Exploring Earth's atmosphere with radio occultation: contributions to weather, climate and space weather

Abstract

Abstract. The launch of the proof-of-concept mission GPS/MET (Global Positioning System/Meteorology) in 1995 began a revolution in profiling Earth's atmosphere through radio occultation (RO). GPS/MET; subsequent single-satellite missions CHAMP (CHAllenging Minisatellite Payload), SAC-C (Satellite de Aplicaciones Cientificas-C), GRACE (Gravity Recovery and Climate Experiment), METOP-A, and TerraSAR-X (Beyerle et al., 2010); and the six-satellite constellation, FORMOSAT-3/COSMIC (Formosa Satellite mission #3/Constellation Observing System for Meteorology, Ionosphere, and Climate) have proven the theoretical capabilities of RO to provide accurate and precise profiles of electron density in the ionosphere and refractivity, containing information on temperature and water vapor, in the stratosphere and troposphere. This paper summarizes results from these RO missions and the applications of RO observations to atmospheric research and operational weather analysis and prediction.

The Equatorial El Niño-Southern Oscillation Signatures Observed by FORMOSAT-3/COSMIC from July 2006 to January 2012

“…Using the precise orbit information of Low Earth Orbit (LEO) and GPS satellites, F3/C provides approximately 1000 -2500 RO soundings per day, distributed nearly uniformly around the globe. The F3/C RO bending angle and refractivity profiles contribute significantly to global atmospheric models and data assimilation systems (see the papers list in Anthes et al 2008 andAnthes 2011). With the six micro-satellites, F3/C provides much higher temporal and spatial resolution measurements lower than 40 km, which also allows us to study the atmospheric structure and dynamics in greater detail (Scherllin-Pirscher et al 2012).…”

“…bom.gov.au/climate/enso). Based on the SOI and Niño 3.4 index published by NOAA, in the FORMOSAT-3/COSMIC (F3/C) observation period: /2010, 2010/2011 are ENSO cold events; and 2008/2009 is an ENSO neutral period (neither El Niño nor La Niña); while 2009/2010 is the strongest ENSO warm event (Lee and McPhaden 2010;Su and Jiang 2013) in the past 12 years (since 1997/1998). Gage and Reid (1987) used radiosonde data at Koror, Republic of Palau, (7.33°N, 134.48°E) and Majuro, Marshall Is., (7.08°N, 171.38°E) to study longitudinal variations in tropical tropopause properties in relation to tropical convection and ENSO events.…”

Tropical temperature variability and Kelvin-wave activity in the UTLS from GPS RO measurements

“…GPS RO temperature retrievals are characterized by high vertical resolution (from about 100 m in the troposphere (Gorbunov et al, 2004) to about 1.5 km in the stratosphere (Kursinski et al, 1997)) and high accuracy (0.7 to 1 K between 8 and 25 km; Scherllin-Pirscher et al, 2011b). Since measurements can be obtained during the day and at night as well as in nearly any meteorological weather conditions, data are available with good coverage in space and time (Anthes, 2011).…”

“…The record consists of 13 years of data extending from January 2002 to December 2014. It includes measurements from CHAMP (2002CHAMP ( to 2008, GRACE (2007GRACE ( to 2014, SAC-C (2006to 2011), and Formosat-3/COSMIC (2006to 2014. Due to the RO measurement principle, these data from different satellites can be merged into a single observational record without the need for explicit calibration or homogenization Schreiner et al, 2007;.…”

The FengYun-3C radio occultation sounder GNOS: a review of the mission and its early results and science applications

“…These missions have demonstrated the unique properties of the GNSS RO technique, such as high vertical resolution, high accuracy, all-weather capability and global coverage (Ware et al, 1996;Gorbunov et al, 1996;Rocken et al, 1997;Leroy, 1997;Steiner et al, 1999), and long-term stability and consistency of different RO mission observations (Foelsche et al, , 2011. Therefore, GNSS RO data products (i.e., bending angle, refractivity, temperature, 10 pressure, water vapor, and ionospheric electron density profiles) have been widely used for numerical weather prediction (NWP) (e.g., Healy and Eyre, 2000;Healy and Thepaut, 2006;Aparicio and Deblonde, 2008;Cucurull and Derber, 2008;Poli et al, 2008;Huang et al, 2010;Le Marshall et al, 2010;Harnisch et al, 2013), global climate monitoring (GCM) (e.g., Steiner et al, 2001Steiner et al, , 2009Steiner et al, , 2013Schmidt et al, 2005Schmidt et al, , 2008Schmidt et al, , 2010Loescher 15 and Kirchengast, 2008;Ho et al, 2009Ho et al, , 2012Foelsche et al, 2011a;Lackner et al, 2011) and space weather research (SWR) (Anthes, 2011;Anthes et al, 2008;Arras et al, 2008;Brahmanandam et al, 2012;Pi et al, 1997;Wickert, 2004;Yue et al, 2015).…”