1. SMALL SCALE SIMULATION AND LIDAR VALIDATION OF A SHALLOW LAKE MICHIGAN LAND BREEZE
GIJS DE BOER(1), GREGORY J. TRIPOLI(1), EDWIN W. ELORANTA(2)
(1) DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCE
(2) SPACE SCIENCE AND ENGINEERING CENTER
THE UNIVERSITY OF WISCONSIN - MADISON
August 9, 2004

2. Overview Introduction Simulation Set Up/Results Simulation Validation
Motivation
Lake-ICE
Simulation Set Up/Results
Simulation Validation
Conclusions
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3. Introduction Two main issues: Implemented Solutions
Small scale events influenced by large scale phenomena
High resolution simulations typically single domain LES (Mayor, 2001; Sha et al., 1997)
Typically do not represent evolution in large scale accurately, and lack large scale influence (Agee & Gluhovsky, 1999)
Validation of small scale simulations
Point measurements
Good for statistical analysis
Often insufficient to cover large areas simulated
Need big picture
Implemented Solutions
Nested simulation covering larger spectrum of scales
Scanning lidar measurements of the atmospheric boundary layer for validation purposes
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4. Lake-ICE Lake-Induced Convection Experiment (Kristovich, 2000)
Winter
UW-Volume Imaging Lidar (UW-VIL) located at Sheboygan Point, Wisconsin
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5. December 21, 1997
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6. December 21, 1997
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7. UW-NMS
University of Wisconsin Non-Hydrostatic Modeling System (Tripoli, 1992)
Important Features
Scalable: Two-Way Grid Nesting
Variably Stepped Topography
Initialized from ECMWF analysis
High resolution (100 m) topographical dataset
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8. Horizontal Resolution (m)
Simulation Set Up
Grid
Horizontal Points
Vertical Points
Horizontal Resolution (m)
Horizontal Size (km) 1
65x65 50
60000
3780x3780 2
77x77
12000
900x900 3
52x52
2400
120x120 4
197x157
480
93.6x74.4 5
452x362
160
72x57.6 6
502x502 32
16x16
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9. Simulation Results
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10. Simulated Backscatter
Based upon passive tracer concentration and relative humidity (Mayor, 2003)
RH vs. Scattering data from Fitzgerald (1982)
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11. Simulated Backscatter
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12. Validation
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13. Validation
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14. Validation
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15. Validation
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16. Validation
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17. Validation
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18. Validation
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19. Conclusions
The UW-NMS can simulate small-scale boundary layer events with respectable accuracy utilizing the nesting technique.
General flow features
Timing of circulation
Lidar data is invaluable for comparison with small-scale numerical simulation in terms of capturing the big picture.
General nature of flow
Variance calculations
Additional comparison techniques should be developed in order to complete more accurate comparison between lidar and model data.
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20. References/Acknowledgements
Agee, E., Gluhovsky, A., 1999: LES Model Sensitivities to Domains, Grids, and Large-Eddy Timescales. Journal of the Atmospheric Sciences, 56,
Agee, E., Gluhovsky, A., 1999: Further Aspects of Large Eddy Simulation Model Statistics and Inconsistencies with Field Data. Journal of the Atmospheric Sciences, 56,
Fitzgerald, J.W., Hoppel, W.A., 1982: The Size and Scattering Coefficient of Urban Aerosol Particles at Washington, DC as a Function of Relative Humidity. Journal of the Atmospheric Sciences, 39,
Mayor, S.D., Tripoli, G.J., Eloranta, E.W., 2003: Evaluating Large-Eddy Simulations Using Volume Imaging Lidar Data. Monthly Weather Review, 131,
Mayor, S.D., 2001: Volume Imaging Lidar Observations and Large-Eddy Simulations of Convective Internal Boundary Layers. PhD Thesis: University of Wisconsin - Madison.
Tripoli, G.J., 1992: A Nonhydrostatic Mesoscale Model Designed to Simulate Scale Interaction. Monthly Weather Review, 120,
Sha, W., Kawamura. T., and Ueda, H., 1991: A Numerical Study on Sea/Land Breezes as a Gravity Current: Kelvin-Helmholtz Billows and Inland Penetration of the Sea-Breeze Front. Journal of the Atmospheric Sciences, 48,
This work was completed under the following grants:
NSF ATM
ARO DAAH G-0195
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21. Model Specifics Arakawa C grid
Tremback/Kessler soil model surface energy budget parameterization
1.5 level TKE predicting turbulence scheme
Deardorf vertical scale length
Vertical scale length used for horizontal as well
Convection parameterization in large domain only
Full microphysics
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22. VIL Schematic/Specs
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