Planetary boundary layer height retrieval using GNSS Radio Occultation over Egypt

Abstract

Global Navigation Satellite System (GNSS) Radio Occultation (RO) is an excellent remote sensing technique for sounding the atmosphere. GNSS satellites send signals through the atmosphere of the Earth, and a GNSS receiver mounted on a Low Earth Orbit (LEO) satellite receives them. Through GNSS RO, refractivity will be estimated, which is considered the main parameter in the determination of planetary boundary layer height (PBLH). This paper presents the use of GNSS RO for the detection of PBLH over Egypt.PBLH is an important parameter to characterize the lower troposphere and plays a significant role in air quality adjustment. GNSS RO can be used to detect PBLH because of its high spatial and temporal coverage. The estimated PBLHs from GNSS RO are compared with PBLH estimated from the European Centre for Medium-range Weather Forecasts (ECMWF) model. This paper introduces the variation of the PBLH over Egypt for the period from 2006 to 2019. GNSS RO PBLH distribution is consistent with that of ECMWF. The maximum value of PBLH (4.75 km) occurs in the summer and its minimum value (0.43 km) occurs in the winter. PBLH shows higher values around 15:00 LT (late afternoon) in Egypt. Our results show that GNSS RO is a promising technique for sensing the atmosphere's dynamics.