Sensitivity of Climate to Changes in NDVISource: Journal of Climate:;2000:;volume( 013 ):;issue: 013::page 2277Author:Bounoua, L.
,
Collatz, G. J.
,
Los, S. O.
,
Sellers, P. J.
,
Dazlich, D. A.
,
Tucker, C. J.
,
Randall, D. A.
DOI: 10.1175/1520-0442(2000)013<2277:SOCTCI>2.0.CO;2Publisher: American Meteorological Society
Abstract: The sensitivity of global and regional climate to changes in vegetation density is investigated using a coupled biosphere?atmosphere model. The magnitude of the vegetation changes and their spatial distribution are based on natural decadal variability of the normalized difference vegetation index (NDVI). Different scenarios using maximum and minimum vegetation cover were derived from satellite records spanning the period 1982?90. Albedo decreased in the northern latitudes and increased in the Tropics with increased NDVI. The increase in vegetation density revealed that the vegetation?s physiological response was constrained by the limits of the available water resources. The difference between the maximum and minimum vegetation scenarios resulted in a 46% increase in absorbed visible solar radiation and a similar increase in gross photosynthetic CO2 uptake on a global annual basis. This increase caused the canopy transpiration and interception fluxes to increase and reduced those from the soil. The redistribution of the surface energy fluxes substantially reduced the Bowen ratio during the growing season, resulting in cooler and moister near-surface climate, except when soil moisture was limiting. Important effects of increased vegetation on climate are a cooling of about 1.8 K in the northern latitudes during the growing season and a slight warming during the winter, which is primarily due to the masking of high albedo of snow by a denser canopy; and a year-round cooling of 0.8 K in the Tropics. These results suggest that increases in vegetation density could partially compensate for parallel increases in greenhouse warming. Increasing vegetation density globally caused both evapotranspiration and precipitation to increase. Evapotranspiration, however, increased more than precipitation, resulting in a global soil-water deficit of about 15%. A spectral analysis on the simulated results showed that changes in the state of vegetation could affect the low-frequency modes of the precipitation distribution and might reduce its low-frequency variability in the Tropics while increasing it in northern latitudes.
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contributor author | Bounoua, L. | |
contributor author | Collatz, G. J. | |
contributor author | Los, S. O. | |
contributor author | Sellers, P. J. | |
contributor author | Dazlich, D. A. | |
contributor author | Tucker, C. J. | |
contributor author | Randall, D. A. | |
date accessioned | 2017-06-09T15:50:58Z | |
date available | 2017-06-09T15:50:58Z | |
date copyright | 2000/07/01 | |
date issued | 2000 | |
identifier issn | 0894-8755 | |
identifier other | ams-5502.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4195090 | |
description abstract | The sensitivity of global and regional climate to changes in vegetation density is investigated using a coupled biosphere?atmosphere model. The magnitude of the vegetation changes and their spatial distribution are based on natural decadal variability of the normalized difference vegetation index (NDVI). Different scenarios using maximum and minimum vegetation cover were derived from satellite records spanning the period 1982?90. Albedo decreased in the northern latitudes and increased in the Tropics with increased NDVI. The increase in vegetation density revealed that the vegetation?s physiological response was constrained by the limits of the available water resources. The difference between the maximum and minimum vegetation scenarios resulted in a 46% increase in absorbed visible solar radiation and a similar increase in gross photosynthetic CO2 uptake on a global annual basis. This increase caused the canopy transpiration and interception fluxes to increase and reduced those from the soil. The redistribution of the surface energy fluxes substantially reduced the Bowen ratio during the growing season, resulting in cooler and moister near-surface climate, except when soil moisture was limiting. Important effects of increased vegetation on climate are a cooling of about 1.8 K in the northern latitudes during the growing season and a slight warming during the winter, which is primarily due to the masking of high albedo of snow by a denser canopy; and a year-round cooling of 0.8 K in the Tropics. These results suggest that increases in vegetation density could partially compensate for parallel increases in greenhouse warming. Increasing vegetation density globally caused both evapotranspiration and precipitation to increase. Evapotranspiration, however, increased more than precipitation, resulting in a global soil-water deficit of about 15%. A spectral analysis on the simulated results showed that changes in the state of vegetation could affect the low-frequency modes of the precipitation distribution and might reduce its low-frequency variability in the Tropics while increasing it in northern latitudes. | |
publisher | American Meteorological Society | |
title | Sensitivity of Climate to Changes in NDVI | |
type | Journal Paper | |
journal volume | 13 | |
journal issue | 13 | |
journal title | Journal of Climate | |
identifier doi | 10.1175/1520-0442(2000)013<2277:SOCTCI>2.0.CO;2 | |
journal fristpage | 2277 | |
journal lastpage | 2292 | |
tree | Journal of Climate:;2000:;volume( 013 ):;issue: 013 | |
contenttype | Fulltext |