Regional climate model of the Arctic atmosphere
Regional climate model of the Arctic atmosphere
复制标题
北极大气区域气候模型
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
B. Machenhauer
中科院分区：
文献类型：
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作者：
K. Dethloff;A. Rinke;R. Lehmann;J. Christensen;M. Botzet;B. Machenhauer
利用高分辨率有限区域模式（HIRLAM）的动力学包和汉堡大气环流模式（ECHAM3）的物理参数化，建立了一个全北极区域气候模式，在50 km水平分辨率下模拟了北极65 oN以北的气候。该模式是由欧洲中期天气预报中心在横向边界上的分析以及在下边界上的气候或实际观测到的海面温度和海冰覆盖所推动的。本文介绍了1991年1月和1990年7月北极对流层和平流层低层气候的模拟结果。在这两个月里，模式相当接近地再现了观测到的月平均环流。虽然地面气温，平均海平面气压和位势的一般空间格局是一致的ECMWF分析，模型显示的偏差时，详细检查的结果。最大的偏差出现在冬季的行星边界层和表面。模式中低估的垂直热湿输送表明，由于边界层过程的垂直输送参数化的改进的必要性。模型模拟和分析之间的对流层差异随着高度的增加而减小。增加海冰厚度可以减小行星边界层的温度偏差。实际观测到的海面温度和海冰覆盖的使用只会导致小的改进模式的偏差相比，气候学的海面温度和海冰覆盖。验证模型计算的位势，辐射通量，地面感热和潜热通量和云对选定的站数据显示模型模拟和观测之间的偏差，由于模型的缺点。第一次验证表明，改进辐射的物理参数化包和海冰厚度和海冰分数的描述是必要的，以减少模式的偏差。
A regional climate model of the whole Arctic using the dynamical package of the High- Resolution Limited Area Model (HIRLAM) and the physical parameterizations of the Hamburg General Circulation Model (ECHAM3) has been applied to simulate the climate of the Arctic north of 65 oN at a 50-km horizontal resolution. The model has been forced by the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses at the lateral boundaries and with climatological or actual observed sea surface temperatures and sea ice cover at the lower boundary. The results of simulating the Arctic climate of the troposphere and lower stratosphere for January 1991 and July 1990 have been described. In both months the model rather closely reproduces the observed monthly mean circulation. While the general spatial patterns of surface air temperature, mean sea level pressure, and geopotential are consistent with the ECMWF analyses, the model shows biases when the results are examined in detail. The largest biases appear during winter in the planetary boundary layer and at the surface. The underestimated vertical heat and humidity transport in the model indicates the necessity of improvements in the parameterizations of vertical transfer due to boundary layer processes. The tropospheric differences between model simulations and analyses decrease with increasing height. The temperature bias in the planetary boundary layer can be reduced by increasing the model sea ice thickness. The use of actual observed sea surface temperatures and sea ice cover leads only to small improvements of the model bias in comparison with climatological sea surface temperatures and sea ice cover. The validation of model computed geopotential, radiative fluxes, surface sensible and latent heat fluxes and clouds against selected station data shows deviations between model simulations and observations due to shortcomings of the model. This first validation indicates that improvements in the physical parameterization packages of radiation and in the description of sea ice thickness and sea ice fraction are necessary to reduce the model bias.