AS.270.103 Lecture Notes - Lecture 23: Radiative Forcing
23 Jan 2017
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Document Summary
Sunspot number is a proxy for amount of solar radiation (little if any trend in the last 30 or 40 years when the warming has been the largest) There"s (cid:271)ee(cid:374) a tre(cid:374)d i(cid:374) co2 (cid:894)do(cid:373)i(cid:374)a(cid:374)t ghg(cid:895) has more of a role than solar output variability: however, other factors are also playing a role. A(cid:374)(cid:374)ual (cid:272)y(cid:272)le (cid:894)flu(cid:272)tuatio(cid:374)s(cid:895) with the (cid:271)reedi(cid:374)g of the earth"s (cid:271)iosphere and variation in biological activity (i. e. growing season of trees taking up of co2) long-term increase. Get a historical record of co2 atmospheric concentration from trapped air bubbles in ice cores. Atmospheric storage, ocean uptake, and inferred terrestrial uptake are balanced out with fossil fuel emissions and deforestation/land use change. Radiative forcing: change in energy balance at the top of the troposphere resulting from a change in an external variable. Increase in radiative forcing from an increase in ghgs. Net radiative forcing is primarily positive because of the large increase in ghgs (net warming)
