Comparison of data from ground-based and satellite measurements of the monthly sum of atmospheric precipitation on the example of Tbilisi city in 2001-2020

Abstract

The data of ground-based (Prec_MS) and satellite (Prec_Sat) measurements of the monthly sum of atmospheric precipitation are compared using the example of Tbilisi in 2001-2020. In particular, the following results are obtained. In general, for all observational data (240 months), Prec_MS values vary from 0 to 267.3 mm, and Prec_Sat - from 3.0 to 184.0 mm. Their average values are 43.6 and 64.8 mm, respectively. Monthly mean values of Prec_MS vary from 16.7 mm (January) to 93.2 mm (May) and Prec_Sat values – from 32.5 mm (December) to 114.4 mm (May). Ground-based measurements are lower than satellite data for all months of the year. The difference between the average values of Prec_MS and Prec_Sat over 20 years varies from -8.8 mm (November) to -33.4 mm (March). Ratio between the average values of Prec_MS and Prec_Sat varies from 40.6 % (January) to 81.5 % (May). There is a direct linear correlation between the studied parameters. For all observational data (240 months) coefficient of correlation is 0.86 (high correlation), for separate month changes from 0.65 (July, moderate correlation) to 0.94 (April, very high correlation). Coefficient of correlation between average values of the studied parameters is 0.97 (very high correlation).