Upwelling and associated heat flux in the equatorial Atlantic inferred from helium isotope disequilibrium
Upwelling and associated heat flux in the equatorial Atlantic inferred from helium isotope disequilibrium
复制标题
根据氦同位素不平衡推断赤道大西洋的上升流和相关热通量
DOI：
10.1029/2009jc005772
复制
发表时间：
2010
影响因子：
--
通讯作者：
B. Bourles
中科院分区：
文献类型：
--
作者：
M. Dengler;J. Sültenfuß;R. Hummels;S. Hüttl-Kabus;B. Bourles
赤道带上的上升流速度太小，不能直接观测到。在这里，我们应用最近提出的间接方法，使用观察到的氦同位素（3 He或4 He）在混合层的不平衡。氦数据是从2005年9月和2006年6月/7月在热带大西洋东部的三次巡航中取样的。应用了一维双箱模型，其中氦空气-海洋气体交换通过混合层下方富含3 He的水的上涌和垂直混合来平衡。混合系数Kv是根据微结构测量估算的，在其中两次航行中，Kv超过了1 × 10− 4 m2/s，使得垂直混合项与气体交换和上升流项具有相同的数量级。总共有54个站点观测到氦不平衡。在计算的上升流速度中，48%小于1.0 × 10− 5 m/s，19%在1.0和2.0 × 10− 5 m/s之间，22%在2.0和4.0 × 10− 5 m/s之间，11%的上升流速度超过这个极限。最高的上升流速度被发现在2006年6月下旬。经向上升流的分布表明赤道不对称，赤道以南1° ~ 2°处的垂直速度高于赤道以北，尤其是10°W处。进入混合层的相关热通量可能高达138 W/m2，但这在很大程度上取决于所选择的上升水来自的深度。通过结合上升流速度与海面温度和生产力分布，2006年6月的平均月赤道上升流率估计为19 Sv，2005年9月的双周平均值估计为24 Sv。
Upwelling velocitieswin the equatorial band are too small to be directly observed. Here, we apply a recently proposed indirect method, using the observed helium isotope (3He or4He) disequilibria in the mixed layer. The helium data were sampled from three cruises in the eastern tropical Atlantic in September 2005 and June/July 2006. A one‐dimensional two‐box model was applied, where the helium air‐sea gas exchange is balanced by upwelling from3He‐rich water below the mixed layer and by vertical mixing. The mixing coefficientsKvwere estimated from microstructure measurements, and on two of the cruises,Kvexceeded 1 × 10−4m2/s, making the vertical mixing term of the same order of magnitude as the gas exchange and the upwelling term. In total, helium disequilibrium was observed on 54 stations. Of the calculated upwelling velocities, 48% were smaller than 1.0 × 10−5m/s, 19% were between 1.0 and 2.0 × 10−5m/s, 22% were between 2.0 and 4.0 × 10−5m/s, and on 11% of upwelling velocities exceeded this limit. The highest upwelling velocities were found in late June 2006. Meridional upwelling distribution indicated an equatorial asymmetry with higher vertical velocities between the equator and 1° to 2° south compared to north of the equator, particularly at 10°W. Associated heat flux into the mixed layer could be as high as 138 W/m2, but this depends strongly on the chosen depths where the upwelled water comes from. By combining upwelling velocities with sea surface temperature and productivity distributions, a mean monthly equatorial upwelling rate of 19 Sv was estimated for June 2006 and a biweekly mean of 24 Sv was estimated for September 2005.
登录
查看更多内容
大西洋和太平洋热带细胞运动学证据的比较
DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
R. Molinari;S. Bauer;D. Snowden;G. Johnson;B. Bourlès;Y. Gouriou;H. Mercier
通讯作者：
H. Mercier
影响因子：
5.2
作者：
S. Grodsky;J. Carton
通讯作者：
J. Carton
影响因子：
5.2
作者：
T. Naegler;P. Ciais;K. Rodgers;I. Levin
通讯作者：
T. Naegler;P. Ciais;K. Rodgers;I. Levin
影响因子：
3.5
作者：
F. Marin;G. Caniaux;B. Bourlès;H. Giordani;Y. Gouriou;E. Key
通讯作者：
F. Marin;G. Caniaux;B. Bourlès;H. Giordani;Y. Gouriou;E. Key
影响因子：
--
作者：
Verena Hormann;P Brandt
通讯作者：
Verena Hormann;P Brandt