caa a22 4500 605475024 CHVBK 20210128100350.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00382-014-2240-3 doi (NATIONALLICENCE)springer-10.1007/s00382-014-2240-3 Modeling of solar radiation management: a comparison of simulations using reduced solar constant and stratospheric sulphate aerosols [Elektronische Daten] [Sirisha Kalidindi, Govindasamy Bala, Angshuman Modak, Ken Caldeira] The climatic effects of Solar Radiation Management (SRM) geoengineering have been often modeled by simply reducing the solar constant. This is most likely valid only for space sunshades and not for atmosphere and surface based SRM methods. In this study, a global climate model is used to evaluate the differences in the climate response to SRM by uniform solar constant reduction and stratospheric aerosols. Our analysis shows that when global mean warming from a doubling of CO2 is nearly cancelled by both these methods, they are similar when important surface and tropospheric climate variables are considered. However, a difference of 1K in the global mean stratospheric (61-9.8hPa) temperature is simulated between the two SRM methods. Further, while the global mean surface diffuse radiation increases by ~23% and direct radiation decreases by about 9% in the case of sulphate aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~1.0%) when solar constant is reduced. When CO2 fertilization effects from elevated CO2 concentration levels are removed, the contribution from shaded leaves to gross primary productivity (GPP) increases by 1.8% in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 15.2% decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~8%) and net primary productivity (~3%). Based on our results we conclude that the climate states produced by a reduction in solar constant and addition of aerosols into the stratosphere can be considered almost similar except for two important aspects: stratospheric temperature change and the consequent implications for the dynamics and the chemistry of the stratosphere and the partitioning of direct versus diffuse radiation reaching the surface. Further, the likely dependence of global hydrological cycle response on aerosol particle size and the latitudinal and height distribution of aerosols is discussed. Springer-Verlag Berlin Heidelberg, 2014 Geoengineering nationallicence Sulphate aerosols nationallicence Stratospheric warming nationallicence Diffuse radiation nationallicence GPP nationallicence Kalidindi Sirisha Divecha Centre for Climate Change and Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, 560 012, Bangalore, India aut Bala Govindasamy Divecha Centre for Climate Change and Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, 560 012, Bangalore, India aut Modak Angshuman Divecha Centre for Climate Change and Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, 560 012, Bangalore, India aut Caldeira Ken Department of Global Ecology, Carnegie Institution, 260 Panama Street, 94305, Stanford, CA, USA aut Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2909-2925 0930-7575 44:9-10<2909 2015 44 382 https://doi.org/10.1007/s00382-014-2240-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-014-2240-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kalidindi Sirisha Divecha Centre for Climate Change and Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, 560 012, Bangalore, India aut NATIONALLICENCE 700 1- Bala Govindasamy Divecha Centre for Climate Change and Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, 560 012, Bangalore, India aut NATIONALLICENCE 700 1- Modak Angshuman Divecha Centre for Climate Change and Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, 560 012, Bangalore, India aut NATIONALLICENCE 700 1- Caldeira Ken Department of Global Ecology, Carnegie Institution, 260 Panama Street, 94305, Stanford, CA, USA aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2909-2925 0930-7575 44:9-10<2909 2015 44 382