Seasonal-scale atmospheric water cycle study using ground-based GPS receivers, Aeronet, and NWP models over the central High Atlas Mountains (Morocco)

Precipitable water vapor PWV is one of the major greenhouse gases. Monitoring Long-term variations in water vapor concentrations, which have a direct effect as a greenhouse gas and involve amplifying other feedbacks such as albedo and clouds. Monitoring of Precipitable water vapor on a continuous and steady basis has become possible over the recent decades due to the increased ground-based GPS receivers at global scale. However, the High Atlas Mountains remained a data-void zone until recently, when some ground-based GPS receiving stations were deployed to monitor geodynamic movements in the High Atlas belt. This paper investigates seasonal changes in precipitable water vapor, moisture transport, and precipitation over the central High Atlas using data from three ground-based GPS (FSSM, OUCA, and TIOU), Aeronet (AErosol RObotic NETwork) (Saada), GPCP, and NCEP reanalysis II over seven years (2016 to 2022). The ZTD (Zenith Tropospheric Delay) and the PWV results using the GipsyX/RTGx software show significantly better results than the Aeronet PWV measurements based on the acquired data. The reanalysis and observations are in good correlation regarding moisture transport and precipitation. Precipitable water increases in late summer, but precipitation peaks in winter and spring over the central high atlas.

Keywords: Precipitable water vapor, GPS, Zenith total delay, Aeronet, NCEP.