نتایج جستجو برای: southern hemisphere

تعداد نتایج: 140572  

Journal: :پژوهش های جغرافیای طبیعی 0
فرامرز خوش اخلاق استادیار دانشکده جغرافیا دانشگاه تهران نوذر قنبری استادیار گروه جغرافیا، دانشگاه آزاد اسلامی واحد کرمانشاه جعفر معصوم پور سماکوش دانشجوی دوره دکتری دانشکده جغرافیا دانشگاه تهران

the southern shores of caspian sea is subjected to several atmospheric factors due to its geographical position. north atlantic oscillation(nao) one of the effective phenomenon's affects the most part of hemisphere included caspian sea. in this research negative and positive phases of nao considered with variability of temperature and precipitation of southern shores of caspian sea in a 30...

Journal: :Ecology letters 2009
Robert R Dunn Donat Agosti Alan N Andersen Xavier Arnan Carsten A Bruhl Xim Cerdá Aaron M Ellison Brian L Fisher Matthew C Fitzpatrick Heloise Gibb Nicholas J Gotelli Aaron D Gove Benoit Guenard Milan Janda Michael Kaspari Edward J Laurent Jean-Philippe Lessard John T Longino Jonathan D Majer Sean B Menke Terrence P McGlynn Catherine L Parr Stacy M Philpott Martin Pfeiffer Javier Retana Andrew V Suarez Heraldo L Vasconcelos Michael D Weiser Nathan J Sanders

Although many taxa show a latitudinal gradient in richness, the relationship between latitude and species richness is often asymmetrical between the northern and southern hemispheres. Here we examine the latitudinal pattern of species richness across 1003 local ant assemblages. We find latitudinal asymmetry, with southern hemisphere sites being more diverse than northern hemisphere sites. Most ...

2013
Mike Patterson

There are fundamental differences between the climate of the Southern and Northern Hemispheres. Largely, these differences are dictated by the obvious differences in the geography of the two hemispheres: the Northern Hemisphere is about 50% land, whereas about 90% of the Southern Hemisphere is ocean. This asymmetry gives a much larger seasonal cycle in the Northern Hemisphere (NH) and reduces t...

2014
Gerardo Chowell Sherry Towers Cécile Viboud Rodrigo Fuentes Viviana Sotomayor

To determine effects of school breaks on influenza virus transmission in the Southern Hemisphere, we analyzed 2004-2010 influenza-like-illness surveillance data from Chile. Winter breaks were significantly associated with a two-thirds temporary incidence reduction among schoolchildren, which supports use of school closure to temporarily reduce illness, especially among schoolchildren, in the So...

2006
Konstantin Y. Vinnikov Claire L. Parkinson

For more than three decades now, satellite passive microwave observations have been used to monitor polar sea ice. Here we utilize sea ice extent trends determined from primarily satellite data for both the Northern and Southern Hemispheres for the period 1972(73)-2004 and compare them with results from simulations by eleven climate models. In the Northern Hemisphere, observations show a statis...

2015
Olusegun Steven Ayodele Oluwole

Seasonal influenza epidemics occur annually during the winter in the northern and southern hemispheres, but timing of peaks and severity vary seasonally. Low humidity, which enhances survival and transmission of influenza virus, is the major risk factor. Both El Niño and La Niña phases of El Niño-southern oscillation (ENSO), which determine inter-annual variation of precipitation, are putative ...

2007
Thorsten Kiefer

Polus Antarctica: Terra Australis Incognita This map, produced in 1642 by Hendrik Hondius, shows the extent of geographical knowledge of the southern hemisphere 365 years ago. Although our geographic knowledge of the region has obviously come a long way since then, the sparsity in the 17th century, shown here, is representative of the current state of our understanding of the paleoclimate of th...

2008
L. Menviel A. Timmermann A. Mouchet O. Timm

[1] It has been previously suggested that changes in the strength and position of the Southern Hemisphere westerlies could be a key contributor to glacial-interglacial atmospheric CO2 variations. To test this hypothesis, we perform a series of sensitivity experiments using an Earth system model of intermediate complexity. A strengthening of the climatological mean surface winds over the Souther...

2016
J. C. Coxon S. E. Milan J. A. Carter L. B. N. Clausen B. J. Anderson H. Korth

We reduce measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) to give the total Birkeland (field-aligned) current flowing in both hemispheres in monthly and hourly bins. We analyze these totals using 6 years of data (2010–2015) to examine solar zenith angle-driven variations in the total Birkeland current flowing in both hemispheres, simultan...

2012
Michael-Shawn Fletcher Patricio Iván Moreno

The prevailing view in the palaeoclimate literature of the last 20 years is that the Southern Westerly Winds (SWW) were intensified over southern Australia and Tasmania during the warmer-than-present early Holocene (11e8 ka). At similar latitudes on the opposite side of the southern mid-latitudes, palaeoclimate studies have suggested a poleward shift of the northern edge of the westerlies and f...

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