Evaluation of Great Lakes Ice Model (GLIM) Real-time Ice Forecasts for Lake Erie during the 2009-201...
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Robert LaPlante NOAA/NWS Cleveland, OH David Schwab Jia Wang NOAA/GLERL Ann Arbor, MI PowerPoint PPT Presentation


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Evaluation of Great Lakes Ice Model (GLIM) Real-time Ice Forecasts for Lake Erie during the 2009-2010 Ice season. Robert LaPlante NOAA/NWS Cleveland, OH David Schwab Jia Wang NOAA/GLERL Ann Arbor, MI 21 March 2010. Outline. Motivation for developing the GLIM Description of the GLIM

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Robert LaPlante NOAA/NWS Cleveland, OH David Schwab Jia Wang NOAA/GLERL Ann Arbor, MI

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Robert laplante noaa nws cleveland oh david schwab jia wang noaa glerl ann arbor mi

Evaluation of Great Lakes Ice Model (GLIM) Real-time Ice Forecasts for Lake Erie during the 2009-2010 Ice season

Robert LaPlante

NOAA/NWS Cleveland, OH

David Schwab

Jia Wang

NOAA/GLERL Ann Arbor, MI

21 March 2010


Outline

Outline

  • Motivation for developing the GLIM

  • Description of the GLIM

  • Preliminary Evaluation of the GLIM

  • Future plans for the GLIM

MODIS 4-9 March 2010


Motivation for the great lakes ice model glim

Motivation for the Great Lakes Ice Model (GLIM)

  • Since the 1980’s a rather primitive method has been employed for forecasting ice on the Great Lakes which has been based on a simple regression method between temperature trends and ice formation for specific points around the lakes

  • Extended temp guidance was used to run the regression with the resultant subjective, general 5 day forecast trend of ice formation/growth/deterioration that has been produced three times a week in text version only


Motivation for the great lakes ice model glim1

Motivation for the Great Lakes Ice Model (GLIM)

  • Since the regression method was only applied to a few points around the lakes, it did not account for other areas of the lakes.

  • The method was woefully simple and outdated

  • In December 2006, NWS Cleveland approached GLERL about developing a quantitative method of forecasting Great Lakes ice with data from the NDFD (National Digital Forecast Database) or NWP model data with the intent to improve the accuracy and specificity of ice forecasts & outlooks, and open and near shore forecasts


Description of the glim

Description of the GLIM

  • GLERL developed the GLIM from 2007-2010

  • GLIM is a combination of the Princeton Ocean Model for hydrodynamics and the Combined Ice Ocean Model tailored for the Great Lakes

  • GLIM which has two modules runs twice a day for Lake Erie as part of the Great Lakes Coastal Forecast system (GLCFS) at NOAA/GLERL at 2 km resolution

    • Hourly Nowcast runs - ingest surface observations

    • Forecast runs from 00 to 12o hours – driven by the NDFD

  • The GLCFS with the GLIM is run using the latest surface forecast meteorological grids from the NWS National Digital Forecast Database (NDFD) out to 5 days


Description of the glim1

Description of the GLIM

  • The initial conditions for the forecast module are based on nowcast runs which use observed meteorological data for atmospheric forcing

  • Nowcasts produce a lake ice state which is used as the initial condition for the forecast module

  • Model output for the GLIM is posted to the web

  • NWS CLE retrieves via ftp the GLIM for AWIPS and GFE


Integration of the glim and ndfd results in the forecast generation of

Integration of the GLIM and NDFD results in the Forecast Generation of:

Surface Water Temperature

Ice Concentration

Ice Thickness

Ice Drift

http://www.glerl.noaa.gov/res/glcfs/erie-ice.php?lake=e&type=F&hr=01

For both the nowcast and forecast components of the GLIM


Preliminary evaluation of the glim

Preliminary Evaluation of the GLIM

  • BOIVerify is a statistical analysis application that is run at many NWS offices to help verify locally produced gridded forecasts from the NDFD

  • BOIVerify was modified at NWS CLE to ingest the GLERL GLIM forecasts of ice concentration and ice cover analysis from the National Ice Center (NIC) to help evaluate the GLIM


Robert laplante noaa nws cleveland oh david schwab jia wang noaa glerl ann arbor mi

MODIS Satellite 2/4/2010

GLERL GLIM Ice Concentration fcst (%) in BOIVerify

NIC observed Ice

Concentration (%) in BOIVerify


Observed nic ice concentration displacement error

Observed NIC Ice concentrationDisplacement error

NIC ice concentration analysis is displaced about 10 miles to the southeast. So for Lake Erie, ice cover is shifted on to the lakeshore of OH, PA, & NY


Nic displacement affects on boiverify

NIC displacement affects on BOIVerify

  • Verification statistics generated by BOIVerify have been compromised with this displacement of the NIC analysis.

  • The NIC has been notified of the error and will hopefully address it soon.


Glim evaluation with boiverify

GLIM Evaluation with BOIVerify

NIC displacement increases the

Number of grid points of nil ice cover

Expected value reduced due to

NIC excessive # of nil grid points near northern Erie lakeshore


Preliminary evaluation of the glim on lake erie

Preliminary Evaluation of the GLIMon Lake Erie

Average Ice Concentration/Coverage (%/100)

Erroneous?

GLIM IC

Julian Day 2010

  • Seasonal Change to average ice concentration was well simulated

  • Realistic spatial coverage with initial freezing of Lake Erie in January

  • Changes in observed spatial coverage not well once lake was mostly frozen


Future plans for the glim

Future Plans for the GLIM

  • Correct NIC ice analysis displacement error

  • Initialize the GLIM with a NIC ice analysis

  • Upon further development, the GLIM will be expanded to the other Great Lakes

  • Additional NDFD fields may be used by the GLIM – snowfall and QPF to make the model more realistic

  • Output from the GLIM may be added to the NDFD


Robert laplante noaa nws cleveland oh david schwab jia wang noaa glerl ann arbor mi

Questions ?

[email protected]


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