Multidecadal changes in ocean transparency: Decrease in a coastal upwelling region and increase offshore
Multidecadal changes in ocean transparency: Decrease in a coastal upwelling region and increase offshore
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DOI：
10.1002/lno.12365
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发表时间：
2023-05
影响因子：
4.5
通讯作者：
M. Kahru;Z. Lee;M. Ohman
中科院分区：
文献类型：
--
作者：
M. Kahru;Z. Lee;M. Ohman
气候变化对海洋生态系统影响的检测通常受到可用时间序列持续时间短的限制。在这里，我们使用 1949 年以来加州洋流生态系统中的海洋透明度测量值（塞奇盘深度，ZSD），并将其与卫星估计值相结合。 ZSD 的历史现场测量在空间和时间上是不规则的，并且由于位置和时间变化引入的偏差而难以在时间序列中解释。我们使用卫星得出的平均气候学对历史 ZSD 测量进行标准化，并创建过去约 73 年的 ZSD 合并原位卫星时间序列。尽管ZSD的年际变率主要是由厄尔尼诺南方涛动相关的变率（在许多地区约占总变率的50%）主导，但在距海岸0-300公里的受北纬27°以北沿海上升流影响的地区，检测到透明度下降的长期趋势，该趋势与生产力的增加相关。相比之下，在近海（距海岸 > 1000 公里）检测到透明度增加（与生产力下降相关）。除了这些总体趋势之外，北纬 27°以南的下加利福尼亚州沿海地区的透明度也在增加。
Detection of the effects of climate change on ocean ecosystems is often limited by the short duration of available time series. Here, we use ocean transparency measurements (the Secchi disk depth, ZSD) in the California Current Ecosystem since 1949 and combine them with satellite estimates. Historic in situ measurements of ZSD were irregular in space and time and are difficult to interpret in time series due to biases introduced by changing locations and timing. We normalize historic ZSD measurements with satellite‐derived mean climatology and create a merged in situ—satellite time series of ZSD for the last ~ 73 yr. Although interannual variability in ZSD is dominated by El Niño Southern Oscillation‐related variability (~ 50% of the total variance in many areas), a secular trend of decreasing transparency that is correlated with increasing productivity is detected 0–300 km from the coast in an area affected by coastal upwelling north of 27°N. In contrast, increasing transparency (correlated with decreasing productivity) is detected offshore (> 1000 km from the coast). In addition to those general trends, transparency is also increasing in coastal area off Baja California south of 27°N.