22 3 Vol.22, No.3 2006 06 JOURNAL OF TROPICAL METEOROLOGY Jun., 2006 1004-4965200603-0253-06 ( 211101) 1999 6 P433 A 1 [13] Xu [4] [5] Emanuel [6] Jascourt [7] Xu [8] upscale development Xu downscale development Xu Bennetts [9] Jascourt (1988) [10] Jascourt (1988) : 2004-12-29; 2005-09-08 40175012 : (1975-),,,, E-mail: puwang@263.net
254 22 [11] Bennetts (1988) [12] and Locatelli (1994) [13] e 1999 6 23 08 24 08 2 1 1 23 12 3033 N 900 hpa 23 14 950 hpa23 16 23 18 23 20 23 22 3033 N 850 hpa 24 06 23 20 24 06 MM5 1999 6 23 08 24 08 (a) (b) 3 1
3 255 (c) (g) (d) (h) (e) (i) (f) (j) 1 a. 23 12 ; b. 23 14 ; c. 23 16 ; d. 23 18 ; e. 23 20 ; f. 23 22 ; g. 23 24 ; h. 24 02 ; i. 24 04 ; j. 24 06
256 22 23 14 32 N 700 hpa 500 hpa 23 16 23 18 24 02 2830 N 900 hpa 800 hpa Bennetts Sharp(1982) [5] 4 Jascourt (1988) [10] 2 30 N 1 x 50 Xu (1986) [8] upscale development 23 18 109112 E 23 20 112115 E Xu (1986) downscale developmentxu (1986) Xu (1986) Xu (1986)23 18 115119 E 24 02 04 115 119 E
3 257 (a) (e) (b) (f) (c) 2 a. 23 18 ; b. 23 20 ; c. 23 22 ; d. 23 24 ; e. 24 02 ; f. 24 04 5 (d) (1) (2)
258 22 [1] REUTER G W, YAU M K. Assessment of slantwise convection in ERICA cyclones[j]. Mon Wea Rev, 1993, 121: 375 386. [2] LAGOUVARDOS K, KOTRONI V. Upper-level frontogenesis: Two case studies from the FRONTS 87 Experiment[J]. Mon Wea Rev, 1995, 123: 1197 1206. [3] MARTIN J E. The structure and evolution of a continental winter cyclone. Part II: Frontal forcing of an extreme snow event[j]. Mon Wea Rev, 1998, 126: 329 348. [4] XU Q, CLARK J H E. The nature of symmetric instability and its similarity to convective and inertial instability[j]. J Atmos Sci, 1985, 42: 2880 2883. [5] BENNETTS D A, SHARP J C. The relevance of conditional symmetric instability to the prediction of mesoscale frontal rainbands[j]. Quart J Roy Meteor Soc, 1982, 108: 595 602. [6] EMANUEL K A. Forced and free mesoscale motions in the atmosphere[j]. Collection of Lecture Notes on Dynamics of Mesometeorological Disturbances. Proc. CIMMS Symp. Norman, OK, University of Oklahoma/NOAA, 191 259. paradox? Bull Amer Meteor Soc, 1980, 78: 2179 2196. [7] JASCOURT S D, LINDSTROM S S, SEMAN C J, ct al. An observation of banded convective development in the presence of weak symmetric stability [J]. Mon Wea Rev, 1988, 116: 175 191. [8] XU Q. Conditional symmetric instability and mesoscale rainbands[j]. Quart J Roy Meteor Soc, 1986, 112: 315 334. [9] BENNETTS D A, HOSKINS B J. Conditional symmetric instability A possible explanation for frontal rainbands[j]. Quart J Roy Meteor Soc, 1979, 105: 945 962. [10] JASCOURT S D, LINDSTROM S S, SEMAN C J, ct al. An observation of banded convective development in the presence of weak symmetric stability [J]. Mon Wea Rev, 1988, 116: 175 191. [11] SAITOH S, TANAKA H. Numerical experiments of conditional symmetric baroclinic instability as a possible cause for frontal rainband formation Part II: Effects of water vapor supply[j]. J Meteor Soc Japan, 1988, 66: 39 53. [12] BENNETTS D A., GRANT J R, MCCALLUM E. An introductory review of fronts Part I: Theory and observations[j]. Meteor Mag, 1988, 117: 357 370. [13] LOCATELLI J D, MARTIN J E, HOBBS P V. A wide coldfrontal rainband and its relationship to frontal topography[j]. Quart J Roy Meteor Soc, 1994, 120: 259 275. THE EVOLUTION AND CIRCULATION FEATURE OF CONVECTIVE-SYMMETRIC INSTABILITY CHENG Yan-hong, LU Han-cheng (The Meteorological Institute of PLAUST, Nanjing 211101, China) Abstract: Using the results of a sensitivity numerical simulation, the evolution and circulation feature of convective-symmetric instability is studied in this paper. The conditional symmetry instability is the intermediate process between the stable and instable states of the atmosphere. The evolution of the atmosphere from the stable to unstable state or from unstable to stable state comes through two stages. The convective-symmetric instability circulation is related with the state and type of the instability. When the conditional instability lies in the lower level and conditional symmetric instability in the upper level, the circulation will have vertical updrafts in the lower level and slantwise updrafts in the upper level. The release of conditional symmetric instability gives rise to a mesoscale rain belt. When the conditional symmetric instability lies in the middle level and conditional instability in the lower and upper levels, the circulation will have updrafts through the total column of the atmosphere. The release of conditional instability gives rise to a mesoscale rain belt. Key words: convective-symmetric instability; evolution; circulation feature