Radiative feedbacks on global precipitation
Radiative feedbacks on global precipitation
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DOI：
10.1088/1748-9326/5/2/025211
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发表时间：
2010-04
影响因子：
6.7
通讯作者：
M. Previdi
中科院分区：
文献类型：
--
作者：
M. Previdi
在政府间气候变化专门委员会（IPCC）第四次评估报告（AR4）模式中，利用辐射核技术量化21世纪对流层能量收支的变化，以便更好地了解全球平均降水的变化。发现对流层辐射冷却的最强反馈与温度和水蒸气的增加有关，水蒸气反馈抵消了由于温度升高导致的辐射冷却增加的很大一部分（~ 39%）。云和地表感热通量反馈虽然没有温度和水汽反馈那么大，但却是全球降水对变暖响应或水文敏感性模式间差异的重要贡献者。辐射强迫因子对对流层能量收支的直接影响也很重要。不断上升的二氧化碳水平减少了对流层的辐射冷却，从而限制了全球降雨量的增加。此外，在一些模式中，由于气溶胶吸收的增加，辐射冷却的进一步减少，这表明气溶胶强迫的差异可以部分解释模式之间水文敏感性的差异。
The radiative kernel technique is employed to quantify twenty-first century changes to the tropospheric energy budget in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) models in order to better understand changes in global-mean precipitation. The strongest feedbacks on the tropospheric radiative cooling are found to be associated with increases in temperature and water vapor, with the water vapor feedback offsetting a significant portion (∼39%) of the increase in radiative cooling due to higher temperatures. Cloud and surface sensible heat flux feedbacks, though not as large in magnitude as the temperature and water vapor feedbacks, are important contributors to the intermodel difference in the global precipitation response to warming, or hydrological sensitivity. The direct effects of radiative forcing agents on the tropospheric energy budget are also important. Rising CO2 levels reduce tropospheric radiative cooling and hence limit the increase in global rainfall. Additionally, in some of the models, further reductions in radiative cooling occur due to increases in absorbing aerosol, suggesting that differences in aerosol forcing can explain part of the difference in hydrological sensitivity between models.