46 6 Vol.46, No.6 2015 11 OCEANOLOGIA ET LIMNOLOGIA SINICA Nov., 2015 1013 * ( 200030), 100m 2010 13 :,,, 16% :,, 258m 35m, 123s 13s, 1 3 ; ; ; ; P444 doi: 10.11693/hyhz20150700186, (, 2005; Kepert, 2010; Smith et al, 2010;, 2013; Sun et al, 2014; Zhang et al, 2015), K, H,, wh K H/ z,,, Lettau (1957) 100m, Bunker(1956) 150 550m, Telford (1964) 125 150 350m, Wong (1966), Deardorff(1972) r c, wh K ( H/ z r),, Deissler(1962), Komori (1983) (2005), Zhang (2012) ( 7), H c * (973), 2013CB430305 ;, 14DZ1205200,, E-mail: zhengyx@mail.typhoon.gov.cn :,, E-mail: liyp@mail.typhoon.gov.cn : 2015-07-16, : 2015-10-09
1264 46, ;,, (Troen et al, 1986; Holtslag et al, 1991;, 2012), 100m,, 1 100m, 24 2 9.6, 117 54, 29m, 35m, 55m, 75m, 95m, 64m, 84m, 104m 124m ( 1) 2010,, 70m/s; 10 23 13 27 (, ), 38m/s, 23km, 23 20, 23 23 2 20 0 25 0 35m 2min, 29m/s, 2 35m 2 min Fig.2 Time series of 2 min averaged wind speed at 35m height of the tower during the typhoon progress Applied Technologies,,, 20Hz ±0.03m/s, ±0.1, ±0.1 C 40 60 C, ±60m/s, ±15m/s (2000),, 2 1 2010 13 ( ) Fig.1 Track of Typhoon Megi in 2010 and location of the observation tower (the red triangle) 2010 13 u, v w x, y, z, u x, y, z u v w 10min u v w (, 2005;, 2012), (Troen et al, 1986; Holtslag et al, 1991;, 2012), (, 2012), T>1min
6 : 1013 1265,, U / z (uw + vw ), U ( 2min ), z, u v w, U / z, (uw + vw ) S ( uw vw ) U / z, S, S, (uw + vw ) U / z,, U / z, 3 95m 35m 2min 3 2, 20 0 23 0 2 0.5 1.5m/s,, 2 1.5 3.0m/s,, 24 2, 35m 95m, (20 12 13 ) (23 13 14 ) (24 12 13 ), S,, 11% 4% 3% 0%,, 4 2010 20 12 13 95( a) 75(b) 55(c), 35m(d) ( uw vw ) U/ z Fig.4 Time series of ( uw vw ) U/ z at 95, 75, 55, and 35m heights in 12: 00 13: 00BT, Oct. 20, 2010 3 95m 35m 2min Fig.3 Time series of 2min averaged wind speed difference between 95m and 35m height 4 20 12 13 95 75 55 35m S, 4 S, ( uw vw ), 35m, S ( A B C ), 5 23 13 14 95m 75m 55m 35m S, 4 S, ( uw vw ), 35m,, 4 S, 21% 8% 5% 2% 6 24 12 13 95m 75m 55m 35m S
1266 46,, (35m) (95m),, S, 16% 6% 5% 2% 3 5 2010 23 13 14 95 75 55 35m ( uw vw ) U/ z Fig.5 Time series of ( uw vw ) U/ z at 95, 75, 55, and 35m heights in 13: 00 14: 00BT, Oct. 23, 2010 6 2010 24 12 13 95 75 55 35m ( uw vw ) U/ z Fig.6 Time series of ( uw vw ) U/ z at 95, 75, 55, and 35m heights in 12: 00 13: 00BT, Oct. 24, 2010, 2 U / z,, ( uw vw ), u v w, ;, u v w, (2012) 10m u w,, 7 20 12 13 95 75 55 35m u w, 4 u w, (u'>0), (w <0);,, u w, 95 75 55 35m u w 0.21 0.35 0.37 0.50(2012), 10m u w 0.49 0.79, u w, u w 7 A B C D ( 4) 8 23 13 14 95 75 55 35m u w, 4 u w, u w, 95 75 55 35m u w
6 : 1013 1267 ( 5) 9 24 12 13 95 75 55 35m u w, 4 u w, 95 75 55 35m u w 0.16 0.29 0.31 0.48, u w u w ( 6) 7 2010 20 12 13 95 75 55 35m u ( ) w ( ) Fig.7 Time series of u (solid line) and w (dotted line) at 95, 75, 55, and 35m heights in 12: 00 13: 00BT, Oct. 20, 2010 9 2010 24 12 13 95 75 55 35m u ( ) w ( ) Fig.9 Time series of u (solid line) and w (dotted line) at 95, 75, 55, and 35m heights in 12: 00 13: 00BT, Oct. 24, 2010 8 2010 23 13 14 95 75 55 35m u ( ) w ( ) Fig.8 Time series of u (solid line) and w (dotted line) at 95, 75, 55, and 35m heights in 13: 00 14: 00BT, Oct. 23, 2010 0.34 0.32 0.40 0.51, u w, (2012) :, ;, 4, (Flay, 1984),
1268 46 : L V Rx ( )d (6) 0 0 T Rx ( )d (7), V, x(t), Rx ( ) x(t), : 2 x R ( ) E[( x( t) x( t )]/ s (8) x s 2 x u w L, : u L 110 490m, 258m; w 20 63m, 35m, 95m 35m u w T 123s 13s, Zhang (2011) 500m 3000m 100m, (2012), 3 7min; 1 3,,,, 5 1013 : (1),, : ;, (2) :, ;,, (3) 258m 35m, 123s 13s, 1 3, 2013.., 28(2): 197 208,,, 2005. I.., 29(3): 417 428,,, 2012. 2009., 70(6): 1188 1199,,, 2005.., 63(6): 915 921,,, 2000.., 5(3): 304 311,,, 2005.., 20(4): 426 435,,, 2012.., 28(1): 61 67 Bunker A F, 1956. Measurements of counter-gradient heat flux in the atmosphere. Aust J Phys, 9: 133 143 Deardorff J W, 1972. Theoretical expression for the countergradient vertical heat flux. J Geophys Res, 77: 5900 5904 Deissler R G, 1962. Turbulence in the presence of a vertical body force and temperature gradient. J Geophys Res, 67(8): 3049 3062 Holtslag A A M, Moeng C -H, 1991. Eddy diffusivity and countergradient transport in the convective atmospheric boundary layer. J Atmos Sci, 48(14): 1690 1698 Kepert J D, 2010. Slab- and height-resolving models of the tropical cyclone boundary layer. Part II: why the simulations differ. Quart J Roy Meteor Soc, 136(652): 1700 1711, doi: 10.1002/qj.685 Komori S, Ueda H, Ogino F et al, 1983. Turbulence structure in stably stratified open-channel flow. J Fluid Mech, 130: 13 26 Lettau H H, Davidson B, 1957. Exploring the Atmosphere s First Mile. Now York: Pergamon Press, 343 Smith R K, Montgomery M T, 2010. Hurricane boundary-layer theory. Quart J Roy Meteor Soc, 136(652): 1665 1670 Sun X M, Barros A P, 2014. High resolution simulation of tropical storm Ivan (2004) in the Southern Appalachians: role of planetary boundary-layer schemes and cumulus parametrization. Quarter J Roy Meteor Soc, 140(683): 1847 1865 Telford J W, Warner J, 1964. Fluxes of heat and vapor in the lower atmosphere derived from aircraft observations. J Atmos Sci, 21(5): 539 548 Troen I B, Mahrt L, 1986. A simple model of the atmospheric boundary layer; sensitivity to surface evaporation.
6 : 1013 1269 Boundary-Layer Meteorol, 37(1): 129 148 Wong E Y J, Brundidge K C, 1966. Vertical and temporal distributions of the heat conductivity and flux. J Atmos Sci, 23(2): 167 178 Zhang J A, Drennan W M, 2012. An observational study of vertical eddy diffusivity in the hurricane boundary layer. J Atmos Sci, 69(11): 3223 3236 Zhang J A, Marks F D, Montgomery M T et al, 2011. An estimation of turbulent characteristics in the low-level region of intense Hurricanes Allen (1980) and Hugo (1989). Mon Wea Rev, 139(5): 1447 1462 Zhang J A, Nolan D S, Rogers R F et al, 2015. Evaluating the impact of improvements in the boundary layer parameterization on hurricane intensity and structure forecasts in HWRF. Mon Wea Rev, 143(8): 3136 3155 Zhu P, 2008. Simulation and parameterization of the turbulent transport in the hurricane boundary layer by large eddies. J Geophys Res, 113(D17), doi: 10.1029/2007JD009643 OBSERVATION ON COUNTER-GRADIENT TRANSPORT OF MOMENTUM FLUX IN LOW ATMOSPHERE BOUNDARY LAYER DURING TYPHOON MEGI ZHENG Yun-Xia, LI Yong-Ping, DUAN Zi-Qiang (Shanghai Typhoon Institute, CMA, Shanghai 200030, China) Abstract To explain the observational data of counter-gradient transport of momentum flux in lower atmospheric boundary layer, we studied very-high-frequency data measured by ultrasonic wind instruments that installed on a multilayer tower (N24 2 9.6, E117 54 ; 100m tall on 29m base above sea level) near sea shore by diagnostic method. A case of landfall typhoon Megi in 2010 was selected. Result show that the counter-gradient transport of momentum occurred in a small proportion (<16%) in lower boundary layer of the typhoon, although it moved along the gradient direction on longer time scale, e.g., one hour. The phenomenon in higher layers was more obvious than that in lower ones, stronger in the area of typhoon core and weakened away from it, and less in early and outskirt of typhoon. The vertical counter-gradient flux of momentum is closely related to the coherent structure of low-frequency disturbance. When wind disturbance in horizontal and vertical directions was in-phase, the counter-gradient flux of momentum would occur easier due to loose coherence structure between the disturbances in the two directions. The averaged spatial scales were 258m and 35m and the temporal scales were 123s and 13s in horizontal and vertical directions respectively, both are smaller than those of common ones of low-frequency disturbances in low layer boundary atmosphere of typhoon. Key words typhoon; boundary layer; counter-gradient flux of momentum; coherent structure