17:15 〜 19:15
[PEM12-P01] Investigation on latitudinal variation and north-south difference in polar mesospheric cloud heights based on 9-year PMC data by Himawari-8/9
キーワード：極中間圏雲、ひまわり8/9号
Polar mesospheric clouds (PMCs) consist of water ice particles that can be produced in the summer at the mesopause region (80-85 km) in the Earth's atmosphere. The formation and dissipation of water ice particles would be generally controlled by water vapor supersaturation conditions, which could be mainly determined by temperature and water vapor in the background atmosphere. Therefore, investigations into PMC characteristics would be an effective way to understand the dynamical and chemical processes in the mesospheric heights.
PMC studies have been performed based on many optical observations from ground and space. Among these, several studies focused on PMC heights. From the lidar observations, it is reported that the PMC heights observed at Rothera (67.5ºS) were approximately 1.3 km lower than those observed at the South Pole (90ºS), suggesting that the PMC heights would be higher at higher latitudes. In addition, observational data from several lidars and imagers showed a north-south difference in the PMC height, in which PMCs in the Southern Hemisphere were approximately 1 km higher than those at the same latitudes in the Northern Hemisphere. Model calculations showed that water vapor supersaturation heights at the South Pole (90ºS) were approximately 2-3 km higher than those at the North Pole (90ºN), and these results were suggested as the main reason for the north-south difference in the PMC height.
In this study, we have analyzed 9-year PMC data obtained from the Geostationary Earth Orbit (GEO) satellites, Himawari-8/9. Himawari-8/9 PMC observations can provide PMC height data with wide latitudinal coverages in both hemispheres. Thus, it would contribute to a more comprehensive understanding of latitudinal variation and north-south difference in polar mesospheric cloud heights. As a result of the data analysis, it is found that the observed PMC heights in the Southern Hemisphere were approximately 1.5 km higher than those in the Northern Hemisphere. In both hemispheres, the observed PMC heights tended to be higher at higher latitudes. These results would be consistent with the previous studies. In the presentation, we will show these results and discuss relationships with water vapor supersaturation heights, which can be calculated from a simple PMC model with temperature and water vapor data obtained from the Microwave Limb Sounder (MLS) onboard the Aura satellite.
PMC studies have been performed based on many optical observations from ground and space. Among these, several studies focused on PMC heights. From the lidar observations, it is reported that the PMC heights observed at Rothera (67.5ºS) were approximately 1.3 km lower than those observed at the South Pole (90ºS), suggesting that the PMC heights would be higher at higher latitudes. In addition, observational data from several lidars and imagers showed a north-south difference in the PMC height, in which PMCs in the Southern Hemisphere were approximately 1 km higher than those at the same latitudes in the Northern Hemisphere. Model calculations showed that water vapor supersaturation heights at the South Pole (90ºS) were approximately 2-3 km higher than those at the North Pole (90ºN), and these results were suggested as the main reason for the north-south difference in the PMC height.
In this study, we have analyzed 9-year PMC data obtained from the Geostationary Earth Orbit (GEO) satellites, Himawari-8/9. Himawari-8/9 PMC observations can provide PMC height data with wide latitudinal coverages in both hemispheres. Thus, it would contribute to a more comprehensive understanding of latitudinal variation and north-south difference in polar mesospheric cloud heights. As a result of the data analysis, it is found that the observed PMC heights in the Southern Hemisphere were approximately 1.5 km higher than those in the Northern Hemisphere. In both hemispheres, the observed PMC heights tended to be higher at higher latitudes. These results would be consistent with the previous studies. In the presentation, we will show these results and discuss relationships with water vapor supersaturation heights, which can be calculated from a simple PMC model with temperature and water vapor data obtained from the Microwave Limb Sounder (MLS) onboard the Aura satellite.