A round Earth for Climate Models

Seminar by Juno Hus from Univeristy of California, Irvine

19 September 2019
10:00 - 11:00

The Seminar is being held in Room 1010 (Jasmin) - Intergrated mechanical engineering building. Click here for the campus map.

Sunlight drives the Earth’s weather, climate, chemistry, and bio-sphere. Recent efforts to improve solar heating codes in climate models focused on more accurate treatment of the absorption spectrum or fractional clouds. A mostly forgotten assumption in climate models is that of a flat Earth atmosphere. Spherical atmospheres intercept 2.5 W·m−2 more sunlight and heat the climate by an additional 1.5 W·m−2 globally. Such a systematic shift, being comparable to the radiative forcing change from pre-industrial to present, is likely to produce a discernible climate shift that would alter a model’s skill in simulating current climate. Regional heating errors, particularly at high latitudes, are several times larger. Unlike flat atmospheres, constituents in a spherical atmosphere, such as clouds and aerosols, alter the total amount of energy received by the Earth. To calculate the net cooling of aerosols in a spherical framework, one must count the increases in both incident and reflected sunlight, thus reducing the aerosol effect by 10 to 14% relative to using just the increase in reflected. Simple fixes to the current flat Earth climate models can correct much of this oversight, although some inconsistencies will remain.