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Title: Interactions between vegetation and climate: radiative and physiological effects of doubled atmospheric co2

Abstract

The radiative and physiological effects of doubled atmospheric carbon dioxide (CO2) on climate are investigated using a coupled biosphere atmosphere model. Five 30-yr climate simulations, designed to assess the radiative and physiological effects of doubled CO2, were compared to a 30-yr control run. When the CO2 concentration was doubled for the vegetation physiological calculations only assuming no changes in vegetation biochemistry, the mean temperature increase over land was rather small (0.3 K) and was associated with a slight decrease in precipitation (20.3 percent). In a second case, the vegetation was assumed to have adapted its biochemistry to a doubled CO2 (2-3 CO2) atmosphere and this down regulation caused a 35 percent decrease in stomatal conductance and a 0.7-K increase in land surface temperature. The response of the terrestrial biosphere to radiative forcing alone that is, a conventional greenhouse warming effect revealed important interactions between the climate and the vegetation. Although the global mean photosynthesis exhibited no change, a slight stimulation was observed in the tropical regions, whereas in the northern latitudes photosynthesis and canopy conductance decreased as a result of high temperature stress during the growing season. This was associated with a temperature increase of more than 2 K greatermore » in the northern latitudes than in the Tropics (4.0 K vs 1.7 K). These interactions also resulted in an asymmetry in the diurnal temperature cycle, especially in the Tropics where the nighttime temperature increase due to radiative forcing was about twice that of the daytime, an effect not discernible in the daily mean temperatures. The radiative forcing resulted in a mean temperature increase over land of 2.6 K and 7 percent increase in precipitation with the least effect in the Tropics. As the physiological effects were imposed along with the radiative effects, the overall temperature increase over land was 2.7 K but with a smaller difference (0.7 K) between the northern latitudes and the Tropics. The radiative forcing resulted in an increase in available energy at the earth's surface and, in the absence of physiological effects, the evapotranspiration increased. However, changes in the physiological control of evapotranspiration due to increased CO2 largely compensated for the radiative effects and reduced the evapotranspiration approximately to its control value.« less

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
834251
Report Number(s):
LBNL-44918
TRN: US200432%%168
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Conference
Resource Relation:
Conference: 79th American Meteorological Society Annual Meeting, Dallas, TX (US), 01/10/1989--01/15/1989; Other Information: PBD: 1 Jun 1997
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ASYMMETRY; BIOCHEMISTRY; BIOSPHERE; CARBON DIOXIDE; CLIMATES; GREENHOUSE GASES; PHOTOSYNTHESIS; PLANTS; PRECIPITATION; REGULATIONS; STIMULATION; TROPICAL REGIONS

Citation Formats

Bounoua, L, Collatz, G J, Sellers, P J, Randall, D A, Dazlich, D A, Los, S O, Berry, J A, Fung, I, Tucker, C J, Field, C B, and Jenson, T G. Interactions between vegetation and climate: radiative and physiological effects of doubled atmospheric co2. United States: N. p., 1997. Web.
Bounoua, L, Collatz, G J, Sellers, P J, Randall, D A, Dazlich, D A, Los, S O, Berry, J A, Fung, I, Tucker, C J, Field, C B, & Jenson, T G. Interactions between vegetation and climate: radiative and physiological effects of doubled atmospheric co2. United States.
Bounoua, L, Collatz, G J, Sellers, P J, Randall, D A, Dazlich, D A, Los, S O, Berry, J A, Fung, I, Tucker, C J, Field, C B, and Jenson, T G. 1997. "Interactions between vegetation and climate: radiative and physiological effects of doubled atmospheric co2". United States.
@article{osti_834251,
title = {Interactions between vegetation and climate: radiative and physiological effects of doubled atmospheric co2},
author = {Bounoua, L and Collatz, G J and Sellers, P J and Randall, D A and Dazlich, D A and Los, S O and Berry, J A and Fung, I and Tucker, C J and Field, C B and Jenson, T G},
abstractNote = {The radiative and physiological effects of doubled atmospheric carbon dioxide (CO2) on climate are investigated using a coupled biosphere atmosphere model. Five 30-yr climate simulations, designed to assess the radiative and physiological effects of doubled CO2, were compared to a 30-yr control run. When the CO2 concentration was doubled for the vegetation physiological calculations only assuming no changes in vegetation biochemistry, the mean temperature increase over land was rather small (0.3 K) and was associated with a slight decrease in precipitation (20.3 percent). In a second case, the vegetation was assumed to have adapted its biochemistry to a doubled CO2 (2-3 CO2) atmosphere and this down regulation caused a 35 percent decrease in stomatal conductance and a 0.7-K increase in land surface temperature. The response of the terrestrial biosphere to radiative forcing alone that is, a conventional greenhouse warming effect revealed important interactions between the climate and the vegetation. Although the global mean photosynthesis exhibited no change, a slight stimulation was observed in the tropical regions, whereas in the northern latitudes photosynthesis and canopy conductance decreased as a result of high temperature stress during the growing season. This was associated with a temperature increase of more than 2 K greater in the northern latitudes than in the Tropics (4.0 K vs 1.7 K). These interactions also resulted in an asymmetry in the diurnal temperature cycle, especially in the Tropics where the nighttime temperature increase due to radiative forcing was about twice that of the daytime, an effect not discernible in the daily mean temperatures. The radiative forcing resulted in a mean temperature increase over land of 2.6 K and 7 percent increase in precipitation with the least effect in the Tropics. As the physiological effects were imposed along with the radiative effects, the overall temperature increase over land was 2.7 K but with a smaller difference (0.7 K) between the northern latitudes and the Tropics. The radiative forcing resulted in an increase in available energy at the earth's surface and, in the absence of physiological effects, the evapotranspiration increased. However, changes in the physiological control of evapotranspiration due to increased CO2 largely compensated for the radiative effects and reduced the evapotranspiration approximately to its control value.},
doi = {},
url = {https://www.osti.gov/biblio/834251}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 1997},
month = {Sun Jun 01 00:00:00 EDT 1997}
}

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