Author: Marc Pace Marcella
Publisher:
ISBN:
Category :
Languages : en
Pages : 282
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Book Description
This dissertation describes the role of land surface processes in shaping semi-arid climates, namely those of Southwest Asia and Northwest Africa. The interactions between dust emissions, irrigation, and climate processes are studied and quantified using a regional climate model to perform a series of carefully designed numerical experiments. The performance of the numerical model is tested by comparing simulation results against observations from satellites and other standard platforms. Modeling results indicate significant improvements in simulating mineral aerosols over Southwest Asia. Results suggest that including representations for sub-grid scale wind gustiness as well as mineral aerosols at the boundaries, improve the model skill in simulating the spatial distribution and magnitude of suspended dust. Over Southwest Asia, a large bias in original simulations of surface temperature is eliminated by improving surface albedo, and including mineral aerosols and irrigation. These modifications reduced other biases associated with simulated surface shortwave incident radiation, surface absorbed radiation, and surface vapor pressure. As a result of these improvements, the model now successfully reproduces the climate of Southwest Asia. Another set of numerical experiments is performed over West Africa focusing on the same processes of dust emissions and irrigation. Over the Sahel region, it is found that both mineral aerosols and irrigation have similar effects on the surrounding climate: cooling of surface temperature, increased surface humidity, but no change in rainfall. With dust, a shallower boundary layer redistributes moisture closer to the surface thus offsetting negative temperature effects on the boundary layer moist static energy. With irrigation, a large reduction of the boundary layer height results in less triggering of convective activity and hence mitigates any increase in convective rainfall efficiency due to irrigation. Lastly, a numerical simulation over West Africa that includes simultaneous representations of dust emissions and irrigation is analyzed. Increased soil moisture, vegetation coverage, and dry deposition due to irrigation result in decreased emissions and suspension of dust. This experiment revealed an additional feedback due to irrigation: warming of the surface temperature due to a reduction in mineral aerosols concentration.
Author: A. Henderson-Sellers
Publisher: Springer Science & Business Media
ISBN: 940113264X
Category : Science
Languages : en
Pages : 237
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Book Description
The chapters in this section place the problems of vegetation and climate interactions in semi-arid regions into the context which recur throughout the book. First, Verstraete and Schwartz review desertification as a process of global change evaluating both the human and climatic factors. The theme of human impact and land management is discussed further by Roberts whose review focuses on semi-arid land-use planning. In the third and final chapter in this section we return to the meteorological theme. Nicholls reviews the effects of El Nino/Southern Oscillation on Australian vegetation stressing, in particular, the interaction between plants and their climatic environment. Vegetatio 91: 3-13, 1991. 3 A. Henderson-Sellers and A. J. Pitman (eds). Vegetation and climate interactions in semi-arid regions. © 1991 Kluwer Academic Publishers. Desertification and global change 2 M. M. Verstraete! & S. A. Schwartz ! Institute for Remote Sensing Applications, CEC Joint Research Centre, Ispra Establishment, TP 440, 1-21020 Ispra (Varese), Italy; 2 Department of Atmospheric, Oceanic and Space Sciences, The University of Michigan, Ann Arbor, MI48109-2143, USA Accepted 24. 8. 1990 Abstract Arid and semiarid regions cover one third of the continental areas on Earth. These regions are very sensitive to a variety of physical, chemical and biological degradation processes collectively called desertification.
Author: Lennart Bengtsson
Publisher: Cambridge University Press
ISBN: 9780521782388
Category : Nature
Languages : en
Pages : 124
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Author: Jianping Huang
Publisher: World Scientific Publishing Company
ISBN: 9789811276170
Category :
Languages : en
Pages : 0
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Book Description
Semi-arid regions are ecological security barriers that prevent arid regions from expanding and turning into deserts. The expansion of arid regions and desertification seriously threaten ecological security, and human society cannot achieve sustainable development in an insecure ecological environment. As the transitional zone between arid and humid regions, semi-arid regions lay the foundation of ecological safety for the development of human society. This book provides an overview of processes and mechanisms that characterize semi-arid climate change both regionally and globally. It explains systematically theoretical concepts, including land-atmosphere interactions, ocean-atmosphere interactions, and factors that contribute to climate change, including the impact of human activities. A summary of recent progress in the research in the field and the future of semi-arid regions are also discussed. This book is a specialized monograph and textbook for graduate students of Earth sciences. It is also suitable for undergraduate or graduate students in related majors such as those engaged in atmospheric science, climate change studies, and Earth sciences.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309031966
Category : Science
Languages : en
Pages : 280
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Author:
Publisher:
ISBN:
Category : Arid regions
Languages : en
Pages : 92
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Author: J -P. Goutorbe
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Michelle Marie Irizarry-Ortiz
Publisher:
ISBN:
Category :
Languages : en
Pages : 312
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Author: Devdutta Sadananda Niyogi
Publisher:
ISBN:
Category : Atmospheric chemistry
Languages : en
Pages : 958
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Author: Jianping Huang
Publisher: World Scientific
ISBN: 9811276196
Category : Science
Languages : en
Pages : 655
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Book Description
Semi-arid regions are ecological security barriers that prevent arid regions from expanding and turning into deserts. The expansion of arid regions and desertification seriously threaten ecological security, and human society cannot achieve sustainable development in an insecure ecological environment. As the transitional zone between arid and humid regions, semi-arid regions lay the foundation of ecological safety for the development of human society.This book provides an overview of processes and mechanisms that characterize semi-arid climate change both regionally and globally. It explains systematically theoretical concepts , including land-atmosphere interactions, ocean-atmosphere interactions, and factors that contribute to climate change, including the impact of human activities. A summary of recent progress in the research in the field and the future of semi-arid regions are also discussed.This book is a specialized monograph and textbook for graduate students of Earth sciences. It is also suitable for undergraduate or graduate students in related majors such as those engaged in atmospheric science, climate change studies, and Earth sciences.
