building mepdg climate files in this presentation….seaupg.org/pdf/2010/thursday/5 sesc...

SEAUPG 2010 ANNUAL CONFERENCE OKLAHOMA CITY, OK

Thursday, December 9, 2010

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Building MEPDG Climate Files

Funded by Mississippi DOT

Research partnersMississippi State UniversityAuburn University, NCATIowa State University, Climate Science Initiative

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In this presentation….Why is climate input importantBuilding historic climate filesBuilding future climate filesImpact on predicted pavement performance

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Pavement Design Variables

Time, years

Granular Base Modulus

Subgrade Modulus

TrafficPCC ModulusCTB Modulus

Each load application

2 8640

HMA Modulus

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Permenant Deformation: Total Rutting in Pavement Layers (inch)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0 18 36 54 72 90 108 126 144 162 180 198

Pavement age, month

Max

imum

Rut

ting

(inch

)

SubTotalACSubTotalGBSubTotalSGTotal RuttingTotalRutReliability

Ac Rutting Design Value = 0.25" Predicted

Rutting90% Reliability

Total

HMA

SubgradeAggr. Base

Design Limit

5 6

Climate Database for Mississippi

Only 12 climate files in Mississippi4 sites with 5‐6 years of climate data8 with 8‐10 years of climate dataStarting with mid 1990s

Need to expand time‐scale to 20+yearNeed to increase spatial coverage



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Limitations of this approach

Do 12 weather sites adequately cover variations in climate for Mississippi?Does the time period of 1996 to present adequately cover expected climate?Does this approach to creating a 20‐year (or 40 year) climate database generate a reasonable expectation of future pavement performance?

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Ames, IA Daily Temperatures

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August 21stTemperature Distribution

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January 21stTemperature Distribution

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Ames Temperature Trends

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Iowa Averages and Extremes

Decade Avg High Avg Low 100°+ events1970s 58.9 37.4 5931980s 59.6 38.1 20731990s 58.4 38.3 235



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http://www.city‐data.com/city/Ames‐Iowa.html

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Development ofClimate Data Input Files

for the MEPDG

Build complete 40‐year historic climate filesBuild 40‐year future climate files

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create a gridded analysis(natural neighbor interpolation)

Step-2

Data from Climate Archive sources

Quality control check of data

Quality control the gridded output

Identify missing data and create values

Create __.hcd file for each CountyStep-3

Step-4 Quality Control the __.hcd file

Step-1

Building better HISTORICAL climate files

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ASOS/AWOS COOP

Observation Interval Hourly Daily

Air Temperature Hourly functional form Daily high/low observed

Wind Speed Verbatim use N/A

Relative Humidity Verbatim use N/A

Percent Sunshine Verbatim use N/A

Precipitation Hourly functional form Daily precip observed

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ASOS/AWOS COOP

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Analysis Grid

NeighborInterpolation

Grid Node

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Complete Historic Files40‐year files (1970‐2010)For each county in the StateCritical for matching climate with pavement data used for calibration

MEPDG climate1985‐2000 pavement and 1995‐2000 climate (3x)HISTORIC climate

1985‐2000 pavement and 1985‐2000 climate

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How should future climate files be built?

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19702010

19802020

19902030

20002040

19702010

19802020

19902030

20002040

Option ‐ 1

Option ‐ 2 24

Monthly Climate “DELTAs” (for 50-year period)

Temperature DELTA = Future Scenario – Contemporary Scenario

Precipitation DELTA = Future Scenario / Contemporary Scenario

Future Scenario

(decade of 2040s)

GLOBAL MODEL35,000 sq-mi patternIncludes: solar radiation & green house gasses changesFrequency: 6 hours over 10 years

REGIONAL MODEL1200 sq-mi patternIncludes: regional geographic features and climate patternsFrequency: 3 minutes

Contemporary Scenario

(decade of 1990s)



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Temperature Distribution

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Average Monthly Temperature

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Average Monthly Precipitation

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JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

T [C] 1.3 1.5 3.2 2.4 2.7 1.9 2.8 2.0 1.7 1.9 2.0 1.4

P [%] -21 -13 40 14 39 13 -17 17 68 -20 37 -11

50-year DELTA’s

1970-2010Historic Climate

2010-2050Virtual Climate

DELTA( per month)



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40-year Future Climate FilesFor each climate region in the StateCritical for predicting pavement performance

MEPDG climate2010-2030 pavement design and 1995-2000 climate (4x)

HISTORIC climate2010-2030 pavement design and 2010-2030 virtual climate

Complete Future Files

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What is the impact of more accurate climate files?

4.5‐in HMA, AC‐303.0‐in AC perm base12‐in A‐2‐4 base

8‐in lime stab subgrade

A‐6 subgrade

9.3‐in JPCP20 ft joint spacingtied PCC shoulder5.7‐in lime stab baseA‐2‐4 subgrade

12.5‐in HMAAC‐30

A‐6 subgrade

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Faulting (M‐H)

‐0.01‐0.005

00.0050.01

0.0150.02

0.0250.03

0.0350.04

0.0450.05

1 2 3 4 5 6 7 8 9 10

Zones

Faul

ting

(in)

Faulting (H‐V)

‐0.01‐0.0051E‐170.0050.01

0.0150.02

0.0250.03

0.0350.04

0.0450.05

1 2 3 4 5 6 7 8 9 10

Zones

Faul

ting

(in)

9.3‐in JPCP

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Rutting (M‐H)

‐0.05

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6 7 8 9 10

Zones

Rutt

ing

(in)

Rutting (H‐V)

M‐V Zone(1‐10),

‐0.05

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6 7 8 9 10

Zones

Rutt

ing

(in)

12.5‐in HMA

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Rutting (M‐H)

‐0.05

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6 7 8 9 10

Zones

Rutt

ing

(in)

Rutting (H‐V)

M‐V Zone(1‐10),

‐0.05

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6 7 8 9 10

Zones

Rutt

ing

(in)

4.5‐in HMA



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Month 1st 2nd 3rd 4th 5th Mean S

January 29.3 40.5 48.7 58.3 70.9 49.6 14.9

February 35.0 44.6 52.4 61.0 76.4 53.9 14.9

March 42.8 53.3 60.5 71.2 90.2 63.6 16.9

April 52.6 63.7 71.4 85.4 104.6 75.5 18.7

May 62.4 71.8 81.1 97.3 113.7 85.3 18.9

June 69.5 76.4 88.7 106.8 122.8 92.8 20.2

July 73.7 79.8 93.2 112.9 130.5 98.1 21.7

August 71.8 78.9 90.7 112.8 129.2 96.7 22.0

September 61.8 71.8 80.6 98.4 117.7 86.0 20.6

October 52.0 62.9 70.3 82.3 100.7 73.7 17.4

November 42.6 52.1 58.9 68.6 85.3 61.5 15.3

December 31.7 40.7 48.3 57.6 70.6 49.8 14.0

Pavement Surface Temperature (F)

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Washington (W) - HMA2

0

20

40

60

80

100

120

140

Janu

ary

February

March

April

MayJu

ne July

Augus

t

Septem

ber

Octobe

r

Novem

ber

Decem

ber

tem

pera

ture

(F)

historic - 1st Q MEPDG - 1st Q virtual 1st Qhistoric - avg MEPDG - avg virtual - avghistoric - 5th Q MEPDG - 5th Q virtual - 5th Q

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Zone 4 Rutting Thin HMA

0

0.2

0.4

0.6

0.8

1

1.2

1 61 121 181 241 301 361 421

time (months)

rutti

ng (i

nche

s)

MEPDG HIST VIRT

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SE Superpave Pooled FundDeveloping MEPDG Climate Files

40-yr (1970-2010) Historic files (each county)40-yr (2010-2050) Future “virtual” files (each region)

1-2 States in pool ~$44,000 / State3-5 States in pool ~$38,000 / State6+ States in pool ~$34,000 / State

building mepdg climate files in this presentation….seaupg.org/pdf/2010/thursday/5 sesc...

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