Isotopic, chemical and crystallographic characteristics of first-year sea ice from Breid Bay (Princess Ragnhild Coast — Antarctica)
Isotopic, chemical and crystallographic characteristics of first-year sea ice from Breid Bay (Princess Ragnhild Coast — Antarctica)
复制标题
布雷德湾（拉格希尔德公主海岸 — 南极洲）第一年海冰的同位素、化学和晶体学特征
作者：
J. Tison;J. Haren
本文描述了来自南极Syowa站附近的Breid湾的一个1.64米长的一年海冰核心的冰结构、氘含量和钠浓度的详细概况。核心主要由巴西冰（77%）组成，这是最近对威德尔海地区第一年海冰覆盖的扩展研究中观察到的一个共同特征。既没有雪冰，也没有血小板冰。地核的其余部分由凝结冰组成。典型的冰板/盐水片的亚结构只出现在地核的底部。否则，细粒冰就会被“夹”在巴西冰层之间。它缺乏晶内亚结构，但在水平面上表现出较强的织构伸长和c轴聚集。分析了布雷德湾第一年海冰覆盖的演变过程。动力学成分在威德尔海东部发挥了重要作用，但在这一地区似乎不太重要，因为热力学可以很好地解释岩心的同位素、化学和结构特征。有人提出，地核的最上层是由风和波引起的湍流产生的冰。一旦提供了固结的冰盖，通过凝结冰的形成和由水柱中的热盐对流过程引发的冰的产生，冰的生长以较慢的速度进行。较低的细粒凝结冰和冰凌交替层可能是由与一年中的主要气象事件有关的冰水界面的循环热和盐度制度造成的。
A detailed profile of the ice fabric, the deuterium content and the sodium concentration of a 1.64 m long, first-year sea-ice core from Breid Bay, near Syowa station (Antarctica), is described. The core consists mainly of frazil ice (77%), a common feature observed in recent extended studies of the first-year sea-ice cover in the Weddell Sea area. Neither snow ice, nor platelet ice is present. The remainder of the core consists of congelation ice. The typical substructure of ice plates/brine lamellae occurs only at the bottom of the core. Otherwise fine-grained congelation ice is ‘sandwiched’ between layers of frazil. It lacks the intracrystalline substructure but shows a strong textural elongation and c-axis clustering in the horizontal plane. The evolution processes of the first-year sea-ice cover in Breid Bay are analysed. The dynamical component, demonstrated to play a major role in the eastern Weddell Sea, seems to be of minor importance in this area, where thermodynamics satisfactorily explains the isotopic, chemical and textural characteristics of the core. It is proposed that the topmost part of the core consists of frazil ice produced by wind- and wave-induced turbulence. Once a consolidated ice cover is provided, the growth proceeds at a slower rate, through congelation ice formation and frazil ice production, initiated by thermohaline convection processes in the water column. The lower alternate layers of fine grained congelation ice and frazil ice could result from cyclic thermal and salinity regimes at the ice-water interface, connected with the major meteorological events of the year.