Studies on the Impacts of 3D-VAR Assimilation of Satellite Observations on the Simulation of Monsoon Depressions over India - Data Assimilation for Atmospheric, Oceanic and Hydrologic Applications - page 643

Fig. 26.1 The 36 km (outer domain) and 12 km (inner domain) utilized in this study

3D-VAR after 6 h of forecast; i.e., from 19 September 2006 00 UTC and has ingested
the ATOVS observations in a 12 h interval up to 00 UTC 20 September 2006.
The model is subsequently integrated for the next 60 h in a free forecast mode
without any further assimilation of the satellite data. The third experiment is named
as the “MODIS run” in which the vertical profiles of temperature and humidity
observations from the MODIS satellite have been assimilated in 12 h interval from
18 September 2006 18 UTC to 19 September 2006 18 UTC and the model was
subsequently run in a free forecast mode up to 22 September 2006 12 UTC. The
high resolution MODIS data is subjected to “thinning” before ingesting the data to
the observational pre-processor. The fourth experiment, named as the “SSM/I run” is
similar to the ATOVS experiment except that it incorporates SSM/I total precipitable
water (TPW) instead of ATOVS temperature and humidity observations. All the
model runs are subjected to a 6 h interval data cycling to maintain the dynamical
consistency of the model simulation The CTRL run is subjected to data cycling
without any assimilation of observations ( Chen et al. 2008 ). Figure 26.1 shows the
model domains with the outer domain depicting horizontal grid resolution of 36 km
while the inner domain shows the 12 km horizontal resolution. All the results shown
in this article are from the finer 12 km resolution only.