Near-Surface Salinity Reveals the Oceanic Sources of Moisture for Australian Precipitation through Atmospheric Moisture Transport
Near-Surface Salinity Reveals the Oceanic Sources of Moisture for Australian Precipitation through Atmospheric Moisture Transport
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DOI：
10.1175/jcli-d-19-0579.1
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发表时间：
2020-08
影响因子：
4.9
通讯作者：
S. Rathore;N. Bindoff;C. Ummenhofer;H. Phillips;M. Feng
中科院分区：
文献类型：
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作者：
S. Rathore;N. Bindoff;C. Ummenhofer;H. Phillips;M. Feng
海表盐度（SSS）的长期趋势表明，由于人类引起的气候变化，全球水文循环加剧。这项研究表明，SSS的变化也可以用来作为一个跨季节的年际时间尺度上的陆地降水的措施，并找到水分的来源。厄尔尼诺-南方涛动/印度洋偶极子（ENSO/IOD）事件期间的季节合成被用来了解澳大利亚上空的水汽输送和降水的变化，以及它们与SSS变率的关系。随着ENSO/IOD事件的发展，印度洋-太平洋暖池区出现了正或负的SSS异常，并伴随着向澳大利亚的大气水汽输送异常。在同时发生的拉尼娜和负IOD事件期间，海洋大陆（澳大利亚北部）周围的盐度异常表明淡水输出，并与在澳大利亚上空汇聚的显著水分输送有关，从而产生异常潮湿条件。相反，在厄尔尼诺和正IOD事件同时发生期间，澳大利亚上空的水汽输送散度异常导致异常干燥条件。SSS和大气水汽输送之间的关系也适用于纯ENSO/IOD事件，但在大小和空间格局上有所不同。ENSO/IOD事件期间水汽通量散度与SSS异常之间的显著型相关，突出了相关的海气耦合。澳大利亚极端水文气候事件的案例研究（例如，2010/11年布里斯班洪水）表明，SSS的变化发生在ENSO/IOD事件高峰之前。这提出了前景，跟踪SSS的变化可以帮助预测澳大利亚的降雨。
The long-term trend of sea surface salinity (SSS) reveals an intensification of the global hydrological cycle due to human-induced climate change. This study demonstrates that SSS variability can also be used as a measure of terrestrial precipitation on interseasonal to interannual time scales, and to locate the source of moisture. Seasonal composites during El Niño–Southern Oscillation/Indian Ocean dipole (ENSO/IOD) events are used to understand the variations of moisture transport and precipitation over Australia, and their association with SSS variability. As ENSO/IOD events evolve, patterns of positive or negative SSS anomaly emerge in the Indo-Pacific warm pool region and are accompanied by atmospheric moisture transport anomalies toward Australia. During co-occurring La Niña and negative IOD events, salty anomalies around the Maritime Continent (north of Australia) indicate freshwater export and are associated with a significant moisture transport that converges over Australia to create anomalous wet conditions. In contrast, during co-occurring El Niño and positive IOD events, a moisture transport divergence anomaly over Australia results in anomalous dry conditions. The relationship between SSS and atmospheric moisture transport also holds for pure ENSO/IOD events but varies in magnitude and spatial pattern. The significant pattern correlation between the moisture flux divergence and SSS anomaly during the ENSO/IOD events highlights the associated ocean–atmosphere coupling. A case study of the extreme hydroclimatic events of Australia (e.g., the 2010/11 Brisbane flood) demonstrates that the changes in SSS occur before the peak of ENSO/IOD events. This raises the prospect that tracking of SSS variability could aid the prediction of Australian rainfall.