Climatology of cloud and radiation fields in a numerical weather prediction model     

R. I. Cullather  Harshvardhan  K. A. Campana 《Theoretical and Applied Climatology》1997,57(1-2):11-33

Summary Satellite-derived datasets are used to verify the cloud cover and radiation field generated by a T62 (horizontal resolution) version of the operational global model at the National Meteorological Centre (NMC). An ensemble of five day forecasts for July 1985 is used, as well as 30 day climatological forecasts for July 1985, October 1985, January 1986, and April 1986.Monthly averages of radiation fields are compared with Earth Radiation Budget Experiment (ERBE) data. For the four months examined, clear-sky outgoing longwave radiation (clear-sky OLR) and absorbed shortwave radiation (clear-sky SW) tend to agree roughly with ERBE. Model global mean OLR, however, exceeds that of ERBE by 10 W m^–2.Comparison of effective cloud cover to corresponding fields cataloged by the International Satellite Cloud Climatology Project (ISCCP C1) reveals deficiencies in the amount of supersaturation cloudiness and the vertical distribution of convective clouds. Large inaccuracies in model radiation fields are closely related to deficiencies in the cloud parameterization. An inventory of model cloudiness, in comparison to satellite data, is conducted.With 18 Figures  相似文献   

基于FY-3/IRAS利用非线性模式反演OLR   总被引：1，自引：0，他引：1       下载免费PDF全文

吴晓  白文广 《应用气象学报》2017,28(2):189-199

FY-3系列卫星星载IRAS仪器设有26个通道,其中20个通道用于探测地球大气在红外波段的热辐射,通道辐射率代表了地球大气系统在大气顶的向外辐射光谱信息,与总波段的射出长波辐射（OLR）通量相关性高。该文基于逐线辐射传输模式计算软件LBLRTM对全球2521条大气廓线的大气顶射出辐射率模拟数据,计算了每条廓线的OLR和FY-3B/IRAS,FY-3C/IRAS通道辐射率,用统计回归方法建立了利用IRAS的多通道辐射率计算OLR的非线性理论回归模式;应用模式和FY-3B/IRAS,FY-3C/IRAS的L1级数据,处理得到2016年4月1-30日的全球日平均、月平均OLR格点产品。与Aqua/CERES,Terra/CERES仪器宽波段观测OLR产品对比表明:对于水平分辨率为1°×1°的全球月平均OLR格点产品,均方根误差为2.22 W·m-2,相关系数为0.9982 W·m-2,平均偏差为-0.2 W·m-2,表明FY-3/IRAS仪器定标及反演模式均达到较高水平。文中还回顾了历史上不同气象卫星的多种OLR反演算法模式,并对不同模式精度进行了比较。  相似文献   

The impact of geophysical parameters on longwave radiation budget at the top and base of the atmosphere     

Man Li C. Wu  Lihsiung Aron Chang  Wm. Smith 《Meteorology and Atmospheric Physics》1991,46(1-2):29-40

Summary The effect of clouds on longwave radiation budget at the top and base of the atmosphere is studied by using the HIRS2/MSU-retrieved temperature and humidity fields, and cloud fields and the International Satellite Cloud Climatology Project-produced fields. Detailed studies are carried out at four selected sites: one at Equatorial Eastern Pacific (ITCZ) area, one at Libyan Desert (Libya), one at Ottawa, Montreal (Ottawa), and one at central Europe (Europe). The monthly mean differences in outgoing longwave radiation (OLR) (the ISCCP-based OLR minus the HIRS2-based OLR), ranging from –2.8 Wm^–2 at ITCZ to –15.4 Wm^–2 at Ottawa, are less than the monthly mean differences in surface downward flux, ranging from –2.7 Wm^–2 at Libya to 40.6 Wm^–2 at the ITCZ. The large differences in surface downward flux are mainly due to large differences in cloud amount and moisture in the low levels of the atmosphere.Monthly mean OLR and surface downward flux can be derived either (1) from instantaneous temperature, humidity, and cloud fields over a month period or (2) from monthly mean temperature, humidity, and cloud fields. The monthly mean OLR and surface downward flux derived from the first approach is compared with the second. The differences in OLR are small, ranging from –0.05 Wm^–2 to 6.2 Wm^–2, and the differences in surface downward flux is also small, ranging from 0.4 Wm^–2 to 6.4 Wm^–2.List of Acronyms AVHRR Advanced Very High Resolution radiometer - ERB Earth Radiation Budget - ERBE Earth Radiation Budget Experiment - FGGE First Global GARP Experiment - GARP Global Atmospheric Research Program - GCM General Circulation Model - GISS Goddard Institute for Space Studies - GLA Goddard Laboratory for Atmospheres - GMS Geostationary Meteorological Satellite - GOES Geostationary Operational Environmental Satellite - HIRS2 High Resolution Infrared Radiation Sounder/2 - ISCCP International Satellite Cloud Climatology Project - IR Infrared - MSU Microwave Sounding Unit - NFOV Narrow Field of View - NOAA National Oceanic and Atmospheric Administration - NESDIS National Environmental Satellite Data Information Service - TOVS TIROS Operational Vertical Sounder With 4 Figures  相似文献   

The atmospheric energy budget and implications for surface fluxes and ocean heat transports   总被引：2，自引：4，他引：2  

K. E. Trenberth  J. M. Caron  D. P. Stepaniak 《Climate Dynamics》2001,17(4):259-276

Comprehensive diagnostic comparisons and evaluations have been carried out with the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) and European Centre for Medium Range Weather Forecasts (ECMWF) reanalyses of the vertically integrated atmospheric energy budgets. For 1979 to 1993 the focus is on the monthly means of the divergence of the atmospheric energy transports. For February 1985 to April 1989, when there are reliable top-of-the-atmosphere (TOA) radiation data from the Earth Radiation Budget Experiment (ERBE), the implied monthly mean surface fluxes are derived and compared with those from the assimilating models and from the Comprehensive Ocean Atmosphere Data Set (COADS), both locally and zonally integrated, to deduce the implied ocean meridional heat transports. While broadscale aspects and some details of both the divergence of atmospheric energy and the surface flux climatological means are reproducible, especially in the zonal means, differences are also readily apparent. Systematic differences are typically ∼20 W m⁻². The evaluation highlights the poor results over land. Land imbalances indicate local errors in the divergence of the atmospheric energy transports for monthly means on scales of 500 km (T31) of 30 W m⁻² in both reanalyses and ∼50 W m⁻² in areas of high topography and over Antarctica for NCEP/NCAR. Over the oceans in the extratropics, the monthly mean anomaly time series of the vertically integrated total energy divergence from the two reanalyses correspond reasonably well, with correlations exceeding 0.7. A common monthly mean climate signal of about 40 W m⁻² is inferred along with local errors of 25 to 30 W m⁻² in most extratropical regions. Except for large scales, there is no useful common signal in the tropics, and reproducibility is especially poor in regions of active convection and where stratocumulus prevails. Although time series of monthly anomalies of surface bulk fluxes from the two models and COADS agree very well over the northern extratropical oceans, the total fields all contain large systematic biases which make them unsuitable for determining ocean heat transports. TOA biases in absorbed shortwave, outgoing longwave and net radiation from both reanalysis models are substantial (>20 W m⁻² in the tropics) and indicate that clouds are a primary source of problems in the model fluxes, both at the surface and the TOA. Time series of monthly COADS surface fluxes are shown to be unreliable south of about 20^∘N where there are fewer than 25 observations per 5^∘ square per month. Only the derived surface fluxes give reasonable implied meridional ocean heat transports. Received: 21 March 2000 / Accepted: 21 June 2000  相似文献   

Use of meteosat data for validation of the diurnal variation of the outgoing longwave radiation produced by ERBE     

F. Cheruy  R.S. Kandel 《Dynamics of Atmospheres and Oceans》1991,16(1-2)

Radiative transfer calculations have been performed to demonstrate the usefulness of the Meteosat observations in the relative narrow-band of the water vapour absorption (WV, 5.7–7.1 μm) in addition to the observations in the atmospheric infrared window (IR, 10.5–12.5 μm) to deduce the integrated thermal outgoing longwave radiation (OLR). A statistical analysis of colocated and nearly simultaneous Meteosat and the Earth Radiation Budget Experiment (ERBE) data has yielded regression coefficients for estimating the OLR with Meteosat data during the months of April and July 1985. These results have been used to study the mean diurnal variation of the outgoing longwave radiation. The results show that in some cases, because of inadequate time sampling, the form (and especially the phase) of the longwave (LW) diurnal cycle is incorrectly determined by ERBE, but that Meteosat data can improve the determination. In nearly all cases, such errors have little or no influence on the determination of monthly mean LW flux fields.  相似文献   

The impact of boundary forcing on RegCM4.2 surface energy budget     

Ivan Güttler  Čedo Branković  Lidija Srnec  Mirta Patarčić 《Climatic change》2014,125(1):67-78

The surface energy budget components from two simulations of the regional climate model RegCM4.2 over the European/North African domain during the period 1989–2005 are analysed. The simulations differ in specified boundary forcings which were obtained from ERA-Interim reanalysis and the HadGEM2-ES Earth system model. Surface radiative and turbulent fluxes are compared against ERA-Interim. Errors in surface radiative fluxes are derived with respect to the Global Energy and Water Cycle Experiment/Surface Radiation Budget satellite-based products. In both space and time, we find a high degree of realism in the RegCM surface energy budget components, but some substantial errors and differences between the two simulations are also present. The most prominent error is an overestimation of the net surface shortwave radiation flux of more than 50 W/m² over central and southeastern Europe during summer months. This error strongly correlates with errors in the representation of total cloud cover, and less strongly with errors in surface albedo. During other seasons, the amplitude of the surface energy budget components is more in line with reference datasets. The errors may limit the usefulness of RegCM simulations in applications (e.g. high-quality simulation-driven impact studies). However, by using a simple diagnostic model for error interpretation, we suggest potential sensitivity studies aiming to reduce the underestimation of cloud cover and overestimation of shortwave radiation flux.  相似文献   

On the angular correction of satellite radiation measurements: The performance of ERBE angular dependence model in the Arctic     

Z. Li 《Theoretical and Applied Climatology》1996,54(3-4):235-248

Summary An angular dependence model (ADM) is needed to convert radiance measurements into fluxes. This paper provides an overview on the progress and issues related to the angular correction of radiation data at the top-of-the-atmosphere (TOA), followed by an investigation on the performance of the Earth Radiation Budget Experiment (ERBE) ADMs in the Arctic during summer. The variation of inferred albedo with viewing geometry indicates the merit of an ADM. The ERBE ADM for land does well as it leads to near constant albedos for given solar zenith angles. The ADM for snow/ice is least satisfactory when applied to the Arctic in summer. The performance of the ocean ADM is acceptable except at large solar zenith angles for which albedo increases with viewing zenith angle. Significant and systematic variation of albedo with viewing angle and relative azimuth angle are manifest when the overcast ERBE ADM is applied to over-cast-over-snow/ice scenes. A methodology for correcting ERBE ADMs was proposed by normalizing the anisotropic factor over bins containing sufficient measurements.With 6 Figures  相似文献   

RETRIEVAL OF QINGHAI-XIZANG SASWR WITH ERBE AND ISCCP DATA          下载免费PDF全文

Gao Ge  Weng Duming 《Acta Meteorologica Sinica》1999,13(3):367-374

In the context of 1985—1988 ERBE and 1984—1988 ISCCP planetary scale albedoes and totalcloudiness in combination with Qinghai-Xizang actinometric measurements,investigation wasperformed of the climatic retrieval of surface absorbed shortwave radiation(SASWR)in theresearch highland.Evidence suggests that the method has given higher fitting accuracy with meanerror of 9.8 W m~(-2),whereupon was calculated the monthly mean SASWR flux density at thegridpoints of 2.5°×2.5°resolution over 25—40°N,75—95°E and 63 stations alongside a set of thedistribution maps prepared for its basic features.  相似文献   

均匀裸土地表土壤热通量计算方法对比及对能量闭合的影响   总被引：2，自引：1，他引：1  

郭阳  左洪超  陈继伟  王晓霞  董龙翔 《气候与环境研究》2015,20(2):177-187

利用"内蒙古微气象观测蒸发试验"的观测资料,对6种地表土壤热通量计算方法(Plate Cal法、TDEC法、谐波法、热传导对流法、振幅法和相位法)进行比较,检验了6种方法在不同干湿地表状况下的适用性,并研究了6种方法计算地表土壤热通量的差异以及对地表能量闭合度的影响。结果表明:一般情况下,Plate Cal法计算的2 cm土壤热通量与观测值最接近,计算结果的均方差为6.9 W/m2。在不同干湿地表状况下,干燥和降水条件下适合使用Plate Cal法,计算结果的均方差分别为14.0 W/m2和30.1 W/m2;湿润条件下适合使用谐波法,计算结果的均方差为21.4 W/m2。6种方法计算的地表土壤热通量存在明显差别,最大相差178.6 W/m2,不同方法计算地表土壤热通量的最大差值超过25 W/m2的时次占样本的96.3%。不同方法计算地表土壤热通量的差异对地表能量闭合度的大小有明显影响,但不影响近地层能量闭合度随湍流混合增强而增大的规律。  相似文献   

Assessment of GEWEX/SRB version 3.0 monthly global radiation dataset over China     

Futing Wu  Congbin Fu 《Meteorology and Atmospheric Physics》2011,112(3-4):155-166

NASA/GEWEX (National Aeronautics and Space Administration/Global Energy and Water Cycle Experiment) Surface Radiation Budget (SRB) has released its latest radiation dataset, version 3.0. We examine the accuracy of the monthly mean global radiation in China using surface-observed radiation (SOR) data at 42 stations during the period 1984?C2004. Overall comparison shows a general overestimation of satellite retrieval radiation data with a bias of 14.6?W?m^?2 and a root mean square error of 25.9?W?m^?2. Differences at individual stations suggested satellite data are consistently higher than surface measurements over eastern China (110°E), but occasional underestimation occurs in Western China, especially Southwest China. Intra-annual variation analysis indicates that SRB satellite radiation can capture the annual cycle well. For trend of global radiations, there are evident discrepancies between satellite retrievals and surface measurements for both the entire period and segmental terms. For the entire period from 1984 to 2004, most stations show a positive trend based on surface measurements, while the majority of collocated pixels show a negative trend. Segmental trends demonstrated that the principal difference occurred during the first period of 1981?C1994. After 1994, the two datasets change similarly. Therefore, trend analysis in terms of detecting global dimming/brightening remains very difficult as surface measurements and satellite products do not agree yet. In addition, some proposals are made towards better understanding of the bias of satellite products and to improve further the satellite retrieval algorithm with better representation of both cloud and aerosol properties.  相似文献   

The global heat balance: heat transports in the atmosphere and ocean   总被引：10，自引：0，他引：10  

Kevin E. Trenberth  Amy Solomon 《Climate Dynamics》1994,10(3):107-134

The heat budget has been computed locally over the entire globe for each month of 1988 using compatible top-of-the-atmosphere radiation from the Earth Radiation Budget Experiment combined with European Centre for Medium Range Weather Forecasts atmospheric data. The effective heat sources and sinks (diabatic heating) and effective moisture sources and sinks for the atmosphere are computed and combined to produce overall estimates of the atmospheric energy divergence and the net flux through the Earth's surface. On an annual mean basis, this is directly related to the divergence of the ocean heat transport, and new computations of the ocean heat transport are made for the ocean basins. Results are presented for January and July, and the annual mean for 1988, along with a comprehensive discussion of errors. While the current results are believed to be the best available at present, there are substantial shortcomings remaining in the estimates of the atmospheric heat and moisture budgets. The issues, which are also present in all previous studies, arise from the diurnal cycle, problems with atmospheric divergence, vertical resolution, spurious mass imbalances, initialized versus uninitialized atmospheric analyses, and postprocessing to produce the atmospheric archive on pressure surfaces. Over land, additional problems arise from the complex surface topography, so that computed surface fluxes are more reliable over the oceans. The use of zonal means to compute ocean transports is shown to produce misleading results because a considerable part of the implied ocean transports is through the land. The need to compute the heat budget locally is demonstrated and results indicate lower ocean transports than in previous residual calculations which are therefore more compatible with direct ocean estimates. A Poisson equation is solved with appropriate boundary conditions of zero normal heat flux through the continental boundaries to obtain the ocean heat transport. Because of the poor observational data base, adjustments to the surface fluxes are necessary over the southern oceans. Error bars are estimated based on the large-scale spurious residuals over land of 30 W m^–2 over 1000 km scales (10¹² m²). In the Atlantic Ocean, a northward transport emerges at all latitudes with peak values of 1.1±0.2 PW (1 standard error) at 20 to 30°N. Comparable values are achieved in the Pacific at 20°N, so that the total is 2.1±0.3 PW. The peak southward transport is at 15 to 20°S of 1.9±0.3 PW made up of strong components from both the Pacific and Indian Oceans and with a heat flux from the Pacific into the Indian Ocean in the Indonesian throughflow. The pattern of poleward heat fluxes is suggestive of a strong role for Ekman transports in the tropical regions.  相似文献   

Estimation of Hourly Solar Radiation at the Surface under Cloudless Conditions on the Tibetan Plateau Using a Simple Radiation Model     

LIANG Hong  ZHANG Renhe  LIU Jingmiao  SUN Zhian  CHENG Xinghong 《大气科学进展》2012,29(4):675-689

In this study,the clear sky hourly global and net solar irradiances at the surface determined using SUNFLUX,a simple parameterization scheme,for three stations(Gaize,Naqu,and Lhasa) on the Tibetan Plateau were evaluated against observation data.Our modeled results agree well with observations.The correlation coefficients between modeled and observed values were > 0.99 for all three stations.The relative error of modeled results,in average was < 7%,and the root-mean-square variance was < 27 W m 2.The solar irradiances in the radiation model were slightly overestimated compared with observation data;there were at least two likely causes.First,the radiative effects of aerosols were not included in the radiation model.Second,solar irradiances determined by thermopile pyranometers include a thermal offset error that causes solar radiation to be slightly underestimated.The solar radiation absorbed by the ozone and water vapor was estimated.The results show that monthly mean solar radiation absorbed by the ozone is < 2% of the global solar radiation(< 14 W m 2).Solar radiation absorbed by water vapor is stronger in summer than in winter.The maximum amount of monthly mean solar radiation absorbed by water vapor can be up to 13% of the global solar radiation(95 W m 2).This indicates that water vapor measurements with high precision are very important for precise determination of solar radiation.  相似文献   

Radiative effects of Pinatubo aerosols in the middle latitudes of the Northern Hemisphere     

B. Wu  D. Lu  Q. Fu 《Theoretical and Applied Climatology》1995,51(1-2):13-23

Summary Using scattering coefficient profiles of the Pinatubo aerosols derived from the observation of skylight polarization and lidar backscattering ratio in Beijing, the radiative effect of Pinatubo aerosols in middle latitudes is assessed by a delta-four-stream radiative transfer model. It is shown that the Pinatubo aerosols significantly change the radiation field. Due to the presence of the volcanic aerosols, the downward short wave flux at the surface decreases with a maximum of 8 W/m² while the upward short wave flux at the top of the atmosphere increases with a maximum of 6.5 W/m². The volcanic aerosols are injected into the region bounded below by the tropopause and up by the 25 km level. The upward and downward radiative fluxes are changed in opposite directions at those two boundaries. Downward short wave fluxes below the tropopause are 7–9 W/m² less than background values and downward long wave fluxes below the tropopause are 2 W/m² more than background values. Upward short wave fluxes above 25 km level is 5–7 W/m² more and upward fluxes above there are about 3 W/m² less.The effects of the Pinatubo aerosols on heating rates are also significant. The maximum increase in the short wave heating rate can be as large as 0.2 K/day at 22 km. The increase in the long wave heating rate is less with a maximum amplitude of about 0.15 K/day. The maximum increase of the total heating rate is about 0.35 K/day, which is comparable with the heating rate caused by the ozone 9.6 µm band in this region.Results of this study are compared with studies of Lacis et al. (1992) and Russell et al. (1993) as well as ERBE measurements. The results generally agree well. Causes for the differences are analyzed.Based on the numerical study, it is also found that the LOWTRAN fresh volcanic model is not representative for the Pinatubo aerosols.With 9 Figures  相似文献   

从Himawari08卫星估算晴空地表长波辐射及其日变化特征初探   总被引：1，自引：0，他引：1  

吴晓  闵敏  董立新 《气候与环境研究》2018,23(1):37-46

通过446183条全球晴空大气廓线的红外辐射传输模拟和统计回归,建立了由Himawari08成像仪通道遥测数据估算晴空地表上行、下行长波辐射通量的反演模式,模式应用于成像仪观测资料,处理出晴空地表上行、下行长波辐射通量实时产品,2016年2~6月的产品精度验证试验结果为:与相同时刻的AQUA卫星CERES仪器同类产品相比,地表上行通量均方根误差R_e=7.9 W/m2,相关系数R=0.9399,地表下行通量R_e=14.5 W/m2,R=0.9586;与由中国地面气象站地面气温和相对湿度观测经Brunt、Brutsaert经验公式计算的实时地表下行长波辐射通量相比,R_e=15.34 W/m2,R=0.8786;与用陆表温度计算的地表上行长波辐射通量相比,R_e=12.6 W/m2,R=0.9977。研究了2016年2、6月的晴空地表长波辐射产品,发现陆地晴空上、下行通量有着与太阳加热地表增温相应的明显日变化特征,峰值出现在12:00（当地时间,下同）至14:00,低谷出现在04:00至07:00,下行通量与上行通量几乎同步变化或约有延时,陆地上2个通量归一化的日变化指数类似一个半正弦曲线,而海面长波辐射通量则没有明显的日变化规律。  相似文献   

长波区间太阳辐射对气候模拟的影响   总被引：1，自引：0，他引：1       下载免费PDF全文

卢鹏  张华  荆现文  王志立 《大气科学学报》2015,38(2):175-183

长波区间的太阳辐射在气候模式中往往被忽略。利用国家气候中心BCC_AGCM2.0.1大气环流模式,采用矩阵算子辐射传输算法,研究了长波区间太阳辐射对气候模式辐射通量和温度模拟结果的影响。结果表明,以ISCCP和CERES辐射资料为标准,考虑长波区间太阳辐射后,长波区间晴空大气地表向下辐射通量平均误差减小2.05 W/m2,均方根误差减少1.29 W/m2;长波区间晴空大气模式顶向上辐射通量平均误差减小0.70 W/m2,均方根误差减小0.21 W/m2;长波区间有云大气地表向下辐射通量平均误差减小1.38 W/m2,均方根误差减小1.03 W/m2;长波区间有云大气模式顶向上辐射通量平均误差减小0.99 W/m2,均方根误差减小0.30 W/m2。以ECMWF再分析资料为标准,考虑长波区间太阳辐射后,赤道地区上对流层—下平流层区域温度的冷偏差得到改善,对流层顶温度平均误差减小0.27 K,均方根误差减小0.25 K。  相似文献   

辐射参数化方案对一个海气耦合模式云和辐射模拟的影响          下载免费PDF全文

汪方  丁一汇徐影 《应用气象学报》2007,18(3):257-265

比较Morcrette辐射方案和Fu_Liou辐射方案对NCC/IAP T63海气耦合模式云和辐射模拟的影响, 结果表明:两种方案模拟的大气顶入射辐射存在明显的差异; 晴空大气Fu_Liou方案的短波吸收能力在全球普遍较Morcrette方案低; 在60°S~60°N之间, Fu_Liou方案模拟的行星反照率更接近于ERBE卫星观测; 在对大气顶净辐射的模拟上, 除了冬季的太平洋和大西洋东岸云量明显减少的部分地区外, Fu_Liou方案对大气顶净辐射的模拟总体上较Morcrette方案有了较为明显的改善; Fu_Liou方案模拟的海洋低层云显著减少, 而热带地区高云的模拟明显增加; 由于采用了“二元云量”算法, 尽管云量有所减少, Fu_Liou方案模拟的云短波吸收作用仍有所增强, 一定程度上改进了Morcrette方案云的短波吸收作用偏弱的现象。  相似文献   

利用NOAA卫星HIRS探测器监测东亚地区辐射收支的研究   总被引：1，自引：0，他引：1  

张文建  董超华  黎光清  赵柏林  朱元竞 《气象学报》1997,55(6):681-691

地球－大气系统的辐射收支是描述地球和宇宙空间能量交换的重要参量，也只有从卫星平台才能直接观测大气顶的地球－大气系统的辐射收支。目前，长期的地－气系统射出长波辐射序列资料是从美国ＮＯＡＡ极轨业务气象卫星的甚高分辨率扫描辐射计测量中计算的，精度不能满足气候监测的要求。本文根据美国ＮＯＡＡ卫星高分辨率红外大气探测器（ＨｉｇｈＲｅｓｏｌｕｔｉｏｎＩｎｆｒａｒｅｄＳｏｕｎｄｅｒ，缩写为ＨＩＲＳ）测量资料，研究了从中推算地球大气系统辐射收支的方法，并对计算出的１９９１年１月份东亚地区的地－气系统的辐射收支各参量、白天和夜间射出长波辐射差别分别进行了对比分析。结果表明，此方法计算的辐射收支分量，能揭示云和地球－大气系统的辐射分布特征及其分布细节，是进行区域气候研究的有效资料。  相似文献   

Performance of Goddard earth observing system GCM column radiation models under heterogeneous cloud conditions     

L. Oreopoulos  M. -D. Chou  M. Khairoutdinov  H. W. Barker  R. F. Cahalan 《Atmospheric Research》2004,72(1-4):365

We test the performance of the shortwave (SW) and longwave (LW) Column Radiation Models (CORAMs) of Chou and collaborators with heterogeneous cloud fields from a single-day global dataset produced by NCAR's Community Atmospheric Model (CAM) with a 2-D Cloud Resolving Model (CRM) installed in each column. The original SW version of the CORAM performs quite well compared to reference Independent Column Approximation (ICA) calculations for boundary fluxes (global error 4 W m⁻² for reflected flux), largely due to the success of a combined overlap and cloud scaling parameterization scheme. The absolute magnitude of errors relative to ICA are even smaller (global error 2 W m⁻² for outgoing flux) for the LW CORAM which applies similar overlap. The vertical distribution of heating and cooling within the atmosphere is also simulated quite well with daily averaged zonal errors always less than 0.3 K/day for SW and 0.6 K/day for LW heating (cooling) rates. The SW CORAM's performance improves by introducing a scheme that accounts for cloud inhomogeneity based on the Gamma Weighted Two Stream Approximation (GWTSA).These results suggest that previous studies demonstrating the inaccuracy of plane-parallel models may have unfairly focused on worst case scenarios, and that current radiative transfer algorithms in General Circulation Models (GCMs) may be more capable than previously thought in estimating realistic spatial and temporal averages of radiative fluxes, as long as they are provided with correct mean cloud profiles. However, even if the errors of our particular CORAMs are small, they seem to be systematic, and their impact can be fully assessed only with GCM climate simulations.  相似文献   

A hybrid technique for computing the monthly mean net longwave surface radiation over oceanic areas     

H. Zhi  Harshvardhan 《Theoretical and Applied Climatology》1993,47(2):65-79

Summary Global maps of the monthly mean net upward longwave radiation flux at the ocean surface have been obtained for April, July, October 1985 and January 1986. These maps were produced by blending information obtained from a combination of general circulation model cloud radiative forcing fields, the top-of-the-atmosphere cloud radiative forcing from ERBE and TOVS profiles and sea surface temperature on ISCCP C1 tapes. The fields are compatible with known meteorological regimes of atmospheric water vapor content and cloudiness. There is a vast area of high net upward longwave radiation flux (> 80 W m^–2) in the eastern Pacific Ocean throughout most of the year. Areas of low net upward longwave radiation flux (< 40 Wm^–2) are the tropical convective regions and extra tropical regions that tend to have persistent low cloud cover. The technique used in this study relies on GCM simulations and so is subject to some of the uncertainties associated with the model. However, all input information regarding temperature, moisture and cloud cover is from satellite data having near global coverage. This feature of the procedure alone warrants its consideration for further use in compiling global maps of the net longwave radiation at the surface over the oceans.With 9 Figures  相似文献   

Impact of physical initialization on cloud forecasts     

H. -S. Lee  T. N. Krishnamurti 《Meteorology and Atmospheric Physics》1995,56(3-4):261-273

Summary The impact of initial data on cloud forecasts by the Florida State University Global Spectral Model (FSUGSM) has been investigated. This work has shown that improving the information content of the initial data by physical initialization has a very strong, positive impact on cloud forecasts. Model spin-up of clouds is considerably reduced. There is an overall better representation of high, middle, low, and total clouds over the tropics and there is a discernible improvement in the prediction of clouds. A strong correlation between cloud shortwave forcing and longwave forcing has been noted in model forecasts with the physically initialized data. This result compares very well with observations from the Earth Radiation Budget Experiment (ERBE).With 10 Figures  相似文献