EXPERIMENTAL STUDY OF REMOTE SENSING OF ATMOSPHERIC AEROSOL SIZE DISTRIBUTION BY COMBINED SOLAR EXTINCTION AND FORWARD SCATTERING METHOD     

Qiu Jinhuan  Wang Hongqi  Zhou Xiuji  Lu Daren 《大气科学进展》1985,2(3):307-315

Combined observations of solar spectral extinction and forward angular scattering are presented. The atmospheric columnar aerosol size distributions in Beijing are retrieved from observed data and the characteristics discussed.  相似文献   

华北区第四纪植被演替与气候变化   总被引：6，自引：0，他引：6       下载免费PDF全文

周昆叔 《地质科学》1984,(2):165-172

文中华北区是指燕山、辽南一线以南、吕梁山以东、渭河谷地与准阳丘陵以北地区。该区属暖温带,即蒙古和东北寒温带、温带区域与华中和华东亚热带区域之间的过渡地带,故第四纪冰期、间冰期气候的变化,对本区的影响表现得很强烈,它引起第四纪植被的明显演替,是我国第四纪植被变化较大的两个区域之一(另一为青藏区)。  相似文献   

风场在预报暴雨发生中的作用——1975年8月上旬特大暴雨的数值实验   总被引：11，自引：6，他引：11  

赵思雄  周晓平 《大气科学》1984,8(1):1-6

本文使用一个细网格的多层原始方程模式对1975年8月上旬(即著名的“758”)特大暴雨过程进行了数值模拟.我们发现: 1)初始风场对于暴雨的发生有相当大的影响,要想得到较好的预报结果,应设法使用实测风为初始资料. 2)交替使用两类光滑算子,可以使得由于采用实测风初值而产生的锯齿波有所削弱.  相似文献   

非矩形网格上的车贝雪夫展开   总被引：1，自引：0，他引：1  

李黄  刘桂芝  周家斌 《气象学报》1984,42(4):407-416

本文指出:在任意不规则的非矩形二维网格上,若采用两步展开的做法,即首先逐行展开,再按列展开就可以对在该网格上给定的函数实现二维车贝雪夫多项式展开。这一推广在实用上有很大的意义。  相似文献   

A numerical study on the meso-scale pollutant dispersion over a sloped surface in the stable boundary layer     

Zhong Shiyuan  Zhou Mingyu  Li Xingsheng 《大气科学进展》1987,4(3):300-312

A numerical model is used to study the properties of pollutant dispersion over a large uniformly-sloped surface in the stable atmospheric boundary layer. By simulating the structure of boundary layer flow to improve the advective wind field and vertical eddy diffusivities included in the advection-diffusion equa-tion, this numerical model permits an estimation of the distribution of pollutant concentration for more real-istic atmospheric diffusion conditions.  相似文献   

层状云对积云发展和降水的影响——一种云与云之间影响的数值模拟   总被引：25，自引：2，他引：25  

黄美元  洪延超  徐华英  周恒 《气象学报》1987,45(1):72-77

利用我们已建立的二维积云降水模式,在相同的大气层结条件下,模拟了孤立积云和层状云中积云的发展和降水情况。结果表明,层状云的存在对积云的发展有显著的促进作用,降水量可加大到几到几十倍,从而认为积层混合云系可能是产生大雨和暴雨的一种重要机构,这与梅雨锋里锋区混合云系常产生暴雨的观测事实比较符合。  相似文献   

夏季印度季风环流系统与我国长江上游区域性持续暴雨的关系   总被引：2，自引：0，他引：2  

周静亚  成秋影 《气象学报》1987,45(2):179-187

本文对夏季6—8月我国长江上游地区56次区域性持续暴雨过程进行了统计分析。指出它们与夏季印度季风环流系统之间存在着密切的联系。给出暴雨期间印度—孟加拉湾地区的温压场和有关气象要素分布的平均形势,计算了暴雨日雨量与其前24h气象要素的相关系数,从而说明长江上游暴雨与印度季风环流系统的相关关系,并指出主要的季风环流影响系统和关键区。  相似文献   

An application of the threshold autoregression procedure to climate analysis and forecasting     

Shi Jiuen  Zhou Qinfang  Xiang Jingtian 《大气科学进展》1986,3(1):134-138

In this paper a nonlinear method of time series analysis-threshold autoregressive (TAR) model in discrete time is used. The TAR procedure consists of four parts: model building, statistical identification, parameter estimation and forecasting.The object of this study is to estimate monthly total precipitation of Shanghai and Beijing by using open loop TAR model. We can see that the trend of forecasting is in agreement with observations.  相似文献   

在地面三角网中布设卫星观测站的最低精度要求     

周忠谟 《武汉大学学报(信息科学版)》1986,(3)

本文从地面三角网和卫星同联合平差的原理出发,讨论了对卫星网的最低精度要求。指出,为改善地面三角网而布设卫星网时,卫星观测站的最低精度主要决定于以下因素: ——地面三角网的精度; ——对地面三角网精度改善程度的要求; 一卫星观测站之间的距离。这里通过模拟计算对卫星网的最低精度要求与上列因素之间的关系作了数字分析,并建立了估算卫星网最低精度的数学模型。预期,在一般情况下,该模型的估算误差将不会超过10％。  相似文献   

THE EFFECT OF ASPECT RATIO ON THE BIFURCATION PROPERTIES OF A DOUBLE PARALLEL-CONNECTION LORENZ SYSTEM     

Zou Chengzhi  Yang Peicai  Zhou Xiuji 《大气科学进展》1986,3(4):406-423

A double parallel-connection (DPC) Lorenz system is developed by performing spectrum truncation of the Galerkin series expansion of the two-dimensional Rayleigh-Benard convection equation. Analyses of the equilibrium states indicate that a convective roll stems from a flow with a given wavenumber first losing its stability for a particular aspect ratio β after a stable laminar flow gets unstable; when β has the value βc able to deprive synchronously two flows with different wavenumbers of stability, occurrences of convective rolls with different wavenumbers depend entirely on the initial conditions, in good agreement with the relevant experimental results. The calculations of the unstablized rolls show that, with a smaller β (as compared with βc), the DPC Lorenz system has the same bifurcation properties as the ordinary Lorenz system; for a moderate β, the system has very complicated periodic, quasi-periodic and phase-locking motions; for a larger β, it results in intermittent chaos and causes mean flows with different numbers of vortices to occur alternately with time. All these indicate that β has substantial effect on the two Lorenz systems coupled through parallel connection in their interaction and the results.  相似文献