Fluorescence excitation and average molecular weight of 46 water soluble organic matter (WSOC) samples extracted from 20 soil types in eastern China were determined. It was found all samples shared similar spectroscopy. A good linear relationship existed between total organic carbon and excitation in the range of 350 to 450 nm though the content of organic carbon and pH of the samples vary in a wide range. No significant correlation between relative excitation intensity and average molecular weight of WSOC and FA was found, but the partial correlation became significant with pH as the controlling factor for WSOC samples. The relative excitation intensity showed a general trend of increasing from south to north in the study area. The pH value might play an important role in regulating the fluorescent spatial variation of WSOC.

New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source.

Western China includes 12 provincial divisions (the 7 provinces of Sichuan, Guizhou, Yunnan, Shaanxi, Gansu, Qinghai and; 5 autonomous regions of Tibet, Ningxia, Xinjiang, Inner Mongolia and Guangxi; and one city of Chongqing), which comprise 71.4% of the national land area, 28.5% of the national population and produce 17.5% of the national GDP in China. There are 17 countries that have riparian relationships with western China, most of which are water-short countries. All are listed by UN ESCAP as countries with potential water crisis. The co-operative development and coordinated management of international rivers in western China is an important step toward the implementation of the national Great Western Development program. Taking into account of the national strategy and object hierarchy, as well as the development demand of the western region, it is necessary to pursue the multi-disciplinary study of the equitable allocation, utilisation, and ecoenvironment protection of transboundary water resources in the region. Such efforts will undoubtedly provide scientific evidence and support for the decision-making of the environmental protection and ecological construction and management in the western regions, the enforcement of the sub-regional economic co-operation, mitigation of trans-boundary conflicts, and enhancing bio-diversity conservation.