42 citations · 223 across the 17 of their papers we have counts for
17 papers
Asymptotic approximations for convection onset with Ekman pumping at low wavenumbers
Sara Tro, Ian Grooms, Keith Julien
Ekman pumping is a phenomenon induced by no-slip boundary conditions in rotating fluids. In the context of Rayleigh-Bénard convection, Ekman pumping causes a significant change in…
Parameterized Ekman boundary layers on the tilted -plane
Sara Tro, Ian Grooms, Keith Julien
Rotating convection is considered on the tilted -plane where gravity and rotation are not aligned. For sufficiently large rotation rates, , the Taylor-Proudman effect results…
A comparison of nonlinear extensions to the ensemble Kalman filter: Gaussian Anamorphosis and Two-Step Ensemble Filters
Ian Grooms
Ensemble Kalman filters are based on a Gaussian assumption, which can limit their performance in some non-Gaussian settings. This paper reviews two nonlinear, non-Gaussian extensio…
Machine Learning Techniques to Construct Patched Analog Ensembles for Data Assimilation
Lucia Minah Yang, Ian Grooms
Using generative models from the machine learning literature to create artificial ensemble members for use within data assimilation schemes has been introduced in [Grooms QJRMS, 20…
A note on the formulation of the Ensemble Adjustment Kalman Filter
Ian Grooms
The ensemble adjustment Kalman filter (EAKF; Anderson, 2001) is one of the earliest ensemble square root filters. This note clarifies the correct formulation of the EAKF, which dep…
A hybrid particle-ensemble Kalman filter for problems with medium nonlinearity
Gregor Robinson, Ian Grooms
A hybrid particle ensemble Kalman filter is developed for problems with medium non-Gaussianity, i.e. problems where the prior is very non-Gaussian but the posterior is approximatel…
Analog ensemble data assimilation and a method for constructing analogs with variational autoencoders
Ian Grooms
It is proposed to use analogs of the forecast mean to generate an ensemble of perturbations for use in ensemble optimal interpolation (EnOI) or ensemble variational (EnVar) methods…
Rigorous bounds on the heat transport of rotating convection with Ekman pumping
B. Pachev, J. P. Whitehead, G. Fantuzzi +1
We establish rigorous upper bounds on the time-averaged heat transport for a model of rotating Rayleigh-Benard convection between no-slip boundaries at infinite Prandtl number and…
Exact instantaneous optimals in the non-geostrophic Eady problem and the detrimental effects of discretization
William Barham, Ian Grooms
We derive exact analytical expressions for flow configurations that optimize the instantaneous growth rate of energy in the linear Eady problem, along with the associated growth ra…
Energy-conserving Galerkin approximations for quasigeostrophic dynamics
Matthew Watwood, Ian Grooms, Keith Julien +1
A method is presented for constructing energy-conserving Galerkin approximations in the vertical coordinate of the full quasigeostrophic model with active surface buoyancy. The der…
Improving particle filter performance by smoothing observations
Gregor Robinson, Ian Grooms, William Kleiber
This article shows that increasing the observation variance at small scales can reduce the ensemble size required to avoid collapse in particle filtering of spatially-extended dyna…
An eddifying Stommel model: Fast eddy effects in a two-box ocean
William Barham, Ian Grooms
A system of stochastic differential equations is formulated describing the heat and salt content of a two-box ocean. Variability in the heat and salt content and in the thermohalin…
Investigations of non-hydrostatic, stably stratified and rapidly rotating flows
David Nieves, Ian Grooms, Keith Juilen +1
We present an investigation of rapidly rotating (small Rossby number ) and stratified turbulence where the stratification strength is varied from weak (large Froude number…
On Gakerkin approximations for the surface-active quasigeostrophic equations
Cesar B. Rocha, William R. Young, Ian Grooms
We study the representation of solutions of the three-dimensional quasigeostrophic (QG) equations using Galerkin series with standard vertical modes, with particular attention to t…
Bounds on Heat Transport in Rapidly Rotating Rayleigh-Bénard Convection
Ian Grooms, Jared P Whitehead
The heat transport in rotating Rayleigh-Bénard convection is considered in the limit of rapid rotation (small Ekman number ) and strong thermal forcing (large Rayleigh number $R…
Asymptotic Behavior of Heat Transport for a Class of Exact Solutions in Rotating Rayleigh-Bénard Convection
Ian Grooms
The non-hydrostatic, quasigeostrophic approximation for rapidly rotating Rayleigh-Bénard convection admits a class of exact `single mode' solutions. These solutions correspond to s…
Stochastic superparameterization in quasigeostrophic turbulence
Ian Grooms, Andrew J Majda
In this article we expand and develop the authors' recent proposed methodology for efficient stochastic superparameterization (SP) algorithms for geophysical turbulence. Geophysica…