Aqua/AMSR-E L2 Ice Concentration

Aqua/AMSR-E L2 Ice Concentration 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 2 product stores the Geophysical quantity from the brightness temperature of level 1 product. This product includes Ice Concentration (IC). The technique uses data from the 6 GHz and 37 GHz channels at vertical polarization to obtain an initial estimate of sea ice concentration and ice temperature. The derived ice temperature is then utilized to estimate the emissivity for the corresponding observations at all the other channels. 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 %. Also, the quality flag for each observation point (Pixel Data Quality) is stored. The provided format is HDF4. Spatial resolution is 10 km. The current version of the product is "Version 7". The generation unit is scene(defined as a half orbit).

Aqua/AMSR-E L2海冰浓度数据集由搭载于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（NASA）的Aqua卫星于2002年5月4日发射进入太阳同步亚回归轨道。Aqua卫星从太空观测与水循环及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通过机械旋转天线扫描地球表面，获取地球表面的辐射亮度数据。各频段均通过垂直极化与水平极化波进行监测，其采用圆锥扫描方式，与地球表面的入射角度标称值为55度，幅宽约1450千米。AMSR-E一度无法维持常规观测所需的天线转速，随后于2012年12月4日以慢转速模式（每分钟2转）恢复观测，但在2015年12月4日，其同样无法维持慢转速模式所需的天线转速，遂自动停止观测与天线旋转。
L2级产品（Level 2 product）存储了源自L1级产品亮度温度的地球物理量，本产品包含海冰浓度（Ice Concentration, IC）。该技术利用垂直极化下的6吉赫兹与37吉赫兹信道数据，初步估算海冰浓度与冰温；随后利用推导得到的冰温，估算其余所有信道对应观测的发射率。与Bootstrap技术（Bootstrap technique）类似，海冰浓度主要通过37吉赫兹与19吉赫兹信道推导得出，但本方法改用发射率替代亮度温度，以最小化海冰温度空间变化带来的误差。最终，推导得到的冰温将通过海冰浓度值进行归一化，使其仅表征卫星观测区域内海冰部分的温度。该物理量的单位为百分比（%）。此外，还存储了每个观测点的质量标记（像素数据质量，Pixel Data Quality）。
本数据集采用HDF4格式存储，空间分辨率为10千米。当前产品版本为"Version 7"，数据生成单元为观测场景（scene，定义为半轨道）。