نتایج جستجو برای: arid and semiarid climate

تعداد نتایج: 16861318  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Michael I Bird Damien O'Grady Sean Ulm

The Pleistocene global dispersal of modern humans required the transit of arid and semiarid regions where the distribution of potable water provided a primary constraint on dispersal pathways. Here, we provide a spatially explicit continental-scale assessment of the opportunities for Pleistocene human occupation of Australia, the driest inhabited continent on Earth. We establish the location an...

2011
Feike A. Dijkstra Jack A. Morgan Joseph C. von Fischer Ronald F. Follett

[1] Semiarid rangelands are a significant global sink for methane (CH4), but this sink strength may be altered by climate change. Methane uptake is sensitive to soil moisture showing a hump‐shaped relationship with a distinct optimum soil moisture level. Both CO2 and temperature affect soil moisture, but the direction of CH4 uptake response may depend on if the system is below or above the soil...

2006

Semiarid environments throughout the world have lost a major part of their woody vegetation and biodiversity due to the effects of wood cutting, cattle grazing and subsistence agriculture. The resulting state is typically used for cattle production, but the productivity of these systems is often very low, and erosion of the unprotected soil is a common problem. Such dry-land degradation is of g...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2010
Peter H Gleick

The management of water resources in arid and semiarid areas has long been a challenge, from ancient Mesopotamia to the modern southwestern United States. As our understanding of the hydrological and climatological cycles has improved, and our ability to manipulate the hydrologic cycle has increased, so too have the challenges associated with managing a limited natural resource for a growing po...

2014
Vernon Henderson Adam Storeygard Uwe Deichmann

This paper documents a significant impact of climate variation on urbanization in sub-Saharan Africa, primarily in arid countries. By lowering farm incomes, reduced moisture availability encourages migration to nearby cities, while wetter conditions slow it. The paper also provides evidence for ruralurban income linkages. In countries with a larger industrial base, reduced moisture shrinks the ...

ژورنال: علوم آب و خاک 2014

One of the main objectives of soil classification systems is to identify the differences of soil properties for management purposes. In this study, the efficiency of American and WRB soil classification systems were compared in order to describe some of soil physical, chemical and mineralogical properties in arid and semiarid regions of central Iran. Khatoon-Abad and Mobarekeh plains as arid re...

2014
J. Vernon Henderson Adam Storeygard Uwe Deichmann

This paper documents a significant impact of climate variation on urbanization in sub-Saharan Africa, primarily in arid countries. By lowering farm incomes, reduced moisture availability encourages migration to nearby cities, while wetter conditions slow it. The paper also provides evidence for ruralurban linkages. In countries where cities are starting to develop an industrial base, reduced mo...

2002
George H. Hargreaves Richard G. Allen

A brief history of development of the 1985 Hargreaves equation and its comparison to evapotranspiration ~ET! predicted by the Food and Agricultural Organization of the United Nations ~FAO! Penman-Monteith method are described to provide background and information helpful in selecting an appropriate reference ET equation under various data situations. Early efforts in irrigation water requiremen...

2017
Farzad Emami

As climate change is projected to impose profound global variations in the freshwater resources, assessing the impacts of the former on the latter is a fundamental task for improving the water management, namely, in arid and semiarid areas, as there a plenty of in countries like Iran. Such is the objective of the present paper, where the impacts of climate change on the water availability in th...

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