Atmospheric remote sensing using global navigation satellite systems: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2

Abstract

The world's first Global Positioning System Radio Occultation (GPS-RO) constellation, the joint Taiwan-U.S. Formosa Satellite No. 3 -Constellation Observing System for Meteorology, Ionosphere & Climate (FORMOSAT-3/COSMIC) has demonstrated the value of GPS-RO data in terrestrial weather, space weather, and climate study. The RO measurement technique was dubbed as "the most accurate and stable thermometer in space" because of its high accuracy, high vertical resolution, and high stability, which does not require calibration. Since its launch in 2006, FOR-MOSAT-3/COSMIC has accumulated over 6.9 million atmospheric and 4.6 million ionospheric RO sounding profiles. Encouraged by the success of FORMOSAT-3/ COSMIC, Taiwan's National Space Organization (NSPO, https://www.nspo.narl. org.tw/index.php?ln=en) and the U.S. National Oceanic and Atmospheric Administration (NOAA) started the planning