莱州湾地区云水资源及开发利用     

于志良  孙绪馥 《地理科学》1995,15(4):351-358

  相似文献   

渤海与东海云雾屏障及其对遥感海洋信息有效性的研究     

刘宝银 《地球信息科学学报》1999,1(2):63-67

本文阐述了渤海与东海云雾屏障作用,使海区能见度降低,即使是中小尺度的海洋信息,历经多年的NOAA卫星监测,均已表明了无论空间分辨率或时间分辨率,能够较完整的获取这一遥感“天窗”信息则概率很低.笔者,结合渤海与东海的云雾和区域海洋特征,NOAA卫星信息的多波段、多时相特点,建立了信息需求分析模型,并示出渤海和东海海洋遥感“天窗”信息的概率排队.  相似文献   

基于2014～～2017年Ka毫米波雷达数据分析北京地区云宏观分布特征     

霍娟  吕达仁  段树  毕永恒 《气候与环境研究》2020,25(1):45-54

本文利用2014年1月至2017年12月Ka毫米波雷达数据对北京地区云宏观特征进行统计分析。云出现率方面，4年平均值约36.3%；冬季最低，夏季最大；月出现率值9月最大，12月最小；出现率日变化有季节差异，春夏两季呈现中午（11:00，北京时间，下同）开始逐步升高至下午17:00后逐步下降的特点，增高幅度大于15%；冬、秋两季日变化特征不显著。高度方面，4年平均云底高约4.9 km，平均云顶高约7.2 km；云顶高和云底高的月变化特征明显，从年初1月开始逐步上升，在6月达到峰值，而后下降到12月达到低值；3～10月，高云（云底高>5 km)占约一半左右比例；厚度小于1 km的云在各月中所占比例最高；厚度1～4 km的云，厚度越大所占比例越低；特别地，厚度大于4 km的云所占比例在4～9月中仅次于厚度小于1 km云的比例。4年期间，北京地区单层云居多约占66.7%，两层云占比约25.2%，两层以上云占8.1%；冬季约80%的云为单层云，而6～9月云层分布变化最多，其中9月单层云比例最低约为40%。本文基于4年高时空分辨率雷达数据对北京地区云分布特征，特别是云垂直分布特征在数值上准确刻画，该项工作在已有云气候研究中尚未见开展，所获得的知识将对了解地区气候特征、区域模式云参数化选择提供参考。  相似文献   

The Vertical Transport of Air Pollutants by Convective Clouds. Part I: A Non-Reactive Cloud Transport Model   总被引：1，自引：0，他引：1  

Kong Fanyou  Qin Yu 《大气科学进展》1993,10(4):415-427

A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and a numerical experiment is completed to simulate the vertical transport of ground-borne, inert gaseous pollutant by deepthunderstorm. The simulation shows that deep convective storm can very effectively transport high concentrated pollutant gas from PBL upward to the upper troposphere in 30 to 40 minutes, where the pollutant spreads laterally outward with strong anvil outflow, forming an extensive high concentration area. Meanwhile, relatively low concentration areas are formed in PBL both below and beside the cloud, mainly caused by dynamic pumping effect and sub-cloud downdraft flow. About 80% of the pollutant gas transported to the upper troposphere is from the layer below 1.5 km AGL (above ground level).  相似文献   

物理初值化在台风数值天气预报中的应用试验          下载免费PDF全文

阎敬华  薛纪善 《应用气象学报》1993,4(2):162-168

根据P.R.Julian(1984)的物理初值化方法，利用有限区数值预报模式，针对台风系统的预报做了物理初值化试验。结果表明，物理初值化不但可以改善台风、低压和副高区域的初始流场形势以及初始降水率，而且可以改善台风强度的发展变化过程和路径的预报，是一种有效可行的方法。  相似文献   

用增强显示云图确定热带气旋强度的方法   总被引：3，自引：3，他引：3       下载免费PDF全文

李修芳  范蕙君 《应用气象学报》1993,4(3):362-369

文章介绍了用增强显示红外云图确定热带气旋强度的方法。利用1983—1988年GMS增强显示云图资料，对中央气象台使用的《用地球同步气象卫星红外云图估计热带气旋强度》的方法中的云特征指数进行了修改与调整，增加了眼区的温度、中心强对流云区和螺旋云带的云顶温度等新的云特征因子。经统计、拟合，得到云特征指数与热带气旋中心附近最大风速、最低海平面气压的对应关系，给出了计算热带气旋强度的人-机交互方法流程，此方法对各种强度的热带气旋都能客观地计算其强度，使用简便，且精度满足业务应用要求。  相似文献   

Estimation　of　Winds　at　Different　Isobaric　Levels　Based　on　the　Observed　Winds　at　850　hPa　Level　Using　Double　Fourier　Series     

S. N. Bavadekar  R. M. Khaladkar 《大气科学进展》1994,11(3):327-334

ＥｓｔｉｍａｔｉｏｎｏｆＷｉｎｄｓａｔＤｉｆｆｅｒｅｎｔlｓｏｂａｒｉｃＬｅｖｅｌｓＢａｓｅｄｏｎｔｈｅＯｂｓｅｒｖｅｄ　Ｗｉｎｄｓａｔ８５０ｈＰａＬｅｖｅｌＵｓｉｎｇＤｏｕｂｌｅＦｏｕｒｉｅｒＳｅｒｉｅｓＳ．Ｎ．ＢａｖａｄｅｋａｒａｎｄＲ．Ｍ．Ｋｈ?..  相似文献   

Computer modelling of clouds at Kleiner Feldberg     

R. N. Colvile  R. Sander  T. W. Choularton  K. N. Bower  D. W. F. Inglis  W. Wobrock  D. Schell  I. B. Svenningsson  A. Wiedensohler  H. -C. Hansson  A. Hallberg  J. A. Ogren  K. J. Noone  M. C. Facchini  S. Fuzzi  G. Orsi  B. G. Arends  W. Winiwarter  T. Schneider  A. Berner 《Journal of Atmospheric Chemistry》1994,19(1-2):189-229

The airflow, cloud microphysics and gas- and aqueous-phase chemistry on Kleiner Feldberg have been modelled for the case study of the evening of 1 November 1990, in order to calculate parameters that are not easily measured in the cloud and thus to aid the interpretation of the GCE experimental data-set. An airflow model has been used to produce the updraught over complex terrain for the cloud model, with some care required to ensure realistic modelling of the strong stable stratification of the atmosphere. An extensive set of measurements has been made self-consistent and used to calculate gas and aerosol input parameters for the model. A typical run of the cloud model has calculated a peak supersaturation of 0.55% which occurs about 20 s after entering cloud where the updraught is 0.6 m s^–1. This figure has been used to calculate the efficiency with which aerosol particles were scavenged; it is higher than that calculated by other methods, and produces a cloud with slightly too many droplets. A broad cloud droplet size spectrum has been produced by varying the model inputs to simulate turbulent mixing and fluctuations in cloud parameters in space and time, and the ability of mixing processes near cloud-base to produce a lower peak supersaturation is discussed. The scavenging of soluble gases by cloud droplets has been observed and departures from Henry's Law in bulk cloud-water samples seen to be caused by variation of pH across the droplet spectrum and the inability of diffusion to adjust initial distributions of highly soluble substances across the spectrum in the time available. Aqueous-phase chemistry has been found to play a minor role in the cloud as modelled, but circumstances in which these processes would be more important are identified.  相似文献   

Electric charge separation in severe storms     

J. W. Telford  P. B. Wagner 《Pure and Applied Geophysics》1979,117(5):891-903

This paper proposes a new model for thunderstorm electric field generation which directly utilizes the dynamic turbulent motion to separate the charges. Postulating a microphysical charge separation mechanism, such as is commonly accepted in most other theories, and which places a negative charge on the larger particles with a positive charge on the smaller ones, it is described how evaporation and cooling at the tops of small cumuli will release the positive charges as ions. These ions migrate to the surrounding cloud as the cooled parcel, with negatively charged particles in it, sinks down through the cloud. Since the sinking parcel contains mostly ice, it will be more buoyant than its surroundings when it reaches rising regions of water cloud, and hence should come to rest near the –10°C level. Thus the cloud will acquire an accumulation of negative charge at about this level before substantial hydrometeors begin falling out of it.  相似文献   

Surface-active substances on rainwater and atmospheric particles     

Winfried Seidl  Gottfried Hänel 《Pure and Applied Geophysics》1983,121(5-6):1077-1093

The surface tension lowering by surface-active substances has been measured on rainwater, melted snow, and dispersions of atmospheric particles in water, with a film balance and a tensiometer. The precipitation water was sampled during 1979, 1980, and 1981 in the city of Frankfurt/Main. From measurements with the film balance technique, normalized concentrations of insoluble and weakly soluble surface-active substances have been estimated. Soluble surface-active substances were determined from measurements with a tensiometer. It was found that the normalized concentration of theinsoluble and weakly soluble surface-active material on rainwater or melted snow shows a maximum during late spring of about 2.5 · 10⁻⁷ moles/l and a minimum during wintertime of about 5 · 10⁻⁸ moles/l. These concentrations are too low to influence significantly the condensation of water vapour on cloud droplets or the evaporation of water from them. Thesoluble surface-active material on rainwater or melted snow was found to have concentrations of the order of 2 · 10⁻⁶ moles/l. These concentrations are also too small to have a significant influence on cloud physical processes.  相似文献