Record Details

Modeling of Solar Radiation Management : A Comparison of Simulations using Reduced Solar Constant and Stratospheric Aerosols

Electronic Theses of Indian Institute of Science

View Archive Info
 
 
Field Value
 
Title Modeling of Solar Radiation Management : A Comparison of Simulations using Reduced Solar Constant and Stratospheric Aerosols
 
Creator Sirisha, K
 
Subject Solar Radiation Management
Stratospheric Aerosols
Solar Constant
Stratospheric Warming
Sunshades
Stratospheric Sulphate Aerosols
Solar Radiation Management (SRM)
Diffuse Radiation
Solar Constant Reduction
Aerosol
Meteorology
 
Description 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 thesis, a global climate model is used to test if the climate response to SRM by stratospheric aerosols and uniform solar constant reduction are similar. 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 (61-9.8 hPa) temperature is simulated between the two SRM methods. Further, while the global mean surface diffuse radiation increases by about 15- 20% and direct radiation decreases by about 8% in the case of sulphate aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~ -1.5%) 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 6 % in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 7% decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~ 1%) and NPP (~ 0.7%). 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.
 
Contributor Bala, G
 
Date 2017-11-21T19:09:45Z
2017-11-21T19:09:45Z
2017-11-22
2014
 
Type Thesis
 
Identifier http://etd.iisc.ernet.in/handle/2005/2775
http://etd.ncsi.iisc.ernet.in/abstracts/3647/G26296-Abs.pdf
 
Language en_US
 
Relation G26296