Meeting Abstract

Publication year: 2008

Pages: H51C-0819-

Journal: Eos, Transactions American Geophysical Union

Volume number: 89

Issue number: 53, Suppl.

Publisher: Wiley

Abstract: 

The hydrology of semiarid steppe ecosystems in general is poorly understood due to data scarcity. Under the increasing pressure of water shortage and steppe degradation, information on the hydrological cycle is needed urgently. Stream water and groundwater samples were collected for a co-isotopic study in the Xilin catchment in Inner Mongolia mainly along the flow path from the headwater area to the lowest part from April to September 2006. Deduced by Triangulation Method, the weighted mean δ¹⁸O and δ D in precipitation were -12.3 ‰ and -86.9‰, respectively, in the Xilin Catchment. The seasonal variations of δ ¹⁸O with monthly mean air temperature and precipitation differ much in cold (dry) and warm (wet) seasons. Annual average δ ¹⁸O values in streamwater gradually increased from -13‰ at headwater area to -10‰ at the lowest part. The increase in the isotopic values is partly due to surface water and groundwater influx with higherδ ¹⁸O values and partly due to evaporation. Sand dunes area which is distributed in the center of the catchment, played a special hydrological role in the Xilin catchment. The analysis of δ ¹⁸O in waters in conjunction with meteorological data and discharge data provided further insight into the water interactions. By using a -0.25‰ /100m altitude gradient and a -2.8‰ mean δ ¹⁸O difference between shallow wells and precipitation, the recharge area, which had a mean altitude about 2100m, lies in the east of Xilin catchment. Spatial and temporal water interactions of precipitation, streamwater and groundwater were evaluated. Precipitation contributed a relative larger portion to the runoff at the lower stream or at the end of runoff season. The groundwater was the main source of streamwater. In April, due to the snowmelt, streamwater may recharge groundwater. Continuous pre-event rainfall had great influence on the δ ¹⁸O value in streamwater.

Harvard Citation style: Wu, J., Barthold, F., Breuer, L., Vache, K., Schneider, K. and Frede, H. (2008) Understanding Catchment Hydrology in Semiarid Steppe Ecosystems of China by Isotopic Composition: a Case Study of the Xilin Catchment
Details, Eos, Transactions American Geophysical Union, 89(53, Suppl.), p. H51C-0819

APA Citation style: Wu, J., Barthold, F., Breuer, L., Vache, K., Schneider, K., & Frede, H. (2008). Understanding Catchment Hydrology in Semiarid Steppe Ecosystems of China by Isotopic Composition: a Case Study of the Xilin Catchment
Details. Eos, Transactions American Geophysical Union. 89(53, Suppl.), H51C-0819.