The Distribution Of N₂O Along The Cruise Tracks And Prydz Bthay During The China27^th Antarctic Expediton

N₂O samples were taken during27thCHINARE （Chinese National AnatacticResearch Expedition） along the cruise tracks and Prydz Bay, Antarctic. A auto staticheadspace technique using CTC autosampler was used for sample analysis, and asemiconductive refrigerator was used to remove moisture from samples. The patternsof N₂O distribution, air-sea fluxes in surface seawater of cruise track and Prydz Baywere studied. The results show:1N₂O concentrations in surface waters vary between5.6-18.1nM, while thesaturation anomaly （SA） vary between-9.9～25.6%, the concentrations increase withlatitude. Sea surface temperature is dominant on surface water concentrationdistribution pattern. However, other factors deviate N₂O concentration fromequilibrium value. SA decrease from north to south, with STF （South Tropic Front） asa turning point. Positive Saturation anomaly of N₂O could be found north of STF,while negative value could be found in the north. The positive N₂O SA value found inthe north of STF may result from active nitrification in tropic region, while negativeN₂O value may be a result of glacier melting water input. However more effort shouldbe made to clarified the actual mechanism for negative mechanism of SA.2The N₂O in Prydz Bay surface seawater is understaturated. It could be result oficemelting water input, solar radiance and Ekman northward transport. The strongstratification hamper the material exchange between surface water and subsurfacewater. The slope break is set as a boundary for Ice shelf waters （ISW） andcircumpolar deep water （CDW）. Except for station IS01, other stations in ISW waterare undersaturated with N₂O, while in CDW, SA generally higher than10%. The N₂Oconcentration is between17-24nM. Upwelling of CDW or local production could bethe reason of over saturation found in CDW.3The relationship between△N₂O and AOU, accompany with DO, nitrate data islimited in explore the forming mechanism of N₂O. N*is used as and indicator ofnitrification and denitrification(N^*=[NO₃-]+[NO₂-]+[NH₄⁺]-16×[PO₄^3-]+2.9). The result shows that the N₂O forming mechanism in Prydz Bay is complicated, bothprocesses could co-exist in this region.4instantaneous fluxes is calculated to evaluate the air-sea exchange in study areas,the air sea flux in tropical region is-1.0to14.0μmol m^-2d^-1; while that of southernocean is-17.0to-1.0μmol m^-2d^-1; Prydz Bay also has a negative fluxes of-11.7to0.3μmol m^-2d^-1; the seasonal air–sea flux of southern ocean is about-0.5TgN. Theseresult suggest that Southern Ocean is a sink for atmospheric N₂O.