Synthetic along-track altimetry data over 1993-2018 from a NEMO-based simulation of the IMHOTEP project

"Synthetic observations" of along-track SSH have been extracted online during the production of the global, NEMO-based experiment ** IMHOTEP-GAIc**, at every single time and locations where a true SLA observation exists in the AVISO database for the along-track altimetry from the TOPEX, Jason-1, Jason-2 and Jason-3 satellite continuous series over the period 1993-2018. This global ocean/sea-ice/iceberg simulation uses the NEMO model, and has a horizontal resolution of 1/4°. The atmospheric forcing applied at the surface is based on the JRA reanalysis (Kobayashi et al., 2015) and varies over the full range of time-scales from 6 hours to multi-decadal. The freshwater runoff forcing applied to the experiment is fully-variable (daily to multi-decadal) based on the ISBA hydrographic reanalysis for rivers (Decharme et al., 2019) and from altimeter data and regional GCM simulations for the liquid and solid discharges from the Greenland ice-sheet (Mouginot et al 2019). These runoffs are only climatological around Antarctica.This synthetic along-track SSH dataset from the model is available over the altimetry period (1993-2018). It is provided there along with a time-mean model SSH (gridded model field) over the same period that can be used as a proxy for mean dynamic topography ("MDT"). See the README file for more information. And online documentation is also available here: https://doc-imhotep.readthedocs.io/en/latest/6-Synthetic-Obs.html沿轨海面高度（along-track Sea Surface Height, SSH）的合成观测值，是在基于NEMO模型的全球试验**IMHOTEP-GAIc**的制作过程中，在线提取自1993-2018年期间，TOPEX、Jason-1、Jason-2及Jason-3卫星连续沿轨测高任务对应的AVISO数据库中所有存在真实海平面异常（Sea Level Anomaly, SLA）观测的时间与位置点。该全球海洋-海冰-冰山模拟采用NEMO模型，水平分辨率为1/4°。试验所施加的表面大气强迫场基于JRA再分析数据（Kobayashi等，2015），其时间尺度覆盖范围从6小时至多年代际。试验所用的淡水径流强迫场为全可变形式（时间尺度覆盖日尺度至多年代际），其中河流径流部分基于ISBA水文再分析数据（Decharme等，2019）；格陵兰冰盖液态与固态径流则结合了测高数据与区域全球气候模型（General Circulation Model, GCM）模拟结果（Mouginot等，2019）。而南极周边区域的径流仅采用气候态数据。该模型生成的合成沿轨海面高度数据集覆盖测高任务时段（1993-2018年）。本次发布同时提供同期的时间平均模型海面高度场（网格化模型场），可作为平均动态地形（Mean Dynamic Topography, MDT）的替代数据。更多信息请参阅README文件，亦可通过以下链接获取在线文档：https://doc-imhotep.readthedocs.io/en/latest/6-Synthetic-Obs.html