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  • Author or Editor: Wayne M. Angevine x
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Margaret A. LeMone
,
Wayne M. Angevine
,
Christopher S. Bretherton
,
Fei Chen
,
Jimy Dudhia
,
Evgeni Fedorovich
,
Kristina B. Katsaros
,
Donald H. Lenschow
,
Larry Mahrt
,
Edward G. Patton
,
Jielun Sun
,
Michael Tjernström
, and
Jeffrey Weil

Abstract

Over the last 100 years, boundary layer meteorology grew from the subject of mostly near-surface observations to a field encompassing diverse atmospheric boundary layers (ABLs) around the world. From the start, researchers drew from an ever-expanding set of disciplines—thermodynamics, soil and plant studies, fluid dynamics and turbulence, cloud microphysics, and aerosol studies. Research expanded upward to include the entire ABL in response to the need to know how particles and trace gases dispersed, and later how to represent the ABL in numerical models of weather and climate (starting in the 1970s–80s); taking advantage of the opportunities afforded by the development of large-eddy simulations (1970s), direct numerical simulations (1990s), and a host of instruments to sample the boundary layer in situ and remotely from the surface, the air, and space. Near-surface flux-profile relationships were developed rapidly between the 1940s and 1970s, when rapid progress shifted to the fair-weather convective boundary layer (CBL), though tropical CBL studies date back to the 1940s. In the 1980s, ABL research began to include the interaction of the ABL with the surface and clouds, the first ABL parameterization schemes emerged; and land surface and ocean surface model development blossomed. Research in subsequent decades has focused on more complex ABLs, often identified by shortcomings or uncertainties in weather and climate models, including the stable boundary layer, the Arctic boundary layer, cloudy boundary layers, and ABLs over heterogeneous surfaces (including cities). The paper closes with a brief summary, some lessons learned, and a look to the future.

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Wayne M. Angevine
,
Christoph J. Senff
,
Allen B. White
,
Eric J. Williams
,
James Koermer
,
Samuel T. K. Miller
,
Robert Talbot
,
Paul E. Johnston
,
Stuart A. McKeen
, and
Tom Downs

Abstract

Air pollution episodes in northern New England often are caused by transport of pollutants over water. Two such episodes in the summer of 2002 are examined (22–23 July and 11–14 August). In both cases, the pollutants that affected coastal New Hampshire and coastal southwest Maine were transported over coastal waters in stable layers at the surface. These layers were at least intermittently turbulent but retained their chemical constituents. The lack of deposition or deep vertical mixing on the overwater trajectories allowed pollutant concentrations to remain strong. The polluted plumes came directly from the Boston, Massachusetts, area. In the 22–23 July case, the trajectories were relatively straight and dominated by synoptic-scale effects, transporting pollution to the Maine coast. On 11–14 August, sea breezes brought polluted air from the coastal waters inland into New Hampshire.

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Joseph B. Olson
,
Jaymes S. Kenyon
,
Irina Djalalova
,
Laura Bianco
,
David D. Turner
,
Yelena Pichugina
,
Aditya Choukulkar
,
Michael D. Toy
,
John M. Brown
,
Wayne M. Angevine
,
Elena Akish
,
Jian-Wen Bao
,
Pedro Jimenez
,
Branko Kosovic
,
Katherine A. Lundquist
,
Caroline Draxl
,
Julie K. Lundquist
,
Jim McCaa
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Katherine McCaffrey
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Kathy Lantz
,
Chuck Long
,
Jim Wilczak
,
Robert Banta
,
Melinda Marquis
,
Stephanie Redfern
,
Larry K. Berg
,
Will Shaw
, and
Joel Cline

Abstract

The primary goal of the Second Wind Forecast Improvement Project (WFIP2) is to advance the state-of-the-art of wind energy forecasting in complex terrain. To achieve this goal, a comprehensive 18-month field measurement campaign was conducted in the region of the Columbia River basin. The observations were used to diagnose and quantify systematic forecast errors in the operational High-Resolution Rapid Refresh (HRRR) model during weather events of particular concern to wind energy forecasting. Examples of such events are cold pools, gap flows, thermal troughs/marine pushes, mountain waves, and topographic wakes. WFIP2 model development has focused on the boundary layer and surface-layer schemes, cloud–radiation interaction, the representation of drag associated with subgrid-scale topography, and the representation of wind farms in the HRRR. Additionally, refinements to numerical methods have helped to improve some of the common forecast error modes, especially the high wind speed biases associated with early erosion of mountain–valley cold pools. This study describes the model development and testing undertaken during WFIP2 and demonstrates forecast improvements. Specifically, WFIP2 found that mean absolute errors in rotor-layer wind speed forecasts could be reduced by 5%–20% in winter by improving the turbulent mixing lengths, horizontal diffusion, and gravity wave drag. The model improvements made in WFIP2 are also shown to be applicable to regions outside of complex terrain. Ongoing and future challenges in model development will also be discussed.

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