Austral High-Latitude Atmospheric Dynamics

南方高纬度大气动力学

• 批准号: 0229251
• 负责人: Gonzalo Hernandez
• 金额: $ 49.58万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0229251&HistoricalAwards=false
• 关键词: Austral; Latitude; Atmospheric; Dynamics

The study and determination of the latitudinal extent of the high-latitude zonal wavenumber one character mesospheric waves recently discovered (by the PI and others) near the South Pole are the most compelling and contemporary investigations in the polar aeronomy. These mesospheric waves have not been observed elsewhere, because at lower latitudes the spectrum is much richer in larger zonal wavenumbers of mesospheric waves that are seldom directly measured. As one approaches the very high latitudes near the rotational poles, the higher wavenumber oscillations observed at lower latitudes must either transform into the observed higher latitude wavenumber one oscillations, or else lose their energy to the mean flow and as heat dissipation. A unique opportunity to determine where and how this oscillation wavenumber mode transition region occurs is offered by the combined and simultaneous observation from the combined and presently-existing ground-based sites at South Pole and Arrival Heights, in conjunction with the TIMED satellite. This is a unique opportunity for investigating this problem, which is unlikely to happen again in the next ten to fifteen years. These investigations can only be carried out in Antarctica because the defining observations must be made from the rotational pole. Another special problem at high geomagnetic latitudes is the existence of persistent and predictable thermospheric vertical neutral winds, first reported by the PI from the South Pole observations. The existence of these vertical winds, likely to be caused by the divergence of the horizontal wind motions due to ion drag, has profound effects on the energetics of this region of the atmosphere. With the present solar activity maximum, a more complete characterization and investigation of these vertical winds becomes possible, because they are geomagnetic activity dependent. These investigations from South Pole, simultaneously with Arrival Heights and the observations of our Austral Alliance colleagues at Mawson and Davis stations, as well as those with the TIMED satellite will enlarge the geographic and geomagnetic coverage of this neutral vertical wind study. These investigations are possible because of the existing highly versatile ground-based Fabry-Perot spectrometers present at South Pole and Arrival Heights. These devices are able to simultaneously and independently address both of these investigations in the mesosphere and thermosphere. The instruments are capable of resolving the zonal wavenumber structure at mesospheric heights while, at the same time, gathering thermospheric neutral wind observations. In addition to the wind motion, the neutral atmosphere kinetic temperatures can simultaneously be observed. These latter measurements provide another powerful tool to understand the behavior and properties of the upper atmosphere at the very high latitudes. The polar aeronomy has become one of the four initiatives in the CEDAR atmospheric community addressing the Global Climate Change effects and their implications.

最近在南极附近发现的高纬度纬向波数一特征中间层波的纬度范围的研究和确定是极地航空学中最引人注目的当代研究。在其他地方没有观测到这些中间层波，因为在低纬度地区，中间层波的纬向波数要丰富得多，而这些波数很少被直接测量到。当一个人接近旋转极点附近的高纬度时，在低纬度观测到的高波数振荡必须转换成观测到的高纬度波数振荡，否则它们的能量就会被平均气流和热耗散掉。结合TIMED卫星，对南极点和到达高地现有地面站点进行联合和同时观测，提供了一个确定振荡波数模式过渡区域发生的位置和方式的独特机会。这是一个研究这个问题的独特机会，在未来的10到15年内不太可能再次发生。这些调查只能在南极洲进行，因为必须从旋转极进行决定性的观测。地磁高纬度地区的另一个特殊问题是存在持续和可预测的热层垂直中性风，这是PI在南极观测中首次报道的。这些垂直风的存在，很可能是由于离子阻力导致水平风运动发散造成的，对这一区域大气的能量学有深远的影响。随着目前太阳活动的最大，对这些垂直风的更完整的表征和研究成为可能，因为它们依赖于地磁活动。这些来自南极的调查，同时还有Mawson和Davis站的南极联盟同事的观测，以及TIMED卫星的观测，将扩大中性垂直风研究的地理和地磁覆盖范围。这些调查是可能的，因为现有的高度通用的地面法布里-珀罗光谱仪存在于南极和到达高地。这些设备能够同时和独立地解决这两个研究在中间层和热层。这些仪器能够解析中间层高度的纬向波数结构，同时收集热层中性风观测资料。除了风的运动外，还可以同时观测到中性大气的动力学温度。后一种测量方法为了解高纬度地区高层大气的行为和特性提供了另一种强有力的工具。极地航空学已经成为雪松大气社区解决全球气候变化影响及其影响的四个倡议之一。