[A-CG36] 衛星による地球環境観測

[ACG36-P13] Sampling simulation of spaceborne precipitation radar

*高橋 暢宏¹ (1.名古屋大学　宇宙地球環境研究所)

キーワード：衛星軌道、全球サンプリング、日変化サンプリング

Precipitation radar observation from space started by Tropical Rainfall Measuring Mission (TRMM) launched in 1997 with the inclination angle of 35 degrees and 350 km of height followed by Global Precipitation Measurement (GPM) core satellite launched in 2014 with inclination angle of 65 degrees and 402.5 km of orbit altitude. When the satellite inclination and orbit height is determined, global sampling efficiency and diurnal sampling are evaluated. For the future precipitation measurement mission, several possibilities of the satellite orbit were discussed such as the inclination of higher than 65 degrees with the satellite altitude of about 450km and sun-synchronous orbit with the altitude of 450 km. In this study, global and diurnal sampling efficiency is evaluated for various inclination angle and satellite altitude. The swath width of the precipitation radar is assumed as 250 km. The satellite orbit is calculated by the method of Crisp et al. [1]. The global sampling is evaluated by counting the days for complete the sampling on the equator with the given swath width. The diurnal sampling is evaluated by counting the days to complete at least one time for all 1x1 degree boxes in the orbit range for 3-, 4-, and 6-hour intervals. The result indicates that the global sampling and diurnal sampling are similar height and inclination dependency. Also, global sampling maps against the observation days (e.g., 1, 1.5 and 2 month) are shown.


Reference

[1] Crisp, N. H., Livadiotti, S., and Roberts, P. C. E., “A Semi-Analytical Method for Calculating Revisit Time for Satellite Constellations with Discontinuous Coverage”, arXiv e-prints, 2018.