Impact of surface heat flux on cold pool dynamics

Abstract:

Cold pools are key components in the triggering and maintenance of convection. What impacts the life cycle and characteristics of cold pools is still poorly understood. In particular it is still unclear how cold pools can potentially die and what is the role of surface heat fluxes vs. turbulent entrainment on their life cycle and characteristics. We here investigate the role f surface heat fluxes on the life cycle and characteristics of cold pools using the System for Atmospheric Modeling (SAM) over an oceanic and continental surface. Using a novel cold pool tracking algorithm and several experiments on surface heat fluxes interaction with cold pools, we show that surface heat fluxes are an important contributor to the life cycle and characteristics of cold pools. Sensible heat flux especially tends to kill cold pools, to reduce their buoyancy anomaly compared to the environment and also to reduce the gust front velocity. Cold pools are also smaller because of surface sensible heating. Sensible heat flux contribution is stronger over the ocean because of the reduced inertia of land surfaces which tends to rapidly track the temperature anomalies induced by the falling unsaturated downdrafts.