西北地区未来降水量变化预测

Predicting Future Precipitation Changes in the Northwest Region of China

利用MAGGIC/ SCENGEN5.3 软件中的14 个大气环流模型预测了西北地区降水量的变化情况,采用AR4 中A1B-AIM、A2ASF 和A1FI 情景来模拟未来CO2 排放情景.结果表明：①2050 年A2ASF 情景下多模型预测西北五省各季节降水量绝对值变化的中位数为-0.2～0.6 mm/ d,但预测的极端值范围变化很大;②根据最佳模型预测,最有可能出现干旱的地区及相应季节为陕西的夏季和冬季、甘肃的夏季及新疆的春季、夏季、冬季.建议使用14 个大气环流模型模拟和最佳模型预测的中位数区间作为置信区间以应对西北地区因气候变化出现的极端气候状况;③14 个大气环流模型模拟与最佳模型预测降水量中位数在大部分西北地区可能略有增大,但在气温相应升高情况下,可能出现干旱情况.

This paper used MAGGIC/SCENGEN 5. 3 software with 14 Atmosphere?Ocean General Circulation Models to forecast the precipitation change of the northwest region of China. Three CO2 emission scenarios in the IPCC Fourth Assessment Report were used, including A1B?AIM, A2ASF and A1FI. The main results are that a) the median values of multi?model predictions in 2050 using A2ASF scenario are around -0.2~0.6 mm/d but the ranges between the minimum/maximum values or outliers are quite large;b) according to the best models’ predictions, the areas which are most likely to face seasonal droughts are Shaanxi Province (summer and winter), Gansu Province ( summer) and Xinjiang Uygur Autonomous Region ( spring, summer and winter) . Thus we recommend using the range between the median values of the 14 models and the best models as confidence interval to deal with the extreme weather conditions caused by climate change and;c) the median values of the 14 models’ predictions and the best models’ predictions show that the increase of precipitation in Northwest China might be mere, but with the increase of temperature, drought might happen.