Processing Strategy for Near Real Time GPS Precipitable Water Vapor Retrieval

• Main Authors: Jeonho Naek, Jae-Won Lee, Byung-Kyu Choi, Jungho Cho
• Format: Article
• Language: English
• Published: Korean Space Science Society (KSSS) 2007-12-01
• Series: Journal of Astronomy and Space Sciences
• Subjects: GPS; PWV retrieval; near real time; sliding window
• Online Access: http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2007/v24n4/OJOOBS_2007_v24n4_275.pdf
• ISSN: 2093-5587; 2093-1409

For the application to the numerical weather prediction (NWP) in active service, it is necessary to ensure that the GPS precipitable water vapor (PWV) data has less than one hour latency and three millimeter accuracy. The comparison and the verification between the daily products from GPS measurement by using the IGS final ephemeris and the conventional meteorological observation has been done in domestic researches. In case of using IGS final ephemeris, GPS measurements can be only post processed in daily basis in three weeks after the observation. Thus this method cannot be applied to any near real-time data processing. In this paper, a GPS data processing method to produce the PWV output with three mm accuracy and one hour latency for the data assimilation in NWP has been planned. For our new data processing strategy, IGS ultra-rapid ephemeris and the sliding window technique are applied. And the results from the new strategy has been verified. The GPS measurements during the first 10 days of January, April, July and October were processed. The results from the observations at Sokcho, where the GPS and radiosonde were collocated, were compared. As the results, a data processing strategy with 0.8 mm of mean bias and 1.7 mm of standard deviation in three minutes forty-three seconds has been established.