基于ASD统计降尺度模型的开都河流域未来气候预估

Future Climate Scenarios Projection in the Kaidu River Basin Based on ASD Statistical Downscaling Model

以开都河流域及周边4个气象站点1961—2000年的日降水、日最高气温和日最低气温及NCEP再分析数据为基础,采用ASD(Automated Statistical Downscaling)统计降尺度模型,对Had CM3模式下A2、B2和A1B 3种气候情景进行降尺度,获得流域未来气候情景。研究结果表明:(1)ASD模型选定的预报因子能较好地解释最高温和最低温,但对降水的模拟效果相对较差。验证期,对降水和气温各5个指标的RMSE分析显示RMSE值均较小,ASD模型在研究区具有一定的适用性;(2)未来3种情景下,相较基准期,降水年变化呈先下降后上升趋势,最高和最低温年变化则持续保持上升趋势,未来山区气温变化较大,平原区降水变化大;降水年内变化存在季节分配不均状况,5月增加最多,7月减少最多。最高和最低温变化则以夏季增温最多、冬季次之,秋季降温最多、春季次之为特点。相比较,A2(高排)情景下降水、气温变化比B2(低排)A1B(中排)情景下更为明显。

Based on the daily precipitation, daily maximum temperature, daily minimum temperature,daily minimum temperature and NCEP（ National Center for Environmental Prediction） reanalysis data of the four meteorological stations in and around the Kaidu river basin from 1961 to 2000, the ASD（ Automated Statistical Downscaling） model was used to downscaled climate scenarios of A2, B2 and A1 B under the Had CM3 mode, which could obtain the future climate scenarios of the basin. Results showed that, firstly,the prediction factors selected by the model could explain the maximum temperature and the minimum temperature well, but the simulation effect onprecipitation was relatively poor. During the verification period, RMSE analysis of 5 indicators of precipitation and temperature showed that RMSE values were small, and the ASD model had certain applicability in the study area. Secondly,under three scenarios, compared with the base period,the annual change of precipitation showed a downward trend firstly and then increased, while the annual change in the maximum and minimum temperature kept constantly increasing. In the future, the temperature in the mountains will change greatly, the precipitation in the plains will change greatly as well. There was an uneven distribution of precipitation change during the year, with the largest increase in May and the largest decrease in July. The maximum and the minimum temperature change showed the characteristics that the largest increase in summer, then in winter, and the largest decrease in autumn, then in spring.Comparatively, precipitation and temperature changed obviously under A2 than B2 and A1 B.