Climatology of mesopause region temperature, zonal wind, and meridional wind over Fort Collins, Colorado (41°N, 105°W), and comparison with model simulations
Climatology of mesopause region temperature, zonal wind, and meridional wind over Fort Collins, Colorado (41°N, 105°W), and comparison with model simulations
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DOI：
10.1029/2007jd008697
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发表时间：
2008-02
影响因子：
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通讯作者：
T. Yuan;C. She;D. Krueger;F. Sassi;R. Garcia;R. Roble;Han L. Liu;H. Schmidt
中科院分区：
文献类型：
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作者：
T. Yuan;C. She;D. Krueger;F. Sassi;R. Garcia;R. Roble;Han L. Liu;H. Schmidt
[1] 2002年5月至2006年4月期间，在科罗拉多州柯林斯堡（北纬41°，西经105°）的科罗拉多州立大学纳激光雷达设施完成了对中层顶区域温度和水平风的多次连续观测，每次观测持续时间超过24小时（称为全日周期观测）。合并数据集由按月分组的 120 个全日周期观测组成，其中 4 月最少有 7 个周期，8 月最多有 18 个周期。分析每个月的数据集以推断平均值和潮汐周期扰动。去除潮汐信号后，月平均值用于研究中层顶区域温度、纬向风和经向风的季节变化。结果与我们目前对中纬度中层顶区域平均温度和风结构的认识在定性上一致，在84 km处观测到夏季中层顶温度为167 K，在94 km处夏季东向纬向风峰值为48 m/s，在～95 km处冬季纬向风反转，在86 km处夏季（极）到冬季（极）经向流峰值为17 m/s。将观测到的温度、纬向风和经向风的平均状态与当前三个大气环流模型的预测进行比较，即具有两种不同重力波场模拟的整个大气群落气候模型版本3（WACCM3）、中性和电离大气汉堡模型（HAMMONIA）以及2003年热层-电离层-中层-电动环流模型的模拟（时间-GCM）。虽然观察和模型预测之间存在总体一致性，但模型预测和观察之间以及不同模型的预测之间存在差异。具体来说，WACCM3 预测的夏季中层顶高度分别比两个 WACCM 运行 HAMMONIA 和 TIME-GCM 低 3 km、8 km、3 km 和 1 km，对应的温度分别为 169 K、170 K、158 K 和 161 K。模型预测夏季东向风峰值在 102 km 处为 71 m/s，在 48 84 km 时为 m/s，93 km 时为 75 m/s，94 km 时为 29 m/s，顺序相同。还比较了冬季纬向风反转的高度和极地经向流的季节性不对称性，并讨论了全日周期观测对于确定平均状态的重要性。
[1] Between May 2002 and April 2006, many continuous observations of mesopause region temperature and horizontal wind, each lasting longer than 24 h (termed full-diurnal-cycle observations), were completed at the Colorado State University Na Lidar Facility in Fort Collins, Colorado (41°N, 105°W). The combined data set consists of 120 full-diurnal-cycle observations binned on a monthly basis, with a minimum of 7 cycles in April and a maximum of 18 cycles in August. Each monthly data set was analyzed to deduce mean values and tidal period perturbations. After removal of tidal signals, monthly mean values are used for the study of seasonal variations in mesopause region temperature, zonal and meridional winds. The results are in qualitative agreement with our current understanding of mean temperature and wind structures in the midlatitude mesopause region with an observed summer mesopause of 167 K at 84 km, summer peak eastward zonal wind of 48 m/s at 94 km, winter zonal wind reversal at ∼95 km, and peak summer (pole) to winter (pole) meridional flow of 17 m/s at 86 km. The observed mean state in temperature, zonal and meridional winds are compared with the predictions of three current general circulation models, i.e., the Whole Atmosphere Community Climate Model version 3 (WACCM3) with two different simulations of gravity wavefields, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), and the 2003 simulation of the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM). While general agreement is found between observation and model predictions, there exist discrepancies between model prediction and observation, as well as among predictions from different models. Specifically, the predicted summer mesopause altitude is lower by 3 km, 8 km, 3 km, and 1 km for WACCM3 the two WACCM runs, HAMMONIA, and TIME-GCM, respectively, and the corresponding temperatures are 169 K, 170 K, 158 K, and 161 K. The model predicted summer eastward zonal wind peaks to 71 m/s at 102 km, to 48 m/s at 84 km, to 75 m/s at 93 km, and to 29 m/s at 94 km, in the same order. The altitude of the winter zonal wind reversal and seasonal asymmetry of the pole-to-pole meridional flow are also compared, and the importance of full-diurnal-cycle observations for the determination of mean states is discussed.