# WEATHER DATA IN AQUATIC EXPOSURE MODELING US EPA ENVIRONMENTAL MODELING PUBLIC MEETING APRIL 28, 2015 Meridith Fry , Gabe Rothman, and Dirk Young US EPA Environmental Fate and Effects Division (EFED)

# Motivation
• Weather contributes importantly to a chemical’s modeled fate and transport • Representative weather is important for conducting pesticide exposure simulations • EFED standard weather files • No longer maintained by NOAA National Climatic Data Center (NCDC) • Only span 1961 - 1990 • L imited to 237 locations nationwide 2

# Outline
• Overview of existing source: SAMSON • Development of new source: NOAA CPC and NCEP/NCAR gridded datasets • Processing and new format • Evaluation of processed dataset • Maintenance and outlook

1 Solar and Meteorological Surface Observation Network (SAMSON) 2 NOAA Climate Prediction Center (CPC) Unified Rain Gauge Analysis 3 NOAA National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) Reanalysis 3

# Existing source: SAMSON Weather Bureau Army Navy (WBAN) SAMSON • 237 National Weather Service (NWS) locations • 1/1/1961 to 12/31/1990 NCDC, 1983, 1992. Climatography of the United States No. 81. National Climatic Data Center, NOAA, Asheville, NC . SCS, 1981. Land Resource Regions and Major Land Resource Areas of the United States. Agriculture Handbook 296. USDA SCS, Washington, DC . http ://www2.epa.gov/exposure- assessment-models/meteorologicaldata

4NOAA CPC and NCEP/NCAR datasets • More expansive and recent ( 1/1/1948 – present ) • Daily weather variables available: Precipitation , Potential Evapotranspiration (PET) *, Temperature, Wind speed, Solar radiation • Uniform national coverage • High spatial resolution, especially precipitation * derived 

# Improved source: NOAA Gridded Weather

SAMSON  NOAA Gridded Locations

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# Source 1: NOAA CPC Daily Total Precipitation NOAA CPC Unified Rain Gauge Analysis (raw format: netCDF )  0.25 x 0.25 degree resolution – lower 48 states  Daily Precipitation (Before 2007) http://www.esrl.noaa.gov/psd/data/gridded/data.unified.daily.conus.html ( 2007 – Present) http://www.esrl.noaa.gov/psd/data/gridded/data.unified.daily.conus.rt.html

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# Source 2: NOAA NCEP/NCAR Other variables NOAA NCEP/NCAR Reanalysis (raw format: netCDF )  2.5 x 2.5 degree resolution – global  Daily Mean Temperature , Wind Speed , Solar Radiation , Potential Evapotranspiration ( derived) http :// www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surfaceflux. html

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# Hargreaves -Samani method (1985) used for its simplicity and comparable performance to Penman - Monteith and other recognized techniques: PETdaily 

### = (0.0023* S ntat,b 

### ) (T b 

### +17.8) (T range 0.5 

### )/10 Where PETdaily = daily potential evapotranspiration ( cm/day) S ntat,b = downward solar radiation flux at nominal top of the atmosphere ( mm/day) T b = daily mean air temperature ( ◦ C) T range = daily maximum minus daily minimum temperature ( ◦ C ) [Droogers and Allen, 2002; Lu et al., 2005; Tuya et al., 2006; Alexandris et al., 2008; Kra , 2012; Weiland et al., 2012] 

# Potential Evapotranspiration: derived

Available from NOAA NCEP/NCAR
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# Weather data processing Harvested 2.5x2.5 - deg . NOAA NCEP/NCAR Weather ( 1961 – 2014) Harvested 0.25x0.25 - deg . NOAA CPC Precipitation (1961 – 2014) Process and Merge Interpolate to 0.25x0.25 - deg . resolution ALL Weather on 0.25x0.25 - deg. grid (1961 – 2014) Interpolate and merge datasets with NCL: https:// www.ncl.ucar.edu/Applications/regrid.shtml Same interpolation technique used by NOAA NCDC to combine NCEP/NCAR Reanalysis with CPC: http:// www.ncdc.noaa.gov/societal-impacts/airstagnation/overview Weather at 237 SAMSON Locations for SWCC (1961 – 2014) 9

# Updated weather data format: **.DVF → .WEA** Main differences • 4 - digit year replaces 2 - digit year • Comma - separated format mmddyy precip pevap temp wind srad 010161 0.00 0.30 9.5 501.6 240.3 010261 0.00 0.21 6.3 368.0 244.3 010361 0.00 0.28 3.5 488.3 303.0 010461 0.00 0.34 4.7 448.3 316.6
m m,dd,yyyy,precip,pevap,temp,wind,srad 01, 01, 1961, 0.00, 0.30, 9.5, 501.6, 240.3 01 , 02, 1961, 0.00, 0.21, 6.3, 368.0, 244.3 01 , 03, 1961, 0.00, 0.28, 3.5, 488.3, 303.0 01 , 04, 1961, 0.00, 0.34, 4.7, 448.3, 316.6 

### . dvf

. wea 10

# Evaluation of processed dataset Quality assurance and quality control Data quality objectives: • From reliable, peer- reviewed source • Processing is transparent, well - documented • Format is standardized and compatible with OPP aquatic exposure models • Model simulations using NOAA weather are reasonable compared to simulations using SAMSON • Maintenance plan 11

# Quality of dataset

• Comparison of spatial and temporal distributions to other datasets (e.g., precipitation, PET)
• Comparison of simulated aquatic concentrations with NOAA weather vs. SAMSON

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# Precipitation and PET distributions

[Fry et al.] 1991 - 2014 Precipitation, Annual Average of Monthly Sums: 1961 - 1990

1991 - 2014 PET H, Annual Sum of Long -term Daily Mean: 1961 - 1990

1991 - 2014

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# CPC vs. Other Precipitation Datasets

1991 - 2014 Precipitation, Annual Average of Monthly Sums: 1961 - 1990

1991 - 2014 1991 - 2014 **[PRISM Climate Group, Oregon State, 2015] 30** **- year Annual Average of monthly sums:**  **1981 -**  **2010**

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# Derived PET vs. Other PET Datasets

1991 - 2014 1991 - 2014 PET H, Annual Sum of Long -term daily mean: 1961 - 1990

1991 - 2014 **[**

**Droogers and Allen, 2002]**  **Annual sum of long -** **term daily mean: 1970 -**  **2000 International Water Management Institute** 

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# Quality of dataset

Pearson’s Correlation Coefficient, r Quantify strength of linear relationship rr = ∑ (xx − ̅ xx ) (yy − � yy) ∑ (xx − ̅ xx ) 2 

### (yy − � yy) 2 

### r = 1 Perfectly positive linear relationship r = 0 No linear relationship r = - 1 Perfectly negative linear relationship 

### • Comparison of spatial and temporal distributions to other datasets (e.g., precipitation, PET). • Comparison of Surface Water Concentration Calculator (SWCC) outputs generated using NOAA dataset to those using SAMSON

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# SWCC comparison: Standard Pond

Results from 7 simulations – each run once with NOAA weather and once with SAMSON weather [Fry et al.] SWCC Standard Pond

17SWCC Standard Pond 

# SWCC comparison: Standard Pond

Results from 7 simulations – each run once with NOAA weather and once with SAMSON weather [Fry et al.] Zoom in of 0 – 40 ppb

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# SWCC comparison: Index Reservoir

[Fry et al.] SWCC Index reservoir



### Results from 7 simulations – each run once with NOAA weather and once with SAMSON weather 19

# SWCC comparisons: Summary Pearson’s correlation coefficient for SWCC simulations ( 1961 - 1990) Standard pond Index reservoir 

### Peak (1 - in - 10 year) 0.996 0.995 4-day Average (1 - in - 10 year) 0.996 0.995 21 -day Average (1 - in - 10 year) 0.998 0.998 60-day Average (1 - in - 10 year) 0.999 0.998 365 -day Average (1 - in - 10 year) 0.988 0.986 Entire Simulation Mean 0.988 0.979 [Fry et al.] 20

# Maintenance plan
• On annual basis, OPP EFED will process prior year • Methodology will remain consistent • Processing is automated 

## • Continue expanding dataset to most recent year

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## • QA/QC as part of Spatial Aquatic Model Quality Assurance Project Plan • Peer- review of methodology • Scientific Advisory Panel – Sept 2015 

# Outlook

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## Questions?

Meridith Fry, Ph.D. Environmental Engineer, EISB Water Quality Tech Team Co - chair Environmental Fate & Effects Division Office of Pesticide Programs U.S. Environmental Protection Agency Email : Fry.Meridith@epa.gov Phone: 703.347.0128 

# Thank you

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