Atmospheric blocking in a high resolution climate model: influences of mean state, orography and eddy forcing
Atmospheric blocking in a high resolution climate model: influences of mean state, orography and eddy forcing
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DOI：
10.1002/asl2.412
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发表时间：
2013-01-01
影响因子：
3
通讯作者：
Roberts, Malcolm
中科院分区：
文献类型：
--
作者：
Berckmans, Julie;Woollings, Tim;Roberts, Malcolm
低估大气阻塞的发生是许多气候模式的一个众所周知的局限性。本文用一个水平分辨率增加的大气模式分析了北方冬季阻塞。欧洲阻塞频率随模式分辨率的增加而增加，这是由于大气变化模式的改善以及平均状态的简单改善。有一些证据表明，欧洲块体的瞬态涡动动量强迫在高分辨率下增加，这可以解释这一点。然而，它也表明，需要增加分辨率的地形实现阻塞的改善，与落基山脉的高度增加作用，以增加大西洋急流的倾斜，并给予较高的平均位势高度超过北方欧洲一致。太平洋地区的阻塞频率也随着大气分辨率的增加而增加，但在这种情况下，地形的改善实际上导致阻塞的减少。版权所有（c）2012皇家气象学会和英国皇家气象局。
An underestimate of atmospheric blocking occurrence is a well-known limitation of many climate models. This article presents an analysis of Northern Hemisphere winter blocking in an atmospheric model with increased horizontal resolution. European blocking frequency increases with model resolution, and this results from an improvement in the atmospheric patterns of variability as well as a simple improvement in the mean state. There is some evidence that the transient eddy momentum forcing of European blocks is increased at high resolution, which could account for this. However, it is also shown that the increase in resolution of the orography is needed to realise the improvement in blocking, consistent with the increase in height of the Rocky Mountains acting to increase the tilt of the Atlantic jet stream and giving higher mean geopotential heights over northern Europe. Blocking frequencies in the Pacific sector are also increased with atmospheric resolution, but in this case the improvement in orography actually leads to a decrease in blocking Copyright (c) 2012 Royal Meteorological Society and British Crown copyright, Met Office.