Quantifying the Impact of Midlatitude Deep Convection on Upper Troposphere/Lower Stratosphere Temperatures and Moisture from Satellite and Reanalysis Data

Deep convection occurs widely throughout the world and can rapidly transport lower tropospheric air into the upper troposphere and lower stratosphere (UTLS). The temperatures at this altitude are a primary control of convective troposphere-stratosphere exchange, which plays a significant role in the climate and radiation budget by modulating the distribution and concentration of various greenhouse gases. Much of the previous research on the effects of deep convection on the UTLS has focused on tropical convection in regions of high convective frequency, such as the Pacific Warm Pool. However, midlatitude convection has gained interest in recent years because water vapor variability in the midlatitude UTLS has been shown to have a large influence on the rate of global climate change. This research studies the UTLS vertical temperature and moisture structure changes near deep convection throughout the midlatitudes. In this analysis, the midlatitudes are separated into three latitude bands and several smaller regions of interest. The deep convection observed from the recently-launched Global Precipitation Measurement (GPM) satellite are collocated with high vertical resolution temperature profiles from COSMIC GPS Radio Occultation satellites, along with moisture profiles from ERA5 reanalysis, for the years 2014 through 2016. The intensity of GPM deep convection is categorized based on maximum 20 and 40 dBZ echo-top height. Temperature and moisture anomalies near deep convection are quantified for each latitude band based on the varying convective intensities. Anomaly structure and magnitude are also analyzed depending on whether convection formed over land or ocean. Finally, anomalies are evaluated in relation to midlatitude lapse-rate and cold-point tropopause height, and a relationship of convective anomaly intensity to double tropopause frequency is determined.