National Center for Atmospheric Research, Boulder, CO 80305, USA.
Science. 2012 Nov 9;338(6108):792-4. doi: 10.1126/science.1227465.
An observable constraint on climate sensitivity, based on variations in mid-tropospheric relative humidity (RH) and their impact on clouds, is proposed. We show that the tropics and subtropics are linked by teleconnections that induce seasonal RH variations that relate strongly to albedo (via clouds), and that this covariability is mimicked in a warming climate. A present-day analog for future trends is thus identified whereby the intensity of subtropical dry zones in models associated with the boreal monsoon is strongly linked to projected cloud trends, reflected solar radiation, and model sensitivity. Many models, particularly those with low climate sensitivity, fail to adequately resolve these teleconnections and hence are identifiably biased. Improving model fidelity in matching observed variations provides a viable path forward for better predicting future climate.
提出了一种基于中层大气相对湿度（RH）变化及其对云的影响的气候敏感性的可观测约束。我们表明，热带和亚热带通过遥相关连接，这些遥相关会引起季节性 RH 变化，这些变化与反照率（通过云）密切相关，而这种可变性在变暖的气候中得到了模拟。因此，确定了一个与未来趋势的现代类比，即与北方季风相关的模型中的亚热带干燥区的强度与预计的云趋势、反射太阳辐射和模型敏感性密切相关。许多模型，特别是那些气候敏感性低的模型，无法充分解决这些遥相关问题，因此存在明显的偏差。提高模型在匹配观测到的变化方面的保真度，为更好地预测未来气候提供了一条可行的途径。
