Transcript What do Pilots Want to Know?

Ensembling Mesoscale
Model Data
National Weather Service, Cleveland, OH
Christopher Mello
• The goal of this presentation is to describe
WRF ensembling software that produces
an ensemble for OPERATIONAL use
across a computer network with limited
bandwidth resources.
Motivation for Software ?
• There was a need to share large
amounts of model data between NOAA
NWS offices with limited computer and
bandwidth resources.
• There was an operational requirement
to present all this model data in timely
and precise manner to weather
forecasters.
Ensemble Example
Ensemble
Domain
WRF model
• Locally produced WRF mesoscale model data
grib files contain over 700 fields and are too
large to transport across the NOAA NWS
computer network due to bandwidth Issues
• However, the vast majority of the fields are
considered not directly useful for operational
weather forecasting
What was the best way to
present data to forecasters?
• Mean fields were operationally the easiest
method to get data directly to forecasters
due to the current state of NWS software.
• Probability fields fields were created as
secondary fields but due to the current
state of NWS software could not be easily
ingested into current NWS forecast
software
What data is the most important for
forecasters?
• A default list of 52 critical operational
meteorological fields from the WRF model
was created using input from six NWS
WFO sites.
• At least 40 additional fields could be
derived later using current image
generating software
Mean Fields
Probability Fields
CLENSEMBLE uses GEMPAK
• GEMPAK software was used to create the
ensemble due to cost and the teams
experience using the software.
• GEMPAK Developers continue to add new
ensemble functionality.
• The direct access to developers made
trouble shooting GEMPAK problems
easier.
Part One:Dissect software
• The dissect software is required to reformat
each ensemble member’s grib files to a
GEMPAK format
• The domain and grid spacing of the final
ensemble has to be defined in a configuration
file.
• The dissect software will resize each member’s
domain and spacing to the domain of the
ensemble
Part One:Dissect software
• 52 fields are extracted
• The files are approximately 5 % of the original
size
Part Two: Create Ensemble
• Ten WRF members can be placed in an
ensemble at a time
• When creating means fields, each
ensemble member is given a weight from
0 % to 100 % in a configuration file
• The total weights of all the members must
equal 100 %
The previous runs can be included if the
data are available
The data output of the mean ensemble fields
is in three different formats; GEMPAK,
grib1 and grib2 format.
Grads imaging software is included to
create gif images of the mean fields
Mean surface wind in NWS GFE software
Probability fields
• The probability fields are produced as gif images
• Each model member is weighted equally
• Future upgrade will included 6, 12 and 24 hour
QPF probabilities fields in grib2 format
Probability of small craft
advisory winds
Probability of getting .05 inches
through 30 hours
Summary
• CLENSEMBLE is an operational tool to provide
real time model data to forecasters
• CLENSEMBLE provides forecasters with
approximately 100 fields
• National Weather Service Offices can share
resources with forecasters
• The academic community can also provide
NWS forecasters real time model data
…Continued…
• Also 6,12, and 24 probability fields will be
provided in a future release
Finally
• The software is in a developmental state
and input to improve future builds is
welcome.
Acknowledgements
• Robert Laplante SOO Cleveland NWS
• Dan Leins WRF focal point CLE NWS
• Ron Murphy ITO BGM
The End…
Thank you
Questions, Comments, Concerns…
Feel free to e-mail
[email protected]
Or
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