Functional expansion of EAR and new observation techniques

该小组的主要目标是通过在最新技术和知识的基础上增加补充硬件和软件来扩大赤道大气雷达的能力。主要研究成果如下：1.我们研制了数字接收机子阵，它构成了一个多基地大气雷达一起。接收器阵列位于距地面1.1km的西面和南面。在2004年和2005年期间进行了两个系列的多基地观测，与传统的大气雷达相比，水平分辨率高得多。提出了一种新的自适应天线技术，该技术考虑了单元间的互耦。对细尺度大气风场进行了详细的分析，揭示了风场中异常强的局域性.从2003年起，连续4年零9个月以精细的时间分辨率监测气象站和京都大学之间卫星链路的信号强度，目的是观察雨衰减和对流层闪烁。本文将这些资料与卫星等外围观测设备的资料相结合，从不同的角度研究了赤道地区降水与大气湍流的相关特征。我们发现了一个非常独特的关系，这是不像在中纬度常见的较低的仰角较长的雨路径长度的性质。这一结果开启了在诸如Ku波段的高频处甚至在赤道区域的低仰角处的更高可用性的可能性。

The main objective of the group is to extend capabilities of the Equatorial Atmosphere Radar by adding supplementary hardware and software based on state-of-the-art technology and knowledge. Major achievements are summarized below:1. We developed digital receiver sub-arrays which constitute a multistatic atmospheric radar together with EAR. The receiver arrays are located at a distance of 1.1km in the west and the south directions from EAR. Two series of multistatic observations were carried out during 2004 and 2005, with a much higher horizontal resolutions compared with conventional atmospheric radars including EAR itself. Anew adaptive antenna technique, which takes into account of the mutual coupling between elements, was developed. Detailed analyses of the fine-scale atmospheric wind field have been made, revealing an unusually strong locality in the wind field.2. Signal intensity of the satellite link between the EAR site and Kyoto University was continuously monitored with a fine time resolution for 4 years 9 months from 2003 aiming to observe the rain attenuation and tropospheric scintillation. By combining these data with those from EAR and other peripheral observational equipments, we studied from various viewpoints the characteristics of the correlation between the rain and atmospheric turbulence at the equatorial region. We found a quite unique relation which is unlike the nature of longer rain path length at lower elevation angles common at the mid-latitude. This result opens the possibility of higher availability at high frequencies such as Ku band even at a low elevation angles at the equatorial region.