Settling of particles in the upper 100 m of the ocean detected with autonomous profiling floats off California
Settling of particles in the upper 100 m of the ocean detected with autonomous profiling floats off California
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DOI：
10.1016/j.dsr.2015.02.001
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发表时间：
2015-05-01
影响因子：
2.4
通讯作者：
Dagg, Michael
中科院分区：
文献类型：
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作者：
Jackson, George A.;Checkley, David M., Jr.;Dagg, Michael
我们已经部署了一个自主剖面浮标SOLOPC，以大约每小时一次的间隔对加州海岸外大于100微米的颗粒浓度进行采样，采样时间长达12天。我们使用这些数据来估计每小时2米深度的总聚集浓度，研究这个难以采样的区域的颗粒沉积动力学。我们发现，即使在一周的时间尺度上，沉积也是高度可变的，大约四分之一的日子发生了可检测到的沉积事件。这些观测大多发生在美国西南海岸，该地区以沿海上升流而闻名，并不一定代表营养较少的地区。我们估计的总沉降率约为50md(-1)，与现场测量和根据混凝模型计算的沉降率一致。观测之间的时间间隔及其垂直分辨率限制了可以测量的速度。要捕获速度小于100md(-1)的近地表集合体的颗粒沉降，需要不超过约0.25d的采样间隔和2m的垂直分辨率。这项技术为研究颗粒的动力学及其在海洋表面附近的沉积提供了一个强大的新工具，海洋表面是出口的起点。(C)2015年提交人。爱思唯尔有限公司出版。
We have deployed an autonomous profiling float, the SOLOPC, to sample the concentration of particles larger than 100 mu m off the California coast at approximately hourly intervals down to at least 100 m for periods as long as 12 d. We used the data to estimate total aggregate concentrations hourly at 2-m depth intervals, studying the dynamics of particle sedimentation in this difficult-to-sample region. We find that even over time scales of a week, sedimentation is highly variable, with detectable sedimentation events on about one quarter of the days. Most of these observations were along the southwest coast of the United States, a region known for its coastal upwelling and not necessarily representative of more oligotrophic regions. The aggregate settling rates that we estimate, on the order of 50 m d(-1), are consistent with in situ measurements and with rates calculated from coagulation models. The time interval between observations and their vertical resolution constrain the velocities that can be measured. To capture particle settling with velocities less than the 100 m d(-1) that is usually reported for near surface aggregates requires a sampling interval no more than about 0.25 d with a 2 m vertical resolution. This technique provides a powerful new tool to study the dynamics of particles and their sedimentation near the ocean surface, where export starts. (C) 2015 The Authors. Published by Elsevier Ltd.