Effects of solar dimming and brightening on the terrestrial carbon sink
Mercado, L.M.; Bellouin, N.; Sitch, S.; Boucher, O.; Huntingford, C.; Cox, P.M.. 2008 Effects of solar dimming and brightening on the terrestrial carbon sink. [Poster] In: American Geophysical Union 2008 Fall Meeting, San Francisco, 15-19 December 2008. (Unpublished)Before downloading, please read NORA policies.
A decrease in total solar radiation (Liepert, 2002, Stanhill and Cohen, 2001, Wild et al., 2005) has been observed at the earth surface over the 1950-1990 period, called solar dimming. Such dimming gradually started to transform into brightening in some regions of the world since the late 1980s (Wild et al. 2005). Both dimming and brightening are likely to be linked to an increase and decrease in cloud cover and scattering and absorption of light by tropospheric and stratospheric aerosols respectively (Kvalevag and Myhre, 2007). Theoretical and observational studies have shown that plant photosynthesis of forest and crop ecosystems is more efficient under diffuse light conditions (Gu et al., 2003, Niyogi et al., 2004, Oliveira et al., 2007, Roderick et al., 2001). However, this effect has not yet been accounted for in global carbon cycle simulations because such models lack the mechanism that includes the diffuse irradiance effects on photosynthesis. The aim of this study is to estimate the impact of changes in radiation during the 1900-2100 period on land productivity and carbon storage. We use a offline version of the land surface scheme of the Hadley centre model (Mercado et al., 2007) which has been modified to account for variations of direct and diffuse radiation on sunlit and shaded canopy photosynthesis. Additionally, we use short wave and photosynthetic active radiation fields reconstructed from the Hadley centre climate model which takes into account the scattering and absorption of light by tropospheric and stratospheric aerosols. We describe the simulation of the land carbon cycle through the dimming-brightening periods, and diagnose the impact that changes in diffuse radiation had on the land carbon sink. We also discuss the implications of these results for the future land carbon-sink, under likely changes in the atmospheric aerosol loading.
|Item Type:||Conference or Workshop Item (Poster)|
|Programmes:||CEH Programmes pre-2009 publications > Biogeochemistry > CC01B Land-surface Feedbacks in the Climate System > CC01.6 Development of the Joint Unified Land Exchange Scheme (JULES) land-surface model
CEH Programmes pre-2009 publications > Biogeochemistry > BG01 Measuring and modelling trace gas, aerosol and carbon > BG01.5 Aerosols
CEH Programmes pre-2009 publications > Biogeochemistry > BG01 Measuring and modelling trace gas, aerosol and carbon > BG01.2 Carbon
|CEH Sections:||Harding (to 31.07.11)|
|Additional Keywords:||Solar dimming and brightening, photosynhtesis,land carbon sink|
|NORA Subject Terms:||Earth Sciences|
|Date made live:||20 Oct 2010 12:30|
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