The accuracy and precision of satellite sea surface temperature (SST) products in nearshore coastal waters are not well known, owing to a lack of in-situ data available for validation. It has been suggested that recreational watersports enthusiasts, who immerse themselves in nearshore coastal waters, be used as a platform to improve sampling and fill this gap. One tool that has been used worldwide by surfers is the Smartfin, which contains a temperature sensor integrated into a surfboard fin. If tools such as the Smartfin are to be considered for satellite validation work, they must be carefully evaluated against state-of-the-art techniques to quantify data quality. In this study, we developed a Simple Oceanographic floating Device (SOD), designed to float on the ocean surface, and deployed it during the 28th Atlantic Meridional Transect (AMT28) research cruise (September and October 2018). We attached a Smartfin to the underside of the SOD, which measured temperature at a depth of ∼0.1 m, in a manner consistent with how it collects data on a surfboard. Additional temperature sensors (an iButton and a TidbiT v2), shaded and positioned a depth of ∼1 m, were also attached to the SOD at some of the stations. Four laboratory comparisons of the SOD sensors (Smartfin, iButton and TidbiT v2) with an accurate temperature probe (±0.0043 K over a range of 273.15 to 323.15 K) were also conducted during the AMT28 voyage, over a temperature range of 290–309 K in a recirculating water bath. Mean differences ($\delta$), referenced to the temperature probe, were removed from the iButton ($\delta =0.292$ K) and a TidbiT v2 sensors ($\delta =0.089$ K), but not from the Smartfin, as it was found to be in excellent agreement with the temperature probe ($\delta =0.005$ K). The SOD was deployed for 20 min periods at 62 stations (predawn and noon) spanning 100 degrees latitude and a gradient in SST of 19 K. Simultaneous measurements of skin SST were collected using an Infrared Sea surface temperature Autonomous Radiometer (ISAR), a state-of-the-art instrument used for satellite validation. Additionally, we extracted simultaneous SST measurements, collected at slightly different depths, from an underway conductivity, temperature and depth (CTD) system. Over all 62 stations, the mean difference ($\delta$) and mean absolute difference ($ϵ$) between Smartfin and the underway CTD were −0.01 and 0.06 K respectively (similar results obtained from comparisons between Smartfin and iButton and Smartfin and TidbiT v2), and the $\delta$ and $ϵ$ between Smartfin and ISAR were 0.09 and 0.12 K respectively. In both comparisons, statistics varied between noon and predawn stations, with differences related to environmental variability (wind speed and sea-air temperature differences) and depth of sampling. Our results add confidence to the use of Smartfin as a citizen science tool for evaluating satellite SST data, and data collected using the SOD and ISAR were shown to be useful for quantifying near-surface temperature gradients.

中文翻译：

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大西洋中Smartfin与红外海面温度辐射仪的比较

由于缺乏原地，近岸沿海水域的卫星海表温度（SST）产品的准确性和精确性尚不为人所知可用于验证的数据。有人建议将沉浸在近岸沿海水域中的休闲水上运动爱好者用作改善采样并填补这一空白的平台。冲浪者在全球范围内使用的一种工具是Smartfin，它包含一个集成在冲浪板鳍中的温度传感器。如果要考虑将诸如Smartfin之类的工具用于卫星验证工作，则必须根据最新技术对它们进行仔细评估，以量化数据质量。在这项研究中，我们开发了一种简单的海洋漂浮装置（SOD），旨在漂浮在海面上，并在第28届大西洋子午线断面（AMT28）研究航行期间（2018年9月和2018年10月）部署了它。我们将Smartfin连接到SOD的底部，该底部在约0.1 m的深度处测量温度，以与其在冲浪板上收集数据的方式一致的方式。在一些站点的SOD上也安装了阴影和定位深度约为1 m的附加温度传感器（iButton和TidbiT v2）。在AMT28航行期间，在290–309 K的温度范围内，还对四个SOD传感器（Smartfin，iButton和TidbiT v2）与一个精确的温度探头（在273.15至323.15 K范围内为±0.0043 K）进行了四个实验室比较。在循环水浴中。均值差异（在AMT28航行期间，在290–309 K的温度范围内，在循环水浴中也进行了0043 K（在273.15至323.15 K范围内）的测量。均值差异（在AMT28航行期间，在290–309 K的温度范围内，在循环水浴中也进行了0043 K（在273.15至323.15 K范围内）的测量。均值差异（$\delta$）（以温度探针为参考）已从iButton（$\delta =0。292$ K）和一个TidbiT v2传感器（$\delta =0。089$ K），但并非来自Smartfin，因为它与温度探头（$\delta =0。005$K）。在62个站点（凌晨和中午）将SOD部署了20分钟，时间跨度为100度，SST的梯度为19K。使用红外海面温度自动辐射仪（ISAR）收集了皮肤SST的同时测量值用于卫星验证的最先进的仪器。此外，我们从正在进行的电导率，温度和深度（CTD）系统中提取了同时进行的SST测量值，并在略有不同的深度处进行了采集。在所有62个电台中，均值差（$\delta$）和平均绝对差（$ϵ$）在Smartfin和正在进行的CTD之间分别为-0.01和0.06 K（通过Smartfin和iButton以及Smartfin和TidbiT v2的比较获得相似的结果），并且 $\delta$ 和 $ϵ$Smartfin和ISAR之间的差分别为0.09和0.12K。在这两个比较中，中午和黎明前的台站之间的统计数据均不同，其差异与环境变异性（风速和海水温度差异）和采样深度有关。我们的结果增加了将Smartfin用作评估卫星SST数据的公民科学工具的信心，并且使用SOD和ISAR收集的数据显示出可用于量化近地表温度梯度。