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Journal of Environmental Hydrology
ISSN 1058-3912 |
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Electronic Journal of the International Association for
Environmental Hydrology
JEH Volume 14 (2006), Paper 18 Posted October 31, 2006 IMPACTS OF CLIMATE FACTORS ON RUNOFF COEFFICIENTS IN THE SOURCE REGIONS OF THE YELLOW RIVER
Chen Liqun1,5 3 College of Water Science, Beijing Normal University, Beijing, China 3 School of Environment, Beijing Normal University, Beijing, China 4 Bureau of Hydrology, Yellow River Conservance Commission, ZhengZhou, China 5 Graduate school of Chinese Academy of sciences, Beijing, China ABSTRACT In the 1990's, runoff at the Tangnaihai hydrologic station experienced a serious decrease which attracted considerable attention. Changes in temperature and rainfall would have an important impact on the availability of water resources. From the point of view of water cycling, runoff coefficients are important indices of water resources conditions in a particular catchment. The Kalinin baseflow separation technique is an improved method based on the characteristics of precipitation and streamflow baseflow. First baseflow is separated, then runoff coefficient(R/P), baseflow coefficient (Br/P) and direct flow coefficient (Dr/P) are estimated. Statistical analyses are applied to assess the impact of precipitation and temperature on runoff coefficients (including Dr/P, Br/P and R/P). Results show that in the source regions of the Yellow River, the mean baseflow coefficient is higher than that of direct runoff. Runoff coefficients are in direct proportion to precipitation and inverse proportion to temperature. The decrease of runoff coefficients in the 1990's are closely related to the decrease in precipitation and increase in temperature. In different subbasins of the source regions of the Yellow River, runoff coefficients responded differently to precipitation and temperature. In the area above the Jimai hydrologic station where temperature is very low, temperature is the main factor influencing the runoff coefficients; runoff coefficients are inversely proportional to temperature, and precipitation has nearly no impact on runoff coefficients. In the subbasin between the Jimai and Maqu hydrologic stations, Dr/P is mainly affected by precipitation while R/P and Br/P are both significantly influenced by precipitation and temperature. In the area between the Maqu and Tangnaihai hydrologic station all three runoff coefficients increased with the rise in annual precipitation, while the direct runoff coefficient is inversely proportional to temperature. In the source regions of the Yellow River with the increase of annual average temperature, the impacts of temperature on runoff coefficients become weak. Reference: Chen L., C. Liu, F. Hao, D. Dai, and J. Liu. 2006. Impacts of climate factors on runoff coefficients in the source regions of the Yellow River. Journal of Environmental Hydrology, Vol. 14, Paper 18. CONTACT: Chen Liqun Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Email: E-mail: chenlq.04b@igsnrr.ac.cn |
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