Smagorinsky, Joseph, 1995: The growth of dynamic meteorology and numerical weather prediction - some personal reflections In Canadian Meteorological Memoirs No. 32: Special Symposium on Atmospheric Research in Canada in Honor of Dr. Warren L. Godson's Fifty Years of Public Service, 48-56. Abstract
The past half century spans a remarkable evolution in the field of dynamic meteorology. Much of this development was the result of the very early exploitation of electronic computers through the introduction of numerical methods.
Thermodynamics, together with hydrodynamics formed the dynamical basis for modelling and simulating the aerological medium. This was understood by L. F. Richardson in formulating his extraordinarily comprehensive proposal at the end of World War I.
At that time technological limitations had precluded a sufficient empirical knowledge of atmospheric phenomenology and its dynamical structure. Another limitation was essentially mathematical, as V. Bjerknes and Richardson had appreciated.
A proposal in 1946 for an unprecedented stored-program computer by the noted scientist John von Neumann at the Institute for Advanced Study (IAS) at Princeton solved a good part of the problem. The IAS meteorology group led by Jule Charney succeeded in dealing with a horizontally non-divergent flow in a two-dimensional domain, but, importantly, non-linear. The ENIAC computer at the Aberdeen Proving Grounds, originally built to calculate artillery firing tables, was the means to the end. This was the beginning of numerical weather prediction as we know it today.
The resulting expanded scope for dynamic meteorology and the scientific legitimacy of environmental prediction are fully detailed.
Smagorinsky, Joseph, 1993: Some historical remarks on the use of non-linear viscosities - 1.1 Introductory remarks In Large Eddy Simulation of Complex Engineering and Geophysical Flows, Proceedings of an International Workshop in Large Eddy Simulation, Cambridge, UK, Cambridge University Press, 1-34.
Smagorinsky, Joseph, 1991: Development of international climate research In Strategies for Future Climate Research, Mojib Latif, ed., Hamburg, Germany, Max Planck Institut für Meteorologie, 9-18.
Smagorinsky, Joseph, 1986: The long range eye of Jerry Namias In Namias Symposium - A special symposium in honor of the 75th birthday of Dr. Jerome Namias, Experimental Climate Forecast Center of Scripps Institution of Oceanography, San Diego, CA, University of California at San Diego, 63-69. Abstract
Namias' very early perceptions of the interactive role of the atmosphere with its lower boundary in shaping future events deserve special attention. Anomalous sea-surface temperature, soil moisture and snow cover "feed-backs" provided a long term "memory" to the atmosphere, not only locally, but also remotely through "teleconnections". So what's new?
Smagorinsky, Joseph, 1986: The AMS's continuing role in promoting communications and setting standards. Bulletin of the American Meteorological Society, 67(8), 938.
Smagorinsky, Joseph, 1986: GARP's objectives in weather prediction: Expectations and realizations In International Conference on Results of Global Weather Experiment and Their Implications for World Weather Watch, ol. I, Geneva, Switzerland, World Meteorological Organization, 19-34.
Smagorinsky, Joseph, 1986: Review of book: "Prophet--or Professor? The life and work of Lewis Fry Richardson," Oliver M. Ashford, and Adam Hilger. EOS, 67(3), 28.
Smagorinsky, Joseph, 1983: The beginnings of numerical weather prediction and general circulation modeling: Early recollections. Advances in Geophysics, 25, 3-37.
Smagorinsky, Joseph, 1983: The Problem of Climate and Climate Variations, WCP-72, Geneva, Switzerland: World Meteorological Organization, 14 pp.
Smagorinsky, Joseph, 1982: Large-scale climate modeling and small-scale physical processes In Land Surface Processes in Atmospheric General Circulation Models, UK, Cambridge University Press, 3-17.
Smagorinsky, Joseph, 1982: Scientific basis for the Monsoon Experiment In Proceedings of International Conference on the Scientific Results of the Monsoon Experiment, ICSU/WMO GARP, 35-45.
Smagorinsky, Joseph, Kirk Bryan, and Syukuro Manabe, et al., 1982: CO2/Climate Review Panel In Carbon Dioxide and Climate: A Second Assessment, Washington, DC, National Academy Press, 1-72.
Smagorinsky, Joseph, 1981: CO2 and climate - a continuing story In Climatic Variations and Variability: Facts and Theories, Amsterdam, The Netherlands, Reidel Publishing Co, 661-687.
Smagorinsky, Joseph, 1981: Epilogue: a perspective of dynamical meteorology In Dynamical Meteorology, New, Methuen, Inc., 205-219.
Smagorinsky, Joseph, 1981: Some thoughts on contemporary global climatic variability In International Nature Pleads Not Guilty, An IFIAS Report on the Project on Drought and Man, Vol. 1, R. V Garcia, ed., New York, NY, Pergamon Press, Inc., 265-296.
Smagorinsky, Joseph, 1980: Climate modelling In Proceedings of the Technical Conference on Climate - Asia and Western Pacific, WMO No., 578, Geneva, Switzerland, World Meteorological Organization, 139-151.
Smagorinsky, Joseph, 1979: Overview of the climate modelling problem In Report of the JOC Study Conference on Climate Models: Performance, Intercomparison and Sensitivity Studies, Vol. I, Global Atmospheric Research Programme, Joint Organizing Committee, GARP Publications No. 22, World Meteorological Organization, 1-12.
Smagorinsky, Joseph, 1979: Topics in dynamical meteorology: 10. Epilogue - A perspective of dynamical meteorology. Weather, 34(4), 126-135.
Smagorinsky, Joseph, and N A Phillips, 1978: Scientific problems of the Global Weather Experiment In The Global Weather Experiment, Perspectives on Its Implementation and Exploitation, Report of the FGGE Advisory Panel to the U.S. Committee for the Global Atmospheric Research Program, National Academy of Sciences, 13-21. Abstract
In this chapter a variety of problems associated directly with the objectives of the Global Weather Experiment are briefly described. The FGGE data set will also enable studies to be made of atmospheric phenomena not directly associated with these objectives. The first three objectives cited in Section 2.5 involve an assessment of the error elements in atmospheric models and attempts to reduce them.
Smagorinsky, Joseph, 1978: History and progress In The Global Weather Experiment, Perspectives on Its Implementation and Exploitation, Report of the FGGE Advisory Panel to the U.S. Committee for the Global Atmospheric Research Program, National Academy of Sciences, 4-12.
Smagorinsky, Joseph, 1977: Modeling and predictability In Energy and Climate, Washington, DC, National Academy of Sciences, 133-139.
Smagorinsky, Joseph, 1974: Global atmospheric modeling and the numerical simulation of climate In Weather and Climate Modification, John Wiley & Sons, 633-686.
Smagorinsky, Joseph, 1972: The general circulation of the atmosphere In Meteorological Challenges: A History, Ottawa, Information Canada, 3-42. Abstract
An awareness of a global scale circulation and attempts to account for the few observed characteristics can be traced back to the seventeenth century. Up until a century ago explanations centered about the symmetric circulation, whereas the essential role of wave disturbances--how they are excited, their energetics and their non-linear characteristics--evolved only recently as aerological observations became available and more powerful theoretical tools were developed. The total fabric was spun from the discovery of fundamental mechanisms governing the large scale flows, such as geostrophy, the conservation of absolute vorticity and baroclinic instability, and their application to the study of such characteristic phenomena as fronts, cyclones and the index cycle.An awareness of a global scale circulation and attempts to account for the few observed characteristics can be traced back to the seventeenth century. Up until a century ago explanations centered about the symmetric circulation, whereas the essential role of wave disturbances--how they are excited, their energetics and their non-linear characteristics--evolved only recently as aerological observations became available and more powerful theoretical tools were developed. The total fabric was spun from the discovery of fundamental mechanisms governing the large scale flows, such as geostrophy, the conservation of absolute vorticity and baroclinic instability, and their application to the study of such characteristic phenomena as fronts, cyclones and the index cycle. Our understanding of interactions involving the tropics, the stratosphere and the lower boundary is still developing, permitting the construction of more sophisticated and comprehensive numerical models with considerable simulative capability. The most clearly promising prospects for the future come from the application of such models to long range prediction and climatic change.
Smagorinsky, Joseph, 1971: Large-scale atmospheric circulation In Man's Impact on the Climate, Cambridge, MA, The MIT Press, 200-204.
Smagorinsky, Joseph, 1971: Numerical simulation of climate modification In Proceedings of the Twelfth Interagency Conference on Weather Modification, 221-226.
Manabe, Syukuro, Joseph Smagorinsky, J L Holloway, Jr, and H Stone, 1970: Simulated climatology of a general circulation model with a hydrologic cycle. III. Effects of increased horizontal computational resolution. Monthly Weather Review, 98(3), 175-212. Abstract PDF
The results of a numerical time integration of a hemispheric general circulation model of the atmosphere with moist processes and a uniform earth's surface has already been published by Manabe, Smagorinsky, and Strickler. In this study, the integration is repeated after halving the midlatitude grid size from approximately 500 to 250 km.
This increase in the resolution of the horizontal finite differences markedly improves the features of the model atmosphere. For example, the system of fronts and the associated cyclone families in the high resolution atmosphere is much more realistic than that in the low resolution atmosphere. Furthermore, the general magnitude and the spectral distribution of eddy kinetic energy are in better agreement with the actual atmosphere as a result of the improvement in resolution.
In order to explain these improvements, an extensive analysis of the energetics of both the low and high resolution atmospheric models is carried out. It is shown that these improvements are due not only to the increase of the accuracy of the finite differences but also to the shift in the scale of dissipation by the nonlinear lateral viscosity toward a smaller scale resulting from the decrease in grid size. In the low resolution atmospheric model, the transfer of energy from eddy to zonal kinetic energy is missing because of excessive subgrid scale dissipation at medium wave numbers, whereas it has significant magnitude in the high resolution atmospheric model. It is speculated that further increase of resolution should improve the results because it tends to separate the characteristic scale of dissipation from that of the source of eddy kinetic energy.
The analysis of the energetics in wave number space clearly demonstrates the differences between the energetics of the different parts of the atmosphere. In middle latitudes there are essential differences between the energetics of the model troposphere and that of the model stratosphere. In the model troposphere, the eddy kinetic energy is produced by the conversion of eddy potential energy in the range of wave numbers from 2 to 8. Part of the energy thus produced is dissipated by the subgrid scale dissipation, and most of the remainder is decascaded to zonal kinetic energy. In the model stratosphere, where very long waves predominate, the eddy kinetic energy is generated in the range of wave numbers from 2 to 3 by the energy supplied from the troposphere. Most of this energy is then decascaded barotropically to zonal kinetic energy.
In the Tropics, eddy kinetic energy is mainly produced by the release of eddy available potential energy generated by the heat of condensation. Although the rate of conversion is maximum at very low wave numbers, the conversion spectrum extends to very high wave numbers.
A box diagram of the energetics of the high resolution moist model shows that the eddy available potential energy is generated by the heat of condensation as well as by energy transfer from the zonal available potential energy. Furthermore, it is noteworthy that the zonal kinetic energy is maintained not only by the barotropic exchange from the eddy kinetic energy but also from the conversions of zonal potential energy. The intensification of the direct tropical cell and the weakening of the indirect Ferrel cell in the middle latitudes caused by the moist processes are responsible for ths positive zonal conversion.
One of the highlights of the results from the integration of the high resolution moist model is the successful simulation of the evolution of fronts and the associated cyclone families. The influence of moist processes upon frontal structure as well as other synoptic features is investigated by comparing the moist model atmosphere with the dry model atmosphere without the effect of the selective heating of condensation. It is found that the heat of condensation significantly reduces the width fronts and the characteristic scale of cyclones in the lower troposphere.
Smagorinsky, Joseph, 1970: Numerical simulation of the global atmosphere In The Global Circulation of the Atmosphere, G. A. Corby, Editor, London, UK, Royal Meteorological Society, 24-41.
Smagorinsky, Joseph, Kikuro Miyakoda, and R F Strickler, 1970: The relative importance of variables in initial conditions for dynamical weather prediction. Tellus, 22(2), 141-157. Abstract
Tests were made to evaluate the relative importance of large errors in some of the variables formally required to specify initial conditions for the time integration of the hydro-thermodynamic equations for the atmospheric motion. The prime purpose was to analyze the adjustment process immediately following the initial disturbance. The variables selected were the surface pressure, the water vapor, the boundary layer temperature, and the boundary layer wind. It is likely that these quantities are not individually nor possibly even collectively essential to the definition of initial conditions because of dynamic coupling. The experiments showed that the predictions appear almost the same after about six hours irrespective of the initial values of these quantities. But after several days, the subsequent error behaves similar to the growth noted in predictability experiments.
Miyakoda, Kikuro, Joseph Smagorinsky, R F Strickler, and G D Hembree, 1969: Experimental extended predictions with a nine-level hemispheric model. Monthly Weather Review, 97(1), 1-76. Abstract PDF
Two-week predictions were made for two winter cases by applying the Geophysical Fluid Dynamics Laboratory high-resolution, nine-level, hemispheric, moist general circulation model. Three versions of the model are discussed: Experiment 1 includes the orography but not the radiative transfer or the turbulent exchange of heat and moisture with the lower boundary; Experiment 2 accounts for all of these effects as well as land-sea contrast; Experiment 3 allows, in addition, the difference in thermal properties between the land-ice and sea-ice surfaces, as well as an 80% relative humidity condensation criterion reduced from the 100% criterion in Experiments 1 and 2.
The computed results are compared with observed data in terms of the evolution of individual cyclonic and anticyclonic patterns, the zonal mean structure of temperature, wind, and humidity, the precipitation over the United States, and the hemispheric energetics.
The forecast near sea level was considerably improved in Experiments 2 and 3 over Experiment 1. The experiment succeeded in forecasting the birth of second and third generation extratropical cyclones and their behavior thereafter. The hemispheric sum of precipitation was increased five times in Experiment 2 over that in Experiment 1, and even more in Experiment 3, the greatest contribution occurring in the Tropics. Two winter cases were considered. The correlation coefficients between the observed and the forecast patterns for the change of 500-mb geopotential height from the initial time remained above 0.5 for 13 days in one case and for 9 days in the other.
There are, however, several defects in the model. The forecast temperature was too low. In the flow pattern the intensities of the Highs and Lows weakened appreciably after 6 or 8 days, reflecting the fact that the forecast of eddy kinetic energy was less than the observed. On the other hand, the intensity of the tropospheric westerlies was too great.
Smagorinsky, Joseph, 1969: Problems and promises of deterministic extended range forecasting. Bulletin of the American Meteorological Society, 50(5), 286-311. Abstract
The past 20 years have encompassed remarkable scientific and technical advances in the atmospheric and oceanic sciences which herald a new era for deterministically predicting atmospheric behavior. Many of the key innovations were directly influenced, if not originated by Harry Wexler during his very productive career. This paper will deal with a critique of recent progress in modeling the atmosphere-ocean system, some of the newly exposed problems, and the needs and expectations for the future.
Smagorinsky, Joseph, 1969: Problems and data needs of global atmospheric models for the 1970's In First USCG National Data Buoy Systems Scientific Advisory Meeting, U.S. Coast Guard Academy, 16-26.
Manabe, Syukuro, and Joseph Smagorinsky, 1967: Simulated climatology of a general circulation model with a hydrologic cycle II. Analysis of the tropical atmosphere. Monthly Weather Review, 95(4), 155-169. Abstract PDF
The thermal and dynamical structure of the tropical atmosphere which emerged from the numerical integration of our general circulation model with a simple hydrologic cycle is analyzed in detail.
According to the results of our analysis, the lapse rate of zonal mean temperature in the model Tropics is super-moist-adiabatic in the lower troposphere, and is sub-moist-adiabatic above the 400-mb. level in qualitative agreement with the observed features in the actual Tropics. The flow field in the model Tropics also displays interesting features. For example, a zone of strong convergence and a belt of heavy rain develops around the equator. Synoptic-scale disturbances such as weak tropical cyclones and shear lines with strong convergence develop and are reminiscent of disturbances in the actual tropical atmosphere. The humid towers, which result from moist convective adjustment and condensation, develop in the central core of the regions of strong upward motion, sometimes reaching the level of the tropical tropopause and thus heating the upper tropical troposphere. This heating compensates for the cooling due to radiation and the meridional circulation.
According to the analysis of the energy budget of the model Tropics, the release of eddy available potential energy, which is mainly generated by the heat of condensation, constitutes the major source of eddy kinetic energy of disturbances prevailing in the model Tropics.
Smagorinsky, Joseph, 1967: The role of numerical modeling. Bulletin of the American Meteorological Society, 48(2), 89-93. Abstract
The World Weather Watch has received much of its impetus from rapid advances in the ability to construct viable theoretical models of the atmosphere, and in fact, of the entire fluid envelope of the Earth. With increased detail and fidelity, these models display a growing capability of simulating the flow, the thermal, and the hydrologic characteristics of the general circulation. This represents a significant maturity of our understanding of the atmosphere as a physical system.The World Weather Watch has received much of its impetus from rapid advances in the ability to construct viable theoretical models of the atmosphere, and in fact, of the entire fluid envelope of the Earth. With increased detail and fidelity, these models display a growing capability of simulating the flow, the thermal, and the hydrologic characteristics of the general circulation. This represents a significant maturity of our understanding of the atmosphere as a physical system. # Furthermore, recent experiments with such models suggest levels of deterministic predictability of the atmosphere which may be valid for weeks in advance.
There are two main and crucial technological obstacles to further scientific development and to its full and rapid exploitation for practical application. # 1) Computers must be at least 100 times faster than the best at present # 2) The structure of the global atmosphere and the oceans must be much better defined through observation.
Smagorinsky, Joseph, 1966: Remarks on mathematical models In IBM Scientific Computing Symposium on the Environmental Sciences, Session 5 - Mathematical models, 241-244.
Manabe, Syukuro, Joseph Smagorinsky, and R F Strickler, 1965: Simulated climatology of a general circulation model with a hydrologic cycle. Monthly Weather Review, 93(12), 769-798. Abstract PDF
A numerical experiment with a general circulation model with a simple hydrologic cycle is performed. The basic framework of this model is identical with that adopted for the previous study [35] except for the incorporation of a simplified hydrologic cycle which consists of the advection of water vapor by large-scale motion, evaporation from the surface, precipitation, and an artificial adjustment to simulate the process of moist convection. This adjustment is performed only when the relative humidity reaches 100 percent and the lapse rate exceeds the moists adiabatic lapse rate. The radiative flux is computed for the climatological distribution of water vapor instead of using the distribution calculated by the prognostic equation of water vapor. A completely wet surface without any heat capacity is chosen as the lower boundary. The initial conditions consist of a completely dry and isothermal atmosphere. A state of quasi-equilibrium is obtained as a reault of the time integration of 187 days. A preliminary analysis of the result is performed for the 40-day period from 148th day to 187th day.
According to this analysis, the hemispheric mean of the rate of precipitation is about 1.06 m./yr. which is close to the estimate of the annual mean rainfall obtained by Budyko [5]. In the Tropics rainfall exceeds evaporation and in the subtropics the latter exceeds the former in qualitative agreement with observation. The difference between them, however, is too exaggerated, and an extremely large export of water vapor from the dry subtropics into the wet Tropics by the meridional circulation takes place. In the troposphere, relative humidity increases with decreasing altitude. In the stratosphere it is very low except at the tropical tropopause, and the mixing ratio of water vapor is extremely small in qualitative agreement with observation. Although water vapor is transported from the troposphere into the stratosphere, it is then transported toward low latitudes and condenses at the tropical tropopause where the temperature is very low and the relative humidity is high.
Based upon a harmonic analysis of the flow field and the surface pressure field, it is concluded that the effect of condensation tends to increase the wave number of the tropospheric flow and surface pressure field. Also, the incorporation of the moist process in the model seems to increase the intensity of meridional circulation in the Tropics. As a result of this increase, the transport of momentum and heat by the meridional circulation in the Tropics is much larger than that obtained from the previous study. In middle latitudes, the poleward transport of total energy in the moist-model atmosphere is less than that in the dry-model atmosphere because of the effect of the poleward transport of latent energy or the heat of condensation. # The latitudinal distributions of radiative fluxes at the top of the atmosphere and at the earth's surface coincide very well with those obtained by London [17] for the actual atmosphere. Bowen's ratio increases with increasing latitude and its magnitude coincides reasonably well with that obtained by Budyko [5] or Jacobs [11] for the ocean surface.
Smagorinsky, Joseph, 1965: Numerical simulation of the atmosphere's general circulation In Large-scale Problems in Physics, IBM Scientific Computing Symposium, Yorktown Heights, NY, IBM, 141-144.
Smagorinsky, Joseph, 1965: Remarks on data processing in meteorology In Proceedings of the WMO/IUGG Symposium on Meteorological Data Processing, WMO Technical Note 73, Geneva, Switzerland, World Meteorological Organization, 1-20.
Smagorinsky, Joseph, 1965: Review of book: "An introduction to the hydrodynamic methods of short period forecasting", by I. A. Kibel. Mathematics of Computation, 19(89), 162-163.
Smagorinsky, Joseph, R F Strickler, W E Sangster, Syukuro Manabe, J L Holloway, Jr, and G D Hembree, 1965: Prediction experiments with a general circulation model In Proceedings of IAMAP/WMO International Symposium - Dynamics of Large-scale Processes, Moscow, Russia, 70-134.
Smagorinsky, Joseph, Syukuro Manabe, and J L Holloway, Jr, 1965: Numerical results from a nine-level general circulation model of the atmosphere. Monthly Weather Review, 93(12), 727-768. Abstract PDF
The "primitive equations of motion" are adopted for this study. The nine levels of the model are distributed so as to resolve surface boundary layer fluxes as well as radiative transfer by ozone, carbon dioxide, and water vapor. The lower boundary is a kinematically uniform land surface without any heat capacity. The stabilizing effect of moist convection is implicitly incorporated into the model by requiring an adjustment of the lapse rate whenever it exceeds the moist adiabatic value. The numerical integrations are performed for the mean annual conditions over a hemisphere starting with an isothermal atmosphere at rest. The spatial distribution of gaseous absorbers is assumed to have the annual mean value of the actual atmosphere and to be constant with time.
A quasi-equilibrium is attained about which a cyclic energy variation occurs with an irregular period of about 2 weeks. The dominant wave number of the meridional component of the wind is 5 to 6 in the troposphere but is reduced to about 3 in the stratosphere. The gross structure and behavior of the tropopause and stratosphere below 30 km. agree reasonably well with observation. The meridional circulation obtained from the computation has a 3-cell structure in the troposphere and tends toward a 2-cell structure with increasing altitude in the stratosphere. Although the level of the jet stream as well as that of the maximum northward transport of momentum coincides with observation, the intensity of the jet stream turns out to be much stronger than the observed annual mean. In the stratosphere the temperature increases with increasing latitude because of the effect of large-scale motion. The magnitude of the increase, however, is smaller than that observed.
A detailed study of the vertical distribution of the budget of kinetic energy, of available potential energy, of heat, and of angular momentum is made. The mechanism for maintaining the kinetic energy of the jet stream and of the stratosphere is discussed. It is concluded that in the model the kinetic energy in the stratosphere is maintained against its conversion into potential energy and dissipation through interaction with the troposphere, which is in qualitative agreement with the results derived from an analysis of the actual atmosphere. In the troposphere, the conversion of potential energy reaches a maximum at about the 500-mb. level. This energy is then transferred to the level of the jet stream and to the surfce boundary layer by the so-called pressure interaction term, thus providing the source of kinetic energy for these two levels at which dissipation is predominant. As with the results of Phillips [27] and Smagorinsky [37], the ratio of eddy kinetic energy to zonal kinetic energy and that of eddy to zonal available potential energy are computed to be much smaller than those of the actual atmosphere.
