction and worst-case environment analysis of electrostatic charging.This International Standard is intended for use to predict future geomagnetic indices and space envi
24、ronment.2 Symbols and abbreviated termsBs Southward component of the interplanetary field (Bs = 0 when Bz 0 and Bs = Bz when Bz 0)Bz North-south component of the interplanetary fieldF10.7 flux Measure of the solar radio flux at a wavelength of 10,7 cm at the earths orbit, given in units of 1022Wm2GL
25、at Geographic latitudeGLon Geographic longitudeIMF Interplanetary magnetic fieldMLat Geomagnetic latitudeMLon Geomagnetic longitudeMHD MagnetohydrodynamicsSq Daily geomagnetic field variations during quiet conditions (Solar quiet)UT Universal time3 General parameters3.1 Geomagnetic field variationsT
26、he geomagnetic field consists of internal and external magnetic fields. The internal (main) magnetic field is produced by source currents that are mostly inside the Earths core and by induced currents present in the solid Earth and the ocean, caused by the temporal variation of external magnetic fie
27、lds. The external magnetic field is produced by magnetospheric and ionospheric currents.The magnetosphere is highly dynamic with time scales ranging from minutes to days. Solar wind is the ultimate source of magnetospheric dynamics. The role played by the IMF (interplanetary magnetic field) northsou
28、th component, Bz, is particularly important, and its southward component, Bs, plays a INTERNATIONAL STANDARD ISO 16698:2013(E) ISO 2013 All rights reserved 1BS ISO 16698:2013ISO 16698:2013(E)fundamental role in substorm and magnetic storm activity through the process of magnetic field line reconnect
29、ion. Solar wind speed also plays an essential role in these dynamics.3.2 Quiet level and disturbance fieldsFive days of every month are selected as the Five International Quietest Days using the Kp index (see 3.4.1). Note that the five quietest days are selected regardless of the absolute level of q
30、uietness. Thus, in a disturbed month, the quietest days may not be very quiet.Derivation: The quietest days (Q-days) of each month are selected using the Kp indices based on three criteria for each day: (1) the sum of the eight Kp values, (2) the sum of squares of the eight Kp values, and (3) the ma
31、ximum of the eight Kp values. According to each of these criteria, a relative order number is assigned to each day of the month; the three order numbers are then averaged and the days with the first to fifth lowest mean order numbers are selected as the five international quietest days.Reference: We
32、bsite of the Deutsches GeoForschungsZentrum (http:/www-app3.gfz-potsdam.de/kp_index/qddescription.html).Once the quiet level is determined using the Five International Quietest Days, disturbance fields can be obtained as deviations from the quiet level of geomagnetic field.3.3 K index (local 3 h ran
33、ge index)The K index is a number in the range 0 (quiet) to 9 (disturbed) that provides a local classification of the variations of the geomagnetic field observed after subtraction of the regular daily variation (Sq). Each activity level relates almost logarithmically to the corresponding disturbance
34、 amplitude of the horizontal field component during a 3 h UT interval. In a day, eight K indices are given in successive 3 h UT (universal time) intervals (0 h to 3 h, 3 h to 6 h, ., 21 h to 24 h UT).Derivation: The ranges R for the H and D (or X and Y) components are defined as the expected differe
35、nce between the highest and lowest deviation, within the three-hour interval, from a smooth curve (a regular daily variation) for that element on a magnetically quiet day. Only the larger value of R, i.e. R for the most disturbed element, is taken as the basis of K. To convert from R to K, a permane
36、nt scale prepared for each observatory is used. Table 1 is an example of the permanent scale for the Niemegk observatory.References: Bartels et al. 1939, Mayaud 1980, Menvielle et al. 2011Table 1 Permanent conversion scale from R to K for Niemegk observatoryRange (nT) 0-5 5-10 10-20 20-40 40-70 70-1
37、20 120-200 200-330 330-500 500K value 0 1 2 3 4 5 6 7 8 93.4 Kp, Kp, ap, and Ap indices (planetary indices)The planetary indices, Kp, Kp, ap, and Ap, are derived from 13 selected mid-latitude observatories (see Table 2). The derivation scheme for each index is described in the corresponding subsecti
38、on.2 ISO 2013 All rights reservedBS ISO 16698:2013ISO 16698:2013(E)Table 2 Thirteen observatories that contributed to the Kp indexObservatory, country Code GLat (N) GLon (E) MLat () NotesMeannook, Canada MEA 54.617 246.667 62.5Sitka, USA SIT 57.058 224.675 60.0Lerwick, Shetland Is.,UK LER 60.133 358
39、.817 58.9Ottawa, Canada OTT 45.400 284.450 58.9 Replaced Agincourt in 1969Uppsala, Sweden UPS 59.903 17.353 58.5 Replaced Lovo in 2004Eskdalemuir, UK ESK 55.317 356.800 54.3Brorfelde, Denmark BJE 55.625 11.672 52.7 Replaced Rude Skov in 1984Fredericksburg, USA FRD 38.205 282.627 51.8 Replaced Chelte
40、nham in 1957Wingst, Germany WNG 53.743 9.073 50.9Niemegk, Germany NGK 52.072 12.675 48.8 Replaced Witteveen in 1988Hartland, UK HAD 50.995 355.517 50.0 Replaced Abinger in 1957Canberra, Australia CNB 35.317 149.367 45.2 Replaced Toolangi in 1981Eyrewell, New Zealand EYR 43.424 172.354 50.2 Replaced
41、Amberley in 19783.4.1 Kp index (planetary 3 h range index)The Kp index is assigned to successive 3 h UT intervals (0 h to 3 h, 3 h to 6 h, ., 21 h to 24 h UT), giving eight values per UT day, and ranges in 28 steps from 0 (quiet) to 9 (disturbed) with intermediate values denoted by , o, or +, result
42、ing in 0o, 0+, 1,1o, 1+, 2, 2o, 2+, ., 8, 8o, 8+, 9, and 9o.Derivation: The K indices at the 13 observatories given in Table 2 are standardized by means of conversion tables that have been established through the rather complicated procedure introduced by Bartels 1949. The standardized K indices, ca
43、lled the Ks index, are averaged using weighting factors to derive the Kp index.References: Bartels 1949, Mayaud 1980, Menvielle et al. 20113.4.2 Kp index (planetary daily range index)Kp is the sum of the eight Kp values of the day.3.4.3 ap index (planetary 3 h equivalent amplitude index)The Kp index
44、 is not linearly related to the geomagnetic disturbances measured in the unit of nT. Instead, the ap index is introduced as it is roughly proportional to the geomagnetic disturbances. One ap unit corresponds to approximately 2 nT of geomagnetic variations.Derivation: The ap index is derived directly
45、 from the Kp index by using the conversion table shown in Table 3.References: Bartels and Veldkamp 1954, Mayaud 1980, Menvielle et al. 2011Table 3 Conversion table from the Kp index to the ap indexKp 0o 0+ 1 1o 1+ 2 2o 2+ 3 3o 3+ 4 4o 4+ap 0 2 3 4 5 6 7 9 12 15 18 22 27 32Kp 5 5o 5+ 6 6o 6+ 7 7o 7+
46、8 8o 8+ 9 9oap 39 48 56 67 80 94 111 132 154 179 207 236 300 400 ISO 2013 All rights reserved 3BS ISO 16698:2013ISO 16698:2013(E)3.4.4 Ap index (planetary daily equivalent amplitude index)The Ap index is the average of the eight values of the ap index in a UT day.3.5 aa index (antipodal amplitude in
47、dex)The aa index is a simple measure of global geomagnetic activity, which can be traced back continuously to 1868.Derivation: The aa index is produced from the K indices of two nearly antipodal magnetic observatories in England and Australia, which are listed in Table 4. The K indices at the two ob
48、servatories are converted back to amplitudes using Table 5. The aa index is computed as an average of the northern and southern values of amplitude using the weighting factors, , shown in Table 4.References: Mayaud 1971Table 4 Observatories in England and Australia contributing to the aa indexObserv
49、atory, country Code Period GLat (N) GLon (E) MLat () Greenwich, England 18681925 1,007Ablinger, England ABN 19261956 51.18 359.62 53.4 0,934Hartland, England HAD 1957 50.97 355.52 54.0 1,059Melbourne, Australia 18681919 0,967Toolangi, Australia TOO 19201979 37.53 145.47 45.6 1,033Canberra, Australia CNB 1979 35.30 149.00 42.9 1,084Table 5 Conversion table from the K index at the aa observatories to amplitudesK index 0 1 2 3 4 5 6 7 8 9Amplitude 2,3 7,3 15 30 55 95 16
