LIDAR%20Observations%20of%20Terrain-induced%20Flow%20and%20Its%20Application%20in%20Airport%20Wind%20Shear%20Monitoring - PowerPoint PPT Presentation

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LIDAR%20Observations%20of%20Terrain-induced%20Flow%20and%20Its%20Application%20in%20Airport%20Wind%20Shear%20Monitoring

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Weather Buoys. Automatic Weather. Stations over Lantau. TDWR. Weather buoy (3) ... Buoy (north) Buoy (south) Land Station (SW1) Wind Changes (E S) 19-23 May 2003 ... – PowerPoint PPT presentation

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Title: LIDAR%20Observations%20of%20Terrain-induced%20Flow%20and%20Its%20Application%20in%20Airport%20Wind%20Shear%20Monitoring


1
LIDAR Observations of Terrain-induced Flow and
Its Application in Airport Wind Shear Monitoring
  • CM Shun, CM Cheng O Lee
  • ICAM/MAP 2003

2
Background
Wind Shear terrain disrupted flow
thunderstorms sea breeze
Weather buoy (3)
Weather Buoys
(12)
TDWR
Sham Wat (2)
Automatic Weather Stations over Lantau
3
LIght Detection And Ranging (LIDAR) System
LIDAR Scanner
Installed in mid-2002 IR (2 µm) ? eye-safe
ATC Building Roof-top
4
LIDAR in Tropical Cyclone
5
Jump Like Feature (11 Nov 2002)
stagnant flow
N 0.0135 s-1 h 465 m U0 5 ms-1 Nh/U0 1.3
gt 0.85 (wave breaking) Weak inversion (0.4ºC)
below 500 m
jump
Lo Fu Tau
465 m
100º
Inversion near 3 km
6
Jump Like Feature (20 Jan 2003)
N 0.013 s-1 h 465 m U0 6 ms-1 Nh/U0 1.0
gt 0.85 (wave breaking) Inversion 1.11.5ºC
500-700 m ?? 3.6 K ? 291 K D 600 m Fr
U0 / (gD)½ 0.7 M h/D 0.8 Schär Smith
(1993) Regime IIb
reverse flow
jump
Lo Fu Tau
reverse flow
095º
Inversion at 500-700 m
7
Jump Structure22-min Sequence (_at_ 2 min)
095º
8
Vortex Shedding12-minute Sequence (_at_ 2 min)
100º
9
Springtime Wind Shear(5 March 2003)
10
Temperature Jump
4ºC
Buoy (north)
5ºC
Buoy (south)
11
Wind Changes (E?S)
Buoy (north)
Buoy (south)
Land Station (SW1)
12
Descent of Warm Jets
00 UTC
0317 UTC
20C
20? 25C
297 K
19C
N 0.02 s-1 h 934 m (Lantau Peak) U0 ? 19
ms-1 Nh/U0 ? 1 (descending flow / hydraulic jump)
  1. How to apply Fr under strong vertical shear?
  2. Contribution of gap-flow?
  3. Interaction between jets?

13
Time - Azimuth Plot of LIDAR radial velocity
14
Conclusions
  • Jump-like features vortex shedding under stable
    conditions are revealed
  • Nh/U0 Fr able to diagnose jump based on Schär
    Smith (1993)
  • Springtime wind shear - interaction of descending
    Sly jet (also a jump?) with surface Ely jet
  • More work is needed to better understand
    phenomena (Nh/U0 Fr in strong vertical shear
    gap-flow dynamics)

15
Thank You!
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