Temporal increases of phosphate and apparent oxygen utilization in the subsurface waters of western subarctic Pacific from 1968 to 1998
Temporal increases of phosphate and apparent oxygen utilization in the subsurface waters of western subarctic Pacific from 1968 to 1998
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DOI：
10.1029/2001gl012948
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发表时间：
2001-09-01
影响因子：
5.2
通讯作者：
Saino, T
中科院分区：
文献类型：
--
作者：
Ono, T;Midorikawa, T;Saino, T
30-年的时间序列中，AOU和磷酸盐的Oyashio次表层域叠加在双底振荡的增加趋势。26.7和27.2 sigma（0）之间等密度线上的AOU和磷酸盐趋势分别平均增加0.9 +/-0.5和0.005 +/-0.003 μ mol/kg/y。这些等密度线上的盐度也显示出0.0008 psu/y的平均线性增加。另一方面，冬季混合层的盐度和密度在观测期间有所下降。观测到的次表层AOU的双十年振荡（平均周期为20 +/-1年）与北太平洋指数的双十年振荡呈负相关（r=-0.88 +/-0.06）。作为次表层磷酸盐和AOU线性增加的原因，我们推测，在此期间，在亚北极北太平洋上层的垂直水交换可能已经减少。在同一时期观测到的Oyashio冬季混合层的盐度和密度的下降趋势支持了这一推测。
30-years time series of AOU and phosphate in the Oyashio sub-surface domain showed an increasing trend superimposed on bidecadal oscillation. AOU and phosphate trend on isopycnals between 26.7 and 27.2 sigma (0) increased by an average of 0.9 +/-0.5 and 0.005 +/-0.003 mu mol/kg/y, respectively. Salinity on these isopycnals also showed an average linear increase of 0.0008 psu/y. Salinity and density of winter mixed layer, on the other hand, was found to have decreased during the observation period. Observed bidecadal oscillation (average period 20 +/-1 y) in subsurface AOU negatively correlated with that of North Pacific Index (r=-0.88 +/-0.06). As the cause of the linear increase of subsurface phosphate and AOU, we speculated that vertical water exchange in the upper layers of the subarctic North Pacific might have been diminished during this period. A decreasing trend of salinity and density of winter mixed layer in Oyashio that was observed during the same period supported this speculation.