Atmospheric Profiling using GPS Radio Occultation over the Australian and Antarctic regions

Monday, 15 December 2014
Robert Norman1, John Le Marshall2, Brett A Carter1, Gottfried Kirchengast3, Simon Alexander4, Chuan-Sheng Wang5 and Kefei Zhang6, (1)RMIT University, Melbourne, VIC, Australia, (2)Bureau of Meteorology, Melbourne, Australia, (3)University of Graz, Graz, Austria, (4)Australian Antarctic Division, Kingston, Australia, (5)National Taipei University, New Taipei City, Taiwan, (6)RMIT Univ, Melbourne, Australia
The space-based Global Positioning System (GPS) Radio Occultation (RO) technique is ideal for sounding the Earth’s atmosphere. The GPS RO technique uses GPS receiver’s on-board Low Earth Orbit (LEO) satellites to measure the received radio signals from GPS satellites. Atmospheric parameter profiles of electron density, temperature, pressure and water vapor can then be obtained using well defined and robust retrieval processes. In this study atmospheric parameter profiles were retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) GPS RO measurements for the years 2007 to 2013 over Australia, Antarctica and their surrounding oceans. The yearly and bi-monthly tropopause height and temperature and climatic trends are investigated and co-located GPS RO and radiosonde atmospheric profiles are compared. Forecast skill scores with and without GPS RO data over the Australian and Antarctic regions are also assessed. Finally, a 3-D ray tracing technique was developed to investigate and improve the GPS RO technique. Simulated results from a tropospheric storm event on GPS RO signal propagation are investigated.