Transcript The Pacific Northwest Mesoscale Forecasting System: An Update

The Puget Sound Regional
Environmental Prediction System
The Big Questions:
1. Can we use atmospheric models to
simulate and forecast local weather
features?
2. Can we create an integrated
regional environmental modeling
system for research and prediction by
coupling preexisting models and using
all operational data assets?
The Atmospheric Model: MM5
The Penn. State/NCAR mesoscale model V3.5
(MM5). A full physics primitive equation
numerical prediction model, it is being run:
• twice a day at 36/12/4 km horizontal grid
spacing. 38 levels forced by the NCEP Global
Forecast System (GFS) run
• 0 to 72h for 36/12
• 0 to 48 h for 4 km
• Twice a day at 36/12km grid spacing forced
by the NCEP Eta Model (available sooner)
Some Comments
• A 4-km model does NOT resolve 4-km scale
features…more like 20-25 km.
• There are major issues (problems) in the
physical parameterizations that we are actively
working to improve, such as:
– Moist physics
– Land surface and boundary-layer physics
– Radiation schemes
24-h MM5 Precip. Bias Scores over W. WA
Timing
Error
Example
Tahoma: A
30
processor
SUN ES
6500 with 4
GB
Memory
Ensemble:
a 20 processor
athlon cluster
WRF Cluster:
The Most
Powerful
Computer:
32-Processor
Athlon Linux
Cluster
The “Audience” for PNW MM5
Products Continues to Increase
Current MM5 System
• Model forecasts are verified against all
regional observations
• Model graphics are available on the web
• Model grids are shipped to some
consortium members (e.g., NWS)
A Vision of an Integrated Regional
Modeling System
Output from the MM5 is now being fed into a
number of modeling and diagnostic systems:
• Distributed Hydrological Model for Western
Washington (PRISM Major Support)
• Calgrid Air Quality Model
• Land Surface Model for Surface Temperature
Prediction
• Smoke, Ventilation, and Fire Guidance
• Transportation Information System
And hopefully soon will be integrated with others
(e.g. Puget Sound)
• Terrain - 150 meter
aggregated from 30 meter
resolution DEM
• Land Cover - 19 classes
aggregated from over 200
GAP classes
• Soils - 3 layers aggregated
from 13 layers (31 different
classes); variable soil depth
from 1-3 meters
• Stream Network - based
on 0.25 km2 source area
DHSVM Distributed Hydrological Prediction System
Calgrid Air Quality Prediction System
Washington State DOT Traveler Information System
U.S. Forest Service Smoke and Fire Management System
Ventilation
Index
U.S. Forest Service
• MM5 grids are sent to the field for running
Eulerian and Lagrangian smoke
plume/dispersion models.
• MM5 output used for fire fighting
operations.
Military Applications
• The NW MM5 is now the main source of
regional forecasts for Navy and Air Force
operations at Whidbey NAS and McChord
Air Force Base, as well as the Everett
Carrier homeport.
Ensemble Forecasting
• A major push has been made toward
ensemble forecasting using the MM5 because
of initial condition and physics uncertainty.
• The goal is to provide probabilistic
predictions, including forecasts of model
skill.
• The MM5 is now being run at 36/12 km
resolution with approximately 25 different
initializations and lateral boundary
conditions, as well as varying model physics.
Regional Ensemble
Configuration
• Makes use of the differing initializations
(and boundary conditions) from major
operational NWP centers (e.g., NCEP,
Navy, Canadian, UKMET, Australian,
Taiwanese, etc) and varying physics
options.
• Early results very encouraging (e.g., using
ensembles to predict forecast skill)
Relating Forecast Skill and Model Spread
Mean Absolute Error of Wind Direction is Far Less When
Spread is Low
Regional Observational Database
Since the mid-1980’s, have collected all
available data networks in the Pacific NW
Data collected and quality controlled in realtime
The database is used for verification of the
regional MM5 forecasts, regional
application, and local research
Puget
Sound
Research on Physical
Parameterizations
• IMPROVE: To improve moist
physics in mesoscale models using
data from the Pacific Northwest.
Multi-investigator project. Data from a
major field experiment
• PBL Parameterization Project:
Evaluation and improvement of MM5
PBL schemes. Sponsored by the
Forest Service
British Columbia
Legend
Washington
UW Convair-580
Airborne Doppler
Radar
Two
IMPROVE
observational
campaigns:
S-Pol Radar
Olympic
Mts.
Offshore Frontal
Study Area
BINET Antenna
Paine Field
Olympic Mts.
Univ. of Washington
NEXRAD Radar
Area of MultiDoppler
Coverage
Wind Profiler
Rawinsonde
Westport
WSRP Dropsondes
Special Raingauges
Columbia R.
PNNL Remote
Sensing Site
90 nm
(168 km)
Washington
Ground Observer
0
S-Pol
Radar
Range
S-Pol
Radar
Range
100 km
Portland
I. Offshore
Frontal
Study
(Wash. Coast,
Jan-Feb 2001)
Oregon
Terrain Heights
Salem
< 100 m
100-500 m
500-1000 m
1000-1500 m
1500-2000 m
2000-3000 m
Orographic
Study Area
Newport
> 3000 m
Rain Gauge Sites in OSA Vicinity
Santiam Pass
OSA ridge crest
Santiam Pass
Orographic Study Area
S-Pol Radar Range
SNOTEL sites
CO-OP rain gauge sites
50 km
Oregon
Medford
California
II. Orographic
Study
(Oregon
Cascades,
Nov-Dec 2001)
Should we go to higher
resolution over Puget Sound?
Modeling Winds in the Columbia
Gorge
Cascade
Locks
Portland
Troutdale
• Strongest winds are at the exit
4-km grid spacing
1.3 km grid spacing
4-km grid spacing
1.3 km grid spacing
Mesoscale Climate Forecasting
• Computer power is now available to run at
high resolution (12km) for 5-10 years
• Driven by GCM climate predictions, could
gain insights into local implications of
global warming.