Evaluating operational AVHRR sea surface temperature data at the coastline using surfers
Evaluating operational AVHRR sea surface temperature data at the coastline using surfers
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DOI：
10.1016/j.ecss.2017.07.011
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发表时间：
2017-09-05
影响因子：
2.8
通讯作者：
Fishwick, James R.
中科院分区：
文献类型：
--
作者：
Brewin, Robert J. W.;de Mora, Lee;Fishwick, James R.
海表面温度(SST)是一个重要的气候变量，可以通过高时空覆盖率的地球观测(EO)进行常规测量。要评估其对应用的适用性，了解EO SST数据的准确性和精确度(性能)至关重要。这需要与同一位置和伴随的现场数据进行比较。由于现场平台的网络相对较大，因此对海洋表层温度数据在公海的表现有很好的了解。然而，在海岸线，由于缺乏现场数据，这一表现并不为人所知。在这里，我们使用了一组冲浪者在三年时间里在英国和爱尔兰沿海水域收集的现场SST测量，以加强我们对海岸线EO SST数据表现的理解。在英国普利茅斯市附近的两个海滩，冲浪者收集的现场SST与两个位于距海岸线类似7公里和类似33公里的自主浮标收集的现场SST进行了比较，结果显示出很好的一致性，差异与站点的空间分隔一致。使用海岸线附近冲浪者现场收集的SST测量和两个自主浮标在近海收集的SST测量，评估了可操作的高级甚高分辨率辐射计(AVHRR)EO SST数据的性能。结果表明：(I)AVHRR在海岸线反演海温的性能显著下降，均方根误差在1.0至2.0摄氏度之间，取决于匹配之间的时间差，显著高于两个离岸站的误差(0.4至0.6摄氏度)；(Ii)AVHRR在海岸线的系统负偏差约为1摄氏度，在两个离岸站没有观察到；以及(Iii)当两个近海站之间的时间差超过3小时时，海岸线的均方根误差增加。利用新的解决方案来改善海岸线的现场采样覆盖范围，例如用传感器标记冲浪者，可以提高我们对沿海地区EO SST数据表现的理解，帮助告知对用于沿海应用的EO SST产品感兴趣的用户。然而，利用海岸线的现场SST数据验证EO SST产品面临着难以协调两种测量的困难，因为这两种测量是在动态和复杂的环境中以不同的空间尺度提供的。(C)2017年作者。爱思唯尔有限公司出版。
Sea surface temperature (SST) is an essential climate variable that can be measured routinely from Earth Observation (EO) with high temporal and spatial coverage. To evaluate its suitability for an application, it is critical to know the accuracy and precision (performance) of the EO SST data. This requires comparisons with co-located and concomitant in situ data. Owing to a relatively large network of in situ platforms there is a good understanding of the performance of EO SST data in the open ocean. However, at the coastline this performance is not well known, impeded by a lack of in situ data. Here, we used in situ SST measurements collected by a group of surfers over a three year period in the coastal waters of the UK and Ireland, to improve our understanding of the performance of EO SST data at the coastline. At two beaches near the city of Plymouth, UK, the in situ SST measurements collected by the surfers were compared with in situ SST collected from two autonomous buoys located similar to 7 km and similar to 33 km from the coastline, and showed good agreement, with discrepancies consistent with the spatial separation of the sites. The in situ SST measurements collected by the surfers around the coastline, and those collected offshore by the two autonomous buoys, were used to evaluate the performance of operational Advanced Very High Resolution Radiometer (AVHRR) EO SST data. Results indicate: (i) a significant reduction in the performance of AVHRR at retrieving SST at the coastline, with root mean square errors in the range of 1.0 to 2.0 degrees C depending on the temporal difference between match-ups, significantly higher than those at the two offshore stations (0.4 to 0.6 degrees C); (ii) a systematic negative bias in the AVHRR retrievals of approximately 1 degrees C at the coastline, not observed at the two offshore stations; and (iii) an increase in the root mean square error at the coastline when the temporal difference between match-ups exceeded three hours. Harnessing new solutions to improve in situ sampling coverage at the coastline, such as tagging surfers with sensors, can improve our understanding of the performance of EO SST data in coastal regions, helping inform users interested in EO SST products for coastal applications. Yet, validating EO SST products using in situ SST data at the coastline is challenged by difficulties reconciling the two measurements, which are provided at different spatial scales in a dynamic and complex environment. (C) 2017 The Authors. Published by Elsevier Ltd.