The Relationship Between Soil Moisture Observed By in Situ Probes and Satellite Derived Surface Wetness in Northern Kazakhstan (Calibrating the Satellite on In Situ Measurements for Near Real Time Monitoring of Spring Wheat Yields)

Abstract:

Soil moisture is the critical factor effecting the production of wheat across northern Kazazhstan, and food security and inter-national stability in central Asia is strongly related to the wheat yield in Kazakhstan. In an effort to understand and monitor how soil moisture effects yields, we used probe data to detect these fluctuations, and relate this variability to satellite derived wetness values. The soil moisture observations provided by probes measurements serve as calibration points to the satellite measurements. The regression equations derived from these relationships, identify the covariance between the quantities. Many of the relationships between the probe data and wetness index were meaningful, and can be used to effectively identify how upper level moisture fluctuates in Northern Kazakhstan during the important period of wheat production. The slope and intercepts of the equations determine the ratio between the two measurements, and the intercept identifies when the soil is effectively dry, relative to the satellite observation. Generally, there were two unique relationships, one for the summer season (June, July and August) and one for May, when there was nominal vegetation covering the surface. Findings from this study were highly significant and can be applied in near real time, in order to monitor the distribution of upper level soil moisture across the northern oblasts of Kazakhstan, where the production of wheat is critical to food security in central Asia.