USING SATELLITE EARTH OBSERVATIONS TO UNDERSTAND THE FACTORS CONTROLLING THE TERRESTRIAL WATER CYCLE IN THE NORTHERN HIGH PLAINS, USA
The results indicate there is a statistically significant correlation with time delays between the different TWC variables and dTWS/dt from GRACE. A relatively strong positive correlation (r = 0.77-0.83) exists between GWL and dTWS/dt with a time delay of 0 to 2 months. Soil moisture is positively correlated with dTWS/dt with little to no delays. However precipitation, vegetation coverage, and land surface temperature variables are negatively correlated (r = -0.4 – -0.6) with GRACE’s dTWS/dt with delays of 2 to 4 months. This could be associated with seasonality, where these variables are relatively higher during the summer season, while dTWS/dt decreases due to high evapotranspiration in this season. The reverse is also true during the winter season. There is consistency in correlation between the different products and GRACE with minor differences in time delays. For example, the correlation values of SM from NLDAS with dTWS/dt and SM from AMSRE with dTWS/dt were nearly equal in magnitude but different in time delay. Further improving this approach may help to predict TWS anomaly from different TWC variables and used to fill the gap between current and future GRACE mission.