Ozone structure in Caribbean hurricanes

Abstract

Using ozone data from model-assimilated satellite measurements in the eastern Caribbean 15–20N, 60–68W, cases were studied when upper tropospheric O3 values declined below 60 ppb. Secondary criteria on convection and circulation isolated two hurricanes for analysis (Irma and Maria 2017). Winds at 150 hPa (14 km) show divergence over the vortex characterized by ozone <50 ppb. Upper tropospheric O3 concentrations >100 ppb appear west of hurricanes, where sinking motions interact with vortex outflow. Past work suggests that high values are important, but here low ozone concentrations near the core are more conspicuous. The low O3 layer formed over the ocean and lifted by the hurricane circulation and convection, indicates vortex – environment interaction, vertical motion and storm intensity. Upper tropospheric O3 concentrations <50 ppb cover an area about double the radius of heavy rainfall >10 mm/h, appearing as a protective envelope around the core.