AMPS 10km MM5AMPS 10km MM5Operational Evaluation ofOperational Evaluation of

Cloud Base/Ceiling Product Cloud Base/Ceiling Product

Bryan M. BurdenBryan M. Burden

Aviation Technical ServicesAviation Technical Services

SPAWARSYSCEN, CharlestonSPAWARSYSCEN, Charleston

Is There a Need?Is There a Need?

Flights AffectedFlights Affected

Accuracy ComponentAccuracy Component

ReliabilityReliability

Forecaster Forecaster CommentsComments

Comments GoodComments Good Comments BadComments Bad

““Good With Major Systems”Good With Major Systems”

““Solid Performer In Good Solid Performer In Good Weather”Weather”

““More Accurate over PolarMore Accurate over Polar Plateau”Plateau”

““Under Forecast Amounts”Under Forecast Amounts”

““Limited Low Clouds Reflected”Limited Low Clouds Reflected”

““Underestimated Low Clouds”Underestimated Low Clouds”

Cloud Base Cloud Base EvaluationEvaluation

Positive & Negative AspectsPositive & Negative Aspects

Help to the ForecasterHelp to the Forecaster

Add to the ProcessAdd to the Process

Where the Data Where the Data Came From Came From

AMPS Model DataAMPS Model Data

Corresponding ObservationsCorresponding Observations

Ice Runway McMurdoIce Runway McMurdo

Compiling DataCompiling Data

60 Model Runs60 Model Runs

1800 Model Hours 1800 Model Hours

Product Output Compared to Product Output Compared to Actual ObservationsActual Observations

Parameters UsedParameters Used

Basic Designators Basic Designators FEW, SCT, BKN, OVCFEW, SCT, BKN, OVC

Model Output Given Ceiling DesignatorsModel Output Given Ceiling Designators

Ceiling Designator Used from Real-Time Ceiling Designator Used from Real-Time Observations Observations

More Emphasis Given to CeilingsMore Emphasis Given to Ceilings

CriteriaCriteria

Ceilings Did Or Did Not MatchCeilings Did Or Did Not Match

Accurate When Ceiling Output < Accurate When Ceiling Output < 3,000ft and Within 1,000ft Of Actual3,000ft and Within 1,000ft Of Actual

Accurate When Ceiling Output Accurate When Ceiling Output 3,000ft and Greater Within 5,000ft 3,000ft and Greater Within 5,000ft Of ActualOf Actual

LimitationsLimitations

Limited Sample SizeLimited Sample Size

Short Duration Short Duration Nov-Dec 2003Nov-Dec 2003

One Location Used One Location Used Ice Runway (NZIR)Ice Runway (NZIR)

First FocusFirst Focus

High Ceiling on OutputHigh Ceiling on Output

Actual Ceiling Much LowerActual Ceiling Much Lower

5 Times Ceiling Forecast5 Times Ceiling Forecast

4 Times Significantly Lower4 Times Significantly Lower

Advancing Low Pressure Advancing Low Pressure SystemSystem

Moving In From the South and Moving In From the South and West Across the Ross Ice ShelfWest Across the Ross Ice Shelf

SynopticSynoptic PatternPattern

ModelModel

FEW050 FEW080 BKN100FEW050 FEW080 BKN100

ActualActual

SCT100 BKN200SCT100 BKN200

ModelModel

FEW050 FEW080 SCT100FEW050 FEW080 SCT100

ActualActual

SCT006 BKN012 OVC140SCT006 BKN012 OVC140

ModelModel

SCT020 BKN030 OVC060SCT020 BKN030 OVC060

ActualActual

FEW030 FEW065 SCT150FEW030 FEW065 SCT150

SummarySummary

Model Output Bias Towards Higher Model Output Bias Towards Higher Cloud HeightsCloud Heights

Lower Clouds 80% of the Time Lower Clouds 80% of the Time Missed or Under Forecast by Model Missed or Under Forecast by Model OutputOutput

Timing IssuesTiming Issues

Too Fast to ClearToo Fast to Clear

Model Adjusted but too LateModel Adjusted but too Late

4 Times Occurred4 Times Occurred

2 Times Missed2 Times Missed

Exiting Low Pressure Exiting Low Pressure SystemSystem

Moving Away To The North Moving Away To The North and East Over Open Ocean and East Over Open Ocean

WaterWater

Synoptic PatternSynoptic Pattern

ModelModel

FEW060 BKN100FEW060 BKN100

ActualActual

FEW012 BKN035 BKN075FEW012 BKN035 BKN075

SummarySummary

Clouds Become Trapped In TerrainClouds Become Trapped In Terrain

Model’s Bias Toward Clearing too Model’s Bias Toward Clearing too QuicklyQuickly

Timing too Fast for Actual OccurrencesTiming too Fast for Actual Occurrences

50% of the Time Not Accurate/Accurate50% of the Time Not Accurate/Accurate

Fork In The Road

Good Forecast OutputGood Forecast Output

Generally Good Weather Good Generally Good Weather Good OutputOutput

Higher the Ceiling the More AccurateHigher the Ceiling the More Accurate

Rates Accurate to Near 80%Rates Accurate to Near 80%

High Pressure RidgeHigh Pressure Ridge

Strengthening Ridge at All Strengthening Ridge at All Levels Of The AtmosphereLevels Of The Atmosphere

Synoptic PatternSynoptic Pattern

ModelModel

FEW160 FEW160

ActualActual

FEW140 FEW180FEW140 FEW180

SummarySummary

Solid Output During Quiet WeatherSolid Output During Quiet Weather

80% Accuracy Between Systems80% Accuracy Between Systems

The Better The Weather, The Better The The Better The Weather, The Better The OutputOutput

ConclusionsConclusions

Objective Evaluation Conducted With Objective Evaluation Conducted With Limited Data and Small ParametersLimited Data and Small Parameters

Get Better Numbers In Open Terrain?Get Better Numbers In Open Terrain?

More Analysis NeededMore Analysis Needed

Continue to Fine Tune Model OutputContinue to Fine Tune Model Output

Questions ? ? ?Questions ? ? ?