0073                                                         Nov.11, 19940005 0078    This update (file name is GSM1194.DAT), of the magnetospheric modeling0076dataset (see Fairfield et al., J.Geophys.Res., v.99, #A6, p.11319, 1994,0078for details and the format description) has been generated on Nov.9, 1994.0081It is based on the previous release of October 1993; the difference from the 0081latter is that several glitches have been found and eliminated, as explained 0010below.00040078  (1) In the earlier version some records, in which the begin time and the0077center of the averaging interval did not belong to the same UT hour, were0078supplied with the wrong value of HOUR (word #3) (by 1 hour larger than the0081correct value).  This error could have affected calculations which explicitly0077used UT values from the dataset. In this version, the erroneous UT values0033are replaced by correct ones.00040083  (2) In the previous version, we used the solar wind parameters from the files0079obtained via the online NODIS system. In those files, missing values of the0081solar wind parameters were filled by 0's, which might lead to ambiguities in 0079some cases. For example, records containing zeros for the solar wind speed 0081could be easily recognized as "no-data" records, since V never falls to zero.0082Similarly, it is very unlikely that all three components of the IMF simultane-0082ously equal zero, so it could also serve as an indicator of the "no-IMF-data" 0082records. However, this way of labeling the "no-data" records becomes ambiguous0078for such parameters as the elevation angle, Vlat, and the azimuthal angle,0075Vlon, of the solar wind flow: it is impossible to distinguish between a0075"no-data" case and that of strictly radial solar wind. In creating this0078upgrade of the dataset, the CD-ROM version of the OMNI files were used, in0071which all digits of missing parameters were filled by 9's, and that0079effectively solved the problem. All missing data are now filled by nines in^^^^^^^^^^^^^^^^^^^^^^^^^^^^^0044the new version of the modeling dataset.00040079  (3) The old version did not completely match the data format description 0080given in the Table 2 of the paper by Fairfield et al., J.Geophys.Res., v.99,0082p.11319, 1994, in that the sequence of the flow angles Vlat and Vlon was oppo-0082site to that given in the Table. Now the correct order is restored in the data0079file so that it corresponds to the documentation: first Vlat and then Vlon.00040083  (4) Due to the interpolation between contiguous hours used for ISEE data, the0082merging code generated "non-standard" digital equivalents for the Kp-index va-0080lues, such as, for example, 18, 22, 29, etc., which do not correspond to any0082elements in the sequence 0,0+,1-,1,1+,2-,2,2+,... .    However, we decided not0082to change these values to standard ones, since, in some cases, such "rounding"0081would be ambiguous. In any case, users interested in the Kp-index can easily 0051make an appropriate standardization themselves.00040082  (5) It was also found that in a small number of HEOS-2 records at distances 0081greater than 17 Re (records ## 45262-45585), the begin times (Bmin, word #4) 0080were inadvertently set equal to zero, creating a small error in the timing. 0083The associated averaging durations (Dmin, word #5) are also unreliable and the 0082AE values are not exactly correct.) The HEOS field averages which, in contrast0079to the rest of the data set, were prepared and provided to us by Principal 0083Investigators (P.C. Hedgecock and B.T. Thomas) about 20 years ago, have several0080important characteristics missing in their data format (e.g. the numbers of 0082points in the averages, the r.m.s. deviations, and durations of the averaging 0084intervals).  Some details of their averaging procedure are also not quite clear.0082For these reasons, we are planning to reprocess all the HEOS data files, using0081the original high-resolution data. When this is accomplished, the Bmin error ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^0080described above will be corrected and the other omitted quantities restored.00040071                      N.A. Tsyganenko                D.H. Fairfield00040079     Internet:     ys2nt@lepvax.gsfc.nasa.gov    u2dhf@lepdhf.gsfc.nasa.gov0067        Phone:     (301)-286-7925                (301)-286-74720067         Fax:      (301)-286-1683                (301)-286-16290009     0067     Mail address:                   Code 695                  0050                                     NASA GSFC0060                                     Greenbelt, MD 20771^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^