نتایج جستجو برای: drought severity

تعداد نتایج: 183107  

2008
J. SHEFFIELD K. M. ANDREADIS E. F. WOOD D. P. LETTENMAIER

Using observation-driven simulations of global terrestrial hydrology and a cluster algorithm that searches for spatially connected regions of soil moisture, the authors identified 296 large-scale drought events (greater than 500 000 km and longer than 3 months) globally for 1950–2000. The drought events were subjected to a severity–area–duration (SAD) analysis to identify and characterize the m...

2001
ELEANOR J. BURKE SIMON J. BROWN NIKOLAOS CHRISTIDIS

Meteorological drought in the Hadley Centre global climate model is assessed using the Palmer Drought Severity Index (PDSI), a commonly used drought index. At interannual time scales, for the majority of the land surface, the model captures the observed relationship between the El Niño–Southern Oscillation and regions of relative wetness and dryness represented by high and low values of the PDS...

Journal: :Remote Sensing 2015
Sergio Vicente-Serrano Daniel Cabello Miquel Tomás-Burguera Natalia Martín-Hernández Santiago Beguería Cesar Azorin-Molina Ahmed El Kenawy

We analyzed potential land degradation processes in semiarid regions worldwide using long time series of remote sensing images and the Normalized Difference Vegetation Index (NDVI) for the period 1981 to 2011. The objectives of the study were to identify semiarid regions showing a marked decrease in potential vegetation activity, indicative of the occurrence of land degradation processes, and t...

Journal: :Remote Sensing 2016
Katarzyna Ewa Lewinska Eva Ivits Mathias Schardt Marc Zebisch

Observed alternation of global and local meteorological patterns governs increasing drought impact, which puts at risk ecological balance and biodiversity of the alpine forest. Despite considerable attention, drought impact on forest ecosystems is still not entirely understood, and comprehensive forest drought monitoring has not been implemented. In this study, we proposed to bridge this gap ex...

2006
Jinbao Li Xiaohua Gou Edward R. Cook Fahu Chen

[1] A robust ring-width chronology developed from two sites of Picea schrenkiana in the central Tien Shan area of northwest China was employed to study regional drought variability. Our analyses demonstrate both temperature and precipitation have significant effects on tree growth, thus both should be considered for climate reconstruction. Regional drought history (1675–2002 A.D.) was therefore...

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)...

Journal: :Remote Sensing 2016
Wenzhe Jiao Lifu Zhang Qing Chang Dongjie Fu Yi Cen Qingxi Tong

Drought is a complex hazard, and it has an impact on agricultural, ecological, and socio-economic systems. The vegetation condition index (VCI), which is derived from remote-sensing data, has been widely used for drought monitoring. However, VCI based on the normalized difference vegetation index (NDVI) does not perform well in certain circumstances. In this study, we examined the utility of th...

2009
EDWARD R. COOK RICHARD SEAGER RICHARD R. HEIM RUSSELL S. VOSE CELINE HERWEIJER CONNIE WOODHOUSE

IPCC Assessment Report 4 model projections suggest that the subtropical dry zones of the world will both dry and expand poleward in the future due to greenhouse warming. The US Southwest is particularly vulnerable in this regard and model projections indicate a progressive drying there out to the end of the 21st century. At the same time, the USA has been in a state of drought over much of the ...

2016
Nicholas J. Bouskill Tana E. Wood Richard Baran Zhao Hao Zaw Ye Ben P. Bowen Hsiao Chien Lim Peter S. Nico Hoi-Ying Holman Benjamin Gilbert Whendee L. Silver Trent R. Northen Eoin L. Brodie

Climate model projections for tropical regions show clear perturbation of precipitation patterns leading to increased frequency and severity of drought in some regions. Previous work has shown declining soil moisture to be a strong driver of changes in microbial trait distribution, however, the feedback of any shift in functional potential on ecosystem properties related to carbon cycling are p...

Journal: Desert 2013
A. Khalili J. Bazrafshan

The present study examined year-to-year variations in areas affected by drought during a period of 39 water yearsin Iran. Ninety-five meteorological stations were chosen to provide near-continuous long-term records, althoughsome data was missing (less than 10%). The missing data points were estimated using a linear correlation methodbetween the reference station with the missing data points and...

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