Estimation of the Tropical Cyclone Diurnal Cycle Using Simulated Observations from the TROPICS NASA Earth Venture Mission

Recent studies suggest a possible link between the diurnal cycle of radiation and structural changes in the lifetime of a tropical cyclone (TC). A coherent diurnal signal exists in the TC cirrus canopy, exhibiting radial rings (“pulses”) of anomalously-cold cloud tops which propagate from the core of the storm towards the outer environment throughout the day. Corresponding to this signal, numerical studies demonstrate enhanced storm convection, precipitation, and changes in storm intensity. Observing these relationships in real-time, however, is a challenge with current observing systems, since storm information is limited to the number of daily satellite overpasses and mainly the evolution of the cloud tops. The advent of the NASA Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) Earth Venture Mission presents an opportunity to address these limitations through measurement of both the inner-core and environmental conditions of TCs with an unprecedented combination of horizontal and temporal resolution. This presentation explores the potential of TROPICS to observe changes due to the daily cycle of radiation, and to relate these changes to hurricane structure and intensity. An idealized, three-dimensional numerical simulation of a TC is produced in Cloud Model 1 (CM1). Synthetic Level-2 TROPICS data products are generated from CM1 data using an orbital simulation of the satellite constellation to calculate the overpasses, and by spatially blurring the CM1 data to TROPICS resolution. Hourly composites of CM1 and proxy-TROPICS temperature and moisture profiles are analyzed to evaluate the thermodynamic environment of the TC diurnal cycle, and comparison of the CM1 results to the TROPICS proxy data investigate the ability of TROPICS to resolve the TC diurnal pulse. Characteristics of the thermodynamic environment of TC diurnal cycle are presented, and further aspects of observing the TC diurnal cycle using TROPICS, including estimation of rain rates and corresponding changes in storm intensity, are explored.