Publications


Wave number selection in the presence of noise: Experimental results

Chaos American Institute of Physics (2018)

D Zhilenko, O Krivonosova, M Gritsevich, PL Read


An experimental investigation of blocking by partial barriers in a rotating baroclinic annulus

Geophysical and Astrophysical Fluid Dynamics (2017) 1-33

SD Marshall, PL Read

© 2017 Informa UK Limited, trading as Taylor & Francis Group We present a series of experimental investigations in which a differentially-heated annulus was used to investigate the effects of topography on rotating, stratified flows with similarities to the Earth’s atmospheric or oceanic circulation. In particular, we compare and investigate blocking effects via partial mechanical barriers to previous experiments by the authors utilising azimuthally-periodic topography. The mechanical obstacle used was an isolated ridge, forming a partial barrier, employed to study the difference between partially blocked and fully unblocked flow. The topography was found to lead to the formation of bottom-trapped waves, as well as impacting the circulation at a level much higher than the top of the ridge. This produced a unique flow structure when the drifting flow and the topography interacted in the form of an “interference” regime at low Taylor number, but forming an erratic “irregular” regime at higher Taylor number. The results also showed evidence of resonant wave-triads, similar to those noted with periodic wavenumber-3 topography by Marshall and Read (Geophys. Astrophys. Fluid Dyn., 2015, 109), though the component wavenumbers of the wave-triads and their impact on the flow were found to depend on the topography in question. With periodic topography, wave-triads were found to occur between both the baroclinic and barotropic components of the zonal wavenumber-3 mode and the wavenumber-6 baroclinic component, whereas with the partial barrier two nonlinear resonant wave-triads were noted, each sharing a common wavenumber-1 mode.


Descent rate models of the synchronization of the Quasi-Biennial Oscillation by the annual cycle in tropical upwelling

Journal of the Atmospheric Sciences American Meteorological Society (2018)

K Rajendran, I Moroz, SM Osprey, P Read

The response of the Quasi-Biennial Oscillation (QBO) to an imposed mean upwelling with a periodic modulation is studied, by modelling the dynamics of the zero wind line at the equator using a class of equations known as ‘descent rate’ models. These are simple mathematical models that capture the essence of QBO synchronization by focusing on the dynamics of the height of the zero wind line. A heuristic descent rate model for the zero wind line is described, and is shown to capture many of the synchronization features seen in previous studies of the QBO. Using a simple transformation, it is then demonstrated that the standard Holton-Lindzen model of the QBO can itself be put into the form of a descent rate model if a quadratic velocity profile is assumed below the zero wind line. The resulting non-autonomous ordinary differential equation captures much of the synchronization behaviour observed in the full Holton-Lindzen partial differential equation. The new class of models provides a novel framework within which to understand synchronization of the QBO, and we demonstrate a close relationship between these models and the circle map well-known in the mathematics literature. Finally, we analyse reanalysis datasets to validate some of the predictions of our descent rate models, and find statistically significant evidence for synchronization of the QBO that is consistent with model behaviour.


Exploring the Atmosphere of Neoproterozoic Earth: The Effect of O-2 on Haze Formation and Composition

ASTROPHYSICAL JOURNAL 858 (2018) ARTN 119

SM Horst, C He, MS Ugelow, AM Jellinek, RT Pierrehumbert, MA Tolbert


Superrotation on Venus, on Titan, and Elsewhere

Annual Review of Earth and Planetary Sciences 46 (2018) 175-202

PL Read, S Lebonnois


Ice-shelf damming in the glacial Arctic Ocean: dynamical regimes of a basin-covering kilometre-thick ice shelf

CRYOSPHERE 11 (2017) 1745-1765

J Nilsson, M Jakobsson, C Borstad, N Kirchner, G Bjork, RT Pierrehumbert, C Stranne


A rotating annulus driven by localized convective forcing: a new atmosphere-like experiment

EXPERIMENTS IN FLUIDS 58 (2017) ARTN 75

H Scolan, PL Read


Phase synchronization of baroclinic waves in a differentially heated rotating annulus experiment subject to periodic forcing with a variable duty cycle.

Chaos (Woodbury, N.Y.) 27 (2017) 127001-

PL Read, X Morice-Atkinson, EJ Allen, AA Castrejón-Pita

A series of laboratory experiments in a thermally driven, rotating fluid annulus are presented that investigate the onset and characteristics of phase synchronization and frequency entrainment between the intrinsic, chaotic, oscillatory amplitude modulation of travelling baroclinic waves and a periodic modulation of the (axisymmetric) thermal boundary conditions, subject to time-dependent coupling. The time-dependence is in the form of a prescribed duty cycle in which the periodic forcing of the boundary conditions is applied for only a fraction δ of each oscillation. For the rest of the oscillation, the boundary conditions are held fixed. Two profiles of forcing were investigated that capture different parts of the sinusoidal variation and δ was varied over the range 0.1≤δ≤1. Reducing δ was found to act in a similar way to a reduction in a constant coupling coefficient in reducing the width of the interval in forcing frequency or period over which complete synchronization was observed (the "Arnol'd tongue") with respect to the detuning, although for the strongest pulse-like forcing profile some degree of synchronization was discernible even at δ=0.1. Complete phase synchronization was obtained within the Arnol'd tongue itself, although the strength of the amplitude modulation of the baroclinic wave was not significantly affected. These experiments demonstrate a possible mechanism for intraseasonal and/or interannual "teleconnections" within the climate system of the Earth and other planets that does not rely on Rossby wave propagation across the planet along great circles.


Regimes of Axisymmetric Flow and Scaling Laws in a Rotating Annulus with Local Convective Forcing

Fluids 2 (2017) 41-41

S Wright, S Su, H Scolan, R Young, P Read


Forward and inverse kinetic energy cascades in Jupiter's turbulent weather layer

NATURE PHYSICS 13 (2017) 1135-+

RMB Young, PL Read


Ertel potential vorticity versus Bernoulli streamfunction on Mars

QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 143 (2017) 37-52

TE Dowling, ME Bradley, J Du, SR Lewis, PL Read


The Martian Planetary Boundary Layer

in The Atmosphere and Climate of Mars, Cambridge University Press (2017) 7

PL Read, B Galperin, SE Larsen, SR Lewis, A Maatanen, A Petrosyan, N Renno, H Savijarvi, T Siili, A Spiga, A Toigo, L Vazquez

7.1 INTRODUCTION The Martian planetary boundary layer (PBL) consists of the layers of the atmosphere closest to the surface, within which interactions between the atmosphere and the surface itself are dominant. In general, this represents the lowest 1–10 km of the atmosphere, within which surface-driven intense convection may take place, with convective plumes and vortices rising to heights in excess of 5–10 km during the day (Thomas and Gierasch, 1985; Haberle et al., 1993b; ...


The Global Circulation

in The Atmosphere and Climate of Mars, Cambridge University Press (2017) 9

JR Barnes, RM Haberle, RJ Wilson, SR Lewis, JR Murphy, PL Read

This volume reviews all aspects of Mars atmospheric science from the surface to space, and from now and into the past.


Observational evidence against strongly stabilizing tropical cloud feedbacks

GEOPHYSICAL RESEARCH LETTERS 44 (2017) 1503-1510

IN Williams, RT Pierrehumbert


Linking the Climate and Thermal Phase Curve of 55 Cancri e

ASTROPHYSICAL JOURNAL 849 (2017) ARTN 152

M Hammond, RT Pierrehumbert


Reconstructing Climate from Glaciers

ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, VOL 45 45 (2017) 649-680

AN Mackintosh, BM Anderson, RT Pierrehumbert


Spectral analysis of Uranus' 2014 bright storm with VLT/SINFONI

ICARUS 264 (2016) 72-89

PGJ Irwin, LN Fletcher, PL Read, D Tice, I de Pater, GS Orton, NA Teanby, GR Davis


Consequences of twenty-first-century policy for multi-millennial climate and sea-level change

NATURE CLIMATE CHANGE 6 (2016) 360-369

PU Clark, JD Shakun, SA Marcott, AC Mix, M Eby, S Kulp, A Levermann, GA Milne, PL Pfister, BD Santer, DP Schrag, S Solomon, TF Stocker, BH Strauss, AJ Weaver, R Winkelmann, D Archer, E Bard, A Goldner, K Lambeck, RT Pierrehumbert, G-K Plattner


How to decarbonize? Look to Sweden

Bulletin of the Atomic Scientists 72 (2016) 105-111

R Pierrehumbert


The solsticial pause on Mars: 2 modelling and investigation of causes

ICARUS 264 (2016) 465-477

DP Mulholland, SR Lewis, PL Read, J-B Madeleine, F Forget

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