Characteristic 20th and 21st century precipitation and temperature patterns and changes over the Greater Horn of Africa
Characteristic 20th and 21st century precipitation and temperature patterns and changes over the Greater Horn of Africa
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DOI：
10.1002/joc.2270
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发表时间：
2012-03-01
期刊：
影响因子：
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通讯作者：
Qiu, Weini
中科院分区：
文献类型：
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作者：
Anyah, Richard O.;Qiu, Weini
根据耦合模式相互比较项目第3版（CMIP 3）模式输出的样本，分析了世纪大非洲之角降水和温度的特征模式和变化。对11个CMIP 3模式的分析表明，从20世纪80年代初开始，在A1 B和A2情景中，赤道东非地区（包括整个大非洲之角）的气温都在显著上升。所有的大气-海洋全球环流模式（AOGCM）分析代表正确的平均年降水周期，但有一个相当大的传播模式之间的捕获占主导地位的双峰。特别是，所有的模型往往高估的高峰期的11月至12月（OND）的季节，而在同一时间的高峰期的3月至4月至5月（MAM）的季节往往集中在5月的模型，而不是4月观察。预测的变化和概率分布的最低温度（Tmin）和最高温度（Tmax）在GHA次区域的基础上构建的PDF从每日值显示出非常不同的分布，目前（19812000年）和未来（20462065年; 20812100年）期间。在参考文献（1981 - 2000）中，为Tmin和Tmax构造的概率分布函数（PDF）在所有季节都具有接近正态（但窄）的分布，而未来时期的概率分布函数则非常多样化，但通常非常长，并向正尾显著偏移。这通常意味着，在GHA地区，模型和集合平均值之间存在着关于未来极端温暖的Tmin和Tmax（更是Tmin）增加的可能性很高的共识。我们的研究结果还表明，显着增加的天数与Tmin和Tmax大于2摄氏度（高于19812000年的平均值）的中间，以及在21世纪世纪结束时，在A1 B和A1的情况。尤其是在6月，7月和8月（JJA）季节，所有92天的季节表明，预计最低温度将在21世纪世纪结束时比1981 - 2000年的平均温度增加2摄氏度以上。版权所有（c）2011皇家气象学会
Characteristic patterns and changes in precipitation and temperature over the Greater Horn of Africa during the 20th and 21st century are analysed based on a sample of Coupled Model Intercomparison Project version 3 (CMIP3) models output. Analysis of the 11 CMIP3 models indicates that the equatorial eastern Africa region (including the entire Greater Horn of Africa (GHA)) have been experiencing a significant increase in temperature beginning in the early 1980s, in both A1B and A2 scenarios. All the Atmosphere Ocean Global Circulation Models (AOGCMs) analysed represent the correct mean annual cycle of precipitation, but there is a fairly large spread among the models in capturing the dominant bimodal peaks. In particular, all the models tend to overestimate the peak of the OctoberNovemberDecember (OND) season, while at the same time the peak of the MarchAprilMay (MAM) season tends to be centered on May in the models instead of April as observed. The projected changes and probability distribution of minimum (Tmin) and maximum (Tmax) temperatures over the GHA sub-region based on PDFs constructed from daily values showed very diverse distributions for the present (19812000) and future (20462065; 20812100) periods. Whereas in the reference (19812000) the probability distribution functions (PDFs) constructed for both Tmin and Tmax, and during all the seasons had a near normal (but narrow) distribution, those of the future periods were quite diverse but generally very elongated, with significant shifts toward the positive tail. This generally implies that there is consensus among models and the ensemble mean about high likelihood of increase in extreme warmer Tmin and Tmax (more so Tmin) in the future over the GHA region. Our results also show significant increase in the number of days with Tmin and Tmax greater the 2 degrees C (above 19812000 average) by the middle as well as the end of 21st century in both the A1B and A1 scenarios. This is especially so during the June, July, and August (JJA) season where all the 92 days of the season indicate projected minimum temperature to increase by more than 2 degrees C above the 19812000 average by the end of 21st century in both scenarios. Copyright (c) 2011 Royal Meteorological Society