Impact of the Generation and Activation of Sea Salt Aerosols on the Evolution of Tropical Cyclone Dumile

Abstract

An original coupling between an aerosol scheme and a two‐moment microphysics scheme has been developed in the cloud‐resolving model Meso‐NH to fully represent the aerosol‐microphysics‐dynamics interactions in tropical cyclones. A first evaluation of this coupling is performed through the simulation of tropical cyclone Dumile (2013) in the South‐West Indian Ocean. MACC (Monitoring Atmospheric Composition and Climate project) analysis and CALIPSO (Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations) data agree about the predominance of sea salt aerosols. The aerosol‐microphysics coupled system reproduces the track and intensity of Dumile well, with a transition from a monsoon depression to a tropical cyclone, and produces ice water contents that compare well with the DARDAR (raDAR/liDAR) product. Using a one‐moment microphysics scheme produces a more intense and symmetric system tracking too far to the west. In the aerosol‐microphysics coupled simulation, sea salt aerosols, the main source of cloud condensation nuclei (CCN), are preferentially produced in regions with high winds and waves, which reinforce convective asymmetries compared to the simulation with the one‐moment scheme. Using a two‐moment microphysics scheme without explicit sea salt emission led to a dramatic weakening of Dumile after 24 hr of simulation due to the consumption and scavenging of all interstitial CCN in the inner core. The importance of explicitly taking account of sea salt aerosol emissions associated with high winds and waves in tropical cyclones is a critical point for simulating long‐lasting systems that need to generate their own CCN.

Mesoscale simulations of tropical cyclone Enawo (March 2017) and its impact on TTL water vapor

“…Simulations of TC Enawo were performed with the Mesoscale, anelastic, and nonhydrostatic model Meso-NH version 5.3 (Lac et al, 2018). Recent Meso-NH simulations have been used successfully to study tropical 165 storms/cyclones over the SWIO (Barbary et al, 2019;Hoarau et al, 2018;Lac et al, 2018;Pianezze et al, 2018).…”

“…over the SWIO. We take advantage of the Meso-NH model that has been previously developed for the simulations of TCs in the SWIO (Hoarau et al, 2018;Pianezze et al, 2018). This study is also part of the CONCIRTO (CONvection CIRrus over the Tropical indian Ocean) project that aims to further our knowledge on 120 how deep convection and cirrus clouds affect the TTL over the SWIO.…”

“…The enhanced air drying was explained by the enhancement of cloud ice deposition growth, which consumes more water vapor in the upper troposphere. The aerosol-microphysics schemes presented in Hoarau et al (2018) can be used in an ocean-waves-atmosphere coupled system (Pianezze et al, 2018) to include the effects…”

Simulation of the effects of sea‐salt aerosols on cloud ice and precipitation of a tropical cyclone

“…Sea-salt aerosols, which have a giant particle radius and high hygroscopicity, can accelerate the formation of rain drops (Rosenfeld et al, 2012). Hoarau et al (2018) pointed out that simulations with two-moment schemes produce TCs with more enhanced convective asymmetries than those produced by one-moment schemes. Sea-salt aerosols play a critical role in TC simulation; because of the scavenging and consumption of interstitial CCN a two-moment scheme without explicit sea-salt emission produces TCs with lower intensity (Hoarau et al, 2018).…”

“…() pointed out that simulations with two‐moment schemes produce TCs with more enhanced convective asymmetries than those produced by one‐moment schemes. Sea‐salt aerosols play a critical role in TC simulation; because of the scavenging and consumption of interstitial CCN a two‐moment scheme without explicit sea‐salt emission produces TCs with lower intensity (Hoarau et al, ). The effect of sea‐salt aerosols on cloud is one of the most uncertain components of the aerosols–climate problem (Meskhidze et al, ).…”