The NASA INCUS Mission - Understanding and Evaluating Convective Storm Dynamics through Tropics-Wide Observations of Convective Mass Flux

The upward transport of air and water within convective storms in the tropics – often referred to as the convective mass flux (CMF) – plays a fundamental role in providing fresh water, generating extreme weather, shaping cloud radiative forcing, and driving the large-scale circulation. In spite of the importance of CMF to weather and climate across the scales, accurately representing CMF within our weather and climate models remains challenging, with recent studies indicating order of magnitude differences in CMF predictions among our current state-of-the-art high-resolution models. Tropics-wide observations of CMF as a function of tropical environments, storm morphology and storm lifecycle would be highly beneficial in furthering our understanding of convective processes and evaluating their representation within our models. The NASA Investigation of Convective Updrafts (INCUS) mission will provide the first ever tropics-wide observations of CMF and its evolution within deep convective storms, one of the most influential, yet unmeasured atmospheric processes.

The INCUS mission is comprised of a train of three smallsats, each of which will carry a Ka-band cloud radar. A passive microwave radiometer will be housed on the middle spacecraft. The three low earth orbit smallsats will be separated by time intervals of 30, 90 and 120 seconds (ts), thereby allowing for the rapid and systematic sampling of the same storm system by all three platforms. A novel approach has been developed in which the changes in radar reflectivity over these short time intervals are related to the CMF. A significant amount of research has already been undertaken in preparation for the INCUS mission. These include: (1) conducting an extensive suite of large-domain, high spatial ( and temporal (30 second output) resolution Regional Atmospheric Modeling System (RAMS) and Weather Research and Forecasting (WRF) model simulations of convective storms within 15 different regions around the tropics; (2) tracking the modeled storm updrafts throughout their lifecycles with the cloud object tracking tool tobac; (3) processing the tracked storm updrafts using instrument forward models; and (4) analyzing ground-based radar observations obtained during the TRACER and ESCAPE field campaigns using newly-developed adaptive scanning techniques. This presentation will provide a brief description of the INCUS mission, as well as the modeling approaches being utilized. This will be followed by three specific highlights arising from this research. First, we will present statistics of the simulated CMF as a function of environment, storm morphology and storm lifetimes. Second, we will examine the temporal scales of updraft variability within the simulated storms. Finally, a proof of concept of the INCUS t approach relating changes in reflectivity to CMF using ground-based radar observations will be provided.