1. Jan 20071 Top-level slides provided by Janusz Eluszkiewicz and Thomas Nehrkorn Atmospheric & Environmental Research, Inc. 131 Hartwell Ave Lexington, Massachusetts 02421 www.aer.com WRF-STILT: Progress Report

2. Atmospheric and Environmental Research, Inc. Jan 2007 2 WRF-STILT Coupling: Current Tasks Coupling of WRF with STILT Mapping of variables and data format conversions Use of time-averaged momentum flux variables for improved mass conservation Use of convective mass fluxes for vertical particle redistributions Sensitivity testing and model evaluation Sensitivity of trajectories and footprints to: Treatment of convection Model resolution Effects of different Met Drivers (WRF, BRAMS, FNL…)

3. Atmospheric and Environmental Research, Inc. Jan 2007 3 WRF-STILT Coupling: Current Tasks Sensitivity testing and model evaluation (cont) Comparison of simulated and observed CO 2 Effect of met drivers (trajectories) on fit to observations Effect of other inputs on fit to observations: Computation of PBL height Computation of radiative forcing Vegetation type and other biosphere parameters Evaluation of relative contributions of near- and far-field GEE, respiration, and other sources and sinks

4. Atmospheric and Environmental Research, Inc. Jan 2007 4 WRF-STILT Coupling: Future Tasks Examine Role of Data Assimilation WRF v2.2 supports analysis and observation nudging +: Improved fit to observations - : may degrade mass conservation of model solution - : requires manual tuning of nudging parameters WRF-4dvar (under development) provides a possible alternative +: Analysis is a model solution, satisfies mass conservation +: Tuning can be based on climatological or ensemble-based error statistics - : requires significant personnel and computer resources AER has experience in both approaches, has worked with NCAR on (MM5) 4dvar development

5. Atmospheric and Environmental Research, Inc. Jan 2007 5 WRF-STILT Coupling: Argyle Results Obs exhibit nighttime spikes not reproduced by simulations Sims exhibit occasional lows (< 340 ppm) Common to WRF and BRAMS NLDAS SWF tends to lower them further Artificially replacing “mixed forest” with “deciduous” eliminates some lows

6. Atmospheric and Environmental Research, Inc. Jan 2007 6 WRF-STILT coupling: Argyle Results The spike on July 4, 02Z caused by uptake in mixed forest - a case of extreme sensitivity to surface typing

7. Atmospheric and Environmental Research, Inc. Jan 2007 7 Footprints: WRF/Nested/BRAMS

8. Atmospheric and Environmental Research, Inc. Jan 2007 8 Water, ice, urban, other Grassland Cropland Savanna Shrubland Mixed Forest Deciduous Forest Subtropical evergreen Dry temperate evergreen Wet temperate evergreen Boreal evergreen

9. Atmospheric and Environmental Research, Inc. Jan 2007 9 SWF: WRF/Nested/BRAMS WRF40 may have hit a sunny spot, but… BRAMS even sunnier Replacing “mixed” with “deciduous” reduces uptake

10. Atmospheric and Environmental Research, Inc. Jan 2007 10 WRF/STILT Coupling: Reversibility WRF dramatically improved over FNL. BRAMS runs not practical (~ weeks to generate a comparable figure).