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Transcript of Http:// This is the footer WRF : “Great North Run” and COPS Ralph Burton, NCAS (Leeds) Alan...
http://www.ncas.ac.ukThis is the footer
WRF : “Great North Run”and COPS
Ralph Burton, NCAS (Leeds)Alan Gadian, NCAS (Leeds)Alison Coals, NCAS (Leeds)
http://www.ncas.ac.uk
“Operational use” : a 1-km forecast model for the north of the UK
“Research use” COPS (Convective and Orographically-induced Precipitation Study)
WRF: examples of use
http://www.ncas.ac.uk
WRF GNR
Great North Run
3 nests with feedbackbetween nests;
81 vertical levels;
Domains are356x196 (@9km)319x322 (@3km)391x328 (@1km)
Inner domain coversfrom Berwickto Nottingham
http://www.ncas.ac.uk
WRF GNR
A useful exercise for PhD students / Postdocs
In Leeds, every Thursday there is a “Chatmosphere”(students and staff discuss the forecast, interesting weather, etc.)
Get students to perform a WRF forecast for the North of England
Takes approx 2 x 2hr teaching sessions for students to be able to do the forecast independently
http://www.ncas.ac.uk
WRF GNR
Ongoing WRF verification / evaluation
Each week a set of forecast plots is produced,allowing an ongoing evaluation of WRFperformance
Forecast plots are archived
http://www.ncas.ac.uk
WRF GNR
Routinely, every Wednesday WRF is run, andthe plots produced on Thursday morning.
Plots produced, for T=0, 1, 2, ..., 60:
Sea – level pressure, surface temps and winds
Precipitation
Skew-T for Leeds-Bradford Airport
850mb theta_e
1000-500mb thickness
http://www.ncas.ac.uk
WRF GNR
SLP, surface winds and temps Precip in last hour
http://www.ncas.ac.uk
WRF GNR: comparison with satellite data
23/02/08:
12Z
T+60
http://www.ncas.ac.uk
23/02/08:
12Z
T+60
http://www.ncas.ac.uk
WRF GNR: comparison with satellite data
23/02/08:
12Z
T+60
Cloud water mixing ratio = 0.1g / Kg
http://www.ncas.ac.uk
Cloud water mixing ratio = 1g / Kg
23/02/08: 12Z : T+60
http://www.ncas.ac.uk
WRF GNR
Skew-T for 23/02/08 12Z: T+60: Nottingham
WRFObserved
http://www.ncas.ac.uk
WRF GNR: 1km results
http://www.ncas.ac.uk
WRF GNR: 1km results
23/02/08:
12Z
(T+60)
http://www.ncas.ac.uk
“Operational use” : a 1-km forecast model for the north of the UK
“Research use” COPS (Convective and Orographically-induced Precipitation Study)
WRF: examples of use
http://www.ncas.ac.uk
COPS
Convective and Orographically-induced Precipitation Study
http://www.cops2007.de
http://www.ncas.ac.uk
COPS WRF
Note the location and orientation (SW-NEish) of the storm cloud
15th July: isolated deep convective cloud
http://www.ncas.ac.uk
WRF COPS
3 Domains:
300 x 300
301 x 301
199 x 199
(6.3km, 2.1km, 700m)
http://www.ncas.ac.uk
COPS WRF
Upward moisture flux at surface; 10m wind vectors
15/07/07 15Z
Strong convergence; relativelyhigh upward moisture flux “upwind”of the convergence line
http://www.ncas.ac.uk
COPS WRF
10m wind vectors over orography with cross-section of Wover the convergence line; 15Z
+ve vertical velocities not appreciable above 5km
Wave-like features
+ve W-ve W
http://www.ncas.ac.uk
COPS WRF
... but: no cloud in the WRF run!
We think we know why this, is and work is still ongoing.
Summary
WRF is used at the University of Leeds in a routineforecast manner
WRF is being used to investigate the 15th July cloud