in , 105 (2011) 113-116

J Brindley, P Read, J Gibbon, A Soward

A laboratory study of global-scale wave interactions in baroclinic flow with topography I: multiple flow regimes


PL Read, SH Risch

Generation of inertia-gravity waves in the rotating thermal annulus by a localised boundary layer instability

Geophys. Astrophys. Fluid Dyn. Taylor & Francis Ltd 105 (2011) 161-181

TNL Jacoby, PL Read, PD Williams, RMB Young

Waves with periods shorter than the inertial period exist in the atmosphere (as inertia-gravity waves) and in the oceans (as Poincare and internal gravity waves). Such waves owe their origin to various mechanisms, but of particular interest are those arising either from local secondary instabilities or spontaneous emission due to loss of balance. These phenomena have been studied in the laboratory, both in the mechanically-forced and the thermally-forced rotating annulus. Their generation mechanisms, especially in the latter system, have not yet been fully understood, however. Here we examine short period waves in a numerical model of the rotating thermal annulus, and show how the results are consistent with those from earlier laboratory experiments. We then show how these waves are consistent with being inertia-gravity waves generated by a localised instability within the thermal boundary layer, the location of which is determined by regions of strong shear and downwelling at certain points within a large-scale baroclinic wave flow. The resulting instability launches small-scale inertia-gravity waves into the geostrophic interior of the flow. Their behaviour is captured in fully nonlinear numerical simulations in a finite-difference, 3D Boussinesq Navier-Stokes model. Such a mechanism has many similarities with those responsible for launching small- and meso-scale inertia-gravity waves in the atmosphere from fronts and local convection.

Climate of the Neoproterozoic


RT Pierrehumbert, DS Abbot, A Voigt, D Koll

Infrared Radiation and Planetary Temperature


RT Pierrehumbert

Bifurcations leading to summer Arctic sea ice loss


DS Abbot, M Silber, RT Pierrehumbert

Thermal structure and dynamics of Saturn's northern springtime disturbance.

Science 332 (2011) 1413-1417

LN Fletcher, BE Hesman, PGJ Irwin, KH Baines, TW Momary, A Sanchez-Lavega, FM Flasar, PL Read, GS Orton, A Simon-Miller, R Hueso, GL Bjoraker, A Mamoutkine, T del Rio-Gaztelurrutia, JM Gomez, B Buratti, RN Clark, PD Nicholson, C Sotin

Saturn's slow seasonal evolution was disrupted in 2010-2011 by the eruption of a bright storm in its northern spring hemisphere. Thermal infrared spectroscopy showed that within a month, the resulting planetary-scale disturbance had generated intense perturbations of atmospheric temperatures, winds, and composition between 20° and 50°N over an entire hemisphere (140,000 kilometers). The tropospheric storm cell produced effects that penetrated hundreds of kilometers into Saturn's stratosphere (to the 1-millibar region). Stratospheric subsidence at the edges of the disturbance produced "beacons" of infrared emission and longitudinal temperature contrasts of 16 kelvin. The disturbance substantially altered atmospheric circulation, transporting material vertically over great distances, modifying stratospheric zonal jets, exciting wave activity and turbulence, and generating a new cold anticyclonic oval in the center of the disturbance at 41°N.

Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia

National Academies Press, 2011

COSTFAGG Concentrations, BOASA Climate, DOEAL Studies, NR Council

The book quantifies the outcomes of different stabilization targets for greenhouse gas concentrations using analyses and information drawn from the scientific literature.

Erratum to "Flow transitions resembling bifurcations of the logistic map in simulations of the baroclinic rotating annulus" [Physica D 237 (2008) 2251-2262] (DOI:10.1016/j.physd.2008.02.014)

Physica D: Nonlinear Phenomena (2011)

RMB Young, PL Read

Sea glacier flow and dust transport on Snowball Earth


D Li, RT Pierrehumbert



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

Some fine points on radiative forcing Reply

PHYSICS TODAY 64 (2011) 12-12

RT Pierrehumbert

Corrigendum to "Breeding and predictability in the baroclinic rotating annulus using a perfect model" published in Nonlin. Processes Geophys., 15, 469–487, 2008

Nonlin. Proc. Geophys. Copernicus Publications 18 (2011) 359-359

RMB Young, PL Read

No abstract.

Synchronization in climate dynamics and other extended systems

Understanding Complex Systems 2010 (2010) 153-176

PL Read, AA Castrejón-Pita

Synchronization is now well established as representing coherent behaviour between two or more otherwise autonomous nonlinear systems subject to some degree of coupling. Such behaviour has mainly been studied to date, however, in relatively low-dimensional discrete systems or networks. But the possibility of similar kinds of behaviour in continuous or extended spatiotemporal systems has many potential practical implications, especially in various areas of geophysics. We review here a range of cyclically varying phenomena within the Earth's climate system for which there may be some evidence or indication of the possibility of synchronized behaviour, albeit perhaps imperfect or highly intermittent. The exploitation of this approach is still at a relatively early stage within climate science and dynamics, in which the climate system is regarded as a hierarchy of many coupled sub-systems with complex nonlinear feedbacks and forcings. The possibility of synchronization between climate oscillations (global or local) and a predictable external forcing raises important questions of how models of such phenomena can be validated and verified, since the resulting response may be relatively insensitive to the details of the model being synchronized. The use of laboratory analogues may therefore have an important role to play in the study of natural systems that can only be observed and for which controlled experiments are impossible. We go on to demonstrate that synchronization can be observed in the laboratory, even in weakly coupled fluid dynamical systems that may serve as direct analogues of the behaviour of major components of the Earth's climate system. The potential implications and observability of these effects in the long-term climate variability of the Earth is further discussed. © 2010 Springer-Verlag Berlin Heidelberg.

Testing the limits of quasi-geostrophic theory: application to observed laboratory flows outside the quasi-geostrophic regime


PD Williams, PL Read, TWN Haine

Synchronization in a pair of thermally coupled rotating baroclinic annuli: understanding atmospheric teleconnections in the laboratory.

Phys Rev Lett 104 (2010) 204501-

AA Castrejón-Pita, PL Read

Synchronization phenomena in a fluid dynamical analogue of atmospheric circulation is studied experimentally by investigating the dynamics of a pair of thermally coupled, rotating baroclinic annulus systems. The coupling between the systems is in the well-known master-slave configuration in both periodic and chaotic regimes. Synchronization tools such as phase dynamics analysis are used to study the dynamics of the coupled system and demonstrate phase synchronization and imperfect phase synchronization, depending upon the coupling strength and parameter mismatch.

The Importance of Ice Vertical Resolution for Snowball Climate and Deglaciation

JOURNAL OF CLIMATE 23 (2010) 6100-6109

DS Abbot, I Eisenman, RT Pierrehumbert

Evidence for Climate Change on Mars

in Solar System Update, Springer (2010) 135-

SR Lewis, PL Read

This book, the first in a series of forthcoming volumes, consists of topical and timely reviews of a number of carefully selected topics in solar systemn science.

Assessing eddy parameterization schemes in a differentially heated rotating annulus experiment

Ocean Modelling 32 (2010) 118-131

E Pérez-Pérez, PL Read, IM Moroz

We investigate three of the most common hypotheses underpinning parameterizations of baroclinic eddy fluxes in the context of the differentially heated rotating annulus experiment. The investigation is carried out over a region of parameter space which embraces the onset of baroclinic instability, the regular wave regime and the onset of irregular flows, the latter of which is arguably most relevant to oceanic conditions. Through diagnostics from a 2D axisymmetric and a 3D eddy-resolving numerical model, it was found that the transport of heat by baroclinic eddies is not strictly an adiabatic process but that diffusive 'ventilation' of the flow in the thermal boundary layers is significant during the nonlinear development of the flow. Total heat transport, however, is conserved overall. Depending on the stages of flow evolution and on the region in parameter space under consideration, either heat, quasi-geostrophic potential vorticity (QGPV) or relative vorticity (QGRV) may become a suitable variable on which to parameterize baroclinic eddy fluxes in a down-gradient manner. These results raise issues for eddy parameterization schemes that rely on these assumptions in ocean and atmosphere models. © 2009 Elsevier Ltd.

Geophysical flows as dynamical systems: the influence of Hide's experiments

ASTRONOMY & GEOPHYSICS 51 (2010) 28-35

M Ghil, PL Read, LA Smith