高低层纬向风异常与西北太平洋热带气旋生成年频数关系的研究

RELATIONSHIPS BETWEEN ZONAL WIND ANOMALIES IN HIGH AND LOW TROPOSPHERE AND ANNUAL FREQUENCY OF NW PACIFIC TROPICAL CYCLONE

采用相关和合成分析方法,研究了热带太平洋地区大尺度高低层纬向风异常与西北太平洋热带气旋生成年频数的关系及其影响的可能机理。结果表明:赤道东太平洋地区ΔU200-ΔU850>0,西太平洋热带地区ΔU200-ΔU850<0,热带太平洋地区沃克环流偏强,西北太平洋热带气旋生成年频数偏多。高低层纬向风异常年,对流层上、下部环流和对流层中垂直运动有显著的特征。在短期气候预测的时间尺度上,前期高低层纬向风异常可以作为预测热带气旋生成年频数的前兆信号。

Relationships and possible mechanisms between large-scale zonal wind anomalies and the annual frequencies of NW Pacific tropical cyclone are investigated with the methods of correlation and composition. It is indicated that when △ U200-△ U850 〉0 in the eastern tropical Pacific and △ U200-△ U850 〈0 in western tropical Pacific, Walker cell is stronger in the Pacific tropical region and the annual frequencies of NW Pacific tropical cyclone are above normal. In the years with zonal wind anomalies, the circulation of high and low troposphere and the vertical motions in the troposphere have significant characteristics. In the time scale of short-range climate prediction, zonal wind anomalies in high and low troposphere are useful as preliminary signal of the annual frequencies prediction of NW Pacific tropical cyclones.