Publications


Universal short-wave instability of two-dimensional eddies in an inviscid fluid.

Physical review letters 57 (1986) 2157-2159

RT Pierrehumbert


Problems and Prospects in Long and Medium Range Weather Forecasting

Journal of Fluid Mechanics 163 (1986) 498-500

RT Pierrehumbert


SPATIALLY AMPLIFYING MODES OF THE CHARNEY BAROCLINIC-INSTABILITY PROBLEM

JOURNAL OF FLUID MECHANICS 170 (1986) 293-317

RT PIERREHUMBERT


Remarks on a paper by Aref and Flinchem

JOURNAL OF FLUID MECHANICS 163 (1986) 21-26

RT Pierrehumbert


STRATIFIED SEMIGEOSTROPHIC FLOW OVER TWO-DIMENSIONAL TOPOGRAPHY IN AN UNBOUNDED ATMOSPHERE

JOURNAL OF THE ATMOSPHERIC SCIENCES 42 (1985) 523-526

RT PIERREHUMBERT


A THEORETICAL-MODEL OF OROGRAPHICALLY MODIFIED CYCLOGENESIS

JOURNAL OF THE ATMOSPHERIC SCIENCES 42 (1985) 1244-1258

RT PIERREHUMBERT


UPSTREAM EFFECTS OF MESOSCALE MOUNTAINS

JOURNAL OF THE ATMOSPHERIC SCIENCES 42 (1985) 977-1003

RT PIERREHUMBERT, B WYMAN


STATIONARY EXTERNAL ROSSBY WAVES IN VERTICAL SHEAR

JOURNAL OF THE ATMOSPHERIC SCIENCES 42 (1985) 865-883

IM HELD, RL PANETTA, RT PIERREHUMBERT


Finite-amplitude, neutral baroclinic eddies and mean flows in an internally heated rotating fluid: 1. Numerical simulations and quasi-geostrophic 'free modes'

Dynamics of Atmospheres and Oceans 9 (1985) 135-207

PL Read

A series of numerical simulations of steady wave flows in a rotating fluid annulus, subject to internal heating and various thermal boundary conditions, is examined to characterise their structures, energetics and potential vorticity transport properties. The last of these characteristics, together with more conventional scaling considerations, indicate the possibility of applying quasi-geostrophic theory to the interior flow in a formulation similar to the inviscid, adiabatic models of Kuo and White. The analytical model of White, describing finite amplitude, neutral baroclinic eddies and mean flows as illustrations of the Charney-Drazin non-acceleration theorem, is then extended to include uniform diabatic heating and the effects of different forms of lateral shear in the background mean zonal flow. Like the solutions discussed by White, those obtained in the present paper consist of steady, internal jet, mean zonal flows, and baroclinic and barotropic Rossby wave components, all having the same three-dimensional wavenumber. Provided the diabatic heating is proportional to the stratification of the background flow, measured by the square of the Brunt-Vaisälä frequency N, the potential vorticity equation remains homogeneous. All the solutions are then characterised by zero net transfer of potential vorticity despite the possibility of non-zero eddy fluxes of heat or momentum and non-trivial Lorenz energy cycles. A series of particular three-component solutions (which, like some of the solutions discussed by White, do not obey conventional lateral boundary conditions) is examined as possible theoretical analogues of the steady waves observed in the numerical simulations of the laboratory flows, and is found to agree encouragingly well in the spatial variations of their mean flows, eddy stream function (pressure) and eddy fluxes of heat and momentum. Potential vorticity fluxes in the numerical simulations are relatively small (though crucially non-zero), supporting the possible analogy with the analytical model and exposing some limitations of the latter in not accounting for weak dissipation and forcing processes present in the laboratory flows. Further implications of the results are discussed, including possible analogies between the laboratory experiments and certain features in planetary atmospheres and oceans. © 1985.


LOCAL AND GLOBAL BAROCLINIC INSTABILITY OF ZONALLY VARYING FLOW

JOURNAL OF THE ATMOSPHERIC SCIENCES 41 (1984) 2141-2162

RT PIERREHUMBERT


LINEAR RESULTS ON THE BARRIER EFFECTS OF MESOSCALE MOUNTAINS

JOURNAL OF THE ATMOSPHERIC SCIENCES 41 (1984) 1356-1367

RT PIERREHUMBERT


FORCED COHERENT STRUCTURES AND LOCAL MULTIPLE EQUILIBRIA IN A BAROTROPIC ATMOSPHERE

JOURNAL OF THE ATMOSPHERIC SCIENCES 41 (1984) 246-257

RT PIERREHUMBERT, P MALGUZZI


OROGRAPHIC DISTORTION OF FRONTS

RIVISTA DI METEOROLOGIA AERONAUTICA 44 (1984) 249-263

RT PIERREHUMBERT


FORMATION OF SHEAR LAYERS UPSTREAM OF THE ALPS

RIVISTA DI METEOROLOGIA AERONAUTICA 44 (1984) 237-248

RT PIERREHUMBERT


An isolated baroclinic eddy as a laboratory analogue of the Great Red Spot on Jupiter

Nature 308 (1984) 45-48

PL Read, R Hide

We have recently presented evidence1 supporting the hypothesis2 that the long-lived large oval atmospheric eddies on Jupiter and Saturn, including Jupiter's anticyclonic Great Red Spot (GRS) and White Ovals and the cyclonic 'barges', are manifestations of 'slantwise' or 'sloping' convection in a rotating fluid, implying that they are involved in the horizontal transport of heat towards or away from the edges of the atmospheric zones or belts in which they occur, and that their kinetic energy derives directly from the action of gravity on the density field associated with horizontal gradients of temperature. These eddies would then be dynamically similar to the highly stable closed 'baroclinic' eddies produced in certain laboratory experiments on thermal convection in a rotating fluid subject to internal heating or cooling1,3. We now present laboratory findings that bear on the interpretation of the isolated nature of the GRS, including the crucial demonstration that a single intense stable baroclinic disturbance that is strongly localized in azimuth can form readily when the impressed conditions are close to the transition from axisymmetric to non-axisymmetric flow. © 1984 Nature Publishing Group.


BOUNDS ON THE GROWTH OF PERTURBATIONS TO NON-PARALLEL STEADY FLOW ON THE BAROTROPIC BETA-PLANE

JOURNAL OF THE ATMOSPHERIC SCIENCES 40 (1983) 1207-1217

RT PIERREHUMBERT


Long-lived eddies in the laboratory and in the atmospheres of Jupiter and Saturn

Nature 302 (1983) 126-129

PL Read, R Hide

The Great Red Spot (GRS), the three White Ovals, and other long-lived anticyclonic eddies in Jupiter's atmosphere might be dynamically similar 1 to the closed, stable baroclinic eddies that were first discovered in laboratory studies of thermal convection in a rotating fluid subject to internal heating and sidewall cooling2,3. We outline here results of new laboratory and numerical experiments on the structure, energetics and stability of such eddies, which strongly support the suggestion that these laboratory and atmospheric flows (including similar eddies found on Saturn 4) might all be manifestations of the same dynamical process - 'sloping' or 'slantwise' convection. Included in our numerical experiments are cases with internal cooling and sidewall heating, in which stable baroclinic eddies with a cyclonic peripheral jet stream at upper levels surrounding a region of slow descent have been produced and studied. We suggest that these cyclonic eddies are dynamically similar to the 'barges' observed in Jupiter's Tropical and Temperate Belts5. © 1983 Nature Publishing Group.


DYNAMICS OF WEATHER REGIMES - QUASI-STATIONARY WAVES AND BLOCKING

MONTHLY WEATHER REVIEW 110 (1982) 1105-1145

BB REINHOLD, RT PIERREHUMBERT


THE TWO-DIMENSIONAL AND 3-DIMENSIONAL INSTABILITIES OF A SPATIALLY PERIODIC SHEAR-LAYER

JOURNAL OF FLUID MECHANICS 114 (1982) 59-82

RT PIERREHUMBERT, SE WIDNALL


The analysis of umkehr observations of stratospheric ozone by a ‘Maximum Entropy’ method

Quarterly Journal of the Royal Meteorological Society 108 (1982) 719-726

PL Read

An application is described of the ‘Maximum Entropy’ (ME) principle to the analysis of umkehr observations of atmospheric ozone. The method is shown to produce results which are comparable with more conventional analyses, and which show a marginally higher correlation with simultaneous ozonesonde measurements than the standard evaluation method. Differences between conventional and ME solutions are attributable to the low intrinsic information content of umkehr observations, and the use of climatological information in addition to observational data in the standard method of analysis. This additional information may also be included in ME solutions, reducing the systematic errors of the simple ME solutions, but possibly degrading that part of the information content of the solution which is due to the observations. Some further meteorological applications of the method are discussed. Copyright © 1982 Royal Meteorological Society

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