The O2/N2 Ratio and CO2 Airborne Southern Ocean (ORCAS) Study

目前，南大洋吸收了大量人类排放到大气中的二氧化碳，但这一碳汇的未来轨迹高度不确定。稀疏的观测和复杂的相互作用的物理和生物过程限制了我们对南纬高纬度地区生物地球化学和气候反馈的理解。南大洋O2/N2比值和CO2气载（ORCAS）研究将促进我们对南大洋对流层O2和CO2海气交换的物理和生物控制的认识。这将通过在南太平洋和南极半岛选定的生物地球化学地点对大气中的O2、CO2、相关气体以及海洋表面特性进行密集的空中调查来实现。ORCAS将利用NSF/NCAR的湾流V （GV）飞机，配备一套高精度的原位和遥感仪器，以及全空气采样器，在南部仲夏进行为期6周的14次飞行。主要目的是观测大尺度对流层O2和CO2的分布，表征垂直O2和CO2梯度的区域尺度关系，并利用海洋表面同步生物光学遥感的拉格朗日边界层预算估算局地尺度O2通量。

The Southern Ocean currently absorbs a significant amount of the atmospheric burden of human produced CO2 emitted into the atmosphere, but the future trajectory of this sink is highly uncertain. Sparse observations and complex interacting physical and biological processes limit our understanding of biogeochemistry and climate feedbacks at high southern latitudes. The O2/N2 Ratio and CO2 Airborne Southern Ocean (ORCAS) Study will advance our understanding of the physical and biological controls on tropospheric air-sea exchange of O2 and CO2 over the Southern Ocean. This will be achieved through intensive airborne surveys of atmospheric O2, CO2, related gases, along with ocean surface properties over selected biogeochemical sites over the South Pacific and the Antarctic Peninsula. ORCAS will utilize the NSF/NCAR Gulfstream V (GV) aircraft with a suite of high precision in situ and remote sensing instruments, and whole-air samplers on 14 flights over an interval of 6 weeks in austral mid-summer. The primary objectives are to observe the large scale tropospheric distributions of O2 and CO2, to characterize regional scale relationships between vertical O2 and CO2 gradients, and to estimate local scale O2 fluxes via Lagrangian boundary layer budgeting with coincident bio-optical remote sensing of the ocean surface.