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  • Author or Editor: Harindra J. S. Fernando x
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Hemantha W. Wijesekera
,
Emily Shroyer
,
Amit Tandon
,
M. Ravichandran
,
Debasis Sengupta
,
S. U. P. Jinadasa
,
Harindra J. S. Fernando
,
Neeraj Agrawal
,
K. Arulananthan
,
G. S. Bhat
,
Mark Baumgartner
,
Jared Buckley
,
Luca Centurioni
,
Patrick Conry
,
J. Thomas Farrar
,
Arnold L. Gordon
,
Verena Hormann
,
Ewa Jarosz
,
Tommy G. Jensen
,
Shaun Johnston
,
Matthias Lankhorst
,
Craig M. Lee
,
Laura S. Leo
,
Iossif Lozovatsky
,
Andrew J. Lucas
,
Jennifer Mackinnon
,
Amala Mahadevan
,
Jonathan Nash
,
Melissa M. Omand
,
Hieu Pham
,
Robert Pinkel
,
Luc Rainville
,
Sanjiv Ramachandran
,
Daniel L. Rudnick
,
Sutanu Sarkar
,
Uwe Send
,
Rashmi Sharma
,
Harper Simmons
,
Kathleen M. Stafford
,
Louis St. Laurent
,
Karan Venayagamoorthy
,
Ramasamy Venkatesan
,
William J. Teague
,
David W. Wang
,
Amy F. Waterhouse
,
Robert Weller
, and
Caitlin B. Whalen

Abstract

Air–Sea Interactions in the Northern Indian Ocean (ASIRI) is an international research effort (2013–17) aimed at understanding and quantifying coupled atmosphere–ocean dynamics of the Bay of Bengal (BoB) with relevance to Indian Ocean monsoons. Working collaboratively, more than 20 research institutions are acquiring field observations coupled with operational and high-resolution models to address scientific issues that have stymied the monsoon predictability. ASIRI combines new and mature observational technologies to resolve submesoscale to regional-scale currents and hydrophysical fields. These data reveal BoB’s sharp frontal features, submesoscale variability, low-salinity lenses and filaments, and shallow mixed layers, with relatively weak turbulent mixing. Observed physical features include energetic high-frequency internal waves in the southern BoB, energetic mesoscale and submesoscale features including an intrathermocline eddy in the central BoB, and a high-resolution view of the exchange along the periphery of Sri Lanka, which includes the 100-km-wide East India Coastal Current (EICC) carrying low-salinity water out of the BoB and an adjacent, broad northward flow (∼300 km wide) that carries high-salinity water into BoB during the northeast monsoon. Atmospheric boundary layer (ABL) observations during the decaying phase of the Madden–Julian oscillation (MJO) permit the study of multiscale atmospheric processes associated with non-MJO phenomena and their impacts on the marine boundary layer. Underway analyses that integrate observations and numerical simulations shed light on how air–sea interactions control the ABL and upper-ocean processes.

Full access
Leila M. V. Carvalho
,
Gert-Jan Duine
,
Craig Clements
,
Stephan F. J. De Wekker
,
Harindra J. S. Fernando
,
David R. Fitzjarrald
,
Robert G. Fovell
,
Charles Jones
,
Zhien Wang
,
Loren White
,
Anthony Bucholtz
,
Matthew J. Brewer
,
William Brown
,
Matt Burkhart
,
Edward Creegan
,
Min Deng
,
Marian de Orla-Barile
,
David Emmitt
,
Steve Greco
,
Terry Hock
,
James Kasic
,
Kiera Malarkey
,
Griffin Modjeski
,
Steven Oncley
,
Alison Rockwell
,
Daisuke Seto
,
Callum Thompson
, and
Holger Vömel

Abstract

Coastal Santa Barbara is among the most exposed communities to wildfire hazards in Southern California. Downslope, dry, and gusty windstorms are frequently observed on the south-facing slopes of the Santa Ynez Mountains that separate the Pacific Ocean from the Santa Ynez valley. These winds, known as “Sundowners,” peak after sunset and are strong throughout the night and early morning. The Sundowner Winds Experiment (SWEX) was a field campaign funded by the National Science Foundation that took place in Santa Barbara, California, between 1 April and 15 May 2022. It was a collaborative effort of 10 institutions to advance understanding and predictability of Sundowners, while providing rich datasets for developing new theories of downslope windstorms in coastal environments with similar geographic and climatic characteristics. Sundowner spatiotemporal characteristics are controlled by complex interactions among atmospheric processes occurring upstream (Santa Ynez valley), and downstream due to the influence of a cool and stable marine boundary layer. SWEX was designed to enhance spatial measurements to resolve local circulations and vertical structure from the surface to the midtroposphere and from the Santa Barbara Channel to the Santa Ynez valley. This article discusses how SWEX brought cutting-edge science and the strengths of multiple ground-based and mobile instrument platforms to bear on this important problem. Among them are flux towers, mobile and stationary lidars, wind profilers, ceilometers, radiosondes, and an aircraft equipped with three lidars and a dropsonde system. The unique features observed during SWEX using this network of sophisticated instruments are discussed here.

Open access
James M. Wilczak
,
Mark Stoelinga
,
Larry K. Berg
,
Justin Sharp
,
Caroline Draxl
,
Katherine McCaffrey
,
Robert M. Banta
,
Laura Bianco
,
Irina Djalalova
,
Julie K. Lundquist
,
Paytsar Muradyan
,
Aditya Choukulkar
,
Laura Leo
,
Timothy Bonin
,
Yelena Pichugina
,
Richard Eckman
,
Charles N. Long
,
Kathleen Lantz
,
Rochelle P. Worsnop
,
Jim Bickford
,
Nicola Bodini
,
Duli Chand
,
Andrew Clifton
,
Joel Cline
,
David R. Cook
,
Harindra J. S. Fernando
,
Katja Friedrich
,
Raghavendra Krishnamurthy
,
Melinda Marquis
,
Jim McCaa
,
Joseph B. Olson
,
Sebastian Otarola-Bustos
,
George Scott
,
William J. Shaw
,
Sonia Wharton
, and
Allen B. White

Abstract

The Second Wind Forecast Improvement Project (WFIP2) is a U.S. Department of Energy (DOE)- and National Oceanic and Atmospheric Administration (NOAA)-funded program, with private-sector and university partners, which aims to improve the accuracy of numerical weather prediction (NWP) model forecasts of wind speed in complex terrain for wind energy applications. A core component of WFIP2 was an 18-month field campaign that took place in the U.S. Pacific Northwest between October 2015 and March 2017. A large suite of instrumentation was deployed in a series of telescoping arrays, ranging from 500 km across to a densely instrumented 2 km × 2 km area similar in size to a high-resolution NWP model grid cell. Observations from these instruments are being used to improve our understanding of the meteorological phenomena that affect wind energy production in complex terrain and to evaluate and improve model physical parameterization schemes. We present several brief case studies using these observations to describe phenomena that are routinely difficult to forecast, including wintertime cold pools, diurnally driven gap flows, and mountain waves/wakes. Observing system and data product improvements developed during WFIP2 are also described.

Full access
Qing Wang
,
Denny P. Alappattu
,
Stephanie Billingsley
,
Byron Blomquist
,
Robert J. Burkholder
,
Adam J. Christman
,
Edward D. Creegan
,
Tony de Paolo
,
Daniel P. Eleuterio
,
Harindra Joseph S. Fernando
,
Kyle B. Franklin
,
Andrey A. Grachev
,
Tracy Haack
,
Thomas R. Hanley
,
Christopher M. Hocut
,
Teddy R. Holt
,
Kate Horgan
,
Haflidi H. Jonsson
,
Robert A. Hale
,
John A. Kalogiros
,
Djamal Khelif
,
Laura S. Leo
,
Richard J. Lind
,
Iossif Lozovatsky
,
Jesus Planella-Morato
,
Swagato Mukherjee
,
Wendell A. Nuss
,
Jonathan Pozderac
,
L. Ted Rogers
,
Ivan Savelyev
,
Dana K. Savidge
,
R. Kipp Shearman
,
Lian Shen
,
Eric Terrill
,
A. Marcela Ulate
,
Qi Wang
,
R. Travis Wendt
,
Russell Wiss
,
Roy K. Woods
,
Luyao Xu
,
Ryan T. Yamaguchi
, and
Caglar Yardim

Abstract

The Coupled Air–Sea Processes and Electromagnetic Ducting Research (CASPER) project aims to better quantify atmospheric effects on the propagation of radar and communication signals in the marine environment. Such effects are associated with vertical gradients of temperature and water vapor in the marine atmospheric surface layer (MASL) and in the capping inversion of the marine atmospheric boundary layer (MABL), as well as the horizontal variations of these vertical gradients. CASPER field measurements emphasized simultaneous characterization of electromagnetic (EM) wave propagation, the propagation environment, and the physical processes that gave rise to the measured refractivity conditions. CASPER modeling efforts utilized state-of-the-art large-eddy simulations (LESs) with a dynamically coupled MASL and phase-resolved ocean surface waves. CASPER-East was the first of two planned field campaigns, conducted in October and November 2015 offshore of Duck, North Carolina. This article highlights the scientific motivations and objectives of CASPER and provides an overview of the CASPER-East field campaign. The CASPER-East sampling strategy enabled us to obtain EM wave propagation loss as well as concurrent environmental refractive conditions along the propagation path. This article highlights the initial results from this sampling strategy showing the range-dependent propagation loss, the atmospheric and upper-oceanic variability along the propagation range, and the MASL thermodynamic profiles measured during CASPER-East.

Full access