SWOT Level 2 Radiometer Brightness Temperatures and Troposphere Interim Data Product Version D

The SWOT Level 2 Radiometer Brightness Temperatures and Troposphere Interim Geophysical Data Record (IGDR) Version D dataset produced by the Surface Water and Ocean Topography (SWOT) mission provides atmospheric water vapor and liquid water content from the Advanced Microwave Radiometer (AMR), a Jason-class radiometer that measures sea surface brightness temperatures at three microwave frequencies (18.7, 23.8 and 34 GHz). Brightness temperatures are processed to estimate the wet troposphere content, atmospheric attenuation to backscatter, cloud liquid water, water vapor content, and wind speed coincident with each range measurement from the nadir altimeter and applied to correct for altimeter range delays caused by atmospheric effects. SWOT is a joint mission between NASA and CNES that launched on December 16, 2022. It aims to measure ocean surface topography with unprecedented resolution and accuracy, as well as map inland water bodies globally.
The interim radiometer dataset consists of discrete measurements along two tracks located approximately 30-km to the left and right of the satellite nadir. The data were processed using the Medium-accuracy (preliminary) Orbit Ephemeris (MOE) with preliminary calibrations applied. They are distributed as one file per half-orbit in netCDF4 file format with a nominal latency of < 1.5 days.

由地表水文与海洋地形（SWOT）任务生成的SWOT D版二级辐射计亮温与对流层临时地球物理数据记录（IGDR）数据集，其数据源自该任务搭载的先进微波辐射计（AMR）——该辐射计属于Jason系列，可在18.7、23.8及34 GHz三个微波频段测量海面亮温，进而获取大气水汽与液态水含量。研究人员将对采集到的亮温数据开展处理，以估算湿对流层含量、大气衰减对后向散射的影响、云液态水、水汽含量，以及与天底高度计每次距离测量同步的风速，并利用上述参数校正大气效应引发的高度计距离延迟。SWOT是美国国家航空航天局（NASA）与法国国家空间研究中心（CNES）联合实施的任务，于2022年12月16日发射升空，其核心目标是以前所未有的分辨率与精度测量海洋表面地形，并完成全球内陆水体的全域测绘。
该临时辐射计数据集包含沿卫星天底轨迹两侧约30公里处的两条航迹采集的离散测量数据。数据采用中精度（初步）轨道星历（MOE）进行处理，并应用了初步校准流程。数据集以半轨为单位进行分发，采用netCDF4文件格式存储，标称数据延迟时长小于1.5天。