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观测资料的四维质量控制:变分法 总被引:7,自引:1,他引:7
利用四维变分资料同化技术,定义了观测资料的误差均差比,并在理论上初步探讨了利用误差均差比来判断资料中重大误差(grosserror)的合理性。利用简单的Lorenz模式进行了一些数值试验,以检验质量控制方案。 相似文献
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神经网络在气象观测资料优化中的应用研究 总被引:3,自引:5,他引:3
利用一种改进的BP算法,对气象观测资料进行优化处理,并把神经网络方法看作是时间序列方法的扩充。利用该算法提出了基于空间相关、时间相关、模式相关三种资料优化处理方案,为气象观测资料的优化提供了一条新方法。利用文中的方法,对黑河地区的观测资料进行了修正实验,取得了比较满意的结果。 相似文献
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本文利用红外云图及TBB资料对“91.6、91.7”安徽大暴雨中的几个时次进行了详细分析,得出了云图暴雨模式。结合该模式,给出了利用云图资料估计降水的简易流程。 相似文献
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通过对2001~2005年长春市紫外线观测资料的分析,得出紫外线强度与总云量、日平均气温有很好的关系,利用2001~2005年紫外线强度的观测资料和同期气象资料,利用回归分析建立了紫外线强度预报方法。 相似文献
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本文介绍了利用静止气象卫星云图导出云迹风资料的原理和方法,并对导出的云迹风资料进行了分析。结果表明,所得结果具有一定的合理性,合理利用这些资料可以弥补台站稀疏的地区资料缺少的缺陷,对天气分析和数值预报有一定的补充作用。 相似文献
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On the basis of the Monin-Obukhov similarity theory, a semi-empirical expression of universal functions is fitted by means of the iteration method. using the gradient observation data of wind and temperature in the surface layer. The characteristics of bulk transfer coefficient are studied and some empirical relationships among the bulk transfer coefficient, the wind speed and temperature are obtained. The applicability of the results is investigated using observation data. 相似文献
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荒漠戈壁大气总体曳力系数和输送系数观测研究 总被引:24,自引:10,他引:14
利用“我国西北干旱区陆一气相互作用观测试验”在甘肃敦煌进行的陆面过程野外试验的观测资料,依据三种不同方法确定了干旱戈壁区动量输送的曳力系数Cd、感热和潜热交换的总体输送系数Ch和Cq。结果表明:尽管这三种方法计算的曳力系数和总体输送系数有一定的差别,但在量级上相当,尤其是Cd和Ch的平均值比较接近。本文还通过对风向的分析,剔除了附近建筑物干扰和来自绿洲湿平流的影响,得到了荒漠戈壁总体输送系数的特征及其与理查孙数的关系。 相似文献
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青藏高原总体输送系数的特征 总被引:17,自引:1,他引:17
利用中日亚洲季风机制合作研究计划设在西藏的 4个自动气象站(AWS)获得的5a多(199年7月~1998年12月)时次密集、观测连续的近地层梯度资料,以最小二乘法确定出相应站点各季节的地表粗糙度,并应用廓线-通量法计算了4站逐日的总体输送系数,分析了其随时间的变化特征。结果表明:青藏高原动量输送系数的多年平均值为3.53×10-3~4.99×10-3,热量输送系数为4.67×10-3~6.73×10-3,并且两种输送系数都存在明显的日变化和季节变化,部分站点还存在较明显的年际变化。另外,还讨论了总体输送系数与近地层大气层结稳定度、地表粗糙度以及地面风速等因子的关系,初步建立了可用常规气象站地面观测资料计算青藏高原总体输送系数的拟合公式。 相似文献
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Turbulent characteristics and bulk transfer coefficients over the desert in the HEIFE area 总被引:1,自引:0,他引:1
Ichiro Tamagawa 《Boundary-Layer Meteorology》1996,77(1):1-20
Observations of surface-layer turbulence and turbulent fluxes were made over a desert in northwestern China as a part of HEIFE (HEIhe river Field Experiment). These show that the normalized variations of the vertical wind component and of the air temperature obey Monin-Obukhov similarity well, especially in free convective conditions. However, the variations of specific humidity do not obey Monin-Obukhov similarity.Mean bulk transfer coefficients of sensible heat and momentum flux are obtained as functions of stability over a wide stability range from the observed data of turbulent fluxes and mast profiles. However, the bulk transfer coefficient for water vapor could not be obtained because of the large scatter of the data. In free convective conditions, the sensible heat flux was found to be approximately proportional to the 1.4 power of temperature difference between the surface and 20m. The bulk transfer coefficient of sensible heat is also obtained as a function of the bulk Richardson number for practical convenience. 相似文献
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THE CHARACTERISTICS OF TURBULENT TRANSPORT IN THE SURFACE LAYER OVER EASTERN TIBET DURING SUMMER 1986
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Ma Shufen 《Acta Meteorologica Sinica》1991,5(4):456-464
The turbulent fluxes for sensible and latent heat and momentum are computed and analyses are carried outabout the factors in terms of the fluxes,with the profile methods,based on the data from the Tibetan(Xi-zang)Plateau Meteorological Experiment in 1986(TIPMEX-86).It is shown that the fluxes of various kindshave evident diurnal variation,and each decade mean diurnal variation is quite different from others.Thesensible heat flux is about 2/3 less in July than in June.The results indicate that the averaged drag coefficient,C_d,and the averaged bulk transfer coefficient of sensible heat,C_h,are 0.0052 and 0.0075 respectively,for theperiod 13 to 28 in June for Nagqu.But for Lhasa,the mean C_d is 0.0056,and the mean C_h is 0.0085,for the period of June 11 to July 20.It is found that C_d and C_h are not only the function of wind velocity,but also influenced by stability conditions and wind and temperature gradients. 相似文献
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陆面上总体输送系数的特征 总被引:7,自引:4,他引:7
利用气象铁塔的风、温梯度资料,对陆面上近地层湍流拖曳系数CD和总体输送系数CH(或CE)的大小和日变化规律进行研究。发现陆面上较粗糙的地表,CD和CH可以比海面上大一个量级左右。而且存在着明显的日变化。它们对地表面动力粗糙度变化的反应较敏感。本工作为气候及大气环流模式研究中陆面参数化过程提供了重要依据。 相似文献
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1986年夏季西藏东部近地层湍流输送特征的分析 总被引:3,自引:0,他引:3
本文以1986年夏季西藏高原气象实验(TIPMEX-86)期间获得的资料为基础,运用廓线方法,计算了实验期间感热、潜热和动量湍流通量并分析了与通量输送有关因子的变化。分析结果表明,各种湍流通量都有明显的日变化、日际变化和旬变化。7月份感热通量比6月份大约减少了2/3以上。计算得出那曲6月13—28日拖曳系联C_d的平均值为0.0052,同期感热通量的整体输送系数C_h为0.0075;而拉萨6月11日—7月20日C_d的平均值为0.0056,同期C_h的平均值为0.0085。根据整体输送系数和各种有关因子的关系分析表明,C_d,C_h不可能用一个常数代表,它们不仅仅是风速的函数,而且其变化还包含了稳定度、风速梯度、温度梯度的综合效应。 相似文献
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Through the use of the hourly wind, air temperature and humidity, sea surface temperature data measured on board the observing vessel Moana Wave and buoy in the warm pool of western Pacific during the IOP of TOGA COARE, we compute the fluxes over sea surface and analyze the characteristics of the variation ofthe latent heat flux with sea surface temperature. During weak rather than strong wind periods a maximum valueof latent heat flux appears at some points of SST, which is caused mainly by the variations of wind, then by the humidity difference between air and sea and the transfer coefficient with SAT. Using correlation analysis. we also analyze the relationship between the fluxes and meteorological elements during weak wind periods. wester lywind burst periods, and convective disturbed periods etc. The main conclusions are that the latent heat flux ismainly determined by wind, sensible heat flux by the potential temperature difference between air and sea and the momentum flux by wind. The precipitation affects the sensible heat flux through the potential temperature difference and wind. 相似文献