Using BOIVerify To evaluate the Great Lakes Ice model

Evaluation of Great Lakes Ice Model (GLIM) Real-time Ice Forecasts for the 2012-2013 Ice seasonRobert LaPlanteChristopher MelloNOAA/NWS Cleveland, OH

Gregory LangJia WangNOAA/GLERL Ann Arbor, MI

9 April 2013

OutlineDescription of the GLIM Comparison of the GLIM to the National Ice Center analysis for the 2012-2013 ice seasonAddition of Vessel Icing parameterFuture plans for the GLIM

MODIS 4-9 March 2010

Description of the GLIMGLIM has been under development by GLERL since 2007 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 all five Great Lakes as part of the Great Lakes Coastal Forecast system (GLCFS) at NOAA/GLERL Hourly Nowcast runs - ingest surface meteorological and daily NIC ice concentration observationsForecast runs from 00 to 12o hours driven by the NDFDThe GLIM is run using the latest surface forecast meteorological grids from the NWS National Digital Forecast Database (NDFD) out to 5 daysGLIM resolution for the Great Lakes

10 km2 km2km5 km2km

Description of the GLIMGLIM Nowcasts of ice concentration are nudged towards the daily NIC ice concentration field and form the initial conditions for the forecast moduleModel output for the GLIM is posted to the web NWS CLE retrieves via ftp the GLIM for AWIPS and GFEGLIM Ice Concentration is nudged toward the NIC ice concentration field which is updated daily

GLIMNICGLERL GLIM included in the GLCFSGreat Lakes Coastal Forecasting System

http://www.glerl.noaa.gov/res/glcfs/Select IceIntegration of the GLIM and NDFD results in the Forecast Generation of:Surface Water TemperatureIce ConcentrationIce ThicknessIce Drift & Vessel Icing

http://www.glerl.noaa.gov/res/glcfs/glcfs-ice.php?lake=e&type=N&hr=00Sources of Error in the GLIM Ice Concentration ForecastError in the daily NIC ice concentration analysisNIC analysis data sources are lagged: ~00 and ~12 UTC RADARSAT passes & previous day ~18 UTC MODIS imagery and current day ~18 UTC MODIS imagery are combined and posted about 00 UTC the next dayVariable observation times add uncertainty due to advective changes and growth and decay of ice coverSubjectivity of the ice analyst in specifying ice edge and concentration Error in the NDFD parameters (wind, temperature, or dewpoint) over the entire Great LakesError within the GLIM: nudging procedure, vertical mixing, or wave mixingWinter TemperaturesWhile still above normal, the 2012-13 winter was colder than the unseasonably mild 2011-2012 winterResultant Great Lakes ice cover increased, especially on shallow Lake ErieMaximum seasonal ice cover attained by lake (GLERL)2011-20122012-2013Lake Ontario 3%15%Lake Superior7%38%Lake Erie 16%85%Lake Michigan17%20%Lake Huron20%40%Assessment of the NIC Ice Analysis

NIC ice analysis was notRealistic at times with ice Concentration decreasingWith air temperaturesBelow freezingTemperatureAssessment of the NIC Ice Analysis

NIC Analysis exhibited Occasional spikes of increasedIce concentration which lastedBut a day or so and were notRealistic. In particular, weWill examine the second, or Day 62 spike on Lake SuperiorWhen the ice cover nearly doubledFor only a day

Lake SuperiorAssessment of the NIC Ice Analysis

Day61Day62Day63

Ice ConcentrationNote the abrupt increase and decrease in ice concentrationFrom Day61 through Day63 overWestern Lake Superior

This High Nowcast, due to the highNIC analysis, produced a high starting forecast

Which, with low air temperatures Leads to these high 1-day, 3-day, and 5-day forecasts

Lake SuperiorChange in GLIM forecastIce Concentration vsChange in NIC ice analysisNIC spikes are apparent in thesex/y plots of the GLIM days 1-3-5 forecasts

Too slow ice growth in GLIMTo fastIce growthToo fastmeltToo slowmeltGLIM tends toGrow or meltIce too slowly inDay 3 and Day 5 forecasts

LakeErieSummary of the GLERL GLIM2012-2013 ice season on Lake ErieGLIM was successfully run over all the Great LakesGLIM nowcasts for 2012-2013 closely matched the NIC ice concentration analysis with daily nudging across all the lakesSince the NIC analysis is not a snap shot of the observed ice coversome uncertainty is introduced into the GLIMSpikes in the daily NIC ice analysis appeared spuriousCompared to NIC analysis, the GLIM 3-day and 5-day forecasts tended to grow and melt ice too slowly on all the LakesDifficult to separate error in NIC analysis and NDFD with error in GLIMPrediction of Vessel Spray Icing with the Great Lake Ice Model18Sea Spray Icing AlgorithmIn the past we used Nomograms of Icing for Various water temperatures:

Sea Spray Icing AlgorithmUsing the work of Overland et al. (1986) & (1990): Icing Predictor: PPR is defined by

GLERL modified the equation for fresh water and used output from the Great Lakes Ice Mode (GLIM) to produce icing classes for all five lakesIcing ClassesIcing classes are determined with the assumption that vessels are steaming into the wind and of 20 -75 meters in length

Vessel Icing over Lake Erie

NIC 31 Jan 2013White area is whereIce has formedPotential Issues Shoreline affects are not accounted for in icing potentialFor a given wind, waves and resultant freezing spray will be less at the start of the fetchThe reduction in freezing spray due to lake ice cover has not been determined, but at some high percentage of ice cover (>70%), freezing spray may be minimalVessel Icing NotesGLERL added the Vessel Icing parameter to its web site http://www.glerl.noaa.gov/res/glcfs/The quality of the freezing spray forecast is dependent on the inputs into the GLIM which include the NDFDSurface WindAir TemperatureSo pay attention (American Forecasters) to the NDFD grids over the entire lake you forecast forFuture Plans for the GLIMGLCFS POM (currently running the GLIM) will not be modifiedGLERL is in the process of developing a new model: an operational FVCOM (Finite Volume Coastal Ocean Model) for Lake ErieVariable grid and much higher resolution for harbors and baysHeat fluxes are being calculated and testing of ice dynamics is expected over the next yearPlan to test the Lake Erie FVCOM this fall at CSDL (Coastal Survey Development Lab)By late summer 2014, FVCOM may be delivered to NCEPRemaining lakes will be modeled by early 2017

Questions ?Robert.laplante@noaa.gov