中国廊坊(39.4°N,116.7°E)中间层和低热层潮汐的季节变化

Seasonal variations of wind tides in mesosphere and lower thermosphere over Langfang,China(39.4°N,116.7°E)

本文利用中国廊坊站(39.4°N,116.7°E)流星雷达在2012年4月1日至2013年3月31日期间的水平风场观测数据,分析了廊坊上空中间层和低热层(MLT,80~100 km)大气纬向风、经向风潮汐的季节变化特征.研究表明:廊坊MLT区域周日潮汐和半日潮汐波动比较显著,有明显的季节变化特征.周日潮汐振幅在88 km以下为半年变化,极大值位于2-3月和10月,极小值位于冬、夏季;在88 km以上为周年变化,振幅冬末春初最强,夏季最弱.周日潮汐相位在秋、冬季比春、夏季提前.半日潮汐主要呈现半年变化,在5月和9月最强,冬、夏季最弱.半日潮汐相位在春、夏季比秋、冬季提前.此外,廊坊风场潮汐的观测结果与WACCM4模式模拟结果进行比较,结果表明两者的主要特征相似,在细节上有显著区别.与40°N附近其他站点风场潮汐观测结果的比较结果表明中纬度MLT风场潮汐有显著的随经度变化特性.

This study uses the wind data from the observation of China Langfang（39.4° N,116.7° E） Meteor Radar（MR） during the 1 April 2012 to 31 March 2013 to investigate the seasonal variations of tides of the Mesospheric and Lower Thermospheric（MLT） winds within 80~100 km altitude regions.The results show that both diurnal and semidiurnal tide dominates the zonal and meridional wind,having obviously seasonal variations.A semiannual variation is found in diurnal tide below 88 km with maxima in February-March/October and minima at summer and winter,whereas the diurnal tide above 88 km has annual variation with amplitude peaking in February at 92 km,with the zonal and meridional component is 42 m/s and 38 m/s.The phase of diurnal tide in autumn and winter leads that in spring and summer.The semidiurnal tide has semiannual variation that strong in May and September and weak at summer and winter.The phase of semidiurnal tide in spring and summer leads that in autumn and winter.WACCM4（Whole Atmosphere Community Climate Model,version 4） can reproduce the seasonal variation of tides,but underestimate the amplitudes.Moreover,the comparison between the tides over Langfang with other stations at about 40° N latitude indicts the tides variation depending on longitude.