A plateau scale soil moisture and soil temperature observatory is established on the Tibetan Plateau for quantifying uncertainties in coarse resolution satellite and model products of soil moisture and soil temperature. The Tibetan Plateau observatory of plateau scale soil moisture and soil temperature (Tibet-Obs) consists of three regional scale in-situ reference networks, including the Naqu network in a cold semiarid climate, the Maqu network in a cold humid climate and the Ngari network in a cold arid climate. These networks provide a representative coverage of the different climate and land surface hydrometeorological conditions on the Tibetan plateau. In this paper the details of the Tibet-Obs are reported. To demonstrate the uniqueness of the Tibet-Obs in quantifying and explaining soil moisture uncertainties in existing coarse satellite products, an analysis is carried out to assess the reliability of several satellite products for the Naqu and the Maqu network areas. It is concluded that global coarse resolution soil moisture products are useful but exhibit till now unreported uncertainties in cold and semiarid regions – use of them would be critically enhanced if uncertainties can be quantified and reduced using in-situ measurements.

In this chapter, the observation of hydrological processes using remote sensing, which is also commonly called Earth observation of hydrological cycle or Earth observation of water cycle, is briefly described. Earth observation of the different components of the water cycle is described in depth including a summary of the current state of the science, its historical development, retrieval methodologies, available data sets, and future research needs. These water-cycle components include clouds and water vapor, precipitation, rainfall, evaporation and transpiration, snow and ice, surface water, river flows and wetlands, soil moisture, groundwater, water quality, as well as water use in agrosystem and ecosystem. The techniques described include passive remote sensing and active remote sensing with optical, thermal, and microwave observations as well as gravimetry, with instruments including spectrometer, spectroradiometer, radar, radiometer, synthetic aperture radar, and gravimeter.

The objective of this project is to develop a quantitative and operational system for nationwide drought monitoring and drought impact assessment for application in agriculture, water resources and environmental management in China using ESA, Chinese and other relevant satellite data as major data source in combination with other data source (e.g. meteorological and drought statistics, etc.). An extension to drought prediction and adaptation to climate change will be made compared to the Dragon I drought monitoring project. In detail the project aims to generate: (1) a real time drought monitoring and prediction system, (2) improved understanding of land surface processes and land-atmosphere interactions over different terrains (e.g. agriculture land, forest, Gobi desert, high plateau, polar environment), (3) improved algorithms for estimation of land surface parameters and heat fluxes, (4) assessment of economic loss caused by drought and adaptation measures under climatic change, (5) training of young scientists in the area of water, climate and environment. In this contribution, progresses in retrievals of soil moisture using data from different methods are addressed, including in-situ observations, direct retrievals using data from satellite sensors and numerical modeling. The used sensors include ASAR, ASCAT, and AMSR-E. The accuracy of available soil moisture products are assessed using in-situ data collected by the Tibetan Plateau soil moisture monitoring network developed for this and other projects.