A GIS application for weather analysis and forecasting  Fig. 7. Super imposition of the wind flow pattern and specific humidity (gm/kg) at 850 hPa level at 5.30 A.M. IST on 17th Dec. 2000, over the surface topography. The red arrows show the wind flow, and the green contour lines with blue colored numbers across show the specific humidity distribution. The multicolored background is the surface created out of the ten minute interval orography of the area. A forecaster need examine the occurrence of all systems of cloud, precipitation, fog, stratus, drizzle, etc. in relation to orographic influences, coastal influences, etc, and also give special attention to diurnal cycles in weather behavior. Only by long experience and close examination of successive weather charts and particularly of current ones, which can be related by the forecaster to the existing weather in his own area, can ability be acquired in applying to actual weather forecasting the physical principles and other meteorological information underlying the weather process as such. The capability of GIS in superimposing the surface topographic features over the atmospheric analysis for interpretation of the dynamics and physical processed in the atmosphere is given in Fig. 7.  Fig. 8. Super imposition of the wind flow pattern and specific humidity (gm/kg) at 850 hPa level at 5.30 A.M. IST on 17th Dec. 2000, over the surface topography. The red arrows show the wind flow, and the green contour lines with blue colored numbers across show the specific humidity distribution. The purple colored contours with black numbers across represent the ten minute interval orography of the area. In fig. 8, the same information provided in Fig. 7 is provided with contour values of topography instead of the orographic surface. This figure shows an example of various ways of presentation of the weather parameters in order to study and understand atmosphere with various angles and perspectives. It is also possible to superimpose the various satellite pictures of cloud, moisture etc. over the weather maps for better interpretation and forecasting of weather. Use of GIS in weather forecasting will certainly improve the capability of the meteorologist in forecasting weather with better skill and accuracy in the days to come. Summary A GIS application has been developed using ArcView of ESRI to serve as an aid in the man - machine - mix approach for preparation of medium range weather forecasts. Weather and climate are integral parts of the geography of a place. In order to prepare weather forecasts, the forecaster plots information of the atmosphere around the globe on a weather chart. The plotted data is analyzed with the help of contours and surfaces to bring out the weather systems in the atmosphere at various levels. The analyzed weather becomes initial condition for the conventional synoptic weather forecasts and GCMs for prognostication of weather in the coming days. The capability of GIS software in handling the spatial data in an easier way coupled with the different analysis tools available make it a viable tool for its adoption in weather forecasting. References
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