Estimation of atmospheric water vapor using MODIS data 1. (case study: Golestan province of Iran)

Atmospheric water vapor (awv) is one of the important parameters in the hydrologic cycle,energy exchange between the surface and the atmosphere,modeling the flow of energy at the ground level and climate change. thus,the estimation of awv has a great importance in the hydrology and climate studies. in this paper,the band ratio method was used for estimating awv content of golestan province in iran using near infrared (nir) moderate resolution imaging spectro radiometer (modis) data. for this purpose,the bands 17,18 and 19 of modis as near-infrared bands and band 2 to remove the ground reflectivity were used. the results showed that the amount of awv in the forests,range-land,agriculture,barren-land,residential and water bodies,were 3.104,2.250,3.791,1.263,2.731,5.247 gr/cm2 respectively. the lower atmospheric water vapor in the barren lands than other land-uses can be considered as lack of rainfall and high evaporation potential in these areas. the results also revealed that the use of remote sensing and band ratio method is an appropriate method to estimate awv in a large area. © 2017,university of mohammed premier oujda morocco.