报告题目：年代际方差分解方法及其在北半球大气环流场年代际可预报性研究中的应用
报 告 人：郑小谷教授
单 位：National Institute of Water and Atmospheric Research, New Zealand
时 间：2016年4月28日（周四）上午10:00
地 点：大气所40号楼319会议室
A decadal variance decomposition method is applied to the Northern Hemisphere (NH) 500-hPa geopotential height (GPH) and the sea level pressure (SLP) taken from the Last Millennium (850-1850 AD) experiment with the coupled climate model CCSM4, to estimate the contribution of the intra-decadal variability to the inter-decadal variability. By removing the intra-decadal variability from the total inter-decadal variability, the residual variability is more likely to be associated with slowly varying external forcings and slow-decadal climate processes，and therefore is referred to as slow-decadal variability. The results show that the (multi-)decadal changes of the NH 500-hPa GPH are primarily dominated by slow-decadal variability, whereas the NH SLP field is primarily dominated by the intra-decadal variability. At both pressure levels, the leading intra-decadal modes each have features related to the El Ni？o-Southern Oscillation (ENSO), the intra-decadal variability of the Pacific Decadal Oscillation (PDO) and the Arctic Oscillation (AO); while the leading slow-decadal modes are associated with external radiative forcing (mostly with volcanic aerosol loadings),the Atlantic Multi-decadal Oscillation (AMO) and the slow-decadal variability of AO and PDO. Moreover, the radiative forcing has much weaker effect to the SLP than that to the 500-hPa GPH.
