HR: 0800h
AN: H11B-1267    [Abstracts]
TI: Reconstruction of Soil Moisture and Vegetation Water Use Conditions Based on Tree-Ring Widths From Qilian Juniper in Qaidam Basin, Northwestern China
AU: * Yin, Z
EM: zyin@sandiego.edu
AF: Marine Science and Environmental Studies, University of San Diego, 5998 Alcala Park, San Diego, CA 92110 United States
AU: Shao, X
EM: shaoxm@igsnrr.ac.cn
AF: Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Rd., Beijing, 100101 China
AU: Liang, E
H11B-1267 AF: Institute of Tibetan Plateau Research, Chinese Academy of Sciences, 18 Shuangqing Rd., Beijing, 100085 China
AU: Qin, N
H11B-1267 AF: Qinghai Climate Data Center, Qinghai Meteorological Bureau, Xining, 810001 China
AB: Tree-ring widths have been used widely in studies of environmental changes and reconstructions of past climate. Eleven tree-ring chronologies of approximately 800-1500 years long were developed from Qilian juniper (Sabina przewalskii Kom.) for the eastern part of the Qaidam Basin, northwestern China. The study area is located in an arid/semi-arid region with desert and dry grassland vegetation, but sparse juniper trees can be found on mountain slopes of 3600-4200 m above sea level, along the northeastern margin of the Tibetan Plateau. Previous studies have revealed that ring widths are positively correlated to May and June precipitation, but negatively correlated to temperature of the same months in this region, indicating that water use stress is the most limiting factor for tree growth during the growing season. We performed water balance modeling based on 1955-2002 meteorological data. We found that the tree-ring width is strongly correlated with variables representing soil moisture conditions obtained from the model. Specifically we considered actual evapotranspiration representing the combined effect of water use demand and moisture availability, deficit as the difference between potential evapotranspiration and actual evapotranspiration, representing the severity of water use shortage, and relative soil moisture as the measure of moisture availability. For certain individual months, such as May and June, and various bi-monthly and seasonal combinations (e.g., May-June, April-July, January to July, and July of previous year to current June), the tree-ring chronologies can explain more than 70% of the variation in the soil moisture variables in regression analysis, indicating very good potential for reconstruction of regional soil moisture conditions in the past.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1637 Regional climate change
DE: 1833 Hydroclimatology
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: Fall Meeting 2005