نتایج جستجو برای: drought monitoring

تعداد نتایج: 328710  

2015
Donald A. Wilhite

Given worldwide experience with drought during the past several decades and the magnitude of associated impacts, it is apparent that vulnerability to extended periods of water shortage is escalating. Developing a national or provincial drought policy and preparedness plan is a complicated but essential first step toward reducing societal vulnerability. Until recently, nations had devoted little...

2016
David. A. Robinson Scott B. Jones Inma Lebron Sabine Reinsch María T. Domínguez Andrew R. Smith Davey L. Jones Miles R. Marshall Bridget A. Emmett

Ecosystems may exhibit alternative stable states (ASS) in response to environmental change. Modelling and observational data broadly support the theory of ASS, however evidence from manipulation experiments supporting this theory is limited. Here, we provide long-term manipulation and observation data supporting the existence of drought induced alternative stable soil moisture states (irreversi...

2014
Liam Cavin

1. The effect of extreme climate events on ecosystems is an important driver of the bioticresponse to climate change. For forests, extreme drought has been linked to negativeeffects such as large scale mortality and reduced primary production. However, theresponse of plant communities to extreme drought events remains poorly understood. 2. We used mortality data from a long term mon...

Journal: :تحقیقات آب و خاک ایران 0
محبوبه زارع زاده مهریزی کارشناسی ارشد، دانشگاه تربیت مدرس سعید مرید دانشیار، دانشگاه تربیت مدرس

drought is among the natural disasters that causes heavy damages to water resources and makes managers face serious challenges. drought monitoring is one of the important measures to manage droughts. different indices and methods employing varied indicators, have been developed in this regard. in this paper it is aimed to compare two well known meteorological indices of spi and edi with a hydro...

Journal: :The New phytologist 2010
Oliver L Phillips Geertje van der Heijden Simon L Lewis Gabriela López-González Luiz E O C Aragão Jon Lloyd Yadvinder Malhi Abel Monteagudo Samuel Almeida Esteban Alvarez Dávila Iêda Amaral Sandy Andelman Ana Andrade Luzmila Arroyo Gerardo Aymard Tim R Baker Lilian Blanc Damien Bonal Atila Cristina Alves de Oliveira Kuo-Jung Chao Nallaret Dávila Cardozo Lola da Costa Ted R Feldpausch Joshua B Fisher Nikolaos M Fyllas Maria Aparecida Freitas David Galbraith Emanuel Gloor Niro Higuchi Eurídice Honorio Eliana Jiménez Helen Keeling Tim J Killeen Jon C Lovett Patrick Meir Casimiro Mendoza Alexandra Morel Percy Núñez Vargas Sandra Patiño Kelvin S-H Peh Antonio Peña Cruz Adriana Prieto Carlos A Quesada Fredy Ramírez Hirma Ramírez Agustín Rudas Rafael Salamão Michael Schwarz Javier Silva Marcos Silveira J W Ferry Slik Bonaventure Sonké Anne Sota Thomas Juliana Stropp James R D Taplin Rodolfo Vásquez Emilio Vilanova

*The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. *We assembled available data on tropical forest tree stem mortality before, during, and after recent droug...

Introduction Drought is a natural and recurrent phenomenon.  It is considered ‘a natural disaster’ whenever it occurs in an intensive manner in highly populated regions, resulting in significant damage (material and human) and loss (socioeconomic). Although drought occurs in areas with different climatic conditions. But more is happening in arid and semi-arid areas with less annual rainfall. I...

2011
D. 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...

Journal: :فیزیک زمین و فضا 0
مهدی قمقامی دانشجوی دکترای هواشناسی کشاورزی، دانشگاه تهران، ایران نوذر قهرمان دانشیار، گروه مهندسی آبیاری و آبادانی، پردیس کشاورزی و منابع طبیعی، دانشگاه تهران، ایران سمیه حجابی دانشجوی دکترای هواشناسی کشاورزی، دانشگاه تهران، ایران

climate change that the human faces is a somewhat unavoidable phenomenon. successful management of water resources needs recognition and perception of climate change in order to cope with water scarcity. the water scarcity is created by natural forcings such as drought, which is affected by regional climate. in other words, variation of climate variables as a result of climate change leads to v...

Drought as a natural but temporary imbalance of water availability is the interaction between natural environment and human life resulting in diminished water resources availability and reduced carrying capacity of the ecosystems. Drought indices are essential elements for an efficient drought monitoring system. These indices make the transforming information of climatic anomalies easier and al...

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