Aqua/AMSR-E L3 18.7GHz-H Mean for Brightness Temperature (1-Day, 0.25 deg)

Aqua/AMSR-E L3 18.7GHz-H Mean for Brightness Temperature (1-Day, 0.25 deg) dataset is obtained from the AMSR-E sensor onboard Aqua and produced by the Japan Aerospace Exploration Agency (JAXA). Aqua of NASA was launched on May 4th, 2002 in Sun-synchronous sub-recurrent Orbit. Aqua observes various kinds of physical phenomena related to water and energy circulation from space. Aqua data promoted the research activities for interactions between the atmosphere, oceans and lands, and their effects on climate changes. AMSR-E scans the Earth's surface by mechanically rotating the antenna and acquires radiance data of the Earth's surface. Each frequency band is monitored by vertical and horizontal polarized wave. It conically scans and keeps an angle of incidence on the earth surface (a nominal of 55 degrees) and accomplishes a swath width of about 1450 km. The AMSR-E reached its limit to maintain the antenna rotation speed necessary for regular observations, and the AMSR-E restarted its observation in slow rotation mode (2 rotations per minute) on December 4, 2012. However, the AMSR-E reached its limit to maintain the antenna rotation speed necessary for slow rotation mode and it automatically halted its observation and rotation on December 4, 2015. Level 3 data inputs level 1B and level 2 data and projected to the map in accordance with the specified projection technique (Equi-Rectangular (EQR) or Polar Stereographic (PS)), and then averaged temporally and spatially. These statistical values are computed for observation data on ascending orbit and descending orbit respectively. This product includes daily mean Brightness Temperature at 18.7GHz horizontal polarized wave. Values that are calculated from sensor counts and are proportional to the power of observed electromagnetic wave. Unit is Kelvin. The provided format is HDF4. The statistical period is 1 day. The current version of the product is "Version 3". The projection method is EQR and PS. The generation unit is global.

Aqua/AMSR-E L3级18.7GHz水平极化亮温日均值（0.25°分辨率）数据集由搭载于Aqua卫星的高级微波扫描辐射计地球观测系统（Advanced Microwave Scanning Radiometer - Earth Observing System，AMSR-E）采集，日本宇宙航空研究开发机构（Japan Aerospace Exploration Agency，JAXA）制作。Aqua卫星由美国国家航空航天局（National Aeronautics and Space Administration，NASA）于2002年5月4日送入太阳同步亚回归轨道。该卫星通过太空观测与水循环、能量循环相关的多种物理现象，其数据推动了大气、海洋与陆地间相互作用及其对气候变化影响的研究工作。AMSR-E通过机械旋转天线扫描地球表面，获取地球表面的辐射数据；每个频段均采用垂直极化与水平极化波探测，采用圆锥扫描方式，与地球表面的入射角固定为标称值55度，幅宽约1450千米。AMSR-E曾因无法维持常规观测所需的天线转速而暂停观测，并于2012年12月4日切换至慢速旋转模式（每分钟2转）恢复观测，但在2015年12月4日，其再次因无法维持慢速旋转模式所需的天线转速，自动终止了观测与天线旋转动作。L3级数据以1B级和2级数据为输入，按照指定投影技术（等距圆柱投影（Equi-Rectangular，EQR）或极射赤平投影（Polar Stereographic，PS））投影至地图坐标系，随后进行时空平均处理。该统计值分别针对升轨与降轨的观测数据计算得到。本产品包含18.7GHz水平极化波段的日平均亮温，该亮温值由传感器计数转换得到，与观测到的电磁波功率成正比，单位为开尔文。数据提供格式为HDF4，统计周期为1日，当前版本为"Version 3"，投影方式包括EQR与PS，生成范围为全球。