Jeremy A. Sauer
National Center for Atmospheric Research
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Featured researches published by Jeremy A. Sauer.
Journal of the Atmospheric Sciences | 2016
Domingo Muñoz-Esparza; Jeremy A. Sauer; Rodman R. Linn; Branko Kosovic
AbstractMesoscale models are considered to be the state of the art in modeling mountain-wave flows. Herein, the authors investigate the role and accuracy of planetary boundary layer (PBL) parameterizations in handling the interaction between large-scale mountain waves and the atmospheric boundary layer. To that end, recent large-eddy simulation (LES) results of mountain waves over a symmetric two-dimensional bell-shaped hill are used and compared to four commonly used PBL schemes. It is found that one-dimensional PBL parameterizations produce reasonable agreement with the LES results in terms of vertical wavelength, amplitude of velocity, and turbulent kinetic energy distribution in the downhill shooting-flow region. However, the assumption of horizontal homogeneity in PBL parameterizations does not hold in the context of these complex flow configurations. This inappropriate modeling assumption results in a vertical wavelength shift, producing errors of approximately 10 m s−1 at downstream locations becau...
Journal of Advances in Modeling Earth Systems | 2017
Domingo Muñoz-Esparza; Julie K. Lundquist; Jeremy A. Sauer; Branko Kosovic; Rodman R. Linn
Multiscale modeling of a diurnal cycle of real-world conditions is presented for the first time, validated using data from the CWEX-13 field experiment. Dynamical downscaling from synoptic-scale down to resolved three-dimensional eddies in the atmospheric boundary layer (ABL) was performed, spanning 4 orders of magnitude in horizontal grid resolution: from 111 km down to 8.2 m (30 m) in stable (convective) conditions. Computationally efficient mesoscale-to-microscale transition was made possible by the generalized cell perturbation method with time-varying parameters derived from mesoscale forcing conditions, which substantially reduced the fetch to achieve fully developed turbulence. In addition, careful design of the simulations was made to inhibit the presence of under-resolved convection at convection-resolving mesoscale resolution and to ensure proper turbulence representation in stably-stratified conditions. Comparison to in situ wind-profiling lidar and near-surface sonic anemometer measurements demonstrated the ability to reproduce the ABL structure throughout the entire diurnal cycle with a high degree of fidelity. The multiscale simulations exhibit realistic atmospheric features such as convective rolls and global intermittency. Also, the diurnal evolution of turbulence was accurately simulated, with probability density functions of resolved turbulent velocity fluctuations nearly identical to the lidar measurements. Explicit representation of turbulence in the stably-stratified ABL was found to provide the right balance with larger scales, resulting in the development of intra-hour variability as observed by the wind lidar; this variability was not captured by the mesoscale model. Moreover, multiscale simulations improved mean ABL characteristics such as horizontal velocity, vertical wind shear, and turbulence.
Journal of the Atmospheric Sciences | 2016
Jeremy A. Sauer; Domingo Muñoz-Esparza; Jesse M. Canfield; Keeley Rochelle Costigan; Rodman R. Linn; Young-Joon Kim
AbstractThe impact of atmospheric boundary layer (ABL) interactions with large-scale stably stratified flow over an isolated, two-dimensional hill is investigated using turbulence-resolving large-eddy simulations. The onset of internal gravity wave breaking and leeside flow response regimes of trapped lee waves and nonlinear breakdown (or hydraulic-jump-like state) as they depend on the classical inverse Froude number, Fr−1 = Nh/Ug, is explored in detail. Here, N is the Brunt–Vaisala frequency, h is the hill height, and Ug is the geostrophic wind. The results here demonstrate that the presence of a turbulent ABL influences mountain wave (MW) development in critical aspects, such as dissipation of trapped lee waves and amplified stagnation zone turbulence through Kelvin–Helmholtz instability. It is shown that the nature of interactions between the large-scale flow and the ABL is better characterized by a proposed inverse compensated Froude number, = N(h − zi)/Ug, where zi is the ABL height. In addition, it...
Archive | 2016
Keeley Rochelle Costigan; Jeremy A. Sauer; Bryan J. Travis; Manvendra K. Dubey
This slide deals with the following: Affordable artificial neural network and mini-sensor system to locate and quantify methane leaks on a well pad; ARPA-e project schematic for monitoring methane leaks
Archive | 2015
Keeley Rochelle Costigan; Jeremy A. Sauer; Manvendra K. Dubey
This report discusses the ghgas IC project which when applied, allows for an evaluation of LANLs HIGRAD model which can be used to create atmospheric simulations.
Land | 2017
Russell A. Parsons; Rodman R. Linn; François Pimont; Chad M. Hoffman; Jeremy A. Sauer; Judith Winterkamp; Carolyn Hull Sieg; W. Matt Jolly
In: Viegas, D. X., ed. Proceedings of the VI International Conference on Forest Fire Research; 15-2018 November 2010; Coimbra, Portugal. Coimbra, Portugal: University of Coimbra. 14 p. | 2010
Russell A. Parsons; Jeremy A. Sauer; Rodman R. Linn
Archive | 2018
François Pimont; Jean-Luc Dupuy; Rodman Linn; Jeremy A. Sauer
Geophysical Research Letters | 2018
Domingo Muñoz-Esparza; Robert Sharman; Jeremy A. Sauer; Branko Kosovic
Journal of Advances in Modeling Earth Systems | 2017
Domingo Muñoz-Esparza; Julie K. Lundquist; Jeremy A. Sauer; Branko Kosovic; Rodman R. Linn