Precipitable water vapour retrieval and analysis over Nigeria from ground and spaced-based GNSS observations

Abstract

The recent development of the Global Navigation Satellite Systems (GNSS) radio occultation (RO) technique has overcome many observational limitations inherent in conventional atmospheric sounding instruments and offers an exciting potential for meteorological and climatic researches. This study examines the practicability of GNSS RO technique in observing the atmosphere over Nigeria. A prominent climate change indicator (precipitable water vapour (PWV)) dominant in the upper-tropospheric and lower-stratospheric region were derived from COSMIC profiles (2013-2016) over Nigeria, the results revealed very prominent seasonal patterns in the GNSS RO derived PWV which precisely describes the atmosphere and seasons of the Nigerian region. The PWV agree with ground-based GNSS measurements in the range of -0.40 to 5.58 mm. With the expected improvements and follow on missions for the GNSS RO missions, the quantity and quality of occultation events will improve and lengthen in the Nigerian region thereby making the GNSS RO technique an indispensable tool for future operational atmospheric and climate research in Nigeria and the sub-Sahara Africa region at large.