温州至莆田登陆台风对平阳暴雨的影响研究

Study on the Rainstorm in Pingyang Associated with Typhoons Making Landfall between Wenzhou and Putian

摘要: 利用NCEP/NCAR 2.5˚ × 2.5˚每日4次再分析资料对2007~2017年温州至莆田登陆台风对平阳雨量影响进行研究。结果表明：温州至莆田登陆台风一般会对平阳雨量造成明显影响，雨量分布多为西多东少型，登陆后路径为北上和西移。明显影响台风的相对湿度较大、水汽通量较大，低层有明显偏东急流和强烈上升运动，高层强辐散、低层强辐合。有冷空气的渗透，一般也会造成明显的雨量影响。温州至宁德登陆的台风，700 hPa相对湿度超过92.5%，850 hPa水汽通量超过17 × 10⁻² g∙cm⁻¹∙hPa⁻¹∙s⁻¹，850 hPa有12 m/s以上的偏东急流，850 hPa垂直速度ω < −0.35 pa/s，200 hPa散度 > 1.5 × 10⁻⁵ s⁻¹、925 hPa散度 < −2 × 10⁻⁵ s⁻¹，更容易出现明显影响；福州至莆田登陆的台风，700 hPa相对湿度超过82.5%，850 hPa水汽通量超过20 × 10⁻² g∙cm⁻¹∙hPa⁻¹∙s⁻¹，850 hPa有14 m/s以上的偏东急流，850 hPa垂直速度ω < −0.3 pa/s，200 hPa散度 > 0.6 × 10⁻⁵ s⁻¹、925 hPa散度 < −2 × 10⁻⁵ s⁻¹，更容易出现明显影响。

Abstract: Using reanalysis data of NCEP/NCAR 2.5˚ × 2.5˚ four times a day, the impact of typhoon making landfall between Wenzhou and Putian during 2007~2017 on rainfall in Pingyang is analyzed. The results show that the typhoon making landfall between Wenzhou and Putian will bring obvious precipitation to Pingyang, and the rainfall in the west is more than the east, and the path after landing is northward and westward. The characteristics of typhoon with obvious influence are large relative humidity and water vapor channel, the low troposphere has E jet and strong ascending motion, the high troposphere has strong divergence and the lower has strong convergence. If there is penetration of cold air, it will also cause obvious rainfall effects. The 700 hPa lative humidity exceeds 92.5% when the typhoon lands in Wenzhou to Ningde, the 850 hPa water vapor flux exceeds 17 × 10⁻² g∙cm⁻¹•hPa⁻¹•s⁻¹, the 850 hPa eastward jet exceeds 12 m/s, the 850 hPa vertical velocity is less than −0.35 pa/s, the 200 hPa divergence is greater than 1.5 ×10⁻⁵ s⁻¹, the 925 hPa divergence is less than −2 × 10⁻⁵ s⁻¹, which is more likely to have obvious impact. The 700 hPa relative humidity exceeds 82.5% when the typhoon lands in Fuzhou to Putian, the 850 hPa water vapor flux exceeds 20 × 10⁻² g•cm⁻¹∙hPa⁻¹∙s⁻¹, the 850 hPa eastward jet exceeds 14 m/s, the 850 hPa vertical velocity is less than −0.3 pa/s, the 200 hPa divergence is greater than 0.6 × 10⁻⁵ s⁻¹, the 925 hPa divergence is less than −2 ×10⁻⁵ s⁻¹, which is more likely to have obvious impact.