The relationship between aerosol loading and the vertical structure and intensity of deep convection, lightning, and lightning produced NOX will be examined for six regions as a function of convective…

This is a $570,920 grant awarded by the National Aeronautics and Space Administration (NASA) to the University of Maryland, College Park (UMD) on October 25, 2019 for research examining the relationship between aerosol loading and the vertical structure and intensity of deep convection, lightning, and lightning-produced nitrogen oxides. The project will leverage data from NASA's CloudSat and CALIPSO satellites, the Geostationary Lightning Mapper (GLM), and meteorological reanalysis products to investigate these relationships across six different regions with varying weather regimes and aerosol types. The outcome will be an improved understanding of the impact of aerosol-cloud interactions on deep convection, lightning flash rates, and lightning-nitrogen oxide production, which can reduce uncertainties in atmospheric composition and climate modeling. There is no set-aside designation for this grant. UMD is the prime recipient, and the study is part of the university's ongoing research and collaboration with NASA.

The relationship between aerosol loading and the vertical structure and intensity of deep convection, lightning, and lightning produced NOX will be examined for six regions as a function of convective regime using cloudsat/calipso and ancillary data sets including the NASA merra-2 reanalysis and the geostationary lightning mapper (GLM). For each of these regions, the intensity of deep convective features will be evaluated using cloudsat-derived metrics related to storm intensity and lightning flash rate including center of gravity, deep convective cloud-top, mixed phase depth, ICE water path, along-track extent of deep convection, and midtropospheric reflectivity lapse rate. In order to isolate the aerosol effect on convective development and flash rates from other effects, the value of several environmental variables will be extracted from the ecmwf and/or merra-2 reanalyses including convective available potential energy (cape), normalized cape, mid-tropospheric relative humidity, equivalent potential temperature, and lower tropospheric temperature lapse rate and used to BIN the cloudsat/ calipso aerosol and cloud retrievals into meteorological regimes. For each regime, variations in the deep convective metrics will be examined for periods of low- and high-aerosol loading, which will be determined using AOD and/or vertically-integrated aerosol extinction profiles for selected atmospheric layers from calipso and merra-2 and relative humidity corrected visibility data from eastern china. Six regions with different weather regimes and aerosol types and multiple time periods of interest are chosen to leverage past, on-going, or future projects designed to assess the impact of deep convection on atmospheric composition and/or the impact of aerosols on deep convection. For example, the gulf of mexico region is chosen as a study area because the research team is studying nitrogen oxide production per flash in this region as part of an ongoing NASA aura science team project. The eastern U.S. And amazon basin are chosen due to the availability of GLM data and because past studies in these regions have revealed a relationship between aerosol amounts and convective intensity / lightning flash rates. Argentina is chosen as a focus area because of upcoming NSF relampago-DOE cacti field campaigns in late 2018 and early 2019 designed to study the morphology of convective systems in southeast south america and relationships with aerosol. The western pacific with moderate aerosol loading and eastern china with high aerosol loading are chosen because these are locations where members of the research team have studied the relationship between aerosol amount and deep convective intensity. For each region, we will determine the role aerosol loading and properties play in determining the intensity of cloudsat convective features. The intensity parameters for lightning will include lightning flash rates, and where available NOX columns attributed to recent lightning extracted from NO2 columns from OMI or the recently launched tropomi instrument. The observed response of convective features including flash rate to varying aerosol amounts will then be compared to the modeled response obtained with the NASA geos-5 model using a one-moment microphysics scheme and a two-moment aerosol-aware microphysics scheme. If warranted, modifications to the flash rate and/or NOX production per flash parameterizations in geos-5 will be implemented. The outcome of this project will be an improved understanding of the impact of aerosol-cloud interactions on deep convection, lightning flash rates, and lightning-no production. Ultimately, this information can be used to reduce uncertainties in predictions of atmospheric composition trends and radiative forcing by coupled chemistry-climate models. The investigators have rich experiences and complimentary expertise pertaining to the proposed study