نتایج جستجو برای: drought magnitude

تعداد نتایج: 170566  

M. Elhaeesahar M. Masoudi

The Standardized Precipitation Index (SPI) is a widely used drought index to provide good estimations of the intensity, magnitude and spatial extent of droughts. The objective of this study was to analyze the spatial pattern of drought by SPI index. In this paper, patterns of drought hazard in Khuzestan are evaluated according to the data of 17 weather stations during data recording. The influe...

2007
Hong Wu Leen-Kiat Soh Ashok Samal Xun-Hong Chen

A streamflow drought event, defined by applying the threshold level approach on streamflow time series, is composed of three parameters: duration, severity and magnitude. This study reveals statistical characteristics on streamflow drought event parameters and detects spatial and temporal trends in the streamflow drought in terms of frequency, duration and severity in Nebraska. The studies are ...

2001
Olga V. Wilhelmi Donald A. Wilhite

Recent drought events in the United States and the magnitude of drought losses indicate the continuing vulnerability of the country to drought. Until recently, drought management in many states, including Nebraska, has been largely response oriented with little or no attention to mitigation and preparedness. In 1998, Nebraska began to revise its drought plan in order to place more emphasis on m...

Journal: :iranian journal of science and technology (sciences) 2014
m. masoudi

the percent of normal precipitation index (pnpi) is a widely used drought index to provide good estimations about the intensity, magnitude and spatial extent of droughts. the objective of this study was analyzing spatial pattern of drought by pnpi index. in this paper, according to the data of 40 stations in iran, during 1967-2009, the pattern of drought hazard is evaluated. influenced zone of ...

2017
Shangzhi Zhong Hua Chai Yueqiao Xu Yan Li Jian-Ying Ma Wei Sun

Whether photosynthetic pathway differences exist in the amplitude of nighttime variations in the carbon isotope composition of leaf dark-respired CO2 (δ13Cl) and respiratory apparent isotope fractionation relative to biomass (ΔR,biomass) in response to drought stress is unclear. These differences, if present, would be important for the partitioning of C3-C4 mixed ecosystem C fluxes. We measured...

2012
A. Bano F. Ullah

The effect of drought stress and abscisic acid (ABA) applied at tillering stage (55 days after sowing) was compared in 2 wheat cultivars differing in drought tolerance. The activities of superoxide dismutase (SOD) and peroxidase (POD) and contents of endogenous ABA in plants were measured at 3 days of drought stress in cv. Chakwal-97 (drought tolerant) and cv. Punjab-96 (drought susceptible). A...

Drought is one of the most complex natural hazards that affect natural systems and different parts of an ecosystem in various ways. Evaluation of drought behavior such as determining the time of its occurrence, understanding the relationships between types of drought, and recognizing its characteristics such as magnitude, severity, and duration of drought periods can be an important aid in wate...

2016
Constanze Buhk Marcel Kämmer Carl Beierkuhnlein Anke Jentsch Jürgen Kreyling Hermann F. Jungkunst

Climate projections propose that drought stress will become challenging for establishing trees. The magnitude of stress is dependent on tree species, provenance, and most likely also highly influenced by soil quality. European Beech (Fagus sylvatica) is of major ecological and economical importance in Central European forests. The species has an especially wide physiological and ecological ampl...

2016
Yulong Zhao Yankai Wang Hao Yang Wei Wang Jianyu Wu Xiuli Hu

Drought stress is one of major factors resulting in maize yield loss. The roles of abscisic acid (ABA) have been widely studied in crops in response to drought stress. However, more attention is needed to identify key ABA-related proteins and also gain deeper molecular insights about drought stress in maize. Based on this need, the physiology and proteomics of the ABA-deficient maize mutant vp5...

Journal: :آب و خاک 0
سید بهروز حسینی یعقوب دین پژوه جعفر نیکبخت

introduction: drought is a creeping natural phenomenon, which can occur in any region. such phenomenon not only affects the region subjected to drought, but its adverse effects can also be extended to other adjacent regions. this phenomenon mainly starts with water deficiency (say less than long- term mean of variable under study such as rainfall, streamflow, groundwater level or soil moisture)...

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