Diverse effects of aerosol forcing distribution and magnitude on tropical zonal circulation

• The effect of anthropogenic direct aerosol radiative forcing on tropical zonal circulation has been investigated using the climate-system model EC-Earth2.5 The relatively low forcing resulting from only modeling the direct aerosol effect led to a negligible tropical mean temperature and precipitation response. Nevertheless, the aerosol direct radiative forcing had a considerable local impact on the Indian Ocean Walker circulation cell, which experienced a decreased intensity during the fall, winter, and spring season. Partitioning the aerosol radiative forcing into a scattering and an absorbing part revealed that the scattering aerosol dominated the circulation response. Including the aerosol cloud albedo effect, on the other hand, led to a tropical-wide cooling and sub sequent precipitation reduction. The results indicate that relatively low aerosol direct radiative forcing can lead to substantial local effects on the tropical zonal overturning circulation and precipitation without necessarily relying on a tropical wide cooling and a thermodynamic scaling argument.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Meteorologi och atmosfärforskning (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Meteorology and Atmospheric Sciences (hsv//eng)

Keyword

atmosfärvetenskap och oceanografi

Atmospheric Sciences and Oceanography

Publication and Content Type

vet (subject category)

ovr (subject category)