Publication Date:
2023-04-25
Description:
The radio occultation (RO) observations using multiple small satellites are expected not to be interrupted by a thick global cloud layer at about 48–70 km altitudes, and to enable frequent observations of the global vertical temperature distribution at 40–90 km altitudes. In this study, we focus on a phenomenon peculiar to Venus called “cold collar”, in which the polar region becomes warmer than the surrounding latitudes of 60–80 ° at 65 km altitude, and the Observation System Simulation Experiment (OSSE) is carried out assuming RO observation by satellites to be launched in the future. For the Venus assimilation system, “ALEDAS-V” (AFES LETKF Data Assimilation System for Venus) based on LETKF (Local Ensemble Transform Kalman Filter) is used. For the ensemble forecast, the Venus general circulation model “AFES-Venus” is used. For the pseudo-observation data, we use the temperature output of the IPSL Venus GCM (now called the Venus “Planetary Climate Model; PCM”) which represent ideal cold collar by radiative forcing. The temperature at 40–90 km altitudes corresponding to observation points obtained by orbit calculations is used as pseudo-observation data. As a result, while the experiment without assimilation (free run) cannot reproduce the cold collar at 67 km altitude, the RO OSSE reproduces it.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
