Winter Water (WW) is a feature in the upper layers of the Southern Ocean during austral summer. The interaction of this cold water with surface and deeper subsurface layers can alter the heat budget as well as the carbon cycle. However, the structure and characteristics of the WW in the Southern Ocean is poorly understood due to the lack of in-situ data. In this study, hydrographic data collected from the Indian expeditions during 2010 and 2011 and from other expeditions during 2003, 2006 and 2007 in the Southern Ocean have been utilized to understand the WW variability and its characteristics in the region between 40°E and 90°E. The analysis shows large zonal variations in the distribution of WW during austral summer. East of 60°E, the WW shows warmer temperature with weaker gradients than the western side, which is observed to have a larger meridional extension. The high frequency of eddies, surface warming and upwelling of the Upper Circumpolar Deep Water due to shallow bathymetric features of the Kerguelen Plateau situated in the eastern side of the study region is proposed as the major mechanisms for this variability. The direct impact of Southern Annular Mode on WW variability is investigated and a short term response is observed.

在南方夏季，冬季水（WW）是南大洋上层的一个特征。这种冷水与表层和更深的地下层的相互作用会改变热量收支以及碳循环。然而，由于缺乏原地，人们对南大洋WW的结构和特征了解甚少数据。在这项研究中，利用2010年和2011年印度探险队以及2003年，2006年和2007年南洋其他探险队收集的水文数据来了解40°E至90°之间区域的WW变异性及其特征。 E．分析表明，在南方夏季，WW的分布存在较大的纬向变化。在60°E以东，WW显示的温度比西侧的温度更高，且梯度较弱，这被认为具有更大的子午线延伸。提出了由位于研究区域东部的克格伦高原的浅水深特征引起的高涡旋，上极极地深水的表面变暖和上升流是这种变化的主要机制。