Mr. YuhanBian, Zhangping Meteorological Bureau, Fujian
Prof. Jie Wang, School of Hydrology and Water Resources, NUIST
Objectives
Soil moisture (SM) plays a crucial role in the hydrological cycle due to its frequent interaction with surface water and groundwater. Currently, there are two primary methods for monitoring SM: field measurement and remote sensing-based retrieval. However, field SM measurement is limited in large-scale areas with complex terrain as it can not reflect the spatial heterogeneity of SM. On the other hand, remote sensing-based retrieval from optical or radar imagery can acquire SM data at a larger scale, but its obstacle is the limited maximum detection depth of 1-5 cm. SM levels affect various soil and plant dynamics, where surface SM refers to the water in the upper 10 cm of soil, and root zone SM refers to the water available to plants, generally considered to be in the upper 200 cm of soil. Consequently, a new method for obtaining SM should be developed to overcome these issues.
Conclusions
(1) the estimated SM changes generally showed good temporal agreement with each SM product in the research area, except for the Yellow River basin and the HaiheRiver basin. This could be due to significant differences in the soil discrepancy characteristics during the permafrost and non-permafrost periods in these basins, which affected the SM changes detected using microwaves.
(2) the estimated SM changes showed high spatial and temporal correlation with all other products in the Pearl River basin, indicating that the estimation method is highly applicable in this basin.
(3) while the proposed method can estimate SM of all soil layers above groundwater level, it does not consider the changes of biological water and the influence of human activities, which may introduce some uncertainty.