Advancing Spaceborne Observations of Atmospheric Convection: Addressing Sampling Challenges with the WIVERN Mission

Convective storms occur globally, especially over the tropical oceans, and span a wide range of scales influenced by diverse environmental factors. Advancing our understanding of convective storms requires unraveling the complex relationships between convective dynamics, microphysical processes, and environmental forcing. These critical relationships demand statistically significant observations to inform model development and enable robust verification.

Satellite observations along with reanalysis have provided a wealth of information on the relationship between the environment and the mesoscale organization of convection, however, no such comprehensive global dataset exist for convective dynamics. Key attributes of such a dataset (e.g. capturing updrafts, mass fluxes, and storm three-dimensional structure) remain undefined, particularly for exploring the relationship between convective dynamics and the near-storm environment.

In this research, we use kilometer-scale simulations from diverse tropical oceanic basins, to explore the attributes of a global convective dynamics dataset, including sampling size, sensitivity to updraft magnitude, and associated uncertainties. By under-sampling the model, we define the minimum sampling size required for a statistically significant dataset capable of mapping the relationship between updrafts and environmental conditions. The analysis will allow us to specify the sampling characteristics needed for a satellite-based observing system to provide such data globally.

Our findings support the case for the Wind Velocity Radar Nephoscope (WIVERN) mission which is one of two candidate missions currently in Phase A studies for potential selection as the Earth Explorer 11 mission under the European Space Agency’s FutureEO programme.  WIVERN proposes a conically scanning Doppler radar in polar orbit, offering a swath of approximately 800 km at a viewing angle of 42^o. We demonstrate how these measurements, offered by WIVERN’s unprecedented spatiotemporal sampling, facilitate the reconstruction of vertical motions and the three-dimensional vertical distribution of ice mass in mesoscale systems. Additionally, we examine the robustness of the relationship between the convective updrafts dataset and the environment, focusing on the sensitivity to the updraft magnitude detection limit.