关键词: 淮河流域, 气候变化情景, 径流深, 回归模型

Abstract:

The increasing greenhouse gas in atmosphere will lead to an increase of 1.1-3.1 o C in mean annual temperature (MAT) in next century as predicted by IPCC (2001). Such an increase in temperature will considerably alter the current regimes of precipitation, hydrological cycle and thus water resources. The impacts of these changes will be particularly severe in arid and semi-arid regions around the world. In China, it may be most severe in North China and Northwest China, shown by some previous investigations.The Huaihe drainage basin (111°55'-120°45'E, 31°-36°N) is located in the transitional belt of the sub-tropical and temperate zones in eastern China. The MAT is 11-16 o C.The mean annual precipitation(MAP) is 883 mm, 50-80% of which falls during May-August in upstreams of Huaihe River and areas south of it or June-September in other areas with mean annual runoff depth being ～231 mm. The Huaihe drainage basin is economically significant as both industry and agriculture are rather developed. A general assessment on climate-change effects on runoff may be still somehow helpful for the regional water resources management and economic development and planning in the future. We have therefore selected the Huaihe drainage basin as our study area in this research. We assume an increase of 1, 2 and 3 o C in MAT and mean seasonal temperature(MST), and a change of 20%, 10% and 0% in MAP and mean seasonal precipitation(MSP). Then 15 climate-change scenarios were constructed by integrating each temperature change with each precipitation change. The general structure of a nonlinear model on climate factors and runoff relationship was established with multi-variable regression method. Then by analyzing meteorological and hydrological data of 20 years for three sub-catchments of the Huaihe drainage basin, mean annual and seasonal values of temperature, precipitation and runoff were respectively calculated from the corresponding month values. Furthermore, mathematical models relating mean annual runoff to MAP and MAP and relating mean seasonal runoff to MAP and MAP were established with the aforementioned calculated data. Runoff was subsequently estimated with statistical model for the sub-catchments under the 15 climate-change scenarios.The results allow a preliminary assessment of influences of the climatic changes on runoff in the near future. Runoff will generally increase with increase in precipitation and decrease with temperature rise. For a given climate-change scenario, the responses of runoff of different sub-catchments vary, which may reflect the differences in physical characteristics and their influences on runoff in different sub-catchments. For a given sub-catchment, the responses of each season's runoff to each of the climate-change scenarios also vary, which may manifest monsoon climate influence on runoff. The dry-and-warm climatic conditions may dramatically reduce runoff and hence have severe or even disastrous effects on economic development in this area.

Key words: the Huaihe drainage basin, climate change scenario, runoff, regressive model