The airborne radio occultation (ARO) technique is based on precise measurements of Global Navigation Satellite Systems (GNSS) signal delays collected from a receiver onboard an aircraft from setting or rising GNSS satellites. The excess signal delay induced by propagation through the atmosphere can be converted to ray path refractive bending, which is further interpreted in terms of the refractive index, pressure, temperature, and moisture of a stratified atmosphere. ARO inherits the advantages of high vertical resolution and all-weather capability of spaceborne RO observations and has the additional advantage of continuous and dense sampling of the targeted storm area. The horizontal drift of the representative tangent point retrieval coordinate is an important characteristic of ARO profiles, which greatly extends the sensing area from underneath the aircraft to both sides of the flight track (up to 500 km). This ARO dataset complements the dropsonde, flight level meteorological, and Doppler radar observations by providing simultaneous measurements at no additional expendable cost in the reconnaissance flights.  

ARO observations were retrieved from the research aircraft (NOAA G-IV and AFRC WC-130s) deployed in the atmospheric river reconnaissance (AR Recon) campaigns. The research flights were conducted over a wide area over the Pacific, from the US West Coast to Guam.

The National Science Foundation sponsors the collection and processing of the ARO data via funding AGS-1642650 and AGS-1454125. The work was carried out in collaboration with CW3E/UCSD under the Atmospheric River Research Program, which is sponsored by the California Department of Water Resources and the US Army Corps of Engineers.

Identifier 	Aircraft_type	Agency	Tail#
N49T 		G-IVSP 		NOAA 	N49RF
N43T		WP-3  		NOAA   	N43RF
A0XT  		WC-130  	USAF	AF30X, X-0,1,...,9

More information about AR Recon. can be found here: https://cw3e.ucsd.edu/arrecon_data/

GNSS ARO data is also available at the Haase group: https://agsweb.ucsd.edu/gnss-aro/

The data format follows the standard spaceborne RO data format: https://cdaac-www.cosmic.ucar.edu/cdaac/doc/formats.html

Contact:

Jennifer Haase (jhaase@ucsd.edu)

Bing Cao (bic020@ucsd.edu)