نتایج جستجو برای: meteorological drought

تعداد نتایج: 52943  

2011
Michael Michaelian Edward H Hogg Ronald J Hall Eric Arsenault

Drought-induced, regional-scale dieback of forests has emerged as a global concern that is expected to escalate under model projections of climate change. Since 2000, drought of unusual severity, extent, and duration has affected large areas of western North America, leading to regional-scale dieback of forests in the southwestern US. We report on drought impacts on forests in a region farther ...

Sustainable development of agriculture is facing with several challenges such as climate change resulting change in the pattern of weather parameters as well as crop water requirements. In this research, due to the important role of agricultural activities whitin Urmia Lake Basin in the production of various agricultural products such as wheat, the possibility of supplying the plant's water req...

Journal: Desert 2019
H. Azarnivand H. Khosravi, M. Behrang Manesh P. Dehghana S. Ahmadi

     Drought is a disaster phenomenon especially in arid and semi-arid areas. Vegetation and its production play a main role in the social and economic issues in every country. In this study, Standardized Precipitation Index (SPI) and Normalized Difference Vegetation Index (NDVI) data have been used to monitor drought and the vegetation condition in Sonqor Abad in, Kermanshah province.  Meteoro...

Journal: :ecopersia 2014
somayeh mashari eshghabad ebrahim omidvar karim solaimani

drought is a climatic phenomenon that causes much detrimental influence on ecological environments. this research investigates the performance of meteorological drought indices in different time scales in thetajan basin in iran. indices undergone in this study include: percent normal precipitation index (pnpi), z-score index (zsi), standard precipitation index (spi), china z index (czi), modifi...

Introduction: Drought is recognized as a slow, creeping phenomenon that can accelerates the expansion of desertification in different regions especially in arid and semi-arid area with its effect on the agricultural sectors, water resources and vegetation cover. Positioning of Iran in the world arid and semi-arid belt is exposed to drought and water crisis and desertification. Drought monitorin...

Journal: :Ecological applications : a publication of the Ecological Society of America 2011
L Spadavecchia M Williams B E Law

We present an analysis of the relative magnitude and contribution of parameter and driver uncertainty to the confidence intervals on estimates of net carbon fluxes. Model parameters may be difficult or impractical to measure, while driver fields are rarely complete, with data gaps due to sensor failure and sparse observational networks. Parameters are generally derived through some optimization...

2015
Jianping Yang Chunping Tan Shijin Wang Shengxia Wang Yuan Yang Hongju Chen Arjen Y. Hoekstra

The Ningxia Hui Autonomous Region (NX region) of Northwestern China is threatened by increased meteorological drought induced by climate change (CC) and constraints on water supply from the Yellow River. Thus, the NX region is representative of attempts to adapt to CC and variability in China’s arid regions. Field visits, a questionnaire and in situ inspections were conducted in 2012–2014 to un...

2015
Y. B. Yao Q. Zhang J. S. Wang J. L. Shang Y. Wang J. Shi L. Y. Han

A drought index analytical method based on a relative moisture index was used to evaluate meteorological data between 1958 and 2012 and study the temporal variation, spatial distribution, and sub-regional evolution characteristics of spring drought in Southwest China. The results showed a decreasing frequency of spring drought in the West Sichuan Plateau, Southwest Sichuan Upland, and Yunnan Pl...

2015
Ali Behrangi Paul C. Loikith Eric J. Fetzer Hai M. Nguyen Stephanie L. Granger Christina Anagnostopoulou

The fraction of land area over the Continental United States experiencing extreme hot and dry conditions has been increasing over the past several decades, consistent with expectation from anthropogenic climate change. A clear concurrent change in precipitation, however, has not been confirmed. Vapor pressure deficit (VPD), combining temperature and humidity, is utilized here as an indicator of...

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