Trends in continental temperature and humidity directly linked to ocean warming
Trends in continental temperature and humidity directly linked to ocean warming
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DOI：
10.1073/pnas.1722312115
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发表时间：
2018-05-08
影响因子：
11.1
通讯作者：
O'Gorman, Paul A.
中科院分区：
文献类型：
--
作者：
Byrne, Michael P.;O'Gorman, Paul A.
近几十年来，陆地表面比海洋表面变暖得多，相对湿度在陆地上下降。陆地上变暖加剧和相对湿度下降也是未来气候预测的主要特征，对气候变化的影响有影响。一个新兴的研究机构已经表明，大气动力学和湿度预算的约束对于预测未来的陆地-海洋对比是多么重要，但这些想法并没有被用来调查近几十年来的温度和湿度记录。在这里，我们展示了1979年至2016年期间在陆地上观察到的温度和湿度变化如何与邻近海洋的变暖有关。一个简单的分析理论，基于大气动力学和水分输送，预测在陆地和海洋上的湿静态能量的变化相等，在陆地和海洋上的特定湿度的变化相等。该理论被证明是一致的陆地温度和湿度的观测趋势，海洋变暖。放大的陆地变暖是需要的增加潮湿的静态能量在干燥的土地，以匹配在海洋上，和陆地相对湿度下降，因为陆地特定的湿度是通过水分输送到海洋变暖较弱。然而，有相当大的变化，最适合的趋势，在陆地相对湿度，需要进一步调查，这可能与大气环流和陆面特性的变化等因素。
In recent decades, the land surface has warmed substantially more than the ocean surface, and relative humidity has fallen over land. Amplified warming and declining relative humidity over land are also dominant features of future climate projections, with implications for climate-change impacts. An emerging body of research has shown how constraints from atmospheric dynamics and moisture budgets are important for projected future land-ocean contrasts, but these ideas have not been used to investigate temperature and humidity records over recent decades. Here we show how both the temperature and humidity changes observed over land between 1979 and 2016 are linked to warming over neighboring oceans. A simple analytical theory, based on atmospheric dynamics and moisture transport, predicts equal changes in moist static energy over land and ocean and equal fractional changes in specific humidity over land and ocean. The theory is shown to be consistent with the observed trends in land temperature and humidity given the warming over ocean. Amplified land warming is needed for the increase in moist static energy over drier land to match that over ocean, and land relative humidity decreases because land specific humidity is linked via moisture transport to the weaker warming over ocean. However, there is considerable variability about the best-fit trend in land relative humidity that requires further investigation and which may be related to factors such as changes in atmospheric circulations and land-surface properties.