CONVECTIVE ACTIVITIES IN THE ATMOSPHERIC BOUNDARY LAYER OVER THE PLATEAU IN WESTERN CHINA

Chen Zhi; Zhou Mingyu; Qian Fenlan; Li Shiming; Su Lirong; Xu Xiangde; Chen Lianshou; Wang Jizhi

Vol.13, NO.2, 2002

Article Contents

Article Navigation > Journal of Applied Meteorological Science > 2002 > 13(2): 142-155

Chen Zhi, Zhou Mingyu, Qian Fenlan, et al. Convective activities in the atmospheric boundary layer over the Plateau in western China. J Appl Meteor Sci, 2002, 13(2): 142-155.

Citation:

Chen Zhi, Zhou Mingyu, Qian Fenlan, et al. Convective activities in the atmospheric boundary layer over the Plateau in western China. J Appl Meteor Sci, 2002, 13(2): 142-155.

Chen Zhi, Zhou Mingyu, Qian Fenlan, et al. Convective activities in the atmospheric boundary layer over the Plateau in western China. J Appl Meteor Sci, 2002, 13(2): 142-155.

Citation:

Chen Zhi, Zhou Mingyu, Qian Fenlan, et al. Convective activities in the atmospheric boundary layer over the Plateau in western China. J Appl Meteor Sci, 2002, 13(2): 142-155.

PDF( 1609 KB)

CONVECTIVE ACTIVITIES IN THE ATMOSPHERIC BOUNDARY LAYER OVER THE PLATEAU IN WESTERN CHINA

1.
National Research Center for Marine Environmental Forecasts, Beijing 100081
2.
Chinese Academy of Meteorological Sciences, Beijing 100081

Received Date: 2000-04-20
Rev Recd Date: 2000-10-20
Publish Date: 2002-04-30

Abstract

Abstract

The convective phenomena in the atmospheric boundary layer on the Tibetan plateau are analyzed based on data Doppler sodars, the radiosonde system whit high resolution, and satellite images during the second field experiment of atmospheric sciences on the Tibetan Plateau in 1998. Strong convective activities were detected by sodars. The vertical velocity in the thermal plume exceeds 1 m/s. The time scales of the convective plumes are about 1.4 hours and they appear as organized mesoscale and small-scale turbulent motions. The physical mechanisms of the developing and maintaining of strong convection in the plateau boundary layer can be described as following. The strong convective activities are related with the intense total radiation in the plateau area, the strong baroclinity in the plateau boundary layer induced by the inhomogeneous heat status of the underlying surface caused by the complicated terrain, and the advection effects in the plateau boundary layer. With these effects, strong organized large eddies can occur in the boundary layer. The thermal plumes formed from the eddies develop upward and can be combined to from large thermal convective cells. Some convective cells can be combined with convective cloud clusters, in which the full convective mixture occurs when these eddies exceed the condensation level. The latent heat during the condensation process can help the cloud clusters to develop further, and the cloud clusters can become larger cloud groups, which can be seen in the satellite images.
- Tibetan Plateau;
- Atmospheric boundary layer;
- Convection

FullText(HTML)

References(20)

Figures and Tables

图 1 高原中尺度积云对流发展与东移的4个过程

(a) 初始形成; (b) 发展与组织; (c) 成熟阶段; (d) 东移下高原 (时间分别为1998年6月24日02 :00、05 :00、09 :00和11 :00 UTC)

DownLoad: Full-Size Img PowerPoint

图 2 当雄站声雷达探测的垂直速度高度-时间剖面 (单位:m·s^-1)

(a)1998年5月20日; (b)1998年6月24日

DownLoad: Full-Size Img PowerPoint

图 3 声雷达探测的水平风速随高度分布

(a)1998年5月20日; (b)1998年6月24日

DownLoad: Full-Size Img PowerPoint

图 4 1998年6月24日当雄站位温随高度分布

(a)10 :00;(b)13 :00;(c)19 :00

DownLoad: Full-Size Img PowerPoint

图 5 声雷达探测的边界层100~200 m垂直运动变化

(a)1998年5月20日; (b)1998年6月24日

DownLoad: Full-Size Img PowerPoint

图 6 1998年6月24日当雄站垂直速度谱密度分布

DownLoad: Full-Size Img PowerPoint

图 7 1998年5月20日100 m, 200 m (a, b) 和6月24日100 m, 200 m (c, d) 高度上当雄站声雷达探测垂直速度的频数分布

DownLoad: Full-Size Img PowerPoint

图 8 1998年6月24日白天 (a)、夜间 (b) 和6月13日夜间 (c) 当雄站4 m高度上湍流垂直速度样本频数分布

DownLoad: Full-Size Img PowerPoint

图 9 1998年6月24日当雄站声雷达和湍流测量的热通量比较

DownLoad: Full-Size Img PowerPoint

表 1 对流运动上升区和下沉区所占的百分数

表 2 不同时间、地点浮力项和切变项结果的比较

References

[1]	Grant D R.Some aspects of convection as measured from aircraft.Quart.J.Roy.Meteor.Soc., 1965, 91:268-281. doi: 10.1002/(ISSN)1477-870X
[2]	Hall F F, Edinger J C Jr, Neff W D.Convective plumes in the planetary boundary layer investigated with an acoustic sounder.J.Appl.Meteor., 1975, 14:513-523. doi: 10.1175/1520-0450(1975)014<0513:CPITPB>2.0.CO;2
[3]	Greenhut G K, Khalsa S J S.Updraft and downdraft events in the atmospheric boundary layer over the equatorial Pacific Ocean.J.Atmos.Sci., 1982, 39:1803-1818. doi: 10.1175/1520-0469(1982)039<1803:UADEIT>2.0.CO;2
[4]	Drobinski P, Brown R, Flamant P H, et al.Evidence of organized large eddies by ground-based Doppler lidar, sonic anemometer and sodar.Boundary-Layer Meteor., 1998, 88:343-361. doi: 10.1023/A:1001167212584
[5]	Kalogiros J A, Helmis C G, Asimakopoulos D N, et al.Estimation of ABL parameters using the vertical velocity measurements of an acoustic sounder.Boundary-Layer Meteor., 1999, 91:413-449. doi: 10.1023/A:1001898022176
[6]	Deardorf J W, Willis G E.Further results from a laboratory model of the convective planetary boundary layer.Boundary-Layer Meteor., 1985, 32:205-236. doi: 10.1007/BF00121880
[7]	Foster R C.An analytical model for planetary boundary layer roll vortices:[Ph.D.Thesis].Seattle:Dept.Atmos.Sci., University of Washington, 1996.
[8]	Foster R C, Brown R A.An large-scale PBL modeling :Surface wind and latent heat flux comparisons.Global Atmos.Ocean Syst., 1994, 2:199-219.
[9]	章基嘉, 朱抱真, 朱福康, 等.青藏高原气象学进展.北京:科学出版社, 1988.14-89.
[10]	Lenschow D H, Patel V, Isbell A.Measurement of fine scale structure at the top of marine stratocumulus.Preprint Volume, 8th Symposium on Turbulence and Diffusion, 25-29 April 1988.Boston:American Meteor.Soc.
[11]	周明煜, 吕乃平.大气对流边界层热力湍流过程的研究.气象学报, 1987, 45(4):451-458. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB198704009.htm
[12]	Greenhut G K, Khalsa S J S.Convective elements in the marine atmospheric boundary layer.Part I:Conditional sampling statistics.J.Climate and Applied Meteorology, 1987, 26:813-822. doi: 10.1175/1520-0450(1987)026<0813:CEITMA>2.0.CO;2
[13]	Gogowithch J M.Characteristics of vertical turbulent velocities in the urban convective boundary layer.Boundary-Layer Meteor., 1986, 35:387-407. doi: 10.1007/BF00118566
[14]	Taconet O, Weill A.Convective plumes in the atmospheric boundary layer as observed with an acoustic Doppler Sodar.Boundary-Layer Meteor., 1983, 25:143-158. doi: 10.1007/BF00123971
[15]	Taconet O, Weill A.Vertical velocity field in the convective boundary layer as observed with an acoustic Doppler Sodar.Boundary-Layer Meteor., 1982, 23:133-151. doi: 10.1007/BF00123292
[16]	周明煜, 陈炎涓, 吕乃平, 等.声雷达探测与直接测量温度结构系数的对比研究.地球物理学报, 1982, 25:492-499. http://www.cnki.com.cn/Article/CJFDTOTAL-DQWX198206001.htm
[17]	Wyndaard J C, Izumi Y, Collins S A, Jr.Behavior of the refractive-index-structure parameter near the ground.J.Opt.Soc.Am., 1971, 61:1646-1650. doi: 10.1364/JOSA.61.001646
[18]	LeMone M A.Modulation of turbulence energy by longitudinal rolls in an unstable planetary boundary layer.J.Atmos.Sci., 1976, 33:1308-1320. doi: 10.1175/1520-0469(1976)033<1308:MOTEBL>2.0.CO;2
[19]	Brümmer B.Structure, dynamics and energetics of boundary layer rolls from KonTur aircraft observations.Beitr.Phys.Atmos., 1985, 58:237-254.
[20]	Weckwerth T M, Wilson J W, Wakimoto R M, et al.Horizontal convective rolls:Determining the environmental conditions supporting their existence and characteristics.Mon.Wea.Rev., 1997, 125:505-526. doi: 10.1175/1520-0493(1997)125<0505:HCRDTE>2.0.CO;2