omega = u*d(psfc)/dx + v*d(psfc)/dy
to
omega = 0.
06/18/96 Divergence and omega were corrected due to a slight
error found in implementation of the O'Brien adjustment scheme.06/18/96 Surface winds were corrected at R/V Shiyan 3 and R/V Kexue 1. Previous winds were off by about 12 degrees.
The 06/18/96 changes resulted in omega changes from the previous version of the analyses that were greater than 50% from the surface to 975 mb (where omegas are quite small), decreasing to less than 10% above 800 mb and to less than 1% above 500 mb.
07/06/96 Surface fields were corrected in files fields.ifa and advect.ifa on 11/09/92 at 12UTC due to some bad data that made it into the surface analyses at this time.
09/23/96 Date information was corrected in file misc.ifa. In the original version of the file the date associated with data at 00 UTC was incorrect.
11/13/96 Improved surface analyses by assuming that data were from surface only if the height of the observations were within 10 m of station height. Also, bad surface humidities were removed (i.e., specific humidities less than 10 g/kg). The impact of this latter improvement will be most noteable from 11/17/92 to 01/04/93 when surface humidities at Kapinga were often considered bad (i.e., too low). The main effect of these changes, of course, are to the surface data themselves. The overall effect was to increase the IOP IFA daily averaged rainfall (estimated from the Q2 budget) from 8.166 mm/day to 8.207 mm/day (or an increase of 0.041 mm/day).
04/16/02 The version 2.0 analysis uses the NCAR/ATD humidity corrected
sonde data (Wang et al. 2002). Also, we employed a spurious divergence
correction (Haertel et al. 2002). The overall effect of these corrections
was to increase the IOP IFA daily averaged rainfall (estimated from
the Q2 budget) to 8.40 mm/day and
10/21/02 The version 2.1 analysis corrects the humidity variables
for temperatures below freezing.
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