An Analytical Model for Spatially Varying Clear-Sky CO2 Forcing

Instantaneous clear-sky CO2 forcing is known to vary by several W/m² over the globe, but the climate factors which control this are not well understood. Building upon the work of Wilson (2012), we build a first-principles, analytical model for CO2 forcing which requires as input only the temperatures at the surface and roughly 30 hPa, as well as column relative humidity. This model quantitatively captures global variations in clear-sky CO2 forcing, and shows that the meridional forcing gradient is directly attributable to the meridional surface temperature gradient.