1. Nesting from MESO to LES to Study Cloud Dynamics and Microphysics Nick Heath 1,3, Henry Fuelberg 1 Simone Tanelli 2, Joe Turk 2 1 Department of Earth, Ocean and Atmospheric Science Florida State University 2 Jet Propulsion Laboratory California Institute of Technology 3 NASA Earth and Space Science Fellowship

2. “Petri dish” approach to LES Thermodynamic Profile Large-scale tendencies Great for understanding single cloud processes Ignores broader-scale meteorological variability and convective feedbacks with environment

3. Nested-LES modeling approach 12.15 km 4.05 km 1.35 km 450 m 150 m 2 September 2013 MESO provides ICs and BCs to LES MESO 12.15 – 4.05 – 1.35 km 74 Vertical Levels NARR initialization Kain-Fritsch Cu Morrison MP LES 450 – 150 m 147 Vertical Levels 1.5 order TKE turbulence closure Morrison MP

4. Goals of our research Compare high-resolution WRF simulations of convection to APR-2, and other aircraft data, to determine: 1)Can the nested-LES adequately simulate the observed convection? 2)Is there a major improvement moving to LES, or is MESO sufficient? 3) Can we expand our knowledge of convective processes from these nested-LES simulations?

5. Meteorological AIRCRAFT SAMPLING OVERVIEW

6. Courtesy NASA Langley

7. DC-8 Learjet Extensive sampling of growing convection Ground Radar CPL APR-2

8. Meteorological Overview Qualitative Comparisons MESO,LES, Ground Radar, and APR-2

9. 1.35 km 450 m Analysis over red domain only “MESO” “LES”

10. MESOLES-450 LES-150OBS Reflectivity (dBZ) at 1 km

11. MESO LES-450 APR-2 -5 km -8 km -5 km -8 km -5 km -8 km

12. Meteorological Overview Quantitative Analysis WRF vs. Aircraft OBS

13. Defining Convective Clouds Aircraft (MMS): |w| > 1 m s -1 for 500 m 2D-S Concentration > 5 L -1 (LeMone and Zipser 1980) Model Output: |w| > 1 m s -1 Q_total > 0.01 g kg -1 Flight Path

14. Convective Downdrafts MESOLES-450

15. MESO Thermal Buoyancy Excess graupel production Downdrafts initiated aloft struggle to become negatively buoyant due to latent heat Downdrafts weaker than OBS Downward Acceleration Upward Acceleration

16. LES-450 Less graupel production Downdrafts negatively buoyant aloft Better agreement with OBS Thermal Buoyancy Downward Acceleration Upward Acceleration Convective transport might not be captured by MESO and GCMs

17. Nested-LES promising tool to improve convective simulations Nested-LES simulated better dynamics  better microphysics  better dynamics Better Microphysics Better Dynamics High-resolution aircraft observations critical for validating LES results Better Dynamics Better Microphysics

19. Robert Houze