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以美国NOAA波传播实验室估算大气折射率湍流结构系数的模式为基础，经过数值试验和观测对比调试，给出了一个得到我国雷达测值验证的实用的C2n估算模式。 相似文献
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研究出一个以热量平衡方法为基础的融雪模式。这个模式考虑了雪面和整个雪盖两方面的热量平衡,并同时预报雪面温度和冻结深度。运行此模式需要实测的或估算的入射辐射资料。融雪和雪面温度的计算值与观测值是一致的。检验了融雪与最大液水含量、热传导率和雪反照率等几个参数的关系。发现随着液水含量或热传导率增加,融雪量就减少。反照率对估算融雪具有很大的作用。利用本模式,估算了583km~2流域的径流量,并且用水坝的入流量资料加以证实。 相似文献
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采用MODIS资料和美国发展的MODIS大气温、湿度廓线统计反演算法,估算大气温度、湿度廓线作为初始场,应用101层快速透过率模式(PFAAST)估算了大气透过率,并采用Newton非线性迭代算法反演中国西北荒漠戈壁地区大气温度廓线。结果表明:该方法对边界层高度及以上部分的大气温度反演得比较好,误差基本都在2 K范围内,边界层范围内的温度反演误差较大,反演误差与气溶胶光学厚度增量和地表温度估算误差呈显著正相关关系,与大气水汽混合比的关系较差。文中从敏感性试验和理论分析角度阐述了地表温度和气溶胶光学厚度估算误差对大气温度反演误差的影响,发现不同光谱波段的地表温度权重均随地表温度的增加有不同程度增加,地表温度反演误差增加将增加地表温度权重,提高地表温度估算误差有助于提高地表温度权重的精度;荒漠戈壁地区大气边界层中气溶胶浓度较高,光学厚度较大,使边界层大气透过率降低,进而降低卫星红外遥感波段的地表温度权重和空气温度权重。由于该模式没有很好地考虑边界层中沙尘气溶胶的影响,使卫星反演的大气透过率偏高,以至于高估地表温度权重和大气温度权重,使得反演的表面温度和空气温度偏低。该研究结合太阳光度计获得的光学厚度资料,采用统计方法对气溶胶效应引起的大气透过率误差和表面温度估算误差进行校正,并对物理算法进行本地化改进,实现了边界层温度廓线的反演。 相似文献
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对2013—2014年EC-thin和T639模式山东省旬温度预报产品进行检验分析,结果表明:模式旬平均温度预报产品预报准确率高于旬最高、旬最低温度预报产品,模式阈值K为2℃的预报准确率均比K为1℃高30%左右。EC-thin模式较T639模式预报旬平均温度预报效果最好,平均误差最小。EC-thin模式预报旬最高温度偏低,预报旬最低温度偏高。对于旬平均温度预报,订正后的T639模式预报准确率在鲁中西部地区略优于EC-thin模式,其他区域均为EC-thin模式较优。EC-thin模式旬最低温度预报产品在鲁西北东部和半岛部分地区预报效果最好,在鲁西北西部和鲁西南部分地区预报效果最差。旬最高温度预报产品在鲁西北东部和鲁东南地区预报效果最好,鲁中西部和半岛东部地区预报效果最差。去除平均误差的订正方法对模式旬温度预报准确率的提高有一定效果,但不能明显改善。 相似文献
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成都区域气象中心业务数值预报产品检验分析 总被引：3，自引：0，他引：3
依据国家气象中心T213、T639全球模式、成都区域中心实时运行的AREM、GRAPES和MM5中尺度数值模式预报结果,对2008年5~9月进行了日降水量和2m温度检验。结果表明:(1)模式对昆明、南京、广州、长沙、北京和郑州温度预报优于温江、兰州和拉萨站,其中拉萨站温度预报与实况偏差最大,即模式对我国中部及南部地区温度预报与实况近似程度高于西部地区。(2)东部地区中雨及以上量级降水评分高于西部,西部4个城市中以昆明站评分最高,反映模式对我国西部城市降雨预报能力偏弱。 相似文献
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成都区域气象中心业务数值预报产品检验分析 总被引：3，自引：0，他引：3
依据国家气象中心T213、T639全球模式、成都区域中心实时运行的AREM、GRAPES和MM5中尺度数值模式预报结果,对2008年5～9月进行了日降水量和2m温度检验。结果表明：（1）模式对昆明、南京、广州、长沙、北京和郑州温度预报优于温江、兰州和拉萨站,其中拉萨站温度预报与实况偏差最大,即模式对我国中部及南部地区温度预报与实况近似程度高于西部地区。（2）东部地区中雨及以上量级降水评分高于西部,西部4个城市中以昆明站评分最高,反映模式对我国西部城市降雨预报能力偏弱。 相似文献
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2006年T213模式在江苏的降水和温度检验评估 总被引：5，自引：1，他引：4
为了了解T213模式在江苏区域的预报性能,对该模式在江苏区域的降水和温度预报进行了检验和评估.检验结果表明,在江苏区域,T213模式晴雨预报正确率近70%,模式对降水预报具有一定的指示作用,影响中小量级降水TS评分的主要因素是模式预报的虚假降水成分较多,中等以上量级则存在降水中心落区预报偏差较大的情况.T213模式温度预报值系统性偏低3 ℃左右,模式分析场的温度偏低且与实况误差较大,是造成这种情况的主要原因,因此进行温度订正是必要的. 相似文献
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The relationship between the factor of temperature difference of the near-surface layer(T_(1000 hPa)-T_(2m))and sea fog is analyzed using the NCEP reanalysis with a horizontal resolution of l°xl°(2000 to 2011) and the station observations(2010 to 2011).The element is treated as the prediction variable factor in the GRAPES model and used to improve the regional prediction of sea fog on Guangdong coastland.(1) The relationship between this factor and the occurrence of sea fog is explicit:When the sea fog happens,the value of this factor is always large in some specific periods,and the negative value of this factor decreases significantly or turns positive,suggesting the enhancement of warm and moist advection of air flow near the surface,which favors the development of sea fog.(2) The transportation of warm and moist advection over Guangdong coastland is featured by some stages and the jumping among these states.It also gets stronger over time.Meanwhile,the northward propagation of warm and moist advection is quite consistent with the northward advancing of sea fog from south to north along the coastland of China.(3) The GRAPES model can well simulate and realize the factor of near-surface temperature difference.Besides,the accuracy of regional prediction of marine fog,the relevant threat score and Heidke skill score are all improved when the factor is involved. 相似文献
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Steric sea level rise over the Mediterranean Sea: present climate and scenario simulations 总被引：3，自引：0，他引：3
A. Carillo G. Sannino V. Artale P. M. Ruti S. Calmanti A. Dell’Aquila 《Climate Dynamics》2012,39(9-10):2167-2184
A regional atmosphere–ocean coupled model has been used to estimate sea level rise in the Mediterranean basin under present and future conditions. A present climate simulation has been forced by ERA40 reanalysis covering the period 1958–2001. Moreover a simulation has been forced by the global coupled model ECHAM5-MPIOM under present climate conditions for the period 1951–2000. Two other 50-year simulations have been performed under the SRESA1B scenario for the twenty-first century and differ only in temperature and salinity profiles used to relax the ocean model in the Atlantic buffer zone. The present climate simulation has been verified in terms of temperature, salinity and sea level against observed data, showing good performances both in mean values and variability over the whole Mediterranean Sea and over different sub-basins. The future scenario simulations show that the steric sea level averaged over the entire basin rises of about 2 or 7?cm in 50?years depending on the Atlantic boundary conditions. The difference of about 1?°C and 0.5?psu in the upper layers of the Atlantic sea reflects mainly on the halosteric component that contributes negatively to the sea level rise, when fresher and colder boundary conditions are used in the Atlantic buffer zone, and positively in the other case. The impact of the boundary conditions is not uniform in the basin and is particularly strong in some easternmost regions. 相似文献
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Modelling the response of glaciers to climate change by applying volume-area scaling in combination with a high resolution GCM 总被引：4，自引：0，他引：4
A seasonally and regionally differentiated glacier model is used to estimate the contribution that glaciers are likely to
make to global sea level rise over a period of 70 years. A high resolution general circulation model (ECHAM4 T106) is used
to estimate temperature and precipitation changes for a doubled CO2 climate and serves as input for the glacier model. Volume-area relations are used to take into account the reduction of glacier
area resulting from greenhouse warming. Each glacieriated region has a specified glacier size distribution, defined by the
number of glaciers in a size class and a mean area. Changes in glacier volume are calculated by a precipitation dependent
mass balance sensitivity. The model predicts a global sea level rise of 57 mm over a period of 70 years. This corresponds
to a sensitivity of 0.86 mm yr−1K−1. Assuming a constant glacier area as done in earlier work leads to an overestimation of 19% for the contribution to sea level
rise.
Received: 16 August 2000 / Accepted: 21 May 2001 相似文献
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M. A. Gouvas N. K. Sakellariou H. D. Kambezidis 《Meteorology and Atmospheric Physics》2011,110(3-4):143-149
In this study, regression equations to estimate the monthly and annual values of the mean maximum and mean minimum air temperatures in Greece are derived. For this purpose, data from 87 meteorological stations distributed all over Greece are used. Geographical parameters, i.e., altitude, latitude, longitude, minimum distance from the sea and an index of terrain morphology, are used as independent variables. These equations explain 79?C97% of the variance of the temperature values and have standard error of estimate between 0.59 and 1.20°C. Data from 37 other meteorological stations are used to validate the accuracy of the equations. Topographic or climatic factors, which could not be introduced into the equations, are responsible for most temperature residuals >0.5°C or <?0.5°C. Moreover, some particular emphasis has been given to the values of the regression coefficient for the altitude, since it is the estimator for the mean lapse rate of air temperature. 相似文献
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Using a 5-layer P-o mixed coordinates primitive equations model, a process of heavy rain is simulated that occurred over the middle-and lower-reaches of the Changjiang River on July 1-2, 1991 and numerical experiments are done of the effects of sea surface temperature (SST) anomalies over different waters on the precipitation. The result has shown that the appearance of SST anomaly is followed in a short term (2 or 3 days) by. A change in the pattern of circulation as well as in precipitation to some extent. 相似文献
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关于海面湍流通量参数化的两种方案试验 总被引：2，自引：0，他引：2
本文对海气间湍流通量计算的参数化进行了两个方案的试验。第一个是对气候模式ＣＣＭ３中的计算方案作了改进,用半解析的计算方法代替纯迭代的方法,减少了计算量而达到相同精度。第二个是用Ｂｒｕｔｓａｅｒｔ提出的廓线函数计算海面通量,达到了当前最精确模式相同的精度。这二种方案均可用于大气模式或用于由实测气象资料求通量。 相似文献
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Pasquill stability categories or similar classifications can be used to estimate dispersion of airborne material. Such categories are defined in terms of synoptic surface-layer variables. In order to transpose experience gained over land to sea, the different boundary conditions over land and sea must be considered. Using the assumption that the turbulence intensity and hence diffusion will be the same over land and sea if the boundary conditions expressed by sensible heat flux and shear stress are equal, a conversion is derived. With a reasonable degree of accuracy, synoptic parameters, mean wind speed and air sea temperature difference can be used at sea to specify stability categories.During the course of this research, it was found that Golder's relation between stability categories and Monin-Obukhov length can not be used at sea, since this relationship must depend on the Bowen ratio and albedo. 相似文献
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D. Bala Subrahamanyam Radhika Ramachandran S. Indira Rani P. K. Kunhikrishnan B. Prasad Kumar 《Boundary-Layer Meteorology》2008,127(2):333-344
Surface-layer meteorological observations obtained from oceanic buoys over the Korean Strait and the Yellow Sea are used to
estimate surface-layer turbulent fluxes of heat, moisture and momentum over the East-Asian Marginal Seas. Special emphasis
is paid towards explanation of the impact of the Tsushima warm current flowing through the Korean Strait on air–sea interface
fluxes. During the active phase of the Tsushima warm current, when the difference in sea surface temperature and air temperature
becomes as large as 8°C, the sensible heat flux increases to a value of about 135 W m−2, while the latent heat flux is around 200 W m−2. The study attempts to broaden our understanding on the air-sea interaction processes over the Yellow Sea and Korean Strait. 相似文献
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Duanjun Lu L. White R. S. Reddy Quinton L. Williams Paul J. Croft 《Meteorology and Atmospheric Physics》2011,111(3-4):75-90
Three models, MM5, COAMPS, and WRF, have been applied for the warm season in 2003 and the cool season in 2003?C2004 to evaluate their performances. All models run over the same domain area covering the north Gulf Mexico and southeastern United States (US) region with the same spatial resolution of 27?km. It was found that the temporal variations of the mean error distribution and strength at 24 and 36?h were rather weak for surface temperature, sea level pressure, and surface wind speed for all models. A warm bias in surface temperature forecasts dominated over land during the warm season, whereas a cool bias existed during the cool season. The MM5 and WRF produced negative biases of sea level pressure during the warm season and positive biases during the cool season while the COAMPS yielded a similar distribution of sea level pressure biases during both seasons. During both seasons, similar surface wind speed biases produced by each model included a high wind speed forecast over most areas by MM5 while the COAMPS and WRF yielded weak surface winds over the western Plains and stronger surface winds over the eastern Plains. Root-mean-squared errors revealed that the forecast of surface temperature, sea level pressure, and surface wind speed were degraded with the increase of forecast time. For rainfall evaluation, it was found that the MM5 underpredicted seasonal precipitation while the COAMPS and WRF overpredicted. The bias scores revealed that the MM5 yielded an underprediction of the coverage of precipitation areas, especially for heavier rainfall events. The MM5 presented the lower threat score at lighter rainfall events compared to the COAMPS and WRF. For moderate and heavier thresholds, all models lacked forecast accuracy. The WRF accuracy in predicting precipitation was heavily dependent upon the performance of the selected cumulus parameterization scheme. Use of the Grell?CDevenyi and Bette?CMiller?CJanjic schemes helps suppress precipitation overprediction. 相似文献