WRAP RMC Phase II Wind Blown Dust Project Results Status ENVIRON International Corporation and University of California, Riverside Dust Emission Joint

WRAP RMC Phase II Wind Blown Dust Project

Results & Status

ENVIRON International Corporationand

University of California, Riverside

Dust Emission Joint Forum MeetingLas Vegas, NV

November 16, 2004

Phase II Project Overview• Develop improved general methodology based on Phase I

recommendations and recent literature review • Update gridded PM inventory of WB Dust for 2002 using the Inter-

RPO regional modeling domain • Develop of surface friction velocities and threshold friction

velocities• Develop improved emission flux relationships• Improve vacant land characterization

– Disturbance– Land use type– Reservoirs

• Conduct model performance evaluation

General Formulation for Emissions Estimation

• Dust = f(LULC,z0,u*,u*th,SC)

• u* = f(u,z0)

• u*th = f(z0)

• z0 = f(LULC)

Threshold Friction Velocities• u*th determined from relations developed by Marticorena, et

al, (1997)

u*t = 0.31e7.44x(Zo)

R2 = 0.60

u*t = 0.30e7.22x(Zo)

0

0.5

1

1.5

2

2.5

3

0.00001 0.0001 0.001 0.01 0.1 1

zo (cm)

u *t (

m s-1

)

wind tunnel data Marticorena et al. 1997Expon. (wind tunnel data) Expon. (Marticorena et al. 1997)

Emission Rates• Depends on soil type; based on results of Alfaro and

Gomes (2001)

FFSF = 2.45x10-6 (u*)

3.97

FSF = 9.33x10-7 (u*)

2.44

MSF = 1.243x10-7(u*)

2.64

CSF = 1.24x10-7 (u*)

3.44

0.000000001

0.00000001

0.0000001

0.000001

0.00001

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Friction Velocity (m s-1)

Emis

sion

Flu

x (F

, g c

m-2

s-1)

FSSFSMSCSPower (FSS)Power (FS)Power (MS)Power (CS)

NLCD Summary

NLCD Land Use Summary (Continental US)

Land Use Type Total Area (acres) % % excluding waterWater 98,484,739 5.0%Urban 35,629,865 1.8% 1.9%Barren 37,204,176 1.9% 2.0%Forest 556,424,387 28.1% 29.6%Shrubland 355,796,082 18.0% 18.9%Grasslands 302,601,621 15.3% 16.1%Agricultural 515,624,831 26.0% 27.4%Wetlands 78,127,135 3.9% 4.2%Total 1,979,892,836 100.0%

Total excluding water 1,881,408,097 100.0%

Dust Code 3 4 6 7

Land use category Ag. Grass Shrubs Barren

Surface roughness (cm) 0.031 0.1 0.05 0.002

Threshold friction Velocity (mile/h) 8.33 13.81 9.62 6.81

Threshold wind velocity at 38m height (mile/h) 29.50 44.25 32.75 28.50

Characteristics of Dust Categories

Soil CharacteristicsU.S. soil texture Chatenet (1996) Chatenet (1996)

Soil Texture (from Chamley, 1987) Groupings

sand sand CS

loamy sand sand CS

sandy loam silty sand MS

sandy clay loam clayey sand MS

sandy clay clayey sand MS

(medium) loam clayey silty sand MS

clay loam clayey silty sand MS

silty loam clayey sandy silt FS

silty clay loam clayey silt FFS

silt silt FFS

silty clay silty clay FFS

clay sandy clay FS (10-50% sand, 75-50% clay)

clay sandy silty clay FS (10-45% sand, 12-45% silt, 35-75% clay)

Reservoir Characteristics

• All soils assumed loose, undisturbed• Dust events limited to 10hrs/day

– Sensitivity simulations conducted based on above assumptions

• Rain events: Dust re-initiated after set number of days dependent on soil texture, amount of rainfall and season

Number of days after rain event to re-initiate wind erosion

• Rainfall > 2 inches • Rainfall < 2 inchesSoil type Spring/Fall Summer Winter

Sand 3 2.1 4.2

Sandy Loam 3 2.1 4.2

Fine Sand Loam

3 2.1 4.2

Loam 4 2.9 3.8

Silt Loam 4 2.9 3.8

Sandy Clay Loam

4 2.9 3.8

Clay Loam 5 3.6 7.2

Silty Clay Loam

6 4.3 8.6

Clay 7 5 10

Soil type Spring/Fall Summer Winter

Sand 1 0.7 1.4

Sandy Loam 1 0.7 1.4

Fine Sand Loam 1 0.7 1.4

Loam 2 1.4 2.8

Silt Loam 2 1.4 2.8

Sandy Clay Loam 2 1.4 2.8

Clay Loam 3 2 4

Silty Clay Loam 4 2.8 5.6

Clay 5 3.6 7.2

Model Sensitivity Simulations

• Run a :– No limitation on dust event duration– All soils considered loose undisturbed

• Run b :– Dust events limited to 10 hrs/day– All soils considered loose undisturbed

Model Sensitivity Simulations

• Run c :– No limitation on dust event duration – Assume 10% of barren, grass & shrublands area is disturbed– Threshold velocity for grass & shrublands = 0.5 * undisturbed value– Threshold velocity for barren lands = .27 * undisturbed value

• Run d :– Dust events limited to 10 hrs/day for undisturbed soils– Assume 10% of barren, grass & shrublands area is disturbed– Threshold velocity for grass & shrublands = 0.5 * undisturbed value– Threshold velocity for barren lands = .27 * undisturbed value

Model ResultsScenario a: no limit on duration; all soils loose, undisturbed

Dust emissions, Scenario a

60.2%18.4%

20.4%

1.0%Dust Code 3 - AgDust Code 4 - GrasslandsDust Code 6 - ShrublandsDust Code 7 - Barren

Model ResultsScenario b: event duration <=10 hrs/day; all soils loose, undisturbed

Dust emissions, Scenario b

61.7%15.7%

21.5%

1.1% Dust Code 3 - AgDust Code 4 - GrasslandsDust Code 6 - ShrublandsDust Code 7 - Barren

Model ResultsScenario c: no limit on duration; assume 10% disturbed area for grass,

shrub, barren lands

Dust emissions, Scenario c

48.6%

26.0%

23.3%

2.1% Dust Code 3 - AgDust Code 4 - GrasslandsDust Code 6 - ShrublandsDust Code 7 - Barren

Model ResultsScenario d: event duration <= 10hrs/day for disturbed soils; assume 10%

disturbed area for grass, shrub, barren landsDust emissions, Scenario d

42.9%

28.6%

25.7%

2.8%Dust Code 3 - AgDust Code 4 - GrasslandsDust Code 6 - ShrublandsDust Code 7 - Barren

Dust Totals for WRAP Statestons/year

Scenario WRAP States Domain Total (US only)

a 2,222,219 9,451,368

b 1,310,120 5,228,818

c 3,077,196 11,098,731

d 2,165,096 6,876,180

1996 2,240,288 4,366,907

Annual PM10Dust Yearly Total by State

Western States

0

200000

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600000

800000

1000000

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1800000

AZ

AR

CA

CO ID IA KS

LA

MN

MO

MT

NE

NV

NM

ND

OK

OR

SD

TX

UT

WA

WI

WY

State

Ton/

y

scen ascen bscen cscen d1996

Annual PM10Dust Yearly Total by State

WRAP States

0

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900000

1000000

AZ

CA

CO ID MT

NV

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WA

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State

Ton/

y

scen a

scen b

scen c

scen d

1996

Comparison of Monthly Dust EmissionsMonthly Dust Emissions

0.0

500000.0

1000000.0

1500000.0

2000000.0

2500000.0

3000000.0

3500000.0

4000000.0

4500000.0

1 2 3 4 5 6 7 8 9 10 11 12

month

Ton/

Mon

th

scen a scen b

scen c scen d

Dust from Category 3 (Ag land)PM10 Yearly Total

0

50000

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Ton/

y

scen ascen bscen cscen d

Annual PM10 from Ag Land for WRAP States

Dust from Category 4 (Grass land)PM10 Yearly Total

0

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320000

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CO ID MT

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Ton/

y

scen a

scen b

scen c

scen d

Annual PM10 from Grass Land for WRAP States

Dust from Category 6 (Shrub land)PM10 Yearly Total

0

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Ton/

y


Annual PM10 from Shrub Land for WRAP States

Dust from Category 7 (Barren land)PM10 Yearly Total

0

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50000

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CO ID MT

NV

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Ton/

y


Annual PM10 from Barren Land for WRAP States

Scenario b Annual PM10 from All Dust Categories for WRAP States

Dust from all Categories for Scenario bPM10 Yearly Total

0

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CO ID MT

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Ton/

y

Dust Code 3 - Ag

Dust Code 4 - Grasslands

Dust Code 6 - Shrublands

Dust Code 7 - Barren

Scenario d Annual PM10 from All Dust Categories for WRAP States

Dust from all Categories for Scenario dPM10 Yearly Total

0

30000

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AZ

CA

CO ID MT

NV

NM

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Ton/

y

Dust Code 3 - AgDust Code 4 - GrasslandsDust Code 6 - ShrublandsDust Code 7 - Barren

2002 Annual PMC Scenario a: no limit on duration; all soils loose, undisturbed

2002 Annual PMC Scenario b: event duration <=10 hrs/day; all soils loose, undisturbed

2002 Annual PMC Scenario c: no limit on duration; assume 10% disturbed area for grass,

shrub, barren lands

2002 Annual PMC Scenario d: event duration <=10 hrs/day; assume 10% disturbed area for

grass, shrub, barren lands

2002 Annual PMC Scenario b: event duration <=10 hrs/day; all soils loose, undisturbed

2002 Seasonal PMC

Model Limitations• Grid resolution

– Coarse resolution of met data can’t resolve high wind events; wind gusts

• LULC and Soils data– LULC not detailed enough on a regional-scale– Soils data lacks depth of layers, moisture data

• Agricultural land adjustments– No agricultural data for Eastern states (prepared for WRAP &

CENRAP regions only)– Data gaps in Ag Census

Model Performance Evaluation1. Evaluate model results for reasonableness and accuracy

– Compare predicted WB dust emissions near IMPROVE monitors with measured IMPROVE dust extinction (Bdust)

2. Enhancements to CMAQ to track WB and other dust– Evaluate model CMAQ model performance with and without

WB dust emissions

3. Refined model performance evaluation using results of Etyemezian, et al.

– For events characterized as wind blown dust events, determine whether dust model predicts impacts

2002 Coarse Mass

Seasonal Coarse Mass (2002)

Annual Fine & Coarse Mass (2003)

Model Performance Evaluation (1)• Evaluate model results for reasonableness and accuracy• Compare predicted WB dust emissions near IMPROVE monitors with

measured IMPROVE dust extinction (Bdust)

– Identify occurrences of:1) Zero WB dust and near-zero Bdust

2) Enhanced WB dust and near-zero Bdust

3) No WB dust and elevated Bdust

4) Enhanced WB dust and elevated Bdust

• Modeled dust averaged over 5 x 5 block of grid cells centered on IMPROVE sites

• Daily averaged model results paired (in time & space) with monitored data

• Compare modeled PM with Bextdust

– Bextdust = [FS] + 0.6[CM]

Model Performance Evaluation (1)YELL

0

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Normalized DUST_Bext

Nor

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PM

10 (a

vg5x

5)

YELL

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Model Performance Evaluation (1)

ZION

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ZION

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Model Performance Evaluation (1)YOSE

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YOSE

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LOST

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LOST

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CAPI

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MELA

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KALM

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PORE

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GUMO

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MORA

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DEVA

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BADL

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BADL

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• Enhancements to CMAQ to track WB and other dust emissions separately

• Run CMAQ w/ and w/o WB Dust emissions• Evaluate CMAQ model results with and with out WB dust

emissions


January, 2002


July, 2002


Model Performance Evaluation (3)• Refined model performance evaluation using results of

Etyemezian, et al.• For events characterized as wind blown dust events, determine

whether dust model predicts impacts• Model and measurements agree …

– Analyze for trends– Systematic over- or under-prediction ?

• Model and measurements disagree …– Wind speed errors ? – Landuse type mischaracterization ?– Other ?

Analyses on-going based on DRI project results

Next Steps• Complete Model Performance Evaluation (end of year)• Address deficiencies in Ag data for the Eastern States

– Assume constant crop canopy %– Develop generic crop calendars, crop canopy % , etc.– Collect detailed Ag data from Eastern States

• Re-run model w/ latest MM5 data• Make use of 12-km resolution MM5 data• Apply to small region for verification of methods, assumptions• Apply transport fraction by county for air quality model

applications

Documents

WRAP RMC Phase II Wind Blown Dust Project Results Status ENVIRON International Corporation and University of California, Riverside Dust Emission Joint