N2O在全球变化扮演重要角色，海洋是N2O的主要来源之一。然而，南大洋N2O的研究至今仍十分有限。本研究针对调查发现的南大洋表层海水N2O不饱和现象，提出科学假说：1）普里兹湾陆缘水边界两侧水体N2O分布特征受不同物理控制过程和生物形成机制影响，陆缘水边界混合过程促进锋面区域次表层水体中N2O生产；2）南大洋表层海水应存在融冰水和降水输入等机制，在夏季强烈的层化作用下维持N2O不饱和状态；3）上述过程作用共同促使夏季南大洋成为大气N2O的汇。为证实上述假说，本项目拟展开若干航次，采集N2O, H2O、N2O稳定同位素，以及化学物理参数，探讨南大洋不同海区N2O形成机制，建立模型模拟表层海水N2O不饱和状态的驱动机制；最终通过遥感和海气通量等方法，评估夏季南大洋汇强度，及其对全球N2O收支的贡献。

N2O is one of the most important green house gases and ozone deplector which is more and more concerned by researchers recently. Ocean is regarded as one of the most important N2O sources. However, little is known so far about the role Sothern Ocean plays in global N2O budget, thought it was considered as the most significant oceanic N2O source area. Three hypothesis were put forward according to the results of field work:1) N2O in ice shelf waters and circumpolar deep waters are formed by different mechanism and affected by different physical processes; mixing of these two water masses enhence production of N2O in subsurface water near the Continental Water Boundary, 2) undersaturation of N2O in surface Southern Ocean is maintained by gracier melt water, wet deposition and strong stratification during summer 3) above processes make Southern Ocean a sink for N2O during summer time. To prove these hypothesis,several cruises is planned to take N2O, H2O and N2O stable isotopic sample. using these and nutrient, CTD data,forming mechanism of N2O will be discussed. Model will be set up to stimulate the processes that sustain the undersaturation of N2O in Southern Ocean surface water and analysis its driving mechanism. Finaly, air-sea fluxes model combine with remote sensing will be used to estimate the sink strength of Southern Ocean and its impact on global N2O budget.