## 6 Discussion  
A small constellation of PRO observations is proposed as a means to obtain independent, observational verification of the convective transition behavior exhibited amongst  
Figure 10: **(a)** A P/E event from GLONASS occurring near 132022 UTC on 6 August 2018, from a simulated eight-satellite constellation. The location is the Tasman Sea between Australia and New Zealand. The associated PRO locations are numbered alongside the associated 200-km ray path, overlaid upon the ATMS 165 GHz TB from the NOAA-20 overpass at 140517 UTC. The orbit track of NOAA-20 is in the dashed black line. The descending orbit tracks of each of the receiving satellites are shown in the blue dashed lines (the leading satellite 1 is a solid line). **(b)** The distribution of events as a function of the maximum value of the distance from the receiving satellite subtrack and the endpoints of each ray path segment (left vertical axis). The solid red line represents the cumulative fraction (right vertical axis). The series of horizontal dashed lines indicate the equivalent cumulative fraction coverage that can be provided by passive MW sensors onboard current satellites (lowest line = GMI only, next line above = GMI + DMSP F-17 SSMIS..., highest line = all six sensors. The satellite and sensor names are as follows: DMSP = Defense Meteorological Satellite Program, NPP = National Polar Orbiting Partnership, JPSS = Joint Polar Satellite System, GPM = Global Precipitation Measurement. The Special Sensor Microwave Imager Sounder (SSMIS) is the passive MW sensor on the DMSP F-17 satellite, the Microwave Humidity Sounder (MHS) onboard the MetOp satellites, the GPM Microwave Imager (GMI) onboard the GPM satellite, and the Advanced Technology Microwave Sounder (ATMS) onboard the NPP and NOAA-20 satellites. multiple climate models and to assess this transition across multiple tropical regions. A resampling method was carried out to ascertain the required minimum number of observations using real-world observations from COSMIC RO and the GPM IMRG precipitation. The number of profile observations (N) required to discriminate the convective transition relationship by 1K tropospheric temperature was determined for each of five tropical oceanic regions. The results show that N is between 5000 to 30,000 observations, depending upon the oceanic region, with more observations required for the tropical Atlantic Ocean. Orbit simulations were carried out to determine how many joint precipitation and environment (P/E) events would result from a constellation of satellites, each separated by 2 min, defined where at least one PRO observation captures a heavy precipitation event and at least one other PRO observation captures the region outside of the heavy precipitation. The 30, 60, and 98-degree orbit inclinations provide slightly more data during this same period relative to the 45-degree inclination. An inclination of 30 degrees concentrates the observations in the preferred \(\pm\)20-degree tropical latitudes, and the 60-degree inclination is closer to the inclination of the GNSS satellites. While the 98-degree inclination provides the largest fraction of events exceeding 100-km separation distance, it would lack the capability to sample across the diurnal cycle. A 475-km altitude, 45-degree inclination baseline orbit represents a tradeoff between a slightly longer orbit duration with the advantage of a higher percentage of P/E events possessing the desired 50-150 km ray path separation distance. There is very little difference in these values if the orbit altitude is raised from 475 km to 600 km. With the ability of the RO observation to profile the temperature along each ray path, the separation of the first and last satellites provides an additional opportunity to estimate (one component of) the profile of the thermal wind (up to a constant of integration), in the geostrophic approximation. The thermal wind is the wind that flows parallel to the temperature gradient in the troposphere, away from the boundary layer where drag effects are significant.