نتایج جستجو برای: palmer drought severity index

تعداد نتایج: 561124  

Journal: :Frontiers in Environmental Science 2023

Droughts have become more powerful and frequent, affecting people for longer periods than any other natural disaster, particularly in eastern Africa. The unprecedented climate change has increased the severity, duration, frequency of droughts. objectives this study were to evaluate performances different drought indices spatiotemporal characterization Bilate river watershed that represents part...

2006
Steven W. Leavitt Austin Long

Stomata1 closure during yriods of moisture deficiency should theoretically lead to elevated C/12C ratios as reduction of available C02 leads to diminished photosynthetic discrimination against 13c in favor of 12C. Stable-carbon isotope ratio chronologies developed from 5-yr tree-ring groups at 17 sites in six southwestern states were tested for a drought relationship by first fitting a spline c...

Journal: :اکو هیدرولوژی 0
یعقوب نیازی دانشجوی دکتری علوم و مهندسی آبخیزداری، دانشکدۀ منابع طبیعی، دانشگاه یزد علی طالبی دانشیار دانشکدۀ منابع طبیعی، دانشگاه یزد محمد حسین مختاری استادیار دانشکده منابع طبیعی، دانشگاه یزد مجید وظیفه دوست استادیار گروه مهندسی آب دانشگاه گیلان

monitoring and evolution of drought is the first step in any drought management system. in this study, evaluation of a new indexa new method is provided to monitor the severity of drought with remote sensing combined drought index (rcdi). the index is based on the fact that drought is a natural phenomenon caused by a combination of various factors such as a shortage in the amount of precipitati...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2011
Daniel B Nelson Mark B Abbott Byron Steinman Pratigya J Polissar Nathan D Stansell Joseph D Ortiz Michael F Rosenmeier Bruce P Finney Jon Riedel

We present a 6,000-yr record of changing water balance in the Pacific Northwest inferred from measurements of carbonate δ(18)O and grayscale on a sediment core collected from Castor Lake, Washington. This subdecadally resolved drought record tracks the 1,500-yr tree-ring-based Palmer Drought Severity Index reconstructions of Cook et al. [Cook ER, Woodhouse CA, Eakin CM, Meko DM, Stahle DW (2004...

2015
M. Dubrovsky Mark D. Svoboda M. Trnka Michael J. Hayes Donald A. Wilhite P. Hlavinka M. D. Svoboda M. J. Hayes D. A. Wilhite

The common versions (referred to as self-calibrated here) of the Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI) are calibrated and then applied to the same weather series. Therefore, the distribution of the index values is about the same for any weather series. We introduce here the relative SPI and PDSI, abbreviated as rSPI and rPDSI. These are calibrated u...

2003
Dominique Bachelet Ronald P. Neilson Thomas Hickler Raymond J. Drapek James M. Lenihan Martin T. Sykes Benjamin Smith Stephen Sitch Kirsten Thonicke

[1] Simulations of potential vegetation distribution, natural fire frequency, carbon pools, and fluxes are presented for two DGVMs (Dynamic Global Vegetation Models) from the second phase of the Vegetation/Ecosystem Modeling and Analysis Project. Results link vegetation dynamics to biogeochemical cycling for the conterminous United States. Two climate change scenarios were used: a moderately wa...

Journal: :IOP Conference Series: Earth and Environmental Science 2020

2008
A. Loukas

This paper evaluates climate change effects on drought severity in the region of Thessaly, Greece. The Standardized Precipitation Index (SPI) has been used for estimation of drought severity. A geographical information system is applied for the division of Thessaly region to twelve hydrological homogeneous areas based on their geomorphology. Mean monthly precipitation values from 50 precipitati...

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