AMSR & AMSR-E & AMSR-2 数据下载

AMSR卫星系列：

• AMSR搭载于JAXA ADEOS-II卫星上于2002年12月14日发射。该卫星太阳能电池板在2003年10月25日失效；
• AMSR-E搭载于NASA EOS Aqua卫星上于2002年5月4日发射升空，该传感器已于2011年10月4日停止工作；
• AMSR-2搭载于JAXA GCOM-W1卫星上于2012年5月18日升空，该传感器目前仍在运行中。

• Level1 and Higher Level Products  

AMSR2 is a multi-frequency microwave radiometer. It measures weak microwave emission (6.9 -89.0GHz) from the surface and the atmosphere of the Earth. AMSR2 products are categorized according to the processing levels. Level 1A (L1A) products consist of raw observation counts,antenna temperature conversion coefficients, etc... Level 1B (L1B) products contain brightness temperatures which is converted from L1A count values using the conversion coefficients. Level 2(L2) products contain geophysical parameters which primarily related to water and derived from the L1B products. AMSR2 derived geophysical parameters are shown in Table 2. L1 and L2 is swath data with geolocation information.  

• Level1 Resampling Products (L1R)（Only in AMSR-2）

AMSR2 geophysical parameters are calculated by combining multiple AMSR2 frequencies and polarizations. In that case, there is no consistency with latitude and longitude of same observation point because of different footprint size. AMSR2 provides product call L1R that resamples the L1B product using pre-calculated resampling coefficients to adjust data for lower frequency resolutions. The center latitude and longitude of data is adjusted to the 89 GHz A channel receiver data.Resampling converts the brightness temperature at a higher resolution frequency to a brightness temperature at a lower resolution frequency. Resampling data based on 6.9, 10.7, 23.8, 36.5GHz footprint size is created. 6 GHz and 7 GHz data sets have the same spatial resolution; therefore, a shared set of resampling data is created. 18 GHz and 23 GHz data sets have almost the same resolution, but 23 GHz resolution is slightly lower; therefore, one set of resampling data is created matching the 23 GHz resolution. Table 6 shows L1R data and frequencies selected for resampling.  

• Level 3 Products

Level 3 (L3) products are global gridded products at two different resolutions (0.1 and 0.25
degrees). Products make ground projections on the globe and in the North Pole and South Pole
regions by taking the time and spatial averages of the L1B and L2 standard products. L3 products of
brightness temperatures are called L3TB and those of geophysical parameters are called L3GEO.
Daily and monthly statistical products are created for both ascending and descending data sets. L2
and L3GEO products are also called as higher level products.  [1]

 Fig.1 Relationship between swath and global data

AMSR数据下载链接（JAXA网站）：
https://gcom-w1.jaxa.jp/auth.html

AMSR数据下载方法（此方法仅支持.h5格式下载）：
启动FileZilla软件（FileZilla软件可以自己在Google中搜索下载），输入Host Name、User Name、Password以及Port Number，如图2所示。

Fig.2

成功连接后，下载界面如图3所示。

Fig.3 FileZilla下载页面

网站中数据的存储结构如图4所示。[2]

Fig.4 数据存储结构

注意：

❶FileZilla软件不要从参考网页所给的下载链接下载，建议使用Google搜索下载最新版本。

❷FileZilla软件仅支持下载.h5格式的数据，GeoTIFF与NetCDF格式不支持下载。

参考：

[1]AMSR-2 User Guide Book.PDF,2nd Edition,March 2013.

[2]http://gcom-w1.jaxa.jp/sftp_man.html

数据下载页面提供了3种方式供大家下载，如Fig.5所示：

①Categories or Physical Parameters(目录或物理参数法)：
该方法将数据以Fig.6中Atmosphere、Ocean、Cryosphere、Land以及Brightness temperature 五种类型进行划分，每种类型数据下再按照Pyhsical Parameters进行区分查询下载；
②Explanations(解释)：
数据显示方式同目录或物理参数法；

③Satellites or Sensors(卫星或传感器)：

该种方法以Fig.7的形式进行发布。
关于卫星的介绍如Fig.8所示，更多信息可以查看http://gcom-w1.jaxa.jp/contents/AMSR_series_en.pdf

三颗卫星数据的特点：

1. GCON-W1/AMSR2、Aqua/AMSR-E、ADEOS-II/AMSR三种卫星均包含Level 1-Level3三个级别的产品；
2. Aqua/AMSR-E、ADEOS-II/AMSR产品的构成完全相同；
3. Level 1以及Level 3中均包含亮温（Brightness Temperature）数据，不同之处在于GCOM-W1卫星Level 1 除了提供L1B亮温数据，还将数据分辨率进行重采样形成L1R数据。

Fig.5

Fig.6

Fig.7

Fig.8