Seasonal–latitudinal variations of PMC particle size from SME measurements for the northern 1983 season and SNOE measurements for the northern 2000 and southern 2000/2001 seasons

摘要: The ultraviolet spectrometers (UVS) on the solar mesosphere explorer (SME) and student nitric oxide (SNOE) measured scattered limb radiance at small large scattering angles from polar mesospheric clouds (PMCs). SME data are for northern summer hemisphere (NH) in 1983 1984. SNOE measurements NH 2000 southern (SH) 2000/2001 season. From this database, we deduce modal particle size angle asymmetry radiance. This quantity is determined as a function of time within PMC season, latitude, assuming several models depending adopted distribution shape. For assumed spherical particles with Gaussian width 14 nm, results show mode sizes that vary about 35 to 60 nm throughout under same assumption high latitudes grows systematically seasonal onset, 25 maximum 45 30 days after solstice. Lower similar dependence, but smaller sizes. SH display more complicated variability. Generally, variability cloud height anti-correlated seasons analyzed here. Particle generally than those NH, consistent bias brightness, previous satellite studies. These interpreted terms our understanding microphysics inter-hemispheric differences temperature dynamics. Our quantitative radius depend constant width. If varies latitude or time, calculated gradients would be different.