Aqua/AMSR-E L3 Ice Concentration (1-Day, 0.25 deg)

Aqua/AMSR-E L3 Ice Concentration (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 Ice Concentration (IC). Ice concentrations are derived mainly from 37 GHz and 19 GHz channels, as in the Bootstrap technique, but makes use of emissivity instead of brightness temperatures to minimizes errors associated with spatial changes in sea ice temperatures. The ice temperature is in the end normalized using the derived ice concentration value, for it to represent temperature only of the sea ice part of the satellite observational area. The physical quantity unit is %. The provided format is HDF4. The statistical period is 1 day. The spatial resolution is 0.25 deg. The current version of the product is "Version 7". The projection method is PS. The generation unit is global.

Aqua/AMSR-E L3级海冰浓度（1日统计、0.25度空间分辨率）数据集由搭载于Aqua卫星的AMSR-E传感器获取，由日本宇宙航空研究开发机构（Japan Aerospace Exploration Agency, JAXA）制作。美国国家航空航天局（National Aeronautics and Space Administration, NASA）的Aqua卫星于2002年5月4日发射至太阳同步次回归轨道，从太空观测与水循环、能量循环相关的各类物理现象，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相关研究。AMSR-E通过天线机械旋转扫描地球表面，获取地球表面的辐亮度数据。各频段均通过垂直极化与水平极化波进行信号监测，采用圆锥扫描模式，与地表保持固定入射角（标称值55度），扫描幅宽约1450千米。AMSR-E曾无法维持常规观测所需的天线转速，于2012年12月4日切换至低速旋转模式（每分钟2转）恢复观测，但后续又无法维持该模式下的转速，最终于2015年12月4日自动停止观测与天线旋转。L3级数据以L1B与L2级数据为输入，按照指定投影技术（等经纬度投影（Equi-Rectangular, EQR）或极地方位投影（Polar Stereographic, PS））投影至地理坐标系，随后进行时间与空间平均处理。上述统计值分别针对升轨与降轨的观测数据计算得到。本产品包含日均海冰浓度（Ice Concentration, IC）。海冰浓度的推导主要采用Bootstrap反演算法，使用37GHz与19GHz频段，相较于该算法，本产品利用发射率替代亮温，以最小化海冰温度空间变化带来的反演误差。最终通过推导得到的海冰浓度值对海冰温度进行归一化处理，使其仅表征卫星观测区域内海冰部分的温度。本产品的物理量单位为百分比（%），数据提供格式为HDF4，统计周期为1日，空间分辨率为0.25度，当前产品版本为"Version 7"，投影方式为极地方位投影（PS），产品生成范围为全球。