Ship-based Observations of Cloud Surface Radiative Forcing during the Dynamics of the Madden-Julian Oscillation (DYNAMO) Field Program

Cloud radiative forcing (CRF) – defined as the difference between the observed radiative flux and the flux that would be observed in clear skies – is a simple index of the influence of clouds on the surface heat budget. In this paper we will present measurements of surface CRF obtained during the DYNAMO field program aboard the R/V Revelle. DYNAMO was conducted in the India Ocean between September 2011 and January 2012. Revelle conducted four cruise legs with much of the operations near 0 S 85 E. Solar and IR downward fluxes were observed with a mix of standard thermal radiometers. Our analysis will include linking CRF to bulk cloud properties (base height, top height, and integrated liquid water content). We will show that CRF dominates the variability of the net heat surface budget. Results from DYNAMO will be compared with several recent tropical convection field programs (TOGA COARE, JASMINE, and EPIC).