نتایج جستجو برای: trend and seasonal variability of rainfall
تعداد نتایج: 24076736 فیلتر نتایج به سال:
The purpose of this study is to determine the long-term variations in rainfall data as well as to identify wet and dry periods of 35 synoptic stations in Iran. In order to know the variation of rainfall in studied stations, average maps, coefficient of variation and skewness were drawn. Then, using the Mann-Kendall test, the significance of the trend on each station was tested at 95% confidence...
This study examines space-time characteristics of seasonal rainfall predictability in a tropical region, by analyzing observed data and model simulations over Senegal. Predictability is analyzed in terms of the spatial coherence of observed interannual variability at the station scale, and within-ensemble coherence of general circulation model (GCM) simulations with observed sea surface tempera...
Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter m...
A hidden Markov model (HMM) is used to describe daily rainfall occurrence at ten gauge stations in the state of Ceará in northeast Brazil during the February–April wet season 1975–2002. The model assumes that rainfall occurrence is governed by a few discrete states, with Markovian daily transitions between them. Four “hidden” rainfall states are identified. One pair of the states represents wet...
Rainfall variability has a significant impact on crop production with manifestations in frequent crop failure in semiarid areas. This study used the parameterized APSIM crop model to investigate how rainfall variability may affect yields of improved sorghum varieties based on long-term historical rainfall and projected climate. Analyses of historical rainfall indicate a mix of nonsignificant an...
A k-means cluster analysis is used to summarize unfiltered daily atmospheric variability at regional-scale over the western Sahel and eastern tropical North Atlantic during the boreal summer season (July—September, JAS) 1961—1998. It employs zonal and meridional regional wind fields at 925, 700 and 200 hPa from the European Centre for Medium Range Weather Forecast Reanalyses. An 8-cluster solut...
Erosion rate has temporal variability and shows a cyclic fluctuation in each year as well as the factors influence it due to the seasonality of climate. This study was done to determine the seasonal variability of rainfall erosivity and suspended sediment and also to found out critical times in term of erosion risk in Kasiliyan watershed. The appropriate indices of monthly rainfall erosivity we...
The continuous occurrence of changes in the global climate causes significant variability in the seasonal and intra-seasonal rainfall pattern, which often leads to frequent floods and droughts in India. To reduce the magnitude of effect of such natural calamities and for better management of water resources, it is essential to predict the rainfall, well in advance. In this study the possible re...
there is a need to analyze and map rainfall erosivity to assess soil erosion at the regional scale. the objectives of this study were to develop a regional model to estimate seasonal erosivity from seasonal rainfall data and to study temporal and spatial distribution of rainfall erosivity for the gorganrood drainage basin in the northeast of iran. six gauging stations with a high temporal reso...
this study investigates the atmospheric circulation associated with extreme rainfall events over the coastal west africa. the rainfall data of this study were obtained from the global precipitation climatology centre (gpcc), spanning from 1981 to 2010. the atmospheric datasets were also obtained from the era-interim reanalysis. the study employed the z-index to categorize dry and wet years into...
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