CODE drifter observations from the DDR20 experiment in the NW Mediterranean Sea

In October 2020, the LaMMA Consortium carried out a field measurement campaign in the Southern Ligurian Sea (SLS) as part of the DDR20 – Drifter Demonstration and Research 2020 experiment. Organized by CMRE and supported by several EU-funded projects (SICOMAR plus, JERICO-S3, SINAPSI, and IMPACT), the campaign focused on the deployment of CODE drifters (Davis, 1985; Poulain, 1999). 
The drifters used were specifically acquired by LaMMA through the IMPACT project. Designed to monitor surface currents in the upper meter of the water column while minimizing wind influence, these were MAXO-manufactured CODE models equipped with SPOT Globalstar TRACE modules. The modules feature high-accuracy GPS receivers (<10 m) and transmit position data every 5 minutes, with an estimated velocity accuracy of around 3 cm/s.
A total of 26 drifters were deployed over a few hours, arranged in a 3 km × 3 km square grid in waters about 100 meters deep (centered at Lat: 43°16′N, Lon: 10°14′E). Five were recovered within 1 to 3 days, while the rest eventually beached after drifting for several days. Drifters operating near the coast used cellular networks to transmit data, whereas those farther offshore switched to satellite communication. The resulting dataset spans from October 8 to November 8, 2020, with positions recorded at 5-minute intervals. Some gaps are present due to occasional transmission issues or device malfunctions.
This dataset supports the validation and performance analysis of HF radar measurements in coastal areas, as discussed in Doronzo et al. (2025).

References:
-  Davis, R.E. (1985). Drifter observations of coastal surface currents during CODE: The method and descriptive view. Journal of Geophysical Research: Oceans, 90(C3), 4741–4755. https://doi.org/10.1029/JC090iC03p04741
- Poulain, P.-M. (1999). Drifter observations of surface circulation in the Adriatic Sea between December 1994 and March 1996. Journal of Marine Systems, 20(1–4), 231–253. https://doi.org/10.1016/S0924-7963(98)00084-0
- http://interreg-maritime.eu/web/impact
- Doronzo, B.; Bendoni, M.; Taddei, S.; Boccacci, A.; Brandini, C. Validating HF Radar Current Accuracy via Lagrangian Measurements and Radar-to-Radar Comparisons in Highly Variable Surface Currents. Remote Sens. 2025, 17, 1243. https://doi.org/10.3390/rs17071243

2020年10月，拉马马联盟（LaMMA Consortium）于南利古里亚海（Southern Ligurian Sea, SLS）开展野外测量作业，作为DDR20——浮标演示与研究2020（Drifter Demonstration and Research 2020）实验的组成部分。本次作业由CMRE组织，获得多项欧盟资助项目支持，包括SICOMAR plus、JERICO-S3、SINAPSI及IMPACT，核心内容为部署CODE浮标（CODE drifters），相关技术背景可参考Davis（1985）与Poulain（1999）的研究成果。

本次使用的浮标由拉马马联盟通过IMPACT项目专项采购。该类浮标旨在监测水柱上层1米的表层海流，同时最大限度削弱风力干扰，为MAXO公司生产的CODE型号浮标，搭载SPOT Globalstar TRACE通信模块。模块配备高精度GPS接收机（GPS Receiver，定位精度<10米），每5分钟传输一次位置数据，估算流速精度约为3厘米/秒。

本次作业共在数小时内完成26台浮标的部署，布设区域为水深约100米的海域，以纬度43°16′N、经度10°14′E为中心，形成3千米×3千米的方形网格。其中5台浮标在1至3天内被回收，其余浮标在漂流数日后最终搁浅。近岸作业的浮标通过蜂窝网络传输数据，远海作业的浮标则切换为卫星通信。本数据集的时间跨度为2020年10月8日至11月8日，位置数据以5分钟间隔记录，偶发的传输故障或设备失灵会导致部分数据缺失。

正如Doronzo等人（2025）的研究所述，本数据集可用于沿海地区高频雷达（High Frequency radar, HF radar）测量结果的验证与性能分析。

参考文献：
- Davis, R.E. (1985). CODE实验期间沿海表层海流的浮标观测：方法与描述性分析. 地球物理研究杂志：海洋卷，90(C3)，4741–4755. https://doi.org/10.1029/JC090iC03p04741
- Poulain, P.-M. (1999). 1994年12月至1996年3月亚得里亚海表层环流的浮标观测. 海洋系统杂志，20(1–4)，231–253. https://doi.org/10.1016/S0924-7963(98)00084-0
- http://interreg-maritime.eu/web/impact
- Doronzo, B.; Bendoni, M.; Taddei, S.; Boccacci, A.; Brandini, C. 强变率表层海流场景下基于拉格朗日测量与雷达间比对的高频雷达流场精度验证. 遥感（Remote Sens.）, 2025, 17, 1243. https://doi.org/10.3390/rs17071243