Past and future scenarios of the effect of carbon dioxide on plant growth and transpiration for three vegetation types of southwestern France

[摘要] The sensitivity of an operational CO₂-responsive land surface model(the ISBA-A-gs model of Météo-France) to the atmospheric CO₂concentration, (CO₂), is investigated for 3 vegetation types (winterwheat, irrigated maize, coniferous forest). Past (1960) and future (2050)scenarios of (CO₂) corresponding to 320 ppm and 550 ppm, respectively,are explored. The sensitivity study is performed for 4 annual cyclespresenting contrasting conditions of precipitation regime and airtemperature, based on continuous measurements performed on the SMOSREX sitenear Toulouse, in southwestern France. A significant CO₂-drivenreduction of canopy conductance is simulated for the irrigated maize and theconiferous forest. The reduction is particularly large for maize, from 2000to 2050 (−18%), and triggers a drop in optimum irrigation (−30 mmy⁻¹). In the case of wheat, the response is more complex, with an equaloccurrence of enhanced or reduced canopy conductance.

[学科分类] 大气科学