Pressure Sensor Drifts in Argo and Their Impacts
Pressure Sensor Drifts in Argo and Their Impacts
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DOI：
10.1175/2011jtecho831.1
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发表时间：
2011-08-01
影响因子：
2.2
通讯作者：
Wijffels, Susan E.
中科院分区：
文献类型：
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作者：
Barker, Paul M.;Dunn, Jeff R.;Wijffels, Susan E.
近年来，通过实施Argo方案，自主剖面浮标已成为现场海洋观测系统的主要组成部分。这些数据现在是估计全球海洋热含量演变和相关的热空间海平面上升的主要投入。自主剖面探测器（APEX）是Argo浮标的主要类型（类似于62%），这些浮标中的大部分报告的压力测量值未对传感器漂移进行校正，其大小和来源在本文中进行了描述。其余的Argo浮标类型被设计为自动自我校正任何压力漂移。只有大约57%的APEX浮标剖面（或类似于38%的Argo剖面）可以被校正，但分发数据的数据中心通常没有这样做（截至2009年1月）。介绍了一种APEX浮标的压力校正方法，并将其应用于Argo数据集。使用校正后的Argo数据集和化学上可用的未校正数据集（截至2009年1月）的估计值之间的比较表明，压力校正消除了海洋温度，盐度和thermosteric海平面场的显着区域误差。在全球平均值中，43%的不可校正的APEX浮子剖面（或类似于28%的Argo剖面）似乎在很大程度上抵消了具有正压漂移的可校正APEX浮子剖面的影响。虽然大约一半的不可校正的APEX曲线原则上可以在不久的将来恢复（在包含允许校正的技术信息之后），但另一半的负压漂移被截断为零（由于固件限制），这不允许校正。因此，任何无法校正偏差的Argo压力分布都应排除在全球变化研究之外。这项研究强调，目前需要进行仔细分析，以发现和消除海洋观测中微妙但系统性的误差。
In recent years, autonomous profiling floats have become the prime component of the in situ ocean observing system through the implementation of the Argo program. These data are now the dominant input to estimates of the evolution of the global ocean heat content and associated thermosteric sea level rise. The Autonomous Profiling Explorer (APEX) is the dominant type of Argo float (similar to 62%), and a large portion of these floats report pressure measurements that are uncorrected for sensor drift, the size and source of which are described herein. The remaining Argo float types are designed to automatically self-correct for any pressure drift. Only about 57% of the APEX float profiles (or similar to 38% Argo profiles) can be corrected, but this typically has not been done by the data centers that distribute the data (as of January 2009). A pressure correction method for APEX floats is described and applied to the Argo dataset. A comparison between estimates using the corrected Argo dataset and the publically available uncorrected dataset (as of January 2009) reveals that the pressure corrections remove significant regional errors from ocean temperature, salinity, and thermosteric sea level fields. In the global mean, 43% of uncorrectable APEX float profiles (or similar to 28% Argo profiles) appear to largely offset the effect of the correctable APEX float profiles with positive pressure drifts. While about half of the uncorrectable APEX profiles can, in principle, be recovered in the near future (after inclusion of technical information that allows for corrections), the other half have negative pressure drifts truncated to zero (resulting from firmware limitations), which do not allow for corrections. Therefore, any Argo pressure profile that cannot be corrected for biases should be excluded from global change research. This study underscores the ongoing need for careful analyses to detect and remove subtle but systematic errors in ocean observations.