Publications


Experimental monthly long-range forecasts for the United Kingdom: part II, a real-time long-range forecast by an ensemble of numerical integrations.

Meteorological Magazine 115 (1986) 337-349

JM Murphy, TN Palmer

The use of an ensemble of integrations for long-range prediction has been studied with a hemispheric version of the Meteorological Office 5-level general circulation model. Some results, showing the potential of the technique, are described. The method is now being used with the global 11-level model to produce real-time long- range forecasts for the long-range forecasting conference in the Synoptic Climatology Branch of the Meteorological Office. Results from the first of these real-time ensemble forecasts are discussed. -Authors


A possible relationship between some 'severe' winters in North America and enhanced convective activity over the tropical West Pacific.

Monthly Weather Review 114 (1986) 648-651

TN Palmer, JA Owen

From observations and a variety of general circulation modeling evidence, it is suggested that the exceptionally cold weather experienced over much of the US during some recent winter months (eg January 1985, December 1976-February 1977) was associated with enhanced latent heat release over the tropical West Pacific. The mechanism associated with such enhancement may not be unique.- Authors


Response of the uk Meteorological Office General Circulation model to Sea-Surface Temperature Anomalies in the Tropical Pacific Ocean

Elsevier Oceanography Series 40 (1985) 83-107

TN Palmer

A number of tropical Pacific SST anomaly experiments, run on the UK Meteorological Office 11-level general circulation model in perpetual January mode, are described. It is found that the model's extratropical response can be statistically significant as far downstream as the European continent depending on the anomaly used, but is sensitive to the specification of orography in the model. A realistic response to a composite El Niño SST anomaly is obtained in the extratropics provided envelope orography replaces the standard orographic specification. A negative East Pacific anomaly run revealed that aspects of the tropical response are not readily explained by linear theory and some possible reasons for this are proposed. The extratropical response appears in some experiments to be qualitatively consistent with a downstream Rossby wavetrain and this has been tested using a baro-tropic model. In other experiments, and in the Southern Hemisphere, this is less clear. The extent to which the extratropical response is maintained by cyclogenesis in mid-latitudes remains to be firmly established though preliminary results suggest it is important. The extratropical response is sensitive to relatively weak SST anomalies in the tropical West Pacific. © 1985, Elsevier B.V. All rights reserved.


A NOTE ON THE GENERAL CONCEPT OF WAVE BREAKING FOR ROSSBY AND GRAVITY-WAVES

PURE AND APPLIED GEOPHYSICS 123 (1985) 964-975

ME MCINTYRE, TN PALMER


A modelling and observational study of the relationship between sea surface temperature in the North‐West atlantic and the atmospheric general circulation

The Quarterly Journal of the Royal Meteorological Society 111 (1985) 947-975

TN Palmer, S Zhaobo

Results from four pairs of 50‐day wintertime integrations of the Meteorological Office's 5‐level general circulation model, with warm and cold sea surface temperature (s.s.t.) anomalies of about 3 K in the northwest Atlantic, are described. Difference fields between the warm and cold integrations are statistically significant at the 1% level with positive geopotential height over the central north Atlantic, and weaker negative height over Europe. the storm track over the Atlantic is displaced from its normal position. Results from four further pairs of integrations with halved s.s.t. anomalies are also described. the response is approximately linear, with systematic differences in 500 mb geopotential height over the Atlantic, parts of which are just significant at the 10% level with half the full s.s.t. anomaly. Overall, however, the model's response is weaker than could be obtained with tropical s.s.t. anomalies of the same magnitude. Results from the model integrations are compared with results from an observational study of the relationship between wintertime s.s.t. in the north‐west Atlantic, and mean sea level pressure and 500mb height. Two independent 30‐year periods were chosen for study, thus minimizing the influence of long‐term trends in s.s.t. Over the Atlantic and Europe the model results compared well with the observations. With s.s.t. data lagging the atmosphere by one month, the observational study appears to show that the s.s.t. anomalies are initially forced by perturbations in the atmospheric circulation. With s.s.t. data leading the atmosphere by one month results show that atmospheric and s.s.t. anomalies are most persistent in the period October to December. Throughout the winter these lagged relationships are much weaker and not statistically significant. Diagnostics of E‐vector divergence from the GCM experiments are used to suggest that anomalous baroclinic wave activity over the Atlantic is important as a momentum forcing for the anomalous time‐mean flow pattern. On the other hand, the role of thermal forcing, provided by anomalous diabatic heating and transient eddy heat flux convergence, may be important. to substantiate this statement, a simple linear steadystate two‐layer model of the response to extratropical thermal forcing is described. With a suitable basic state flow, and a mid tropospheric heat source (given mainly by the transient eddy heat flux convergence), the response is shown to be equivalent barotropic with a downstream ridge and ascent over the thermal source. Conversely, results from an ocean mixed layer model are discussed which suggest that warm s.s.t. anomalies could be maintained by a positive surface pressure perturbation positioned downstream of the anomaly, through anomalous northward advection of warm ocean water by Ekman drift currents. This northward advection would balance the sensible and latent heat loss into the atmosphere over the s.s.t. anomaly. Hence it is possible that some positive ocean‐atmosphere feedback may account for the persistence of such atmospheric and oceanic anomalies. Copyright © 1985 Royal Meteorological Society


THE SURF ZONE IN THE STRATOSPHERE

JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS 46 (1984) 825-849

ME MCINTYRE, TN PALMER


Response of two atmospheric general circulation models to sea- surface temperature anomalies in the tropical East and West Pacific.

Nature 310 (1984) 483-485

TN Palmer, DA Mansfield

We present several atmospheric general circulation experiments which model the atmospheric response to SST anomalies in the tropical East and West Pacific. We have found that the extratropical response to a relatively small West Pacific anomaly can be stronger than, and qualitatively different from the response to a much larger East Pacific anomaly. These experiments suggest a possible explanation for the difference in mid-latitude response during the 1976-77 El Nino winter and the El Nino winters of 1972-73 and 1982-83.-from Authors


THE IMPORTANCE OF NONLINEAR-WAVE PROCESSES IN A QUIESCENT WINTER STRATOSPHERE

QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 110 (1984) 289-301

J AUSTIN, TN PALMER


BREAKING PLANETARY-WAVES IN THE STRATOSPHERE

NATURE 305 (1983) 593-600

ME MCINTYRE, TN PALMER


Stratospheric sudden coolings and the role of nonlinear wave interactions in preconditioning the circumpolar flow.

Journal of the Atmospheric Sciences 40 (1983) 909-928

TN Palmer, CPF Hsu

The mechanisms responsible for the transition of the circumpolar flow from its normal midwinter state to this preconditioned state are investigated through a combination of observational numerical and theoretical studies. For the 1978-79 winter, this transition occurred during the substantial wavenumber-1 minor warming of January 1979, and the characteristic structure associated with the preconditioned mean zonal flow was established four days after the peak of this warming, during a period of intense high latitude acceleration.-from Authors


SIMULATIONS OF AN OBSERVED STRATOSPHERIC WARMING WITH QUASIGEOSTROPHIC REFRACTIVE-INDEX AS A MODEL DIAGNOSTIC

QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 108 (1982) 475-502

N BUTCHART, SA CLOUGH, TN PALMER, PJ TREVELYAN


PROPERTIES OF THE ELIASSEN-PALM FLUX FOR PLANETARY SCALE MOTIONS

JOURNAL OF THE ATMOSPHERIC SCIENCES 39 (1982) 992-997

TN PALMER


Generalization of Cowling's Theorem

Geophysical & Astrophysical Fluid Dynamics 19 (1982) 301-309

R Hide, TN Palmer

An extension of Cowling's neutral point argument shows that no axisymmetric poloidal magnetic field can be maintained by self-exciting dynamo action in an electrically-conducting fluid against the dissipative effects of Ohmic heating. This generalizes previous results to cases where the magnetic field can be non-steady, the fluid compressible and the (scalar) coefficients of magnetic permeability and electrical conductivity dependent on position and time. © Gordon and Breach Science Publishers Inc., 1982


ASPECTS OF STRATOSPHERIC SUDDEN WARMINGS STUDIED FROM A TRANSFORMED EULERIAN-MEAN VIEWPOINT

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 86 (1981) 9679-9687

TN PALMER


DIAGNOSTIC STUDY OF A WAVENUMBER-2 STRATOSPHERIC SUDDEN WARMING IN A TRANSFORMED EULERIAN-MEAN FORMALISM

JOURNAL OF THE ATMOSPHERIC SCIENCES 38 (1981) 844-855

TN PALMER


Gravitational energy-momentum: The Einstein pseudotensor reexamined

General Relativity and Gravitation 12 (1980) 149-154

TN Palmer

By using a suitable two-point scalar field, a covariant formulation of the Einstein pseudotensor is given. A unique choice of scalar field is made possible by examining the role of linear and angular momentum in their correct geometric context. It is shown that, contrary to many text-book statements, linear momentum is not generated by infinitesimal coordinate transformations on space-time. Use is made of the nonintersecting lifted geodesies on the tangent bundle, TM, to space-time, to define a globally regular three-dimensional Lagrangian submanifold of TM, relative to an observer at some point z in space-time. By integrating over this submanifold rather than a necessarily singular spacelike hypersurface, gravitational linear and angular momentum, relative to z, are defined, and shown to have sensible physical properties. © 1980 Plenum Publishing Corporation.


OBSERVATION AND SIMULATION OF A STRATOSPHERIC SUDDEN WARMING

GEOPHYSICAL JOURNAL OF THE ROYAL ASTRONOMICAL SOCIETY 61 (1980) 222-222

TN PALMER, SA CLOUGH


On the Magnetic Flux Linkage of an Electrically-Conducting Fluid: A Treatment of the Relativistic Case Using the Exterior Calculus Formalism

Geophysical & Astrophysical Fluid Dynamics 12 (1979) 177-180

TN Palmer

Hide's (1979) theorem on the rnagnetic flux linkage of an electrically-conducting fluid is extended to the fully general relativistic case by rederiving the theorem in the elegant and succinct formalism of Cartan's exterior calculus. © Gordon and Breach Science Publishers Ltd., 1979


Incorporation of climatology into a Backus‐Gilbert variational scheme for atmospheric temperature retrieval

Quarterly Journal of the Royal Meteorological Society 105 (1979) 803-809

TN Palmer

A method is proposed for explicitly incorporating climatological information into a Backus‐Gilbert variational scheme for atmospheric temperature retrieval by a remote sounding radiometer. The method is applied to a study of the retrieval ability of a ground‐based microwave radiometer. Copyright © 1979 Royal Meteorological Society


DERRICKS THEOREM IN CURVED SPACE

JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL 12 (1979) L17-L19

TN PALMER

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