2 Cloud Radiative Forcing The short and long wave radiative forcing Csw and Clw shall be a linear function of the cloud cover N with the constants of proportionality Msw = -78 W/m2 and mw = 35 W/m2 Albedo, greenhouse effect and emissivity of the clear sky atmosphere are do = 0.1, g = 0.3 and = 1. a) For which cloud cover Neg is the radiation balance o = SWI-LWT + Csw + Clw (see assignment 1 for SWI and LWD) balanced, if the equilibrium temperature of the earth is Teq = 288K? Which radiative forcing o do you get for, 0.01, 0.05 and 0.1 deviations from Neq? (word Ilmlt 200; 2 marks) b) Compute the equilibrium temperature as a function of the cloud cover from N= 0 to N = 1. (word Ilmit 100; 2 marks) c) Geo-engineering: We assume the climate sensitivity to CO2 forcing is: n=0.5K/W/m2 We further assume a doubling of the CO2 concentrations is an effective forcing of 6 W/m2. Considering the cloud cover model above (2a): By how much would you need to increase the cloud cover to counteract the warming of the doubling of the CO2 concentrations? (word Ilmit 200; 2 marks) 2 Cloud Radiative Forcing The short and long wave radiative forcing Csw and Clw shall be a linear function of the cloud cover N with the constants of proportionality Msw = -78 W/m2 and mw = 35 W/m2 Albedo, greenhouse effect and emissivity of the clear sky atmosphere are do = 0.1, g = 0.3 and = 1. a) For which cloud cover Neg is the radiation balance o = SWI-LWT + Csw + Clw (see assignment 1 for SWI and LWD) balanced, if the equilibrium temperature of the earth is Teq = 288K? Which radiative forcing o do you get for, 0.01, 0.05 and 0.1 deviations from Neq? (word Ilmlt 200; 2 marks) b) Compute the equilibrium temperature as a function of the cloud cover from N= 0 to N = 1. (word Ilmit 100; 2 marks) c) Geo-engineering: We assume the climate sensitivity to CO2 forcing is: n=0.5K/W/m2 We further assume a doubling of the CO2 concentrations is an effective forcing of 6 W/m2. Considering the cloud cover model above (2a): By how much would you need to increase the cloud cover to counteract the warming of the doubling of the CO2 concentrations? (word Ilmit 200; 2 marks)