wmo symposium toulouse 2005 wind forecasting at hong kong international airport s.y. lau hong kong...
TRANSCRIPT
WMO SymposiumToulouse 2005
Wind Forecasting at Hong Kong International
Airport
S.Y. LauHong Kong Observatory
WMO SymposiumToulouse 2005
2 types of user requirements
• Air traffic controllers – Runway change – headwind/tailwind
• Dry – 10 kt, Wet – 5 kt• Nowcasting – extension of monitoring network
through the installation of weather buoys and LIDAR
• Airlines/pilots– Crosswind limit
• Wide body plane - 20 kt• Usually of the order of 18 to 24 hours – statistical and
probabilistic forecast
WMO SymposiumToulouse 2005
Strong crosswind due to Kompasu
WMO SymposiumToulouse 2005
Probability of 20 kt crosswind if the forecast track is perfect
Probability isopleths
4
17
WMO SymposiumToulouse 2005
Track perturbation
• Statistical– Based on past (1999-2002) forecast
position errors
• Dynamical– Based on NWP model spread from model
ensemble– ECMWF, JMA, NCEP, UKMO, JMA Typhoon
model, HKO ORSM
WMO SymposiumToulouse 2005
25 perturbed tracks within 85% the bivariate Gaussian
distribution for position uncertainties
11
22
33
44
5 5
66
77
88
9910
10
11 11
1212
1313
14
14
15
15
1616
1717
18
18
19
1920
20
2121
2222
23 23
2424
25
25
25
1)(|
k kkI trPrWPtP
WMO SymposiumToulouse 2005
Track of Kompasu
July 2004
WMO SymposiumToulouse 2005
statistical
dynamical
WMO SymposiumToulouse 2005
WMO SymposiumToulouse 2005
User Interface
WMO SymposiumToulouse 2005
WMO SymposiumToulouse 2005
Limitations
• Probability isopleths not separated according to TC intensity
• Size of TC not taken into account• Asymmetric structure of TC not taken
into account• Arrival/presence of northeast
monsoon could result in earlier onset of high crosswind
WMO SymposiumToulouse 2005
Thank you
WMO SymposiumToulouse 2005
Tornado on 6 Sep 2004
WMO SymposiumToulouse 2005
extension of monitoring networkextension of monitoring network Nowcasting
WMO SymposiumToulouse 2005
AWAREAWARE
• AWARE (Anemometer-based Windshear Alerting Rules – Enhanced) launched in mid-2004
• Based on wind readings at 6 runway anemometers & TMT & 5 weather buoys
• Alerts out of ground truths
TMT
Weatherbuoys
Runway anemometers
Weatherbuoy
WMO SymposiumToulouse 2005
AWARE alert
WMO SymposiumToulouse 2005
Merits of AWARE…Merits of AWARE…
• Enhanced detection of WS associated Enhanced detection of WS associated with:with:– Sea breezeSea breeze– Gust frontGust front– Shear lineShear line
WMO SymposiumToulouse 2005
Nowcastingextension of monitoring networkextension of monitoring network
WMO SymposiumToulouse 2005
Kompasu
Hong Kong