Impact of Upper-tropospheric Environmental Field on Rapid Intensification of Typhoon Hagupit (2020)
-
摘要: 近海迅速增强(RI)是当前台风强度预报中的难点。为加深台风强度变化机理认识和提高台风强度预报水平，利用中国气象局最佳路径数据和ERA5大气再分析资料，分析了历史罕见的东海近海台风“黑格比”(2020)在RI阶段的高层环境场特征，着重探讨了高层环境场影响台风强度的可能过程。结果显示：(1)“黑格比”的RI过程中，南亚高压与热带对流层上部槽之间的强风速带增强了台风东南侧高空外流，中纬度高空槽增强了台风北侧高空外流。(2) 高层环境场与台风高空外流的相互作用有利于台风增强。一方面，有利的高空形势向台风中心传播涡动角动量通量辐合来增强台风高空外流，进而加强高空外流与上升运动形成的次级环流，促进台风中心气压降低和强度增强；另一方面，增强的台风高空外流限制了垂直风切变的发展，从而减弱环境场的通风效应，有助于台风加强。(3) 360 K等熵面上环境场高位涡向台风中心输送，同时平流层“高位涡库”向下打通，可以促进台风高层暖心形成，有利于台风加强。针对高层环境场的综合分析可以为台风强度预报提供一定的参考。Abstract: Rapid intensification (RI) remains a challenge in typhoon intensity forecasting. In order to enhance the understanding of the mechanism behind typhoon intensity variation and to improve the accuracy of typhoon intensity forecasts, this study analyzed the characteristics of the upper-tropospheric environmental field during the RI of Typhoon Hagupit (2020). Using the CMA Tropical Cyclone Best Track Dataset and the ERA5 reanalysis data, the present study discussed the possible mechanisms by which the upper-tropospheric environmental field affected typhoon intensity. The results show that: (1) The upper-level weather systems affecting the intensity of Typhoon Hagupit (2020) mainly included the South Asian high, the tropical upper-tropospheric trough, and the mid-latitude trough. (2) The upper-tropospheric environmental field facilitated the intensification of Typhoon Hagupit (2020) through its interaction with the upper-level outflow of the typhoon. On the one hand, favorable upper-tropospheric circulation enhanced the upper-level outflow by directing the eddy flux convergence of relative angular momentum to propagate toward the typhoon center. This process promoted the secondary circulation formed by the outflow and upward motion, leading to a decrease in the central pressure of Typhoon Hagupit (2020) and an increase in its intensity. On the other hand, the enhanced outflow restricted the development of the vertical wind shear and, consequently, weakened the ventilation effect and intensified the typhoon. (3) On the 360-K isentropic surface, the presence of small-scale positive potential vorticity (PV) anomalies atop the typhoon circulation enhanced the typhoon's intensity. At the same time, the"high-PV pool"in the stratosphere was connected with the positive PV anomaly region in the middle troposphere, which could promote the formation of the upper-level warm core and intensify the typhoon. The present study shows that a comprehensive analysis of the upper-tropospheric environmental field can offer insights for typhoon intensity forecasting.
-
图 1 台风“黑格比”(2020) 的路径与强度变化
a. 移动路径（黑色虚线为24小时警戒线）；b. 最低海平面气压（蓝色，单位：hPa）与最大地面风速（红色，单位：m·s-1）的时间序列。两条垂直参考线分别代表RI开始时刻和RI结束时刻，蓝色阴影区域为RI时段。
图 2 “黑格比”(2020) RI开始时刻（8月2日18时）周围的大尺度环流形势
a. 200 hPa位势高度场（等值线，单位：dagpm）、全风速（填色，单位：m·s-1）、风场；b. 500 hPa位势高度场（等值线，单位：dagpm）、全风速（填色，单位：m·s-1）、风场；c. 850 hPa位势高度场（等值线，单位：dagpm）、水汽通量散度（填色，单位：10-8 g·cm-2·hPa-1·s-1）、水汽通量（箭头）；d. 平均海平面气压（等值线，单位：hPa）、海平面温度（填色，单位：℃）、风场。
图 3 以台风“黑格比”(2020)为中心20 °×20 °范围内的200 hPa风场（箭头）和水平散度场（阴影，单位：10-5 s-1）
a. 8月2日12时；b. 8月2日18时；c. 8月3日00时；d. 8月3日06时；e. 8月3日12时；f. 8月3日18时。蓝色箭头示意台风的高空外流。坐标轴为距离台风中心的经纬度。
图 4 “黑格比”(2020)方位角平均的切向风（等值线，单位：m·s-1）、径向风（阴影，单位：m·s-1）与垂直环流（箭头，径向风-垂直速度×(-10)，单位：m·s-1）
a. 8月2日12时；b. 8月2日18时；c. 8月3日00时；d. 8月3日06时；e. 8月3日12时；f. 8月3日18时。
图 5 以“黑格比”(2020)为中心四个象限内方位角平均的150 hPa径向风（单位：m·s-1）的时间-半径变化
a. 东北象限(NE)；b. 东南象限(SE)；c. 西南象限(SW)；d. 西北象限(NW)。参考线含义同图 1。
图 6 距离台风“黑格比”(2020)中心200~800 km环状范围内平均的环境风垂直分布与各层垂直风切变的时间序列
a. 环境风；b. 垂直风切变，实线：200~850 hPa，虚线：200~500 hPa，点划线：500~850 hPa，单位：m·s-1。参考线含义同图 1。
图 7 台风“黑格比”涡动角动量通量辐合(EFC)的垂直分布与时间演变
a. RI开始时刻（8月2日18时）EFC的半径- 气压分布; b. 100~300 hPa平均的EFC的时间-半径变化。单位：m·s-1·day-1，参考线含义同图 1。
图 8 以台风“黑格比”(2020)为中心20 °×20 °范围内的360 K等熵面上的风场（箭头，单位：m·s-1）和位涡（填色，单位：PVU，等值线为0.5 PVU）
a. 8月2日12时；b. 8月2日18时；c. 8月3日00时；d. 8月3日06时；e. 8月3日12时；f. 8月3日18时。
图 9 台风“黑格比”中心附近的位涡、位温和扰动温度分布
a. 2 °×2 °范围内平均位涡的时间-等熵面分布，单位：PVU；b. 2 °×2 °范围内平均位温的时间-等压面分布，单位：K；c. 2 °×2 °范围内的平均温度减去16 °×16 °范围内的平均温度得到的扰动温度的时间-等压面分布，单位：℃。参考线含义同图 1。
表 1 台风“黑格比”(2020) 强度变化
时间/UTC 风速/(m·s-1) 6 h ΔV/(m·s-1) 12 h ΔV/(m·s-1) 24 h ΔV/(m·s-1) 说明 0118 18 2 5 7 0200 20 3 3 10 0206 23 0 2 10 0212 23 2 7 19 0218 25 5 8 17 RI开始 0300 30 3 12 －2 0306 33 9 9 －5 0312 42 0 －14 －17 0318 42 －14 －14 －19 RI结束 0400 28 0 －3 －5 0403 28 －3 －5 －8 
下载: 导出CSV
-
[1] 卢莹, 赵海坤, 赵丹, 等. 1984-2017年影响中国热带气旋灾害的时空特征分析[J]. 海洋学报(中文版), 2021, 43(6): 45-61. [2] YU H, CHEN G, ZHOU C, et al. Are we reaching the limit of tropical cyclone track predictability in the Western North Pacific?[J]. Bulletin of the American Meteorological Society, 2022, 103(2): E410-E428. [3] 周冠博, 柳龙生, 董林, 等. 2020年西北太平洋台风活动特征和预报难点分析[J]. 气象, 2022, 48(4): 504-515. [4] 向纯怡, 许映龙, 高拴柱, 等. 2021年西北太平洋台风活动特征和预报难点分析[J]. 气象, 2022, 48(9): 1 195-1 208. [5] 张守峰, 余晖, 向纯怡. 中央气象台台风强度综合预报误差分析[J]. 气象, 2015, 41(10): 1 278-1 285. [6] 端义宏, 余晖, 伍荣生. 热带气旋强度变化研究进展[J]. 气象学报, 2005, 63(5): 636-645. [7] 陈建萍, 周伟灿, 尹洁. 国内外热带气旋强度变化研究现状[J]. 气象与减灾研究, 2007, 30(3): 40-47. [8] DAI Y, MAJUMDAR S J, NOLAN D S. Secondary eyewall formation in tropical cyclones by outflow-jet interaction[J]. Journal of the Atmospheric Sciences, 2017, 74(6): 1 941-1 958. [9] RYGLICKI D R, DOYLE J D, HODYSS D, et al. The unexpected rapid intensification of tropical cyclones in moderate vertical wind shear. Part Ⅲ: Outflow-Environment Interaction[J]. Monthly Weather Review, 2019, 147(8): 2 919-2 940. [10] 李艳, 金茹, 高翔. 不同再分析资料对热带气旋Roke(2011)外流-高空急流相互作用的对比[J]. 大气科学学报, 2020, 43(3): 525-536. [11] HOLLAND G J, MERRILL R T. On the dynamics of tropical cyclone structural changes[J]. Quart J Roy Meteor Soc, 1984, 110(465): 723-745. [12] DITCHEK S D, MOLINARI J, VOLLARO D. Tropical cyclone outflow-layer structure and balanced response to eddy forcings[J]. J Atmos Sci, 2017, 74(1): 133-149. [13] RAPPIN E D, MORGAN M C, TRIPOLI G J. The impact of outflow environment on tropical cyclone intensification and structure[J]. Journal of the Atmospheric Sciences, 2011, 68(2): 177-194. [14] CHEN L, GRAY W M. Global view of the upper level outflow pattern associated with tropical cyclone intensity changes during FGGE[R]. Department of Atmospheric Science Paper NO. 392, Colorado State University, Fort. Collins, CO, 1985: 126. [15] MERRILL R T. Characteristics of the Upper-Tropospheric Environmental Flow around Hurricanes[J]. Journal of the Atmospheric Sciences, 1988, 45(11): 1 665-1 677. [16] MERRILL R T. Environmental influences on hurricane intensification[J]. Journal of the Atmospheric Sciences, 1988, 45(11): 1 678-1 687. [17] 李艳, 周灏, 葛旭阳, 等. 西北太平洋迅速加强热带气旋的高空外流特征分析[J]. 热带气象学报, 2017, 33(2): 145-154. [18] BOSART L F, VELDEN C S, BRACKEN W E, et al. Environmental Influences on the Rapid Intensification of Hurricane Opal (1995) over the Gulf of Mexico[J]. Monthly Weather Review, 2000, 128(2): 322-352. [19] MOLINARI J, VOLLARO D. External Influences on Hurricane Intensity. Part I: Outflow Layer Eddy Angular Momentum Fluxes[J]. Journal of the Atmospheric Sciences, 1989, 46(8): 1 093-1 105. [20] YAN Z, GE X, WANG Z, et al. Understanding the impacts of upper-tropospheric cold low on typhoon jongdari (2018) using piecewise potential vorticity inversion[J]. Monthly Weather Review, 2021, 149(5): 1 499-1 515. [21] JIN R, LI Y, CHEN X, et al. Characteristics of the upper-level outflow and its impact on the rapid intensification of Typhoon Roke (2011) [J]. Frontiers in Earth Science, 2023, 10: 1021308. [22] FISCHER M S, TANG B H, CORBOSIERO K L. A climatological analysis of tropical cyclone rapid intensification in environments of upper-Tropospheric Troughs[J]. Monthly Weather Review, 2019, 147(10): 3 693-3 719. [23] MOLINARI J, VOLLARO D, SKUBIS S. External influences on hurricane intensity. 3. Potential Vorticity Structure[J]. Journal of the Atmospheric Sciences, 1995, 52(20): 3 593-3 606. [24] MOLINARI J, SKUBIS S, VOLLARO D, et al. Potential vorticity analysis of tropical cyclone intensification[J]. Journal of the Atmospheric Sciences, 1998, 55(16): 2 632-2 644. [25] LEROUX M D, PLU M, BARBARY D, et al. Dynamical and physical processes leading to tropical cyclone intensification under upperlevel trough forcing[J]. Journal of the Atmospheric Sciences, 2013, 70(8): 2 547-2 565. [26] WANG Y, RAO Y, TAN Z M, et al. A Statistical analysis of the effects of vertical wind shear on tropical cyclone intensity change over the western north pacific[J]. Monthly Weather Review, 2015, 143(9): 3 434-3 453. [27] HUANG Q, GE X, PENG M. Simulation of rapid intensification of super typhoon lekima (2019). part i: evolution characteristics of asymmetric convection under upper-level vertical wind shear[J]. Frontiers in Earth Science, 2021, 9: 739507. [28] HUANG Q, GE X, BI M. Simulation of Rapid Intensification of Super Typhoon Lekima (2019). Part Ⅱ: The critical role of cloud-radiation interaction of asymmetric convection[J]. Frontiers in Earth Science, 2022, 9: 832670. [29] 胡潇杰, 俞宏耀, 於敏佳. 台风"黑格比"近海加强成因及对比分析[J]. 现代农业科技, 2021(9): 187-190, 193. [30] 龚俊强. 台风"黑格比"(2004)近海急剧增强特征及成因分析[J]. 浙江气象, 2022, 43(1): 17-23. [31] YING M, ZHANG W, YU H, et al. An Overview of the China Meteorological Administration tropical cyclone database[J]. J Atmos Oceanic Tech, 2014, 31(2): 287-301. [32] LU X, YU H, YING M, et al. Western North Pacific Tropical Cyclone Database created by the China Meteorological Administration[J]. Adv Atmos Sci, 2021, 38(4): 690-699. [33] WANG B, ZHOU X. Climate Variation and prediction of rapid intensification in tropical cyclones in the Western North Pacific[J]. Meteorology and Atmospheric Physics, 2008, 99(1-2): 1-16. [34] COHEN Y, HARNIK N, HEIFETZ E, et al. On the violation of gradient wind balance at the top of tropical cyclones[J]. Geophysical Research Letters, 2017, 44(15): 8 017-8 026. [35] COHEN Y, DURDEN S L, HARNIK N, et al. Relating observations of gradient nonbalance at the top of hurricanes with their warm core structures[J]. Geophysical Research Letters, 2019, 46(20): 11 510-11 519. [36] COHEN Y, PALDOR N. Lagrangian trajectories at the outflow of tropical cyclones[J]. Quarterly Journal of the Royal Meteorological Society, 2021, 147(734): 58-73. [37] ZEHR R M. Environmental vertical wind shear with hurricane bertha (1996)[J]. Weather and Forecasting, 2003, 18(2): 345-356. [38] HANLEY D, MOLINARI J, KEYSER D. A composite study of the interactions between tropical cyclones and upper-tropospheric troughs [J]. Monthly Weather Review, 2001, 129(10): 2 570-2 584. [39] DEMARIA M, KAPLAN J, BAIK J J. Upper-Level eddy angular momentum fluxes and tropical cyclone intensity change[J]. Journal of the Atmospheric Sciences, 1993, 50(8): 1 133-1 147. [40] MOLINARI J, VOLLARO D. External influences on hurricane intensity. Part Ⅱ: vertical structure and response of the hurricane vortex[J]. J Atmos Sci, 1990, 47(15): 1 902-1 918. [41] 寿绍文. 位涡理论及其应用[J]. 气象, 2010, 36(3): 9-18. [42] BELL M M, MONTGOMERY M T. Observed Structure, Evolution, and potential intensity of category 5 hurricane isabel (2003) from 12 to 14 September[J/OL]. Monthly Weather Review, 2008, 136(6): 2 023-2 046. [43] ZHANG D L, CHEN H. Importance of the upper-level warm core in the rapid intensification of a tropical cyclone: rapid intensification of hurricane[J]. Geophysical Research Letters, 2012, 39, L02806. [44] CHEN H, ZHANG D L. On the Rapid Intensification of Hurricane Wilma (2005). Part Ⅱ: Convective Bursts and the Upper-Level Warm Core[J]. Journal of the Atmospheric Sciences, 2013, 70(1): 146-162. [45] SHI D, CHEN G. Double warm-core structure and potential vorticity diagnosis during the rapid intensification of Supertyphoon Lekima (2019)[J]. Journal of the Atmospheric Sciences, 2021, 78, 2 471-2 492. [46] TANG X, YANG S, PING F, et al. Upper-tropospheric potential vorticity anomaly before the rapid intensification of Typhoon Mujigae (2015) and its response to reduced SST[J]. Atmospheric and Oceanic Science Letters, 2020, 13(5): 390-399. -
点击查看大图
图(9) / 表(1)
计量
- 文章访问数: 21
- HTML全文浏览量: 5
- PDF下载量: 3
- 被引次数: 0
粤公网安备 4401069904700003号