基于统计降尺度模型的博斯腾湖流域未来最高和最低气温变化趋势分析

SDSM统计降尺度模型是解决空间尺度不匹配问题的有效工具,它使气候变化响应研究得以在区域尺度上展开。本文将SDSM模型应用于博斯腾湖流域分析它的适用性,并对流域未来最高和最低气温的变化趋势进行了预测。以日最高气温和最低气温为预报量,选取合适的NCEP大气环流因子为预报因子,建立预报量与预报因子间的回归关系。使用1961-1990、1991-2001年的实测数据和NCEP大气变量分别对SDSM模型进行率定和验证,效果较好。把HadCM3输出的A2、B2情景下的大气环流变量作为模型输入变量,模拟流域未来3个时期(21世纪20、50和90年代)的气温变化。结果显示,流域未来日最高气温和日最低气温都呈现明显上升趋势,升高幅度依次为:日最高气温日平均气温日最低气温,且A2情景下气温增幅略大于B2情景下的增幅;冬季气温增幅最小,夏季增幅最大。分析结果可为博斯腾湖流域开展气候变化的水文响应研究以及气候变化的适应性研究提供科学依据。

Analysis of Trents of Future Temperature in the Bosten Lake Basin Based on a Statistical Downscaling Model

Growing interests in simulating changes in hydrological processes on global and regional scales have been raised by more frequent strong floods and droughts on the global scale induced by climate change,which would have significant impacts on social and economic systems,food security and the survival and development of humans.General circulation models (GCMs) perform reasonably well in simulating current climate in terms of annual or seasonal averages on large spatial scales,thereby showing the capability to provide inputs for studies associated with hydrological responses to climate change on continental or global scale.However,the models perform poorly on small spatial and time scales relevant to regional impact analysis.The Statistical Downscaling Model (SDSM) is considered a very useful tool to address spatial-matching problems.It enables the study of climate change response to be carried out on local scales.In this paper,the applicability of SDSM in the Bosten Lake Basin was evaluated and the model was used to analyze the trends in future maximum and minimum temperature in this watershed.First,maximum temperature and minimum temperature were selected as the predictands.Appropriate meso-scale atmospheric variables were selected as downscaling predictors.Then,a statistical transfer function between them was constructed by the United States National Centers for Environmental Prediction (NCEP) re-analysis data set and observations at four stations.The first 30 years (1961-1990) of the obtained data series (1961-2001) was used to calibrate the model,while the remaining ten years (1991-2001) of data series was used to validate the model.The results show good agreement between the observations and the outputs from the model.On the basis of this,with the outputs of Hadley Centre Coupled Model,version 3 (HadCM3) under A2 and B2 scenarios respectively,the calibrated SDSM model generated future daily temperature series,which were subsequently used to analyze the temporal trends.The results show that there is an obvious increasing trend for the future maximum temperature and minimum temperature in the Bosten Lake Basin on daily,monthly,seasonal and yearly scales,respectively.The increase in the A2 scenario is larger than in the B2 scenario.The largest increase was found in summer while the smallest was in winter.This study would provide a scientific basis for further study of climate change over the Bosten Lake Basin.