Vertical Gradients of Refractivity in the Mesosphere and Atmosphere Retrieved from GPS/MET and CHAMP Radio Occultation Data

Abstract

Fine structures in the vertical gradient of the electron density have been retrieved by means of analysis of the amplitude of radio occultation (RO) data in sporadic E-layers (heights interval 85-110 km). Maximum values of the positive gradients 45.10(9), 48.10(9), 25.10(9), 29.10(9) [m(-3)km(-1)] are located at levels 92, 105 km (GPS/MET event 0393) and 93.5, 100 kin (GPS/MET event 0583). Variations in the vertical gradient of refractivity in the atmosphere have been found for CHAMP RO event 09. Vertical gradient of refractivity changes in interval +/- 5 N-units/km (height interval 3-10 km) and +/- 0.5 N-units/km between levels 11 and 18 km. Vertical distribution of temperature gradient between level 3-37 km reveals features at height 4-6, 9-10 km with positive values of about 6-9 degreesK/km. Amplitude RO data analysis may be used for detailed retrieving vertical gradients of refractivity and temperature in the atmosphere and electron density in the lower ionosphere during CHAMP and future COSMIC RO missions.