大气科学学报
大氣科學學報
대기과학학보
JOURNAL OF NANJING INSTITUTE OF METEOROLOGY
2012年
3期
257-271
,共15页
沈新勇%刘佳%秦南南%朱琳
瀋新勇%劉佳%秦南南%硃琳
침신용%류가%진남남%주림
台风麦莎%正压波动%特征值问题%稳定性%数值模拟
檯風麥莎%正壓波動%特徵值問題%穩定性%數值模擬
태풍맥사%정압파동%특정치문제%은정성%수치모의
Typhoon Matsa%barotropic wave%eigenvalue problem%stability%numerical simulation
利用中尺度WRF模式对2005年8月西北太平洋台风麦莎(Matsa)进行了精细的数值模拟。使用模式输出资料,对正压浅水方程组进行了数值差分计算,分析它在最大强度时刻的正压特征波动结构和稳定性。结果表明,台风麦莎内部包含有沿逆时针方向传播的重力惯性外波和涡旋Ross-by波,两种波动的结构和稳定性存在显著性差异。前者主要存在于台风外围,增长率随波长的减小而增加,台风外围的波动相速度为48.9~68.5m/s;后者主要位于距离台风中心200km内,表现为3波最不稳定,半径100km处相速度约为5m/s。此外,重力惯性外波的扰动风场与高度场基本相垂直,扰动散涡比值大于3倍,甚至达到10^3倍,运动以辐合、辐散为主;涡旋Rossby波的扰动风场基本平行于高度场,扰动散涡比值为10^-1~10^-2,涡旋运动是其主要运动,与内螺旋雨带沿着切向圆周方向的传播具有密切关系。
利用中呎度WRF模式對2005年8月西北太平洋檯風麥莎(Matsa)進行瞭精細的數值模擬。使用模式輸齣資料,對正壓淺水方程組進行瞭數值差分計算,分析它在最大彊度時刻的正壓特徵波動結構和穩定性。結果錶明,檯風麥莎內部包含有沿逆時針方嚮傳播的重力慣性外波和渦鏇Ross-by波,兩種波動的結構和穩定性存在顯著性差異。前者主要存在于檯風外圍,增長率隨波長的減小而增加,檯風外圍的波動相速度為48.9~68.5m/s;後者主要位于距離檯風中心200km內,錶現為3波最不穩定,半徑100km處相速度約為5m/s。此外,重力慣性外波的擾動風場與高度場基本相垂直,擾動散渦比值大于3倍,甚至達到10^3倍,運動以輻閤、輻散為主;渦鏇Rossby波的擾動風場基本平行于高度場,擾動散渦比值為10^-1~10^-2,渦鏇運動是其主要運動,與內螺鏇雨帶沿著切嚮圓週方嚮的傳播具有密切關繫。
이용중척도WRF모식대2005년8월서북태평양태풍맥사(Matsa)진행료정세적수치모의。사용모식수출자료,대정압천수방정조진행료수치차분계산,분석타재최대강도시각적정압특정파동결구화은정성。결과표명,태풍맥사내부포함유연역시침방향전파적중력관성외파화와선Ross-by파,량충파동적결구화은정성존재현저성차이。전자주요존재우태풍외위,증장솔수파장적감소이증가,태풍외위적파동상속도위48.9~68.5m/s;후자주요위우거리태풍중심200km내,표현위3파최불은정,반경100km처상속도약위5m/s。차외,중력관성외파적우동풍장여고도장기본상수직,우동산와비치대우3배,심지체도10^3배,운동이복합、복산위주;와선Rossby파적우동풍장기본평행우고도장,우동산와비치위10^-1~10^-2,와선운동시기주요운동,여내라선우대연착절향원주방향적전파구유밀절관계。
The masoscale WRF model is used to simulate Typhoon Matsa that occurred over the western North Pacific in August 2005. The simulation data are applied to a barotropic shallow water equation to study the barotropic characteristic wave structures and their stabilities when Matsa reaches its peak. The results show that there are counterclockwise-propagating external inertial-gravity waves and vortex Rossby waves inside Matsa, which have different structures and stabilities. The external inertial-gravity waves occur the outer part of Matsa, and their growth rate increases as wavelength reduces, and the wave phase speed over the outer part is 48.9-68.5 m·s^-1. The Rossby waves appear over the 200 km of center area,and their wave number-3 is the most unstable,with 5 m·s^-1 phase speed at the 100 km radius. In addition, the perturbation wind fields of the external inertial-gravity waves are generally perpendicular to the height fields, and the ratio of perturbed divergence to perturbed vorticity is over 3 and could be up to 10^3, indicating that the waves are associated with divergence. The perturbed wind fields of the Rossby waves are generally parallel to the height fields, the ratio of perturbed divergence to perturbed vorticity is 10^-1-10^-2, and the waves are related to vorticity, which is intimately associated with tangential propagation of spiral rainbands.