A closed-cell marine stratocumulus case during the Aerosol and Cloud Experiments in the Eastern North Atlantic(ACE-ENA)aircraft field campaign is selected to examine the heterogeneities of cloud and drizzle microphysi...A closed-cell marine stratocumulus case during the Aerosol and Cloud Experiments in the Eastern North Atlantic(ACE-ENA)aircraft field campaign is selected to examine the heterogeneities of cloud and drizzle microphysical properties and the aerosol-cloud-precipitation interactions.The spatial and vertical variabilities of cloud and drizzle microphysics are found in two different sets of flight legs:Leg-1 and Leg-2,which are parallel and perpendicular to the cloud propagation,respectively.The cloud along Leg-2 was close to adiabatic,where cloud-droplet effective radius and liquid water content linearly increase from cloud base to cloud top with less drizzle.The cloud along Leg-1 was sub-adiabatic with lower clouddroplet number concentration and larger cloud-droplet effective,but higher drizzle droplet number concentration,larger drizzle droplet median diameter and drizzle liquid water content.The heavier drizzle frequency and intensity on Leg-1 were enhanced by the collision-coalescence processes within cloud due to strong turbulence.The sub-cloud precipitation rate on Leg-1 was significantly higher than that along Leg-2.As a result,the sub-cloud accumulation mode aerosols and CCN on Leg-1 were depleted,but the coarse model aerosols increased.This further leads to a counter-intuitive phenomenon that the CCN is less than cloud-droplet number concentration for Leg-1.The average CCN loss rates are −3.89 cm^(-3)h^(-1)and −0.77 cm^(-3)h^(-1) on Leg-1 and Leg-2,respectively.The cloud and drizzle heterogeneities inside the same stratocumulus can significantly alter the sub-cloud aerosols and CCN budget.Hence it should be treated with caution in the aircraft assessment of aerosol-cloud-precipitation interactions.展开更多
基金supported by the NSF grants AGS-2031750 and AGS-2031751supported as part of the “Enabling Aerosol-cloud interactions at GLobal convection-permitting scal ES (EAGLES)” project (74358),funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research, Earth System Modeling program with the subcontract to the University of Arizona
文摘A closed-cell marine stratocumulus case during the Aerosol and Cloud Experiments in the Eastern North Atlantic(ACE-ENA)aircraft field campaign is selected to examine the heterogeneities of cloud and drizzle microphysical properties and the aerosol-cloud-precipitation interactions.The spatial and vertical variabilities of cloud and drizzle microphysics are found in two different sets of flight legs:Leg-1 and Leg-2,which are parallel and perpendicular to the cloud propagation,respectively.The cloud along Leg-2 was close to adiabatic,where cloud-droplet effective radius and liquid water content linearly increase from cloud base to cloud top with less drizzle.The cloud along Leg-1 was sub-adiabatic with lower clouddroplet number concentration and larger cloud-droplet effective,but higher drizzle droplet number concentration,larger drizzle droplet median diameter and drizzle liquid water content.The heavier drizzle frequency and intensity on Leg-1 were enhanced by the collision-coalescence processes within cloud due to strong turbulence.The sub-cloud precipitation rate on Leg-1 was significantly higher than that along Leg-2.As a result,the sub-cloud accumulation mode aerosols and CCN on Leg-1 were depleted,but the coarse model aerosols increased.This further leads to a counter-intuitive phenomenon that the CCN is less than cloud-droplet number concentration for Leg-1.The average CCN loss rates are −3.89 cm^(-3)h^(-1)and −0.77 cm^(-3)h^(-1) on Leg-1 and Leg-2,respectively.The cloud and drizzle heterogeneities inside the same stratocumulus can significantly alter the sub-cloud aerosols and CCN budget.Hence it should be treated with caution in the aircraft assessment of aerosol-cloud-precipitation interactions.
