Changes in temperature and precipitation extremes in the IPCC ensemble of global coupled model simulations
Changes in temperature and precipitation extremes in the IPCC ensemble of global coupled model simulations
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DOI：
10.1175/jcli4066.1
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发表时间：
2007-04-15
影响因子：
4.9
通讯作者：
Hegerl, Gabriele C.
中科院分区：
文献类型：
--
作者：
Kharin, Viatcheslav V.;Zwiers, Francis W.;Hegerl, Gabriele C.
在参加政府间气候变化专门委员会（IPCC）第四次评估报告（AR 4）诊断活动的全球耦合气候模式集合中评估了极端温度和降水及其未来可能的变化。气候极值用近地表温度年极值和24小时降水量的20年回归值表示。在排放情景特别报告（SRES）B1、A1 B和A2排放情景的实验中，记录了2046 - 65年和2081 - 2100年相对于1981 - 2000年极端气候的模拟变化。总的来说，与再分析的估计相比，气候模式在全球尺度上相当好地模拟了当今的暖极端气候。模式在模拟极端寒冷气候时的差异通常大于极端温暖气候，特别是在海冰覆盖的地区。模拟的热带外地区的极端降水是可信的，但热带地区极端降水的不确定性非常大，无论是在模式中还是在现有的基于观测的数据集中，极端温暖的变化通常跟随夏季平均温度的变化。全球平均而言，极端寒冷比极端温暖快30% -40%。极端寒冷天气的过度变暖通常仅限于冰雪和海冰随着全球变暖而消退的地区。除北方极地纬度外，极端降水强度的相对变化一般超过年平均降水的相对变化，特别是在热带和亚热带地区。与极端降水强度增加相一致的是，几乎所有地方（除了少数亚热带地区）等待世纪后期极端降水事件的时间都在减少。多模式多情景的共识，预计在全球平均20年的回报值的24小时降水量的年度极端的变化是，将有一个约6%的增加与全球变暖的每开尔文，与大部分的模型模拟值在4% -10%K-1的范围内。在热带地区的非常大的模型间的分歧表明，一些物理过程与极端降水没有很好地代表模型。这降低了对极端降水量预测变化的信心。
Temperature and precipitation extremes and their potential future changes are evaluated in an ensemble of global coupled climate models participating in the Intergovernmental Panel on Climate Change ( IPCC) diagnostic exercise for the Fourth Assessment Report ( AR4). Climate extremes are expressed in terms of 20- yr return values of annual extremes of near- surface temperature and 24-h precipitation amounts. The simulated changes in extremes are documented for years 2046 - 65 and 2081 - 2100 relative to 1981 - 2000 in experiments with the Special Report on Emissions Scenarios ( SRES) B1, A1B, and A2 emission scenarios.Overall, the climate models simulate present- day warm extremes reasonably well on the global scale, as compared to estimates from reanalyses. The model discrepancies in simulating cold extremes are generally larger than those for warm extremes, especially in sea ice - covered areas. Simulated present- day precipitation extremes are plausible in the extratropics, but uncertainties in extreme precipitation in the Tropics are very large, both in the models and the available observationally based datasets.Changes in warm extremes generally follow changes in the mean summertime temperature. Cold extremes warm faster than warm extremes by about 30% - 40%, globally averaged. The excessive warming of cold extremes is generally confined to regions where snow and sea ice retreat with global warming. With the exception of northern polar latitudes, relative changes in the intensity of precipitation extremes generally exceed relative changes in annual mean precipitation, particularly in tropical and subtropical regions. Consistent with the increased intensity of precipitation extremes, waiting times for late- twentieth- century extreme precipitation events are reduced almost everywhere, with the exception of a few subtropical regions. The multimodel multiscenario consensus on the projected change in the globally averaged 20- yr return values of annual extremes of 24- h precipitation amounts is that there will be an increase of about 6% with each kelvin of global warming, with the bulk of models simulating values in the range of 4% - 10% K-1. The very large intermodel disagreements in the Tropics suggest that some physical processes associated with extreme precipitation are not well represented in models. This reduces confidence in the projected changes in extreme precipitation.