نتایج جستجو برای: شاخص pdsi

تعداد نتایج: 74708  

2016
Scott Steinschneider Michelle Ho Edward R. Cook

This study explores whether it is possible to reconstruct the frequency of extreme precipitation occurrence across the contiguous United States (CONUS) using the Living Blended Drought Atlas (LBDA), a 500 year paleoclimate reconstruction of the summer (June–August) Palmer Drought Severity Index (PDSI). We first identify regions of the country where the LBDA may reflect the occurrence of extreme...

2017
Chang-Hyun Lee Chun Kee Chung Jee-Soo Jang Sung-Min Kim Dong-Kyu Chin Jung-Kil Lee

Lumbar degenerative kyphosis (LDK) is a subgroup of the flat-back syndrome and is most commonly caused by unique life styles, such as a prolonged crouched posture during agricultural work and performing activities of daily living on the floor. Unfortunately, LDK has been used as a byword for degenerative sagittal imbalance, and this sometimes causes confusion. The aim of this review was to eval...

1998
Aiguo Dai Kevin E. Trenberth Thomas R. Karl

The Palmer Drought Severity Index (PDSI) was calculated globally using gridded monthly air temperature and precipitation. From 1900 to 1995, there are large multiyear to decadal variations in the percentage areas in severe drought (PDSI < −3.0) and severe moisture surplus (PDSI > +3.0) over many land areas while secular trends are small. Since the late 1970s, however, there have been some incre...

2004
Anthony L. Westerling Alexander Gershunov Daniel R. Cayan

Strong associations between observed climate anomalies at lags of one season to years in advance and normalized area burned in the western U.S. wildfire season have recently been described using a newly compiled comprehensive gridded western regional fire history (Westerling et al 2001b). Earlier studies of fire scar dendrochronologies and local fire histories have demonstrated that large-scale...

2006
ERIC J. ALFARO ALEXANDER GERSHUNOV DANIEL CAYAN

A statistical model based on canonical correlation analysis (CCA) was used to explore climatic associations and predictability of June–August (JJA) maximum and minimum surface air temperatures (Tmax and Tmin) as well as the frequency of Tmax daily extremes (Tmax90) in the central and western United States (west of 90°W). Explanatory variables are monthly and seasonal Pacific Ocean SST (PSST) an...

ژورنال: مرتع و آبخیزداری 2012
بهنوش فرخ‌زاده حسن احمدی حسین ارزانی, محمد مهدوی مریم آذرخشی,

ایران کشوری واقع در کمربند خشک کره زمین است و همواره با مشکل خشکسالی در بخش های مختلف مواجه بوده است . خشکسالی هر ساله خسارت های زیادی را به پوشش گیاهی طبیعی، کشاورزی و جامعه وارد میکند. یکی از راه‌های پایش خشکسالی استفاده از شاخص‌های خشکسالی می‌باشد. در این پژوهش برای ارزیابی اثر خشکسالی روی تولید علوفه گیاهان مرتعی از شاخص‌های معیار بارش سالانه (SIAP)، بارش استاندارد شده (SPI) و شاخص شدت خشکس...

2006
Martin Valldor Rainer Pöttgen

The new silicide NbPdSi was prepared by melting the elements in an arc-furnace. Well-shaped single crystals were obtained by annealing the sample in an induction furnace. The structure of NbPdSi has been studied by X-ray powder and single crystal diffractometer data: TiNiSi type, Pnma, Z = 4, a= 643.0(1), b= 376.7(1), c= 744.4(2) pm, wR2= 0.0330, 346 F2 values, and 20 variables. The palladium a...

2006
Peter T. Soule

The impacts of severe droughts on human activities, terrestrial ecosystems, and hydrologic systems are wide ranging and easily discernible. Because these impacts are felt at different times by water users, various forms of drought are recognized (e.g. agricultural, hydrological). The purpose of this study is to examine spatial patterns of drought in the contiguous United States on a seasonal ba...

2008
C. P. Kempes O. B. Myers D. D. Breshears

Annual growth of semiarid tree species is generally limited by a period of water deficit and this relationship can be reflected in interannual variation in tree-ring width of semiarid species such as Pinus edulis, a piñon pine that is widely distributed across the southwestern United States. Tree-ring width of P. edulis and other semiarid tree species is most frequently related to annual precip...

2002
Tae-Woong Kim Juan B. Valdés Javier Aparicio

The temporal and spatial characteristics of droughts are investigated to provide a framework for sustainable water resources management in a semi-arid region. Using the Palmer Drought Severity Index (PDSI) as an indicator of drought severity, the characteristics of droughts are examined in the Conchos River Basin in Mexico. This basin is important to both the United States and Mexico, because t...

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