نتایج جستجو برای: reconnaissance drought index (rdi) is based on fitting a log
تعداد نتایج: 16690028 فیلتر نتایج به سال:
reconnaissance drought index (rdi) is based on fitting a log-normal distribution to the ratio of precipitation to evapotranspiration (eto) values in selected periods. in this index value of eto were calculated based on mean temperature by thorenth-waite (th) method. th method, may underestimated eto values comparing to the actual in arid and semi arid regions. the log-normal distribution may no...
There are two types of drought as conceptual drought and operational drought. The three parameters as the beginning, the end and the degree of severity of the drought can be identifying in operational drought by average precipitation in the whole region. One of the methods classified to measure drought is Reconnaissance Drought Index (RDI). Evapotranspiration is calculated using Penman-Monteith...
in order to avoid drought effects, it is essential to detect and monitor the spatial andtemporal changes of the phenomenon. in general, drought indices are made use of toachieve the goals. the main aim followed in this paper is to introduce and assess a newdrought index termed mrdi. mrdi (modified reconnaissance drought index) is thencompared with modified standardized precipitation index (mspi...
In this study, drought characteristics of Arak, Bandar Anzali, Tabriz, Tehran, Rasht, Zahedan, Shiraz and Kerman stations during the statistical period of 1956 to 2015 were studied by Reconnaissance Drought Index (RDI) and Standardized Precipitation Index. Precipitation and temperature data were needed to calculate RDI. Precipitation data was also required to estimate SPI. In this study, Drinc ...
although precipitation is the most important factor which effects rangeland production, but there is little information on the relationship between production and the interactions of climatic factors and specially drought indices. .in this research, the relation between production and climatic factors of rainfall, temperature, evapo- transpiration, and as well as drought indices of standardized...
drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...
Drought is one of the natural phenomena which occurs in all climates in different parts of the world. Iran is located in the dry belt of the world. The increase of desertification, drought reoccurrence, and destruction by human in this geographical region needs more studies on spatial and temporal trend of rainfall. In this study, trends of climatic drought during 1975-76/ 2004-05 in seasonal a...
drought is one of the natural phenomena which occurs in all climates in different parts of the world. iran is located in the dry belt of the world. the increase of desertification, drought reoccurrence, and destruction by human in this geographical region needs more studies on spatial and temporal trend of rainfall. in this study, trends of climatic drought during 1975-76/ 2004-05 in seasonal a...
Droughts are natural events and could lead to declining surface water quality of regional basin. Understanding the complex impacts of drought may help authorities to monitor changes in different regional basin and to make appropriate decision on development of a river basin management plan. In this study 20 years annual precipitation time series from 1994-2013 from 7 synoptic weather stations l...
Drought is a complex phenomenon which can be characterised mainly by its severity, duration and areal extent. Among these three dimensions, drought severity is the key factor which can be used for drought analysis. Drought indices are typically used to assess drought severity in a meaningful way. DrinC (Drought Indices Calculator) is a software package which was developed for providing a simple...
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