The Hemispheric Difference Of The Polar Mesospheric Cloud,Based On The Aeronomy Of Ice In The Mesosphere Satellite

Polar mesospheric clouds occur in the high latitudes of the Earth’s summer mesosphere.In recent years,the formation and changes of polar mesospheric clouds have received extensive attention.With the development of ground-based radar and satellite observation technology,it has been confirmed that polar mesospheric clouds are formed by the accumulation of ice particles in the mesosphere,and the formation of ice particles is affected by the propagation and dissipation of gravity waves at high altitude.In this study,the gravity wave energy density,ice water content,particle radius and cloud albedo data during the polar mesospheric clouds season were extracted,based on the observation data of SOFIE and CIPS instruments onboard AIM satellite during the period 2007-2014 in the Northern Hemisphere(NH)and 2007-2008-2014/2015 in the Southern hemisphere(SH).By comparison between hemispheres,the influence of gravity wave(GW)activity on the formation and variation of noctilucent clouds was analyzed.The results show that:In the NH,the IWC varies from 92.41to 171.332)/6)8)~2;The radius of the PMC is 42.3517±0.9263 nm;The latitudinal distribution of the PMC ranges from 75°to 85°and lasts 20-35 days;The GW energy density is on average 39.6±6.6/6)2).The GW flux generally starts to increase significantly around the summer solstice during the eight PMC seasons in the NH.In 6/8 of these seasons,e.g.,in2007,2008,2009,2010,2013,and 2014,the IWC content is positively correlated with the variation of GW.During these six seasons,when the GW activity is enhanced to reach the maximum,the IWC will start to increase and reach the peak after 0–23 days.In comparison,the IWC in the eight PMC seasons in the Southern Hemisphere(SH)ranges from 73.27 to165.222)/6)8)~2;The mean particle size is 42.37±1.17 nm for the SH.The PMCs range more widely,with latitudes from 70°to 85°and a duration of 25-45 days;The GW energy density is43.65±4.56/6)2),and the GW peaks around 55 days after the solstice.The timing of PMC appearance also varies,with the IWC starting to grow 20 days after the solstice and the GW increasing to peak 55 days after the solstice.In particular,the IWC starts even earlier than the solstice in the seasons of 2012/2013 and 2013/2014.