derived total precipitable water 1°x1° data products at 8:00 hrs
IST and 14:00hrs IST were used for 7,10,17hrs. acquisitions and
12,14hrs. acquisitions respectively. The average atmospheric
turbidity parameters, & and ß, were used for all weather
conditions. The sensitivity analysis showed the degree of
dependence of total insolation on both the parameters. Thus the
proper tuning of turbidity parameters according to changing
weather conditions can increase the accuracy of insolation
retrieval.
4. CONCLUSIONS
Although the present study showed the possibility of insolation
retrieval using geostationary data over India for both clear and
cloudy sky conditions, but its large area validation with more
number of image acquisitions per day and huge real time ground
based observations is the need of the hour. The cloud
attenuation coefficients and turbidity parameters need to be fine
tuned using real time pyranometer and sun photometer
observations. The retrieval of precipitable water for
atmospheric corrections in insolation retrieval scheme will be
possible with the future launch of INSAT-3D having ‘Imager’
with six channels including two thermal bands.
ACKNOWLEDGEMENTS
We are highly thankful to EUMETSAT , Germany to provide
us Meteosat-5 datasets for carrying out this study. We are
grateful to Shri J. S Parihar, Group Director, Agricultural
Resources Group and Director, RSAM, Space Applications
Centre, Ahmedabad for constantly giving us encouragement.
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