Correlative Antarctic and Inter-Hemispheric Dynamics Studies Using the MF Radar at Rothera

This proposal is to continue operation and scientific studies with the middle-frequency (MF, 1-30 MHz) mesospheric radar deployed at the British Antarctic station Rothera in 1996. This system is now a key site in the Antarctic MF radar chain near 68 deg. S, which includes also MF radars at Syowa (Japan) and Davis (Australia) stations. This radar comprises the winds component of a developing instrument suite for the mesosphere-thermosphere (MLT) studies at Rothera - a focus of the new BAS 5-year plan, which also includes the Fe temperature lidar (formerly at South Pole) and the mesopause airglow imager for gravity wave studies (formerly at Halley). The Rothera MF radar has just had its antennas and electronics upgraded to achieve better signal-to-noise ratio and more continuous measurements in height and time. The main focus of the proposed research is to extend the knowledge of the polar mesosphere dynamics. The instrument suite at Rothera is ideally positioned for correlative interhemispheric studies with northern hemisphere sites at Poker Flat, Alaska (65 deg. N) and ALOMAR, Norway (69 deg. N) having comparable instrumentation. Further research efforts performed with continued funding will focus on: (1) multi-instrument collaborative studies at Rothera to quantify as fully as possible the dynamics, structure, and variability of the MLT at that location, (2) multi-site (and multi-instrument) studies of large-scale dynamics and variability in the Antarctic (together with the radars and other instrumentation at Davis and Syowa), and (3) interhemispheric studies employing instruments (e.g., the Na resonance lidar and MF radar) at Poker Flat and ALOMAR. It is expected that these studies will lead to a more detailed understanding of (1) mean, tidal, and planetary wave structures at polar latitudes, (2) seasonal, inter-annual, and short-term variability of these structures, (3) hemispheric differences in the tidal and planetary wave structures arising from different source and wave interaction conditions, and (4) the relative influences of gravity waves in the two hemispheres. Such studies will also contribute more generally to an increased awareness of the role of high-latitude processes in global atmospheric dynamics and variability.本提案旨在延续1996年部署于英国南极罗瑟拉（Rothera）站的中频（MF，1-30 MHz）中层大气雷达的运行与科学研究工作。该系统目前是南纬68度附近南极中频雷达链的关键站点之一，该雷达链还包含位于日本昭和（Syowa）站与澳大利亚戴维斯（Davis）站的中频雷达。 此雷达隶属于罗瑟拉站正在搭建的中层大气-热层（MLT）研究仪器套件中的风场探测分系统——这也是英国南极调查局（British Antarctic Survey, BAS）新五年规划的核心方向之一，该套件还包括原部署于南极点的铁温度激光雷达，以及原设于哈雷（Halley）站的中层顶重力波研究用夜辉成像仪。 罗瑟拉站中频雷达近期完成了天线与电子系统升级，以获得更高的信噪比，并实现更高时空分辨率的连续观测。 本次拟开展研究的核心目标是深化对极地中层大气动力学的认知。罗瑟拉站的仪器套件具备理想的跨半球协同研究条件，可与北半球的阿拉斯加州扑克平地（Poker Flat，北纬65度）、挪威ALOMAR站（北纬69度）等配备同类仪器的站点开展配套研究。 在获得持续资助后，后续研究将聚焦于以下三个方向：(1) 在罗瑟拉站开展多仪器协同观测研究，以尽可能全面地量化该区域中层大气-热层的动力学过程、结构特征与变化特性；(2) 依托多站点（多仪器）开展南极区域大尺度动力学与变化特性研究（联合戴维斯站与昭和站的雷达及其他观测设备）；(3) 结合阿拉斯加扑克平地站与挪威ALOMAR站的观测仪器（如钠共振激光雷达（Na resonance lidar）与中频雷达）开展跨半球对比研究。 预计上述研究将帮助我们更深入地理解：(1) 极地纬度带的平均流、潮汐波与行星波结构；(2) 这些结构的季节、年际与短期变化特性；(3) 因源区与波相互作用条件差异导致的潮汐波与行星波结构的半球差异；(4) 两个半球中重力波的相对影响。此类研究还将进一步推动学界对高纬度过程在全球大气动力学与变化中所发挥作用的认知深化。