Experimental Study On Soil Moisture Profile Inversion

Soil moisture is an important part of the soil, and it plays an important role in energy and material exchange between land and atmosphere. It is an important environment factor and the process parameters of hydrology and meteorology and other disciplines research. In order to accurately depict and understand the interaction of land and atmosphere, we need precise and high resolution soil moisture contour information. But whether by the objective measure or by numerical prediction of land surface process simulation, we are still cannot get soil moisture contour line of space-time continuum and precision meets the requirements. Data assimilation method considering the error of observation information and mode of analog information and fusing observation when dynamic operate numerical model can give soil moisture information of space-time continuum and precision meets the requirements. This study bases on passive microwave inversion products and land surface model, and transfers the shallow soil moisture information to deeper soil layers by land assimilation system LIS. Using this way we can get soil moisture contour information which has high precise and resolution and has smaller error then observation error and simulation error.First, successfully build the land assimilation system LIS on large workstation in NSMC(National Satellite Meteorology Center). Through the initial examination, this system can effectively assimilate observation information, and the soil moisture precision of assimilation is high then soil moisture precision of simulation; Along with the growth of recursive prediction time, assimilation recursive prediction results and observation getting closer and closer.Second, test the AQUA/AMSR-E soil moisture products using the station soil moisture products of China agriculture and meteorological station. The results show that AQUA/AMSR-E soil moisture products can reflect the land surface soil moisture variation characteristics in general, so we can use these products as main observation data sources to assimilate into land data assimilation system LIS.Third, test the assimilation results which base the assimilation of AQUA/AMSR-E soil moisture products using the station soil moisture products of China Agriculture and Meteorological stations and China Ecological stations. Results show that the assimilation results better reflects soil moisture distribution and change characteristic in 2003; Ability of LIS system assimilation in forest ecological system is lower then in meadows and crop ecological system; LIS system assimilation can get soil moisture contour line of space-time continuum and in different vegetation conditions the results of assimilation are all better then the results of simulation.Fourth, data assimilation was done by using China FY-3B/MWRI soil moisture product. The results show that the simulating soil moisture data of LIS system based on FY-3B/MWRI product have very high accuracy, and is comparable with the data from AQUA/AMSR-E product.Finally, try to analyze the drought in Hunan and Jiangxi provinces in 2003 with data assimilation of LIS system by AQUA/AMSR-E products. Assimilation results shows that the simulating soil moisture begins to from the early April in 2003 and the average soil moisture remains at very low level from the summer to next spring, which indicates the drought in that area.A detailed summary is presented in the end.