The Structure and Dynamics of Solitons and Bores in IHOP. Steven E. Koch NOAA Research - Forecast Systems Laboratory Collaborators: Mariusz Pagowski 1 , Cyrille Flamant 2 , James W. Wilson 3 , Frederic Fabry 4 , Wayne Feltz 5 , Geary Schwemmer 6 ,
The Structure and Dynamics of Solitons and Bores in IHOP
Steven E. Koch
NOAA Research - Forecast Systems Laboratory
Mariusz Pagowski1, Cyrille Flamant2, James W. Wilson3,
Frederic Fabry4, Wayne Feltz5, Geary Schwemmer6,
Bart Geerts7, Belay Demoz6, Bruce Gentry6, Dave Whiteman6
1 CIRA / Colorado State University
2 Centre National de la Recherche Scientifique (CNRS), Paris, France
3 National Center for Atmospheric Research
4 Radar Observatory, McGill University
5 CIMSS / University of Wisconsin
6 NASA / Goddard Space Flight Center
7 Department of Atmospheric Sciences, University of Wyoming
A gravity current is a horizontal mass flow driven by its greater density relative to its environment.
An internal bore in the atmosphere is a kind of gravity wave generated by the intrusion of a gravity current into a low-level stable layer.
Passage of the bore results in a sustained elevation of the stable layer. Unlike gravity currents, bores do not transport mass.
A train of amplitude-ordered solitary waves (or soliton) can evolve from bores in some instances. Wave amplitudes vary inversely with their width and are highly dispersive.
The number of waves increases with time, but is limited by turbulent dissipation. The energy of the wave system tends to be concentrated in the first few solitary waves.
Transition of an undular bore into a turbulent bore depends upon its strength (db / h0). Bore strength is determined by the Froude Number and the ratio of the gravity current depth to the inversion depth (d0 / h0)
Houghton and Kasahara (1968)
Homestead observing systems:
The Dual Bore Event of June 4, 2002
Warming or very slight temperature changes occur with passage of both bores
UWKA Flight-Level Data
Bore B seen in
UW King Air Data
at FL 1850 m AGL
vertical air velocity
Numerical Simulations of the Bores
To the movie
The Bore-Soliton Event of June 20, 2002
The evolution of the bore was observed by the LEANDRE 2 DIAL system on the P-3 aircraft alongN-S sections normal to the bore.
S-POL provided PPI & RHI coverage
Four P-3 overpasses occurred over the Homestead Profiling Site, offering comparisons with SRL, GLOW, and MAPR
L2 WVMR retrievals:
800 m horizontal resolution
300 m vertical resolution
S-POL RHIs at 0530 UTC along azimuth 350°
11-km horizontal wavelength at 2.5-km level and 27 m s-1 LLJ seen in S-Pol data are consistent with Leandre-II and ISS observations, respectively