NOTES AND CORRESPONDENCE A Mechanism of Tropical Precipitation Change due to CO 2 Increase
NOTES AND CORRESPONDENCE A Mechanism of Tropical Precipitation Change due to CO 2 Increase
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发表时间：
2004
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通讯作者：
M. Sugi;J. Yoshimura
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作者：
M. Sugi;J. Yoshimura
GCM最近的一项研究表明，当大气CO2增加时，热带环流的减弱与热带降水的轻微增加可能会发生。为了进一步了解与温室气体增加相关的大气温度和降水变化的机制，利用大气环流模式进行了数值试验，研究了CO2增加和海表温度升高的单独影响。研究表明，co2增加的影响是对流层下部的辐射冷却减少，从而导致热带降水减少。当大气CO2浓度增加一倍（四倍）而不改变海温时，模式中热带降水减少约3%（6%）。辐射冷却的减少是CO2 15-mm吸收带和水蒸气吸收带重叠效应的结果。另一方面，海温增加的影响是大气温度和水汽的增加，导致辐射冷却和热带降水的增加。在不改变大气CO2浓度的情况下，海温均匀升高28C，热带降水增加约6%。
A recent GCM study indicates that a weakening of tropical circulation associated with a slight increase in tropical precipitation may occur when atmospheric CO2 is increased. To further understand the mechanism of atmospheric temperature and precipitation changes associated with the greenhouse gas increase, a numerical experiment was conducted using an atmospheric general circulation model to investigate the separate effects of CO2 increase and sea surface temperature (SST) increase. It has been shown that the effect of CO 2 increase is a reduction of radiative cooling in the lower troposphere, leading to a reduction of tropical precipitation. When atmospheric CO2 concentration is doubled (quadrupled) without changing the SST, the tropical precipitation is reduced by about 3% (6%) in the model. The reduction of radiative cooling is a result of the overlap effect of the CO2 15-mm and water vapor absorption bands. On the other hand, the effect of SST increase is the increase in atmospheric temperature and water vapor, leading to increases in radiative cooling and tropical precipitation. When SST is uniformly raised 28C without changing the atmospheric CO2 concentration, the tropical precipitation is increased by about 6%.