CAJ | 학술논문

南半球环状模是南半球热带外大气环流变异的主导模态，对南半球海洋—大气—海冰耦合系统有重要的影响。冰川融化激发的淡水强迫是南大洋的一种重要外强迫。在历史气候记录中，南大洋淡水通量异常曾引发数次全球性气候异常事件。基于海—气完全耦合模式FOAM，在60°S以南的海洋中施加强度为1.0 Sv的理想化淡水通量异常，分析南半球环状模的响应。结果表明：南大洋淡水通量异常可使局地西风增强，且西风的增强在垂向各个层次上均有体现。西风强度的变化导致对流层中大气斜压性增强，平流层中大气斜压性减弱。此外，淡水强迫使环状模的年际变率振幅显著减弱，而年代际变率开始增强，谱能量的变化具有垂向一致性。海温和海冰等外强迫因子的变化对环状模年代际振幅的增强具有重要意义。
남반구배상모시남반구열대외대기배류변이적주도모태，대남반구해양—대기—해빙우합계통유중요적영향。빙천융화격발적담수강박시남대양적일충중요외강박。재역사기후기록중，남대양담수통량이상증인발수차전구성기후이상사건。기우해—기완전우합모식FOAM，재60°S이남적해양중시가강도위1.0 Sv적이상화담수통량이상，분석남반구배상모적향응。결과표명：남대양담수통량이상가사국지서풍증강，차서풍적증강재수향각개층차상균유체현。서풍강도적변화도치대류층중대기사압성증강，평류층중대기사압성감약。차외，담수강박사배상모적년제변솔진폭현저감약，이년대제변솔개시증강，보능량적변화구유수향일치성。해온화해빙등외강박인자적변화대배상모년대제진폭적증강구유중요의의。
Southern Annular Mode (SAM)is a dominant mode of the southern extra-tropical circulation,which can exert a strong influence on the ocean-atmosphere-sea ice coupled system in the Southern Ocean (SO).Fresh-water forcing induced by ice-melting is important for the SO.In historical climate records,SO freshwater flux a-nomaly used to trigger several global climate abnormal events.Based on the ocean-atmosphere fully coupled model FOAM,the response of SAM to idealized freshwater forcing was investigated with 1 .0 Sv freshwater flux anomaly imposed uniformly to the south of 60°S in the SO in order to study the change of SAM induced by the local forc-ing.The results indicate that local westerly wind is significantly strengthened,which can be seen from lower layers to upper layers.Change of westerly wind intensity increases baroclinicity in the troposphere and decreases barocli-nicity in the stratosphere.Moreover,the interannual variability of SAM remarkably weakens,while the interdecadal variability strengthens.Change of spectrum energy is consistent at all vertical layers.Variation of external forcing such as sea surface temperature and sea ice largely contributes to the enhancement of decadal variability of SAM.