in different regions, precipitation takes place with different persistencies and every persistency supplies a share of rainfall days and precipitation. therefore, the importance of rainfall persistence could be evaluated in all places. iran is located in mid-latitude of an arid region, in which the mean rainfall is 250 mm and it has dramatic tempo-spatial changes. rainfalls with short persisten...

Rain Induced attenuation over a terrestrial link operating at 28.75 GHz was measured during the period of Feb., 04 to Jan., 05. at Amritsar ( 31036’ N 740 52’ E) . The paper presents the results in the form of a proposed empirical formula. The experimental results have been measured with those predicted by ITU-R. It is observed that there is a significant difference between the attenuation leve...

This paper investigates the benefits of integrating coarse resolution satellite-derived precipitation estimates with quasi-point rain gauge data for generating a fine spatial resolution precipitation map product. To integrate the two precipitation data sources, a geostatistical downscaling and integration approach is presented that can account for the differences in spatial resolution between d...

Statistical and case study–oriented comparisons of the quantitative precipitation nowcasting (QPN) schemes demonstrated during the first World Weather Research Programme (WWRP) Forecast Demonstration Project (FDP), held in Sydney, Australia, during 2000, served to confirm many of the earlier reported findings regarding QPN algorithm design and performance. With a few notable exceptions, nowcast...

meteorological radars estimate the precipitation using a reflection-precipitation relation as z=arb with a, b coefficients. these coefficients will change from one precipitation to the other one. for the tehran radars they are considered as a=200 and b=1.6. these values are proper when we have moderate precipitations. this assumption causes an error in the estimation of different precipitation ...

Cheatgrass (Bromus tectorum L.) is a winter annual weed that presents a serious obstacle to rangeland restoration in the Intermountain West. The objective of this study was to evaluate factors regulating the size and persistence of cheatgrass carryover seed banks on semiarid sites in western Utah. We prevented current-year seed production in each of four habitats, then tallied emerging seedling...