Updated Sea Ice Products for the NIMBUS 5 Electrically Scanning Microwave Radiometer data from 1972–1977

The Electrically Scanning Microwave Radiometer (ESMR) instrument onboard the NIMBUS 5 satellite was a one-channel microwave radiometer that measured the 19.35 GHz horizontally polarized brightness temperature (TB) from 11 December 1972 to 16 May 1977.Kolbe et. al. (2024) reprocessed this data in order to derive sea Ice concentration for the period and showed that sea ice extend and concentration was indeed recoverable, but one major challenge was that the implemented one-channel algorithm was unable to distinguish first year ice and multiyear ice, resulting in ambiguity between areas with multi-year ice, and areas with low sea ice concentration. Furthermore, since publishing, we have found the applied filtering to be removing too much data, especially after 1975, and on top of that, we have resolved minor data issues.Two datesets are uploaded here, split in to 4 files ;1) A reprocessed version of the data using the methods of Kolbe et. al. (2024), but with some corrections to the output and a new filtering scheme. This is a direct update to https://doi.org/10.5285/34a15b96f1134d9e95b9e486d74e49cf.2) A post processed dataset (LDTPcorrected) where a local dynamical tie point framework has been applied, which resolves the ambiguity by enforcing stability of tiepoints over time.For each dataset a file for each hemisphere (Northern Hemisphere, NH, and Southern Hemisphere (SH)) can be downloadet.The dataset is created using the code available in the referenced github repository https://github.com/EHTellefsen/N5ESMR-SIC-processing

搭载于NIMBUS 5卫星的电气扫描微波辐射计（Electrically Scanning Microwave Radiometer, ESMR）为单通道微波辐射计，自1972年12月11日至1977年5月16日测量了19.35 GHz水平极化亮度温度（TB）。Kolbe等人在2024年对该数据进行再处理，以推导出该时期的海冰浓度，并证实海冰扩展和浓度是可以恢复的。然而，一个主要的挑战在于所实施的单一通道算法无法区分一年冰和多年份冰，导致多年冰区域与低海冰浓度区域之间的模糊性。此外，自发表以来，我们发现所应用的滤波器去除了过多的数据，尤其是在1975年之后，而且我们还解决了少数数据问题。在此上传了两个数据集，分为4个文件；1) 使用Kolbe等人（2024）的方法对数据进行再处理，但对其输出进行了某些校正并采用了一种新的滤波方案。这是对https://doi.org/10.5285/34a15b96f1134d9e95b9e486d74e49cf的直接更新。2) 一个后处理数据集（LDTPcorrected），其中应用了一个局部动态连接点框架，通过强制连接点随时间的稳定性来解决模糊性。对于每个数据集，每个半球（北半球，NH，和南半球，SH）都有一个文件可供下载。该数据集是使用在引用的GitHub存储库https://github.com/EHTellefsen/N5ESMR-SIC-processing中可用的代码创建的。