SMOS ARCTIC SSS L3 maps produced by CATDS CEC LOCEAN

LOCEAN, LOPS, AARI and ACRI-ST have derived improved SMOS SSS maps over the Arctic Ocean based on new SST corrections and new sea ice filtering applied to SSS retrieved from SMOS satellite measurements.
The first version of level 3 (L3) SMOS ARCTIC SSS (weekly and monthly) covers a period from June 2010 to November 2019 above 60°North. The dataset is derived using uncorrected SSS from ESA SMOS SSS v662 level 2 (L2, https://smos.argans.co.uk/docs/deliverables/delivered/ATBD/SO-TN-ARG-GS-0007_L2OS-ATBD_v3.13_160429.pdf). SSS values are reprojected in an Equal-Scalable Earth Grid 2 (EASE, https://nsidc.org/data/ease) with a Northern Hemisphere Azimuthal projection and a resolution of 25km.
REMSS Microwave+Infrared Sea Surface Temperature (SST) optimal interpolation product (http://www.remss.com/measurements/sea-surface-temperature/oisst-description/) is used in order to correct SST related biases.
7-day moving averages of SMOS ESA L2 parameters are produced each day for L3 SSS weekly product. An average considering each day of the month is computed for L3 SSS monthly product. Weekly and monthly uncertainties are estimated through an error propagation of SMOS ESA v662 L2 uncertainty estimates.
Feedbacks from users about the quality of these new products are very welcome, as they are experimental. 

Version of the product:
V1.0: debiasing and sea ice filtering using ACARD + SST effects correction using REMSS SST 
V1.1: generalization of bias correction using ACARD + sea ice filtering using ACARD + SST effects correction using REMSS SST (Methodology presented in "New insights into SMOS sea surface salinity retrievals in the Arctic Ocean »; Supply et al, 2020 ; https://doi.org/10.1016/j.rse.2020.112027)

LOCEAN、LOPS、AARI与ACRI-ST基于针对SMOS卫星反演得到的海表面盐度（Sea Surface Salinity, SSS）数据新增的海表面温度（Sea Surface Temperature, SST）校正方案与海冰滤波方法，优化了北冰洋海域的SMOS SSS绘图产品。

本数据集的首个3级（Level 3, L3）SMOS北极SSS产品（包含周度与月度数据集）覆盖2010年6月至2019年11月北纬60°以北的海域。该数据集源自欧洲空间局（European Space Agency, ESA）SMOS SSS v662 2级（Level 2, L2）未校正SSS数据，原始数据文档可参见：https://smos.argans.co.uk/docs/deliverables/delivered/ATBD/SO-TN-ARG-GS-0007_L2OS-ATBD_v3.13_160429.pdf。SSS数据被重投影至等尺度地球网格2（Equal-Scalable Earth Grid 2, EASE，https://nsidc.org/data/ease），采用北半球方位投影，空间分辨率为25km。

本研究使用REMSS微波+红外海表面温度最优插值产品（http://www.remss.com/measurements/sea-surface-temperature/oisst-description/）以校正SST相关的系统偏差。

针对L3周度SSS产品，每日生成SMOS ESA L2参数的7日滑动平均序列；针对L3月度SSS产品，则基于当月全部日期的均值进行计算。周度与月度不确定性通过对ESA SMOS v662 L2不确定性估计值开展误差传播分析得到。

由于本产品仍处于试验阶段，欢迎用户反馈相关产品质量相关的意见与建议。

产品版本说明：
V1.0：采用ACARD方法进行偏差校正与海冰滤波，并使用REMSS SST完成SST效应校正；
V1.1：推广了基于ACARD的偏差校正方法与海冰滤波流程，并沿用REMSS SST完成SST效应校正（相关方法详见论文"New insights into SMOS sea surface salinity retrievals in the Arctic Ocean"；Supply et al, 2020；https://doi.org/10.1016/j.rse.2020.112027）