Analyzing "grey zone" Turbulent Kinetic Energy predictions in the Boundary Layer from three WRF PBL Schemes over New York City and comparison to Aircraft measurements

Published

January 1, 2024

Author(s)

Austin Hope, Israel Lopez Coto, Kristian Hajny, Jay M Tomlin, Robert Kaeser, Brian Stirm, Anna Karion, James Whetstone, Paul Shepson

Abstract

We conduct WRF simulations at multiple resolutions down to the "grey zone" (9 km, 3 km, 1 km, 333 m) to examine boundary layer turbulence in three planetary boundary layer (PBL) schemes: the well-established MYNN PBL scheme and the two newest PBL schemes added to the main WRF framework, one of which (the SMS-3DTKE scheme) is specifically designed to be scale-aware and avoid the double-counting of TKE in simulations within the "grey zone". We evaluate their performance using aircraft measurements obtained during three research flights just downwind of downtown New York City. The MYNN PBL scheme does the best at simulating TKE, despite it not being scale-aware and slightly underestimating TKE from observations, while the SMS-3DTKE scheme appears to be overly scale-aware for the three flights examined, in particular when combined with the MM5 surface layer scheme, and the EEPS scheme significantly underestimates TKE. In addition, we examine the impact of flow over tall buildings in observed TKE and found that only the windiest day showed a significant increase in TKE directly downwind of Manhattan. This impact was, however, not reproduced by any of the model configurations, regardless of the land use data selected, implying that a more explicit representation of the buildings may be needed to capture the impact of urban surface roughness.

Citation

Journal of Applied Meteorology and Climatology

Pub Type

Journals

Download Paper

https://doi.org/10.1175/JAMC-D-22-0181.1

Local Download

Keywords

WRF, PBL schemes, Turbulent Kinetic Energy, aircraft measurements

Citation

Hope, A. , Lopez Coto, I. , Hajny, K. , Tomlin, J. , Kaeser, R. , Stirm, B. , Karion, A. , Whetstone, J. and Shepson, P. (2024), Analyzing "grey zone" Turbulent Kinetic Energy predictions in the Boundary Layer from three WRF PBL Schemes over New York City and comparison to Aircraft measurements, Journal of Applied Meteorology and Climatology, [online], https://doi.org/10.1175/JAMC-D-22-0181.1, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935438 (Accessed April 27, 2024)