Satellite perspectives on the climatology of aerosols and deep convective overshooting tops
Clouds and aerosols modify Earth’s radiation budget by their so-called greenhouse-versus-albedo effects. A full understanding of the climatological properties of aerosols and clouds is an important step towards characterizing their role within Earth’s weather and climate systems from regional to global scales. Satellite observations have made crucial contributions to monitoring today’s weather and climate by providing global distributions of cloud and aerosol properties.
The first part of this talk focuses on understanding the properties and radiative effects of aerosols in cloudy sky conditions. Over the past few decades, global observations of aerosols are mostly performed for clear-sky conditions by passive sensors in space. Aerosol properties in cloudy sky remain uncertain. Here, we aim at characterizing the global climatological differences between aerosols occurring in clear and cloudy skies by utilizing the observations from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). This answers the question on whether aerosol climatologies from passive sensors are representative of all-sky conditions. Given the high frequency of cirrus cloud occurrence, we also assess the impact of cirrus on the direct aerosol radiative effect with the help from both satellite and field campaign measurements.
The second part of this talk will shift gears to present to you the first climatology of overshooting tops detected from MODIS (Moderate Resolution Imaging Spectroradiometer). Overshooting cloud tops (OT) form in convective storms when strong updrafts penetrate the tropopause. OTs are usually associated with hazardous weather conditions such as large hails, flooding, tornadoes, etc. OT detection from space provides a way to understand climatological distributions of hazardous thunderstorms globally, as well as to characterize the moisture transport to the stratosphere. This talk will introduce our OT detection method applied to MODIS, a near-global OT climatology derived from two-decade MODIS data, as well as the interannual variability of OT and convection over the past twenty years.