نتایج جستجو برای: drought severity

تعداد نتایج: 183107  

Journal: :Journal of Hydrology: Regional Studies 2021

Northeast China is one of the largest agricultural regions in world and a strategically important granary for China. Information on hydrological extremes crucially water management. Yet, comprehensive studies extremes, both extreme flood drought events, based gauge large coverage observations are still lacking This study investigated observed with 124 gauges region ranging from 1950s to present...

2015
Donald A. Wilhite

The development and implementation of a drought policy is intended to alter a nation’s approach to drought management. A national drought policy should establish a clear set of principles or operating guidelines to govern the management of drought and its impacts. The policy should be consistent and equitable for all regions, population groups, and economic sectors and consistent with the goals...

2007
RICHARD SEAGER ROBERT BURGMAN YOCHANAN KUSHNIR AMY CLEMENT JENNIFER MILLER A. E. Douglass

The possible role that tropical Pacific SSTs played in driving the megadroughts over North America during the medieval period is addressed. Fossil coral records from the Palmyra Atoll are used to derive tropical Pacific SSTs for the period from A.D. 1320 to A.D. 1462 and show overall colder conditions as well as extended multidecadal La Niña–like states. The reconstructed SSTs are used to force...

Journal: :Ecology letters 2017
Sarah Greenwood Paloma Ruiz-Benito Jordi Martínez-Vilalta Francisco Lloret Thomas Kitzberger Craig D Allen Rod Fensham Daniel C Laughlin Jens Kattge Gerhard Bönisch Nathan J B Kraft Alistair S Jump

Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of ...

Journal: :آب و خاک 0
ابوالفضل مساعدی محمد قبائی سوق

abstract spi is based on fitting a gamma distribution to precipitation amounts in selected periods. based on current research, the gamma distribution may not be fitted to annual precipitation of some regions. in order to evaluate this subject, annual precipitation have been used during 1958- 2007 at 11 synoptic stations in iran. in first step, values of spi and frequency of different classes of...

Journal: :علوم گیاهان زراعی ایران 0
رضا کشاورز افشار دانشجوی دکتری مسعود کیخواه کارشناس ارشد محمدرضا چائی چی دانشیار، پردیس کشاورزی و منابع طبیعی کرج، دانشکده علوم زراعی و دامی، گروه زراعت و اصلاح نباتات، تخصص: اکولوژی گیاهان زراعی محیا انصاری جوینی دانشجوی دکتری

salinity and drought stress are among the common environmental factors which adversely affect germination and growth of plants. this experiment was conducted to evaluate the effects of salinity and drought stress on turnip seed germination and early growth in seed lab of college of agriculture, university of tehran, during 2010. the experimental design was a complete randomized block with three...

2007
Jingfeng Xiao Qianlai Zhuang

Fire is the dominant disturbance in forest ecosystems across Canada and Alaska, and has important implications for forest ecosystems, terrestrial carbon dioxide emissions and the forestry industry. Large fire activity had increased in Canadian and Alaskan forests during the last four decades of the 20th century. Here we combined the Palmer Drought Severity Index and historical large fire databa...

2014
Zengchao Hao Amir AghaKouchak Navid Nakhjiri Alireza Farahmand

Drought is by far the most costly natural disaster that can lead to widespread impacts, including water and food crises. Here we present data sets available from the Global Integrated Drought Monitoring and Prediction System (GIDMaPS), which provides drought information based on multiple drought indicators. The system provides meteorological and agricultural drought information based on multipl...

2017
Xiang Zhang Renee Obringer Chehan Wei Nengcheng Chen Dev Niyogi

Understanding drought from multiple perspectives is critical due to its complex interactions with crop production, especially in India. However, most studies only provide singular view of drought and lack the integration with specific crop phenology. In this study, four time series of monthly meteorological, hydrological, soil moisture, and vegetation droughts from 1981 to 2013 were reconstruct...

2015
Donald A. Wilhite

Drought is a naturally occurring event that is associated with virtually all climatic regions. Given its slow onset and other characteristics, including its spatial dimensions and duration, impacts are difficult to assess and have been, historically, poorly documented. These impacts are strongly influenced by a society’s exposure to the hazard and the vulnerability of that society to the hazard...

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