The study of this paper focuses on the power angle spectrum (PAS) of the satellite communication downlink in rain environment at millimeter-wave bands. The two-dimension angle distribution expression of the incoherent intensity of the ground receiving antenna in rain is deduced in detail. The coherent intensity is discussed according to the first-order multiple scattering approximation theory. ...

We demonstrate how, from the point of view of energy flow through an open system, rain is analogous to many other relaxational processes in nature such as earthquakes. By identifying rain events as the basic entities of the phenomenon, we show that the number density of rain events per year is inversely proportional to the released water column raised to the power of 1.4. This is the rain equiv...

In this paper, the link quality in SHF and EHF ranges are studied. In order to achieve high data rate higher frequencies must be used – centimeter waves (SHF), millimeter waves (EHF) or optical range. However, there are significant problem when a radio link work in that diapason – rain attenuation and attenuation in earth’s atmosphere. Based on statistical rain rates data for Bulgaria, the link...

The principal subject of this report is a comparison of precipitation on days with seeding with that without seeding, averaged over those rain gauges that on each particular day were "downwind," "upwind," or to the sides. Two estimates of relevant wind directions are used, based on successive radiosondes at Tucson that bracketed the scheduled time of seeding. By use of these radiosondes, the ap...

Methods for size distribution estimation and rainfall type discrimination with estimated phase function using measured reflected laser light by rain droplet are proposed. Preliminary experiments are conducted with Laser ranging instrument and spectral radiometer for estimation of size distribution and rainfall type discrimination as well as phase function of scattering by rain drops. Through th...

Measurements of rain were obtained with a vertically pointing micro radar (MRR) with 1 min time resolution and 50(100) m height resolution at the German Baltic coast on the Zingst peninsula (54.43°N, 12.67°E). The comparison with a conventional rain gauge (30 min integration time) for a fi ve months summer period show a correlation coeffi cient of r = 0.87 for the rainrate and agreement within ...

Technological developments and the trend to go higher and higher in frequency give rise to the need for true space–time rain field models for testing the dynamics of fade countermeasures. There are many models that capture the spatial correlation of rain fields. Worth mentioning are those models based on cell ensembles. However, the rain rate fields created in this way need the introduction of ...

This study examines the warm rain formation process in global and regional cloud-resolving models. Methodologies developed to analyze CloudSat and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations are employed to investigate the cloud-to-precipitation processes and are applied to model results for comparisons with corresponding statistics from the observations. Three ...

Microphysics parameterization plays an important role in Numerical Weather Prediction (NWP). Most NWP models, including the Weather Research Forecast (WRF) model, use single-moment (bulk water) schemes derived based on an assumption of the exponential distribution with a fixed intercept parameter for raindrop size distributions (DSDs) such as the Marshall-Palmer (M-P) DSD model (Marshall and Pa...

A field and laboratory based experiment conducted to assess the effects of different pH ranges of simulated acid rain (2.5, 3.5, 4.5 and 5.5) was studied on chlorophyll and ascorbic acid contents in two cultivars (cv. Himalaya and cv.Kaushik) of a medicinal herb Mentha piperita. Chlorophyll and ascorbic acid contents of leaves were adversely affected at pH 2.5 and 3.5. The effects of simulated ...