نتایج جستجو برای: arctic oscillation

تعداد نتایج: 61620  

Journal: :پژوهش های جغرافیایی (منتشر نمی‏شود) 0
داریوش یاراحمدی استادیار گروه جغرافیا، دانشگاه لرستان قاسم عزیزی دانشیار دانشکده جغرافیا-دانشگاه تهران

in this article the relationship between the amount of seasonal rainfall (autumn, winter and spring) and climate indices in iran have been studied. the climate indices (the southern oscillation(soi),the north atlantic oscillation(nao), arctic oscillation(ao),nino 3/4,the multivariate enso index(mei),trans_ nino index(tni) and the pacific decadal oscillation(pdo) are used as independent variable...

Journal: :Science 2002
Richard E Moritz Cecilia M Bitz Eric J Steig

The pattern of recent surface warming observed in the Arctic exhibits both polar amplification and a strong relation with trends in the Arctic Oscillation mode of atmospheric circulation. Paleoclimate analyses indicate that Arctic surface temperatures were higher during the 20th century than during the preceding few centuries and that polar amplification is a common feature of the past. Paleocl...

Journal: :Geophysical Research Letters 2000

2002
Igor V. Polyakov Mark A. Johnson

Atmospheric and oceanic variability in the Arctic shows the existence of several oscillatory modes. The decadal-scale mode associated with the Arctic Oscillation (AO) and a low-frequency oscillation (LFO) with an approximate time scale of 60-80 years, dominate. Both modes were positive in the 1990s, signifying a prolonged phase of anomalously low atmospheric sea level pressure and above normal ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2011
Benjamin F Clegg Ryan Kelly Gina H Clarke Ian R Walker Feng Sheng Hu

Regional climate responses to large-scale forcings, such as precessional changes in solar irradiation and increases in anthropogenic greenhouse gases, may be nonlinear as a result of complex interactions among earth system components. Such nonlinear behaviors constitute a major source of climate "surprises" with important socioeconomic and ecological implications. Paleorecords are key for eluci...

2003
AD Rosanne D. D’Arrigo Edward R. Cook Michael E. Mann Gordon C. Jacoby

[1] Arctic Oscillation (AO) changes are inferred from a treering reconstruction of a warm-season temperature index. The reconstruction covers AD 1650–1975 and is based largely on chronologies from circumpolar-Arctic and circum-North Atlantic areas. It accounts for 48% of the variance in the instrumental AO record from 1900 to 1975, verifies using independent data, and exhibits its largest varia...

2003
Rosanne D. D’Arrigo Edward R. Cook Michael E. Mann Gordon C. Jacoby

[1] Arctic Oscillation (AO) changes are inferred from a treering reconstruction of a warm-season temperature index. The reconstruction covers AD 1650–1975 and is based largely on chronologies from circumpolar-Arctic and circum-North Atlantic areas. It accounts for 48% of the variance in the instrumental AO record from 1900 to 1975, verifies using independent data, and exhibits its largest varia...

Journal: :Geophysical Research Letters 2002

2005
Stephen J. Déry E. F. Wood

[1] Freshwater discharge to high-latitude oceans in 64 Canadian rivers is investigated. The mean annual discharge rate attains 1252 km yr 1 for an area of 5.6 10 km, equating to a sink of 225 mm yr 1 in the surface water budget of northern Canada (excluding the Arctic Archipelago where insufficient data exist). Application of the Mann-Kendall test to the data reveals a 10% decrease ( 125 km yr ...

2017
Steven H Ferguson Brent G Young David J Yurkowski Randi Anderson Cornelia Willing Ole Nielsen

To assess whether demographic declines of Arctic species at the southern limit of their range will be gradual or punctuated, we compared large-scale environmental patterns including sea ice dynamics to ringed seal (Pusa hispida) reproduction, body condition, recruitment, and stress in Hudson Bay from 2003 to 2013. Aerial surveys suggested a gradual decline in seal density from 1995 to 2013, wit...

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