Climate Fluctuations and Climate Sensitivity Studies

对NCAR CCM在理想地形下的长时间模式运行的初步检验表明，地表温度场可解释为时空中受噪声强迫的系统。线性系统可以解释为具有扩散水平热传输和线性辐射衰减的能量平衡气候模式(EBM)。这两个模型中的表面温度场都有几个有趣的特性。例如，在几千公里的距离上，空间相关统计基本上是各向同性的。空间相关性减弱，特征长度约为1500公里，这与EBM和地表温度资料相一致。线性理论表明，气候学(=时间平均)对点热源的响应应该表现出与等倍空间自相关函数相同的空间模式。CCM表面数据似乎就是这种情况。这些证据有助于解释为什么与数据和GCM相比，EBM在早期的季节周期研究中如此成功，甚至在各种古气候情景中也是如此。这项研究将使用简单的模型来研究气候变化和变化的潜在机制。PI将系统地研究通量和相关的气象场，以澄清气候波动和响应现象明显线性的原因。这项研究很重要，因为它可以洞察气候系统是如何工作的--这是更可信地预测未来气候的先决条件。

Preliminary examination of a long model run of the NCAR CCM with idealized geography indicates that the surface temperature field can be interpreted as an system forced by noise in space- time. The linear system can be interpreted as an energy-balance climate model (EBM) with diffusive horizontal heat transport and linear radiation damping. The surface temperature field in both models has several interesting properties. For example, the spatial correlation statistics are essentially isotropic over distances of a few thousand km. The spatial correlations fall off with a characteristic length of about 1500 km which agrees with the EBM and with surface temperature data. Linear theory suggests that climatological (=time averaged) responses to point heat sources should exhibit a spatial pattern identical to the equal times spatial auto correlation function. This appears to be the case in the CCM surface data. These pieces of evidence help to explain why the EBM has been so successful in earlier studies of the seasonal cycle and even in various paleoclimate scenarios compared to data and GCMs. This research will study the underlying mechanisms of climate variability and change using simple models. The PI will systematically examine the fluxes and related meteorological fields in order to clarify the reasons for the apparant linearity of climate fluctuation and response phenomena. This research is important because it may give insight into how the climate system works - a pre-requisite for more credible predictions of future climates.