Comparing Aircraft Measurements of Atmospheric

Compounds with a Regional Photochemical Model

by Jennifer SchiffelbeinCE 394K GISWR

Fall 2003

Outline Description of Model and Aircraft DataDescription of Model and Aircraft Data

– TexAQS 2000 (Southeast Texas)TexAQS 2000 (Southeast Texas)

Completed WorkCompleted Work– Creating grids & polygons with ArcInfoCreating grids & polygons with ArcInfo– CAMx ProjectionCAMx Projection

Future WorkFuture Work– Spatial & Temporal issuesSpatial & Temporal issues– InterpolationInterpolation

Description of Data:Aircraft

Electra aircraft Electra aircraft – NOAANOAA

Data collectedData collected– Position (GPS x,y,z)Position (GPS x,y,z)

– Air analysis: CO, NOx, OAir analysis: CO, NOx, O33, PM, VOCs….., PM, VOCs…..

– MeteorologicalMeteorological Data frequency: 1 per secondData frequency: 1 per second Duration: 6-7 hours (~26,000 points!)Duration: 6-7 hours (~26,000 points!)

Description of Data:Model

Predicts chemistry of atmosphere over Predicts chemistry of atmosphere over timetime

Inputs: emissions, temperature, Inputs: emissions, temperature, meteorology…meteorology…

Time scale: 1 hourTime scale: 1 hour Structure: 3-D gridStructure: 3-D grid

Description of Data:Model

StructureStructure– Chosen domain: Houston/Galveston Chosen domain: Houston/Galveston

(HG)(HG)– Box = 1 km x 1 km x variable height Box = 1 km x 1 km x variable height

(m)(m)– Horizontal extent: 74 cells x 74 cellsHorizontal extent: 74 cells x 74 cells– Vertical extent: 21 layers from 0 Vertical extent: 21 layers from 0

(ground) to 4106 m(ground) to 4106 m

Completed Work Generate grid (“fishnet”)Generate grid (“fishnet”)

Example: 2x3 gridExample: 2x3 grid– ArcGIS/ArcInfo Workstation/ArcArcGIS/ArcInfo Workstation/Arc

Arc:Arc: workspace mydirectory workspace mydirectory

Arc:Arc: generate generate stockingsstockings

Generate:Generate: fishnet fishnetFishnet Origin Coordinate (X,Y):Fishnet Origin Coordinate (X,Y): 0,0 0,0Y-Axis Coordinate (X,Y):Y-Axis Coordinate (X,Y): 0,2 0,2Cell Size (width, height):Cell Size (width, height): 1,1 1,1Number of Rows, Columns:Number of Rows, Columns: 2,3 2,3Generate:Generate: quit quit

**ItalicsItalics = prompts = prompts*mydirectory = z:\uteid, or c:\mystuff*mydirectory = z:\uteid, or c:\mystuff**red textred text = name of file you must specify = name of file you must specify

Completed Work

Generate gridGenerate grid

– Make map displayableMake map displayableArc:Arc: clean clean stockings drawerstockings drawerArc:Arc: build build drawerdrawer poly polyArc: addxy Arc: addxy drawerdrawerArc: Arc: quitquit (to close Arc window)(to close Arc window)

-Directory “drawer” contains “polygon” grid shapefile-Directory “drawer” contains “polygon” grid shapefile

-“addxy” assigns x-y coordinate to center of each -“addxy” assigns x-y coordinate to center of each grid cellgrid cell**ItalicsItalics = prompts = prompts*mydirectory = z:\uteid, or c:\mystuff*mydirectory = z:\uteid, or c:\mystuff**red textred text = name of file you must specify = name of file you must specify

Completed Work

Generate gridGenerate grid– Example: 2x3 grid resultExample: 2x3 grid result

Completed Work

Generate polygonGenerate polygonExample: 1000x1000 boxExample: 1000x1000 box

Arc:Arc: generate generate bigboxbigboxGenerate:Generate: polygons polygons::ID, {AUTO | X,Y}:ID, {AUTO | X,Y}: 1, auto 1, autoX,Y:X,Y: -1000,0; -1000, 1000; 0,1000; 0,0 -1000,0; -1000, 1000; 0,1000; 0,0X,Y:X,Y: end endID, {AUTO | X,Y}:ID, {AUTO | X,Y}: end endGenerate:Generate: quit quit

*Clean “bigbox” & build as with grid*Clean “bigbox” & build as with grid

Completed Work

Generate polygonGenerate polygon

Example resultsExample results

Completed Work CAMx ProjectionCAMx Projection

– Projection type: Lambert Conformal ConicProjection type: Lambert Conformal Conic– First true latitude: 30°NFirst true latitude: 30°N– Second true latitude: 60°NSecond true latitude: 60°N– Latitude of origin: 40°NLatitude of origin: 40°N– Central meridian: 100°WCentral meridian: 100°W

*Earth datum: Perfect sphere, *Earth datum: Perfect sphere, radius = 6370kmradius = 6370km

*BUT ArcGIS only offers r ~6371 km*BUT ArcGIS only offers r ~6371 km-exact projection difficult to create-exact projection difficult to create

Future Work

Spatial issues:Spatial issues:

*Filter aircraft data points by *Filter aircraft data points by

1.) Is aircraft within HG domain?1.) Is aircraft within HG domain?

2.) Which vertical layer is aircraft in?2.) Which vertical layer is aircraft in?

Future Work Spatial issues:Spatial issues:

1.) Exclude all points outside domain1.) Exclude all points outside domain

Future Work

Spatial issue: Spatial issue:

2.) Which vertical layer is aircraft in?2.) Which vertical layer is aircraft in?

-Horizontal slice-Horizontal slice -Vertical slice-Vertical slice

Future Work Spatial issues:Spatial issues:

2.) Which vertical layer?2.) Which vertical layer?

Aircraft Altitude (sample)

0

1000

2000

3000

4000

5000

15.5 16 16.5 17

time (hours past midnight)

alti

tud

e (m

)

Future Work

Spatial issues:Spatial issues: 2.) Which vertical layer?2.) Which vertical layer?

– Decisiion – Assign points +½(hDecisiion – Assign points +½(hi+1i+1-h-hii) & ) & -½(h-½(hii-h-hi-1i-1) to layer at h) to layer at hii

Future Work

Temporal issue:Temporal issue:– Model hourly species concentrationModel hourly species concentration

Example: 1:00 pm, CO conc. = 50 ppbExample: 1:00 pm, CO conc. = 50 ppb

2:00 pm, CO conc. = 40 ppb2:00 pm, CO conc. = 40 ppb

Aircraft second by second concentrtionAircraft second by second concentrtionExample: 1:32:08 pm, CO conc. = 46 ppbExample: 1:32:08 pm, CO conc. = 46 ppb

How assign time intervals for comparison?How assign time intervals for comparison?- Aircraft points with time betweenAircraft points with time between

*1:31 to 2:30 with 2:00 model*1:31 to 2:30 with 2:00 model

*2:31 to 3:30 with 3:00 model*2:31 to 3:30 with 3:00 model

Future Work

InterpolationInterpolation– Spatial Analyst – Interpolate to RasterSpatial Analyst – Interpolate to Raster

*Try & compare 2-3 methods*Try & compare 2-3 methods

*Consider ~small, spatially concentrated points for *Consider ~small, spatially concentrated points for each time interval and vertical layereach time interval and vertical layer

Concluding Remarks

Complex problemComplex problem– 3 dimensions and time must be 3 dimensions and time must be

consideredconsidered Large volume of dataLarge volume of data

– 74x74 cells = 5476 grid cells per layer74x74 cells = 5476 grid cells per layer– ~26,000 aircraft data points~26,000 aircraft data points

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