Marine heatwaves (MHWs) have recently been recognized as extreme climate events considering their devastating impacts on marine ecosystems. Our study explored the spatial and temporal variability of short (duration <10 days) and long MHWs in nine sub-regions around the Australian coastal region using the original (5-day) and an updated longer duration (10-day) criteria for MHW identification based on gap-free Sea Surface Temperature (SST) analyses from 1981 to 2020. By quantitatively investigating the contribution of ocean warming to short MHWs, we could consider most of the short events as background signals of a dynamic ocean surface over the Australian region. The application of the updated definition highlights areas that are more sensitive to local internal forcings, especially over the main flow of the East Australian Current. Furthermore, the Great Barrier Reef exhibit a larger increasing trend of MHW areas after excluding the short events. By numerically and graphically evaluating the relationship between the sea level anomaly (SLA) and SST metrics over two coastal regions of Australia, it is found that longer MHWs exhibiting two variation trends of large SLA metrics are ENSO dominant in the northwest coastal region (NW), and less ENSO-dominant but geographically-impacted in the southeast coastal region (SETS). However, it is possible that most short events in these two regions are a result of local and intrinsic variability or ocean warming of the water columns rather than the remote modulation of climate modes. Moreover, SLA over the 90th percentile, which successfully observed a subsurface MHW event over the NW region in 2008, has the potential to help identify subsurface MHWs, although limited by application area. Further investigation into the applicability of these, or other similar, updates to the MHW definitions may be warranted, to draw a broadly applicable conclusion to benefit detection and prediction of strong sub-surface MHWs impacting commercial and environmental activities.

中文翻译：

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从海面温度和高度角度看内在短海洋热浪


考虑到海洋热浪（MHW）对海洋生态系统的破坏性影响，海洋热浪最近被认为是极端气候事件。我们的研究使用原始（5 天）和更新的较长持续时间（10 天）的 MHW 标准，探讨了澳大利亚沿海地区九个子区域的短（持续时间 <10 天）和长 MHW 的空间和时间变异性基于 1981 年至 2020 年无间隙海面温度 (SST) 分析的识别。通过定量研究海洋变暖对短 MHW 的贡献，我们可以将大多数短事件视为澳大利亚地区动态海洋表面的背景信号。更新定义的应用突出了对当地内部强迫更敏感的区域，特别是在东澳大利亚洋流的主要流动上。此外，排除短期事件后，大堡礁的MHW面积呈现出更大的增长趋势。通过对澳大利亚两个沿海地区海平面异常（SLA）和海温指标之间的关系进行数值和图形评估，发现呈现大SLA指标两种变化趋势的较长MHW在西北沿海地区（NW）是ENSO主导。 ，东南沿海地区 (SETS) 受 ENSO 影响较小，但受到地理影响。然而，这两个地区的大多数短期事件可能是局部和内在变化或水柱海洋变暖的结果，而不是气候模式的远程调节的结果。此外，2008 年成功观测到西北地区地下 MHW 事件的 90% 的 SLA 具有帮助识别地下 MHW 的潜力，尽管受到应用领域的限制。 可能有必要进一步调查这些或其他类似的 MHW 定义更新的适用性，以得出广泛适用的结论，以对影响商业和环境活动的强地下 MHW 进行效益检测和预测。