冬季黑潮延伸体区域海表温度锋对北太平洋风暴轴的影响

发布时间：2018-01-05 03:06

本文关键词：冬季黑潮延伸体区域海表温度锋对北太平洋风暴轴的影响　出处：《气象学报》2017年01期 　论文类型：期刊论文

【摘要】：利用NOAA最优插值逐日海表温度资料和NCEP/NCAR的逐日大气再分析资料,分析了冬季黑潮延伸体区域海表温度锋的变化及其对北太平洋风暴轴的影响。结果表明,冬季黑潮延伸体区域海表温度锋强度和纬度位置既存在年际变化,也存在年代际变化,且强度和位置的变化是相互独立的。冬季黑潮延伸体区域海表温度锋强度的年际变化对北太平洋风暴轴没有显著的影响,而其年代际变化则对北太平洋风暴轴具有非常显著的影响,当冬季海表温度锋偏强时,大气斜压性在鄂霍次克海及阿拉斯加附近区域上空增强,而在海表温度锋下游至东太平洋区域上空显著减弱,平均有效位能向涡动有效位能的斜压能量转换在45°N以北的太平洋区域上空有所增多,而在30°—45°N的太平洋区域上空有所减少,涡动有效位能向涡动动能的斜压能量转换在35°N以北的西太平洋区域以及45°N以北的东太平洋区域都显著增加,而仅在其南部边缘存在东西带状的减弱区域,导致40°N以北海区北太平洋风暴轴增强,40°N以南海区北太平洋风暴轴减弱,冬季海表温度锋偏弱时则有与之相反的结果。冬季黑潮延伸体区域海表温度锋纬度位置的变化对北太平洋风暴轴也存在较显著的影响,当海表温度锋位置偏北时,在其下游45°N以南的太平洋区域上空大气斜压性减弱,45°N以南的中东太平洋区域上空区域平均有效位能向涡动有效位能、以及涡动有效位能向涡动动能的斜压能量转换都减少;而在45°N以北的太平洋区域上空大气斜压性增强,在阿拉斯加湾附近上空尤其显著,在黑潮延伸体区域附近以及45°N以北的中东太平洋上空平均有效位能向涡动有效位能、以及涡动有效位能向涡动动能的斜压能量转换都显著增加,导致北太平洋风暴轴在其气候平均态轴线两侧呈现北正南负的偶极子形态;海表温度锋位置偏南时则有与之相反的结果。冬季黑潮延伸体区域海表温度锋强度和位置的变化均对北太平洋风暴轴具有显著的影响,其具体的物理机制还需要进一步的研究。
[Abstract]:The NOAA optimal interpolation daily sea surface temperature data and the daily atmospheric reanalysis data of NCEP/NCAR are used. The variation of sea surface temperature front in winter Kuroshio extension region and its influence on the North Pacific storm track are analyzed. The results show that the intensity and latitude position of sea surface temperature front in winter Kuroshio extension region have interannual variations. There are also decadal variations, and the changes of intensity and location are independent of each other. The interannual variation of surface temperature front intensity in the Kuroshio extension region has no significant effect on the North Pacific storm track. The Interdecadal variation has a significant effect on the North Pacific storm track. When the sea surface temperature front is strong in winter, the baroclinic property of the atmosphere increases over the Okhotsk Sea and the area near Alaska. However, from the downstream of the sea surface temperature front to the eastern Pacific region, the baroclinic energy transfer from the mean effective potential energy to the vortex effective potential energy increases over the Pacific region north of 45 掳N. However, at 30 掳-45 掳N, there was a decrease over the Pacific region. The baroclinic energy conversion from vortex potential energy to vortex kinetic energy increases significantly in the western Pacific region north of 35 掳N and the eastern Pacific region north of 45 掳N. However, there are only east-west banded weakening areas in the southern margin of the North Sea, which results in the weakening of the North Pacific storm track in the North Sea region south of 40 掳N. When the sea surface temperature front is weak in winter, the opposite result is found. The variation of latitude position of sea surface temperature front in the Kuroshio extension area also has a significant effect on the north Pacific storm track. When the sea surface temperature front is located northward, the mean effective potential energy over the Middle East Pacific region south of 45 掳N is weakened over the Pacific region south of 45 掳N. And the baroclinic energy conversion from vortex potential energy to vortex kinetic energy is reduced. The atmospheric baroclinic over the Pacific region north of 45 掳N is stronger, especially near the Gulf of Alaska. In the vicinity of the Kuroshio extension and over the Middle East Pacific Ocean north of 45 掳N, the mean effective potential energy to the vortex potential energy and the baroclinic energy conversion from the vortex effective potential energy to the vortex kinetic energy are increased significantly. The results show that the north Pacific storm track shows a negative dipole shape on both sides of its climate mean axis. In winter, the intensity and position of sea surface temperature front in Kuroshio extension area have a significant effect on the north Pacific storm track. Its specific physical mechanism needs further study.
【作者单位】：中国人民解放军理工大学气象海洋学院;中国科学院大气物理研究所LASG国家重点实验室;
【基金】：国家重点基础研究发展计划973项目(2013CB956203) 国家自然科学基金项目(41490642、41475070和41375069)
【分类号】：P731.2
【正文快照】： 1引言黑潮是沿着北太平洋西部边缘向北流动的一支强西边界海流,它具有高温、高盐、流量大、流速大、厚度厚、流幅窄等特征(Nitani,1972;Su,et al,1990;Bryden,et al,1991)。黑潮的主干经吐噶喇海峡进入太平洋后,沿日本列岛南部海区向东的海流被称为黑潮延伸体(Qiu,2003)。冬

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