Some rain rate and rain attenuation statistics at millimeter wavelengths in the tropics

Summary A study of rain rate and rain induced attenuation characteristics over two tropical stations in India has been made. The observed rain rate distributions differ significantly when compared with the CCIR report. The refractive indices have been calculated for certain frequencies at a tropical rain temperature of 20°C showing the variational pattern at different millimeter wavelengths. The present analysis also reveals that in the range 0.05 cm–0.3 cm drop diameter the variations of scattering amplitudes are systematic while in the range 0.4 cm–0.6 cm they are irregular.With 6 Figures     

暴雨微物理结构特征

本文根据长春一次大暴雨雨滴谱资料的统计分析,给出了大暴雨雨滴谱分布、过程降水量的演变、微物理特征量、雨滴最大直径、优势直径、雨强、浓度、雨水含水量、雷达反射因子、雨滴吸收系数、衰减系数、雨滴动能等,以及这些特征量与雨强之间的关系式。     

Parameterization of rain cell properties using an advection-diffusion model and rain gage data

To reduce flooding risks and improve urban drainage management, there is a need to increase the forecasting accuracy for rainfall models on small typical urban time and space scales. Increased rainfall forecasting accuracy will in turn improve runoff prediction and thus, prevent flooding hazards, decrease pollution discharge through combined sewers, increase waste water treatment efficiency, etc. For this purpose, we analyzed the parameters of a two-dimensional stochastic advection-diffusion model including a Fourier domain method and an extended Kalman filter algorithm for investigation of motion, shape, size, and intensity distribution of convective rainfall. The resulting set of model parameters (advective velocity, apparent turbulent diffusion, and development/decay of rainfall rate) is used to study convective rainfall variability. It appears that the speed at which the rainfall cell is advected is not dependent on the cell development stage or apparent diffusion. Instead, there is a dependence between the source/sink term and apparent diffusion. This can be explained by the turbulent updraft of warm air which results in large rainfall intensity increase. This strong turbulence results in larger diffusion (and vice versa). The behavior of the model parameters is therefore physically explainable and relevant. The results can be used as first choice of parameter values when modeling convective rainfall over ungaged areas.     

浅谈酸雨观测

现代工业生产、频繁的交通运输以及居民使用的炉灶,不断向空中排放大量的污染物,如二氧化硫、氮氧化合物、各种尘埃等,其中二氧化硫是最长见的、含量最高的污染物质.大气中的二氧化硫、二氧化氮等,在空气中氧化剂的作用下,溶解于水汽中,以雨、雪等形式下落到地面,当雨、雪等大气降水的PH(酸碱度)值小于5.6时,即成为酸雨.     

安岳县暴雨成因分析

安岳县位于四川盆地中部丘陵地区。无大江大河,水库、塘堰、农田蓄水灌溉,全靠自然降水。自1953年以来．46年中暴雨148天,年平均为3．22天。其中大暴雨20天,特大暴雨1天,年平均分别为0．43天和0．02天。暴雨年气候概率仅0．83％,以出现时段计,气候概率也只有1．29％。但它对安岳县国民经济和人民生命财产休戚相关。其形成主要是有充足的水汽、强烈的垂直运动和较长的降水持续时间等诸多因子紧密配合。     

打炮增雨原因分析

从爆炸冲击波对云的微观影响出发，分析了打炮增雨的道理，并提出了打炮增雨应掌握的条件。     

安岳县暴雨成因分析

安岳县位于四川盆地中部丘陵地区.无大江大河,水库、塘堰、农田蓄水灌溉,全靠自然降水.自1953年以来,46年中暴雨148天,年平均为3.22天,其中大暴雨20天,特大暴雨1天,年平均分别为0.43天和0.02天.暴雨年气候概率仅0.83%,以出现时段计,气候概率也只有1.29%.但它对安岳县国民经济和人民生命财产休戚相关.其形成主要是有充足的水汽、强烈的垂直运动和较长的降水持续时间等诸多因子紧密配合.     

Red dust rain within the Spanish Mediterranean area

Dust rain belongs to the climatological conditions of the Iberian Peninsula's Mediterranean seaboard. Traditionally known as muddy' or bloody rains, red dust rain has become a topical issue as a result of more frequent rainfall of this kind in recent years. In spite of the difficulties that studying this phenomenon involves, owing to the lack of systematically kept records at meteorological observatories, details are provided of the high frequency of such phenomena within the Spanish Mediterranean area, using records from other phenological sources. The study analyzes the chemical composition of red dust rain and the atmospheric factors giving rise to such phenomena. Whether there is a relationship betwen the higher frequency of dust rain and possible changes in global atmospheric circulation is as yet unclear.     

南充暴雨的季节内振荡特征

利用波谱对南充暴雨的季节内振荡进行了分析。结果表明：该地暴雨存在显著的周期倍和分叉特征，与夏季风季节内振荡十分一致。在长中短期暴雨中具有重要的可操作意义。     

南充暴雨的季节内振荡特征

利用波谱对南充暴雨的季节内振荡进行了分析.结果表明:该地暴雨存在显著的周期倍和分叉特征,与夏季风季节内振荡十分一致.在长中短期暴雨中具有重要的可操作意义.