The determination of air‐sea exchange and oceanic mixing rates using 7Be during the Bomex experiment
The determination of air‐sea exchange and oceanic mixing rates using 7Be during the Bomex experiment
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DOI：
10.1029/jc079i030p04481
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发表时间：
1974-10
影响因子：
--
通讯作者：
J. Young;W. Silker
中科院分区：
文献类型：
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作者：
J. Young;W. Silker
1968年和1969年夏天，在巴巴多斯海洋学和气象学实验期间，测量了英属西印度群岛巴巴多斯以东地区空气、雨水和海水中的7 Be和其他放射性核素的浓度。由于海水在取样区的水平运动，海洋中的放射性核素存量变化很快。盐度也有很大的差异，可能是由于亚马孙河水被圭亚那洋流带入取样区域，圭亚那洋流沿沿着南美洲海岸向西北流动。1968年8月15日和1969年6月，法国在南纬23度进行的核试验中发现了大量的103 Ru/95 Zr放射性核素，这些放射性核素很可能是通过圭亚那洋流进入采样区的。1968年8月和1969年5月至7月取样区的降雨使7 Be在海面上的沉积量分别仅为维持所测总量所需的13%和26%。然而，清单可能是由采样区域以外的湿沉降造成的，例如在热带辐合带，随后水被平流输送到采样区域。计算出的7 Be的平均沉降速度为1.0 cm/s，计算出的7 Be通过海面的年平均通量为1.6×10−2 atom cm−2 s−1。计算得到的海中垂直涡动扩散系数从表层的大于7 cm ~ 2/s下降到30-40 m处的0.25- 0.85cm ~ 2/s。
The concentrations of 7Be and other radionuclides were measured in air, rain, and seawater in a region east of Barbados, British West Indies, in the summers of 1968 and 1969 during the Barbados Oceanographic and Meteorological Experiment. The radionuclide inventories in the sea varied rapidly owing to the horizontal motion of seawater through the sampling region. The salinity also varied considerably, presumably as a result of Amazon River water carried into the sampling region by the Guiana current, which flows northwestward along the coast of South America. The 103Ru to 95Zr ratio in the top 15 m of the sea indicated that large amounts of these radionuclides from the French nuclear test series at 23°S beginning July 7, 1968, were transported into the sampling region, probably by the Guiana current, on August 15, 1968, and also in June but not in May of 1969. The deposition Of 7Be on the sea surface by rainfall in the sampling region in August 1968 and May through July 1969 was only 13 and 26%, respectively, of that necessary to maintain the measured inventories. it is possible, however, that the inventories resulted from wet deposition outside the sampling region, such as in the intertropical convergence zone, followed by advective transport of the water into the sampling region. The calculated average deposition velocity Of 7Be was 1.0 cm/s, and the calculated average yearly 7Be flux across the sea surface was 1.6×10−2 atom cm−2 s−1. The calculated vertical eddy diffusion coefficient in the sea decreased from greater than 7 cm2/s at the surface to 0.25–0.85 cm2/s at 30–40 m.