Satellite based assessment of soil moisture and associated factors for vegetation cover: a case study of Pakistan and its adjoining region

摘要

Soil Moisture is a vital requirement for plant growth and its measurement with laboratory instruments is still limited to micro-geographic levels only. However, Satellite remote sensing happens to be efficient for macro scale measurements at regional levels. Soil Moisture depends on factors such as rainfall, temperature, rate of surface run-off and evapotranspiration. To develop a deeper and clearer insight into the interrelationship of these dependent factors, the Remote Sensing (RS) technology is being effectively employed in this study for assessing the seasonal and their inter-annual variations. A Standard NASA GES DISC product of Global Land Data Assimilation System (GLDAS) based on the mathematical algorithms of satellite model data has been employed for this investigation. The data pertaining to Pakistan and adjoining areas was collected for soil moisture, soil temperature, rainfall, surface run-off and total evapotranspiration over the year from January to December 2014 and quarterly from April to June, July to September and October to December. Composite and Seasonal maps as well as time series graphs were used throughout the process. Results for all variables clearly indicate that in high altitude areas, almost every variable has relatively higher values. It was concluded that spatial variations in soil moisture are quite reliant upon land cover types and the amount of precipitation (rainfall).