Impacts of Gulf Stream Weakening on the Transition of Marine Post-Frontal Clouds

The Gulf Stream transports large amounts of heat from the tropics to mid- and high-latitudes. The increased sea surface temperatures (SSTs) due to Gulf Stream influence marine low cloud formation over the western North Atlantic Ocean (WNAO) region. Distinct transition in the morphology of post-frontal clouds over WNAO has been observed during the Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) field campaign (2020-2022). In our recent cloud-resolving model simulations of ACTIVATE cases, the modeled present-day post-frontal clouds show cloud morphology transition consistent with satellite observations. Weather Research and Forecasting model (WRF) sensitivity studies with different Gulf Stream strengths and SST spatial distributions are used to quantify the impacts of Gulf Stream weakening on cloud size distribution, multi-scale mass-flux circulation, and air parcel movements. This research serves as a significant step toward unraveling the complex interactions between cloud processes, marine boundary layer conditions, and climate changes in the crucial WNAO region of the Earth system.