Simulation of the East Asian Subtropical Westerly Jet Stream with GFDL AGCM (AM2.1)          下载免费PDF全文

HUANG Gang  LIU Yong 《大气和海洋科学快报》2011,4(1):24-29

The present study validated the capability of the AM2.1, a model developed at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL), in reproducing the fundamental features of the East Asian Subtropical Westerly Jet Stream (EASWJ). The main behaviors of the EASWJ are also investigated through the reanalysis of observational NCEP/NCAR data. The mean state of the EASWJ, including its intensity, location, structure, and seasonal evolution is generally well-portrayed in the model. Compared with the observation, the model tends to reproduce a weaker jet center. And, during summer, the simulated jet center is northward-situated. Results also demonstrate the model captures the variability of EASWJ during summer well. The results of the empirical orthogonal function (EOF) applied on the zonal wind at 200 hPa (U200) over East Asia for both the observation and simulation indicate an inter-decadal shift around the late 1970s. The correlation coefficient between the corresponding principle components is as great as 0.42 with significance at the 99% confidence level.  相似文献   

Spatio-temporal downscaling of projected precipitation in the 21st century: indication of a wetter monsoon over the Upper Mahanadi Basin,India     

Subbarao Pichuka 《水文科学杂志》2017,62(3):467-482

An attempt is made to assess the future trend of spatio-temporal variation of precipitation over a medium-sized river basin. The Statistical Downscaling Model (SDSM, version 4.2) is used to downscale the outputs from two general circulation models (GCMs) for three future epochs: epoch-1 (2011–2040), epoch-2 (2041–2070) and epoch-3 (2071–2100). Considering the Upper Mahanadi Basin as a test bed, the study results indicate a “wetter” monsoon (June–September) and the annual increase in precipitation is 12% during epoch-3, which is consistent for both GCMs. Monthly analyses indicate that the precipitation totals are likely to increase and the magnitude of increase is greater during monsoon months than non-monsoon months. The number of month-wise daily extremes increases in most months in the year. However, the maximum percentage increase (with respect to baseline period, 1971–2000) in the number of extreme events is found in the non-monsoon months (specifically before and after the monsoon).  相似文献   

An empirical formula to compute snow cover fraction in GCMs   总被引：10，自引：0，他引：10  

WU Tongwen  WU Guoxiong 《大气科学进展》2004,21(4):529-535

There exists great uncertainty in parameterizing snow cover fraction in most general circulation models (GCMs) using various empirical formulae, which has great influence on the performance of GCMs. This work reviews the commonly used relationships between region-averaged snow depth (or snow water equivalent) and snow cover extent (or fraction) and suggests a new empirical formula to compute snow cover fraction, which only depends on the domain-averaged snow depth, for GCMs with different horizontal resolution. The new empirical formula is deduced based on the 10-yr (1978-1987) 0.5°× 0.5° weekly snow depth data of the scanning multichannel microwave radiometer (SMMR) driven from the Nimbus-7 Satellite. Its validation to estimate snow cover for various GCM resolutions was tested using the climatology of NOAA satellite-observed snow cover.  相似文献   

Performance of a Reconfigured Atmospheric General Circulation Model at Low Resolution   总被引：3，自引：2，他引：3  

WEN Xinyu  ZHOU Tianjun  WANG Shaowu  WANG Bin  WAN Hui  LI Jian 《大气科学进展》2007,24(4):712-728

Paleoclimate simulations usually require model runs over a very long time.The fast integration version of a state-of-the-art general circulation model (GCM),which shares the same physical and dynamical processes but with reduced horizontal resolution and increased time step,is usually developed.In this study,we configure a fast version of an atmospheric GCM (AGCM),the Grid Atmospheric Model of IAP/LASG (Institute of Atmospheric Physics/State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics),at low resolution (GAMIL-L,hereafter),and compare the simulation results with the NCEP/NCAR reanalysis and other data to examine its performance.GAMIL-L,which is derived from the original GAMIL,is a finite difference AGCM with 72×40 grids in longitude and latitude and 26 vertical levels.To validate the simulated climatology and variability,two runs were achieved.One was a 60-year control run with fixed climatological monthly sea surface temperature (SST) forcing,and the other was a 50-yr (1950-2000) integration with observational time-varying monthly SST forcing.Comparisons between these two cases and the reanalysis,including intra-seasonal and inter-annual variability are also presented.In addition,the differences between GAMIL-L and the original version of GAMIL are also investigated. The results show that GAMIL-L can capture most of the large-scale dynamical features of the atmosphere, especially in the tropics and mid latitudes,although a few deficiencies exist,such as the underestimated Hadley cell and thereby the weak strength of the Asia summer monsoon.However,the simulated mean states over high latitudes,especially over the polar regions,are not acceptable.Apart from dynamics,the thermodynamic features mainly depend upon the physical parameterization schemes.Since the physical package of GAMIL-L is exactly the same as the original high-resolution version of GAMIL,in which the NCAR Community Atmosphere Model (CAM2) physical package was used,there are only small differences between them in the precipitation and temperature fields.Because our goal is to develop a fast-running AGCM and employ it in the coupled climate system model of IAP/LASG for paleoclimate studies such as ENSO and Australia-Asia monsoon,particular attention has been paid to the model performances in the tropics.More model validations,such as those ran for the Southern Oscillation and South Asia monsoon, indicate that GAMIL-L is reasonably competent and valuable in this regard.  相似文献   

利用步长模拟对青藏高原涡度方差测量法的质量评价   总被引：1，自引：0，他引：1  

S. Metzger  马耀明  T.Markkanen  M. G 《地球科学进展》2006,21(12):1260-1267

利用痕迹模拟方法对青藏高原两处地方涡度方差的测量数据进行了质量分析，揭示了其空间和时间结构。分析表明高达1/3的测量没有达到必要的数据正确假设。尽管这样对潜热、CO2、动量通量的测量基本通过测试，可以适用于基础研究，但是经常发现特定的风矢量违背基本假设条件。感热通量的测量允许使用不间断的连续测量法，然而由于局地地形的影响少量评估指数未能合理解释，但能够指示出组织结构及用于导出边界层中尺度流体模型假说。  相似文献   

A modified ISBA surface scheme for modeling the hydrology of Athabasca River Basin with GCM-scale data     

Ernst Kerkhoven  Thian Yew Gan 《Advances in water resources》2006

A soil–vegetation–atmosphere transfer model (SVAT), interactions between the soil–biosphere–atmosphere (ISBA) of Météo France, is modified and applied to the Athabasca River Basin (ARB) to model its water and energy fluxes. Two meteorological datasets are used: the archived forecasts from the Meteorological Survey of Canada’s Global Environmental Multiscale Model (GEM) and the European Centre for Mid-range Weather Forecasts global re-analysis (ERA-40), representing spatial scales typical of a weather forecasting model and a global circulation model (GCM), respectively. The original treatment of soil moisture and rainfall in ISBA (OISBA) is modified to statistically account for sub-grid heterogeneity of soil moisture and rainfall to produce new, highly non-linear formulations for surface and sub-surface runoff (MISBA). These new formulations can be readily applied to most existing SVATs. Stand alone mode simulations using the GEM data demonstrate that MISBA significantly improves streamflow predictions despite requiring two fewer parameters than OISBA. Simulations using the ERA-40 data show that it is possible to reproduce the annual variation in monthly, mean annual, and annual minimum flows at GCM scales without using downscaling techniques. Finally, simulations using a simple downscaling scheme show that the better performance of higher resolution datasets can be primarily attributed to improved representation of local variation of land cover, topography, and climate.  相似文献   

EXPERIMENTS OF SHORT-TERM CLIMATE PREDICTION BY THE OSU/NCC GCM FOR SUMMER SEASON IN CHINA^*     

GAO Xuejie  ZHAO Zongci 《Acta Meteorologica Sinica》2000,14(3):280-292

By using of an ensemble method,the tests of rainfall for the predictions of the seasonal,interseasonal and annual scales in China during 1982-1995 have been made by the atmospheric GCM/mixed layer ocean and ice model(OSU/NCC).Contrasts between forecasts by the OSU/NCC and the observations show that the model has a certain ability in the prediction of precipitation for summer over China in all of the three different time scales.And it indicates that the interseasonal prediction is the best among the forecasts of three scales.It is also indicated that the prediction is especially acceptable in certain areas.  相似文献   

亚洲沙尘暴的遥感监测方法研究 --以中国-日本合作研究区为例   总被引：4，自引：0，他引：4  

刘志丽  马建文  张国平  周自江 《武汉大学学报(信息科学版)》2005,30(8):708-711,F0003

介绍了亚洲沙尘暴遥感监测的一些新方法,并对监测结果与数据进行了综合分析,这些结果能够为GCM全球尺度沙尘模型提供参数和验证数据。本次研究结果为亚洲沙尘暴的中长期预测/预警系统提供了新的遥感技术方法。  相似文献   

全球气候变化下青藏公路沿线冻土变化响应模型的研究   总被引：16，自引：17，他引：16  

李新  李文君  吴青柏 《冰川冻土》2001,23(1):1-6

利用英国Hadley气候预测与研究中心GCM模型HADCM2预测的气温变化背景，分别提取青藏公路沿线地区在2009年，2049年和2099年的气温参数，考虑年平均气温和年平均地温的关系及年平均地温与海拔，纬度的关系模型，多年冻土下界分布模型和地温带分带，建立青藏公路沿线多年冻土下界分布的响应模型和多年冻土地温带的响应模型，研究结果表明，2009年青藏公路沿线的冻土变化较小，多年冻土极稳定带,稳定带和基本稳定带仅发生微弱的变化，基本稳定过渡带和不稳定带变化较大，多年冻土,逐渐退化，2049年青藏公路沿线多年冻土各地温带变化较大，但仍以基本稳定过渡带和不稳定带变化最大，多年冻土发生较大范围的退化；2099年后青藏公路沿线冻土发生了很大的变化，多年冻土发生大面积的退化，融区面积逐渐增大，多年冻土地温带也发生了较大的变化，其中多年冻土上带仅保留了稳定带，极稳定带全部消失，稳定带和基本稳定带全部转化为不稳定带。  相似文献   

IAP GCM模式大气背景环流在厄尔尼诺年的异常     

王盘兴  刘家铭 《南京气象学院学报》1991,14(4):503-509

本文分析了中国科学院大气物理研究所大气环流模式(IAP GCM)模式大气5～9月平均环流(本文称为背景环流)。结果表明;厄尔尼诺年一系列重要系统(南方涛动、瓦克环流、哈德莱环流、西太平洋副热带高压和热带辐合带)及大范围降水均发生明显异常;北半球西太平洋热带、副热带是环流异常的主要区域。它们与观测资料的分析结果基本一致,从而论证了该模式在低纬环流研究中的应用前景。  相似文献