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  • Author or Editor: John L. Schroeder x
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Michael I. Biggerstaff
,
Louis J. Wicker
,
Jerry Guynes
,
Conrad Ziegler
,
Jerry M. Straka
,
Erik N. Rasmussen
,
Arthur Doggett IV
,
Larry D. Carey
,
John L. Schroeder
, and
Chris Weiss

A group of scientists from three universities across two different states and from one federal research laboratory joined together to build and deploy two mobile C-band Doppler weather radars to enhance research and promote meteorological education. This 5-yr project led to the development of the Shared Mobile Atmospheric Research and Teaching (SMART) radar coalition that built the first mobile C-band Doppler weather radar in the United States and also successfully deployed the first mobile C-band dual-Doppler network in a landfalling hurricane. This accomplishment marked the beginning of an era in which high temporal and spatial resolution precipitation and dual-Doppler wind data over mesoscale (~100 km) regions can be acquired from mobile ground-based platforms during extreme heavy rain and high-wind events.

In this paper, we discuss the rationale for building the mobile observing systems, highlight some of the challenges that were encountered in creating a unique multiagency coalition, provide examples of how the SMART radars have contributed to research and education, and discuss future plans for continued development and management of the radar facility, including how others may use the radars for their own research and teaching programs.

The capability of the SMART radars to measure winds in nonprecipitating environments, to capture rapidly evolving, short-lived, small-scale tornadic circulations, and to sample mesoscale regions with high spatial resolution over broad regions of heavy rainfall is demonstrated. Repeated successful intercepts provide evidence that these radars are capable of being used to study a wide range of atmospheric phenomena.

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Pedro L. Fernández-Cabán
,
A. Addison Alford
,
Martin J. Bell
,
Michael I. Biggerstaff
,
Gordon D. Carrie
,
Brian Hirth
,
Karen Kosiba
,
Brian M. Phillips
,
John L. Schroeder
,
Sean M. Waugh
,
Eric Williford
,
Joshua Wurman
, and
Forrest J. Masters

Abstract

While Hurricane Harvey will best be remembered for record rainfall that led to widespread flooding in southeastern Texas and western Louisiana, the storm also produced some of the most extreme wind speeds ever to be captured by an adaptive mesonet at landfall. This paper describes the unique tools and the strategy used by the Digital Hurricane Consortium (DHC), an ad hoc group of atmospheric scientists and wind engineers, to intercept and collect high-resolution measurements of Harvey’s inner core and eyewall as it passed over Aransas Bay into mainland Texas. The DHC successfully deployed more than 25 observational assets, leading to an unprecedented view of the boundary layer and winds aloft in the eyewall of a major hurricane at landfall. Analysis of anemometric measurements and mobile radar data during heavy convection shows the kinematic structure of the hurricane at landfall and the suspected influence of circulations aloft on surface winds and extreme surface gusts. Evidence of mesoscale vortices in the interior of the eyewall is also presented. Finally, the paper reports on an atmospheric sounding in the inner eyewall that produced an exceptionally large and potentially record value of precipitable water content for observed soundings in the continental United States.

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Julie K. Lundquist
,
James M. Wilczak
,
Ryan Ashton
,
Laura Bianco
,
W. Alan Brewer
,
Aditya Choukulkar
,
Andrew Clifton
,
Mithu Debnath
,
Ruben Delgado
,
Katja Friedrich
,
Scott Gunter
,
Armita Hamidi
,
Giacomo Valerio Iungo
,
Aleya Kaushik
,
Branko Kosović
,
Patrick Langan
,
Adam Lass
,
Evan Lavin
,
Joseph C.-Y. Lee
,
Katherine L. McCaffrey
,
Rob K. Newsom
,
David C. Noone
,
Steven P. Oncley
,
Paul T. Quelet
,
Scott P. Sandberg
,
John L. Schroeder
,
William J. Shaw
,
Lynn Sparling
,
Clara St. Martin
,
Alexandra St. Pe
,
Edward Strobach
,
Ken Tay
,
Brian J. Vanderwende
,
Ann Weickmann
,
Daniel Wolfe
, and
Rochelle Worsnop

Abstract

To assess current capabilities for measuring flow within the atmospheric boundary layer, including within wind farms, the U.S. Department of Energy sponsored the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign at the Boulder Atmospheric Observatory (BAO) in spring 2015. Herein, we summarize the XPIA field experiment, highlight novel measurement approaches, and quantify uncertainties associated with these measurement methods. Line-of-sight velocities measured by scanning lidars and radars exhibit close agreement with tower measurements, despite differences in measurement volumes. Virtual towers of wind measurements, from multiple lidars or radars, also agree well with tower and profiling lidar measurements. Estimates of winds over volumes from scanning lidars and radars are in close agreement, enabling the assessment of spatial variability. Strengths of the radar systems used here include high scan rates, large domain coverage, and availability during most precipitation events, but they struggle at times to provide data during periods with limited atmospheric scatterers. In contrast, for the deployment geometry tested here, the lidars have slower scan rates and less range but provide more data during nonprecipitating atmospheric conditions. Microwave radiometers provide temperature profiles with approximately the same uncertainty as radio acoustic sounding systems (RASS). Using a motion platform, we assess motion-compensation algorithms for lidars to be mounted on offshore platforms. Finally, we highlight cases for validation of mesoscale or large-eddy simulations, providing information on accessing the archived dataset. We conclude that modern remote sensing systems provide a generational improvement in observational capabilities, enabling the resolution of finescale processes critical to understanding inhomogeneous boundary layer flows.

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