Hydrometeorology Products, Services and Supporting Research

1. Hydrometeorology Products, Services and Supporting Research EPA Office of Research and Development Needs Ellen J. Cooter U.S. Environmental Protection Agency Office of Research and Development Prepared for Office of the Federal Coordinator for Meteorological Services and Supporting Research 17 September, 2008

2. Environmental Protection Agency Mission To protect human health and the environment Office of Research and Development Goal To solve problems of national significance and to support our program/regional office needs through integrated, multidisciplinary research 1

3. Integrated Multidisciplinary Research in ORD emissions deposition Air Water Land emissions deposition Soil Acidification Vegetation Ozone exposure Deposition of Toxics to soil and vegetation Eutrophication Acidification TMDL Exposure related pulmonary disease (Ozone, PM2.5) • Examples • Air Quality model development and evaluation • Linking air quality and water quality models • Ecosystem Services Human and Ecosystem Health & Services 2

4. EPA ORD is a consumer of hydrometeorological products, services and supporting research • Recurring Themes • Retrospective applications such as regulatory development • analyses and model evaluation that make use of a combination • of simulated meteorology and historical and near-real time • meteorological observations • Prospective applications such accountability studies • and emerging environmental issues, e.g., climate change • that rely exclusively on meteorological simulations 3

5. Air Quality Model Development and Evaluation for Regulatory Application 4

6. .01 0.5 1.0 2.0 3.0 Synoptic Scale Meteorology 5 August, 2004 20:15 24-hr Precipitation Total Mean Daily Temperature Max. 8-Hour Ozone Forecast Init: 4 Aug (12 Z) Valid: 5 Aug Source: Eder, B., Kang, D., Mathur, R., Yu, S. and Schere, K. 2006. “An operational evaluation of the Eta-CMAQ air quality forecast model.” 5

7. Problem: Air quality model performance is poor along the cold front where • cloud cover and heavy rain dominate • Retrospective Application Needs: • Adoption of the research version of the Weather Research & Forecasting(WRF) (complete) • Higher resolution (NAM) input as boundary conditions (complete) • Assimilation of satellite imagery to improve cloud cover location and extent (in development) • Assimilation of gridded national multi-sensor precipitation analysis data (under consideration) • Prospective Application Needs: • The biggest challenge is that observations or reanalyses cannot be used • to constrain model solutions to realistic outcomes. • Adoption of the WRF model has resulted in some simulation • improvement, but the simulation of summertime cloud location and • extent and precipitation extent, intensity and duration still need further • improvement to adequately support prospective studies. 6

8. Linking Air Quality and Water Quality Models Water Quality Water Quantity 7

9. Linking Air Quality and Water Quality Models: Water Quality • The critical air-water linkage for water quality • regulatory analysis is the delivery of pollutants • from the atmosphere to land and water surfaces • through dry and wet deposition. • Accurate simulation of pollutant mass delivered • to underlying surfaces requires accurate • characterization of all aspects of the chemical • mass balance including in-cloud scavenging and • wet deposition. 8

10. Linking Air Quality and Water Quality Models through Pollutant Scavenging In-Cloud Pollutant Scavenging Gases Hydrometeorological parameter αi = Scavenging coefficient for pollutant i Τwashout = cloud washout time TWF = total water fraction WT = mean total water content Pr = precipitation rate Aerosols 9

11. Linking Air Quality and Water Quality Models through Wet Deposition Limited-source or minimally reactive pollutants such as pesticides and Hg exhibit a strongly logarithmic removal pattern for precipitation depths under 5cm. Removal of more ubiquitous or highly reactive pollutants such as inorganic N exhibit a more linear pattern for precipitation depths under 5cm. Weekly NADP Total Nitrogen Weekly USGS Atrazine Source: Cooter, E.J., Hutzell, W.T., Foreman, W.T. and Majewski, M.S., 2002. “A Regional Atmospheric Fate and Transport Model for Atrazine. 2. Evaluation.” Environ. Sci. Technol., 36: 4593-4599. 10

12. Problem: Models are needed that accurately portray the movement of pollutant from the atmosphere to underlying surfaces • Retrospective Application Needs: • Data to evaluate, verify and, if needed, to improve current in- • cloud process parameterizations. • Access to precipitation rate and volume observation data sets • for model evaluation and potential assimilation. A short term • solution for pollutants whose concentration in rainfall is • approximately volume independent is to scale model • concentrations by observed precipitation volume (under • consideration). • Prospective Application Needs: • Improved model simulation of precipitation rate and volume. 11

13. Linking Air Quality and Water Quality Models: Water Quantity • Hydrologic (quantity)aspects of water quality models are usually • calibrated using many years of USGS stream gauge data and • first order or cooperative meteorological station precipitation. • The most common timestep in water quality models is daily or • monthly, although some models use hourly data. • Inconsistencies between observed and modeled precipitation • lead to inconsistent coupling of air and water quality models. • Poor evaluation results for meteorological simulation models • under current conditions make regulatory water quality model • clients “uncomfortable” with their use in retrospective or • prospective analyses. 12

14. Scale effects Tropical storm simulation failure Are current precipitation simulations adequate to drive a gridded watershed water quality model? Source: Golden, H.E., Knightes, C.D., Cooter, E.J. and Dennis, R.L., 2008. “Modeled watershed runoff associated with variations in precipitation data, with implications for contaminant fluxes: Initial results.” Presented at the Third Interagency Meeting on Research in the Watersheds, 8-11 September, 2008, Estes Park, CO. 13

15. Are there better observed data? r2=0.95 between monthly USGS observed outflow (runoff) and simulated runoff driven by national multi-sensor precipitation analysis (NPA) data* 14 * Results are preliminary

16. Problem(s): Observed precipitation data used to drive water quality applications • is spatially incomplete. • Inconsistencies between these observations and modeled • precipitation lead to inconsistent coupling of air and water quality • models. • Retrospective Application Need: • Apply modifications proposed previously wrt simulation model • and expanded data assimilation to improve precipitation • simulation provided to both air and water quality models. Should • add obs. nudging. • Preliminary results suggest that a water quality model run on • a monthly timestep can be efficiently calibrated using widely • spaced cooperative station timeseries, but then applied using the • same finer resolution, gridded data used to nudge metr. model • simulations. • Prospective Application Need: • Need to improve model simulation of both summer • convective precipitation and tropical storm events. 15

17. Hyrdometeorological Product, Service and Support Needs for Ecosystem Services Research 16

18. Most of this information already exists, but may need further processing to meet the spatial and temporal needs of the Program. Effective communication is a key limiting factor. 17

19. Summary • Retrospective Application Needs: • Observational or reanalysis-based assimilation datasets, e.g., satellite, • multi-source precipitation analysis are critical. Availability of new • products needs to be effectively communicated. • The gridded multi-sensor precipitation analysis database holds • promise for air quality model performance improvement and more • consistent quality and water quality model linkage. It needs to be • maintained and ease-of-access improved. • Prospective Application Needs: • Continued research is needed to, in the absence of observation nudging, • identify and communicate to the applications community a set of “best • modeling practices” to adequately reproduce the observed precipitation • climate (e.g. support for NARRCAP-type studies). • Identification or, if needed, development of new cloud and precipitation • parameterizations that will simultaneously reproduce the full suite of • hydrometeorological and non-hydrometeorological variables. 18

20. Disclaimer Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

21. Other Needs • Human Exposure: • water borne diseases and disease vectors • recreational area closures due to storm water runoff or combined sewage • overflow events • Water Supply and Quality: • water treatment infrastructure • water distribution systems • septic system issues • leaky underground storage tanks • groundwater supplies and community drinking water systems • Homeland Security: • Hazardous waste release