Quality Evaluation of the European Space Agency Climate Change Initiative Soil Moisture Product in Gansu Province

The European Space Agency Climate Change Initiative Soil Moisture (ESA-CCI SM) product can provide soil volumetric water content data with high spatiotemporal coverage and a long time series. We used Gansu province as the study site for ESA-CCI SM testing. Automatic soil moisture station data was used to evaluate the ESA-CCI SM product by analyzing the spatiotemporal variation characteristics of soil moisture in a long time series. The ESA-CCI SM product showed the best correlation to observed values in the Longdong region (R=0.70), followed by the Longnan, Longdong, and Ganmin regions. Overall, 92% of the sites had correlation coefficients that were significant at a=0.01. ESA-CCI SM indicated that the northwestern regions are more arid while the southeastern regions are more humid. Soil moisture showed significant seasonal variation, with autumn being relatively more humid, followed by summer while winter and spring were drier.