The modern approach to understanding Earth rotation irregularities deals with interacting physical constituents as diverse as a liquid, magnetic core, a visco-elastic mantle, and liquid and gaseous external layers, each with internal motions and responding to external forces. The global character of the observational evidence is a major challenge to theoreticians who develop dynamical models of the behavior of each layer. No single theory can explain the complete set of observed irregularities. The monitoring of Earth rotation itself includes the participation of worldwide space geodetic and astronomical programs, leading to intensive international cooperation. The symposium will focus on those aspects of Earth rotation studies that imply, or even create, bridges between scientific disciplines.
Lead Convener: M. Feissel (IAG), Observatoire de Paris, Central Bureau, International Earth Rotation Service, 61, Avenue d'Observatoire, F-75014 Paris (FRANCE); tel: +33-1-4051-2226; fax: +33-1-40-51-22-91; e-mail: email@example.com.
Co-conveners: D. Cartwright (UK), R. Hide (UK), R. Sabadini (ITALY), J. Wahr (USA), P. Brosche (GERMANY).
This symposium will address a number of related and multidisciplinary topics important to the improvement of the parameterization of sub-grid atmospheric and land surface processes in atmospheric models. Results being produced by international projects such as GEWEX and BAHC will be presented. Following an integrating opening session, the symposium will follow the four themes of: Status of land-surface process models (PILPS and RICE), coordinated by Ann Henderson-Sellers; Land-surface process model development, coordinated by Alfred Becker, and Clouds fields and readiative properties coordinated by Erhard Raschke. The symposium and related workshops (see below) have been approved by the Bureaus of IAHS and IAMAS. The symposium will be coordinated with WCRP/GEWEX, IGBP/BAHC, WMO, and UNESCO and UNEP, ICASVR (lead Committee on behalf of IAHS), ICRSDT, ICWRS and the relevent IAMAS Commissions. For simplicity, all correspondence should be addressed to the Lead Convener.
Lead Convener: John Schaake, (IAHS), National Weather Service, Office of Hydrology, W/0H3; 1325 East-West Highway, Silver Spring, MD 20910 (USA); tel: 1-301-713-1660; fax: 1-301-713-0963.
Co-convener: A. Henderson-Sellers (IAMAS), (AUSTRALIA)
Major topics of the workshop will be evapotranspiration, soil moisture, and snow-water equivalent. A context with GEWEX activities, perhaps GCIP, should be sought.
Lead Convener: Richard Armstrong (IAHS), CIRFS, Campus Box 449, University of Colorado, Boulder, CO 80309 (USA); tel: 1-303-492-1818; fax: 1-303-492-2468.
Co-convener: A. Chedin (FRANCE).
Mountains exert substantial influence upon the continental-scale fractures of the hydrological cycle and they contribute, sometimes crucially, to available water resources of various climatic zones. This workshop is conceived as a contribution to GEWEX and is geared to seeking a better understanding and improved modelling of the larger-scale features of the complex hydrometeorological processes of mountainous regions.
Lead Convener: Herbert Lang, (IAHS), Institute of Geography, ETH, Winterhurerstrasse 190, CH-8057 Zurich (SWITZERLAND); tel: +01-257-52-31; fax: +01-362-51-97.
Co-convener: Hugh Davis (SWITZERLAND).
This workshop will consider techniques for dynamic monitoring and estimation of water fluxes over the continents and the oceans at regional to global scales. Topics suited to this workshop are intercomparison of models with observations; results from regional-to-global-scale observational and modelling studies of water vapor transport; techniques for data manipulation and visualization; results from GEWEX activities, including GCIP, GVAP, and GEWEX Asian Monsoonal Experiment (GAME), and scaling issues in flux parameterizations.
Lead Convener: Kendal McGuffie, (IAMAS), Department of Applied Physics, University of Technology, Sydney, P.O. Box 123, Broadway, NSW 2007 (AUSTRALIA); tel: +61-2-330-2204; fax: +61-2-330-2219.
Co-convener: Klaus Wilke (GERMANY).
This symposium will communicate results of recent observational and modeling efforts to understand the continuum of air-sea interactions that take place in the Western Pacific warm pool, from microscale turbulent fluxes of heat, moisture, and momentum across the interface to the mesoscale and synoptic-scale motions in the ocean and atmosphere that modulate these fluxes. Timescales of interest range from a few minutes to a few years, with emphasis on nonstationary processes. A particular objective is to address issues of scale interactions, with the intent to improve parameterizations of subgrid-scale processes in coupled ocean-atmosphere models. Emphasis will be on results derived from TOGA/COARE. However, selected papers of different origin, but addressing air-sea interaction processes of importance in TOGA/COARE, will be included.
Lead Convener: Yoshiaki Toba, Faculty of Science, Tohoku University, Physical Oceanography, Laboratory, Sendai 980-77 (JAPAN); tel: +81-22-245-3695; fax: +81-22-227-3671.
Co-conveners: Peter J. Webster (USA), Roger Lukas (USA), Yury A. Volkov (RUSSIA), Greg J. Holland (AUSTRALIA).
This symposium has as its goal the examination of similarities and differences between oceans, lakes, and the atmosphere with regard to the structure of small-scale turbulence and internal waves, and with regard to how turbulence and internal waves interact with large-scale dynamics in the three different environments. Modelling/theoretical papers that assess the importance of these interactions of small-scale processes with the large-scale flow will be encouraged.
Lead Convener: Michael C. Gregg, Applied Physics Laboratory and School of Oceanography, University of Washington, 1013 N. E. 40th Street, Seattle, WA 98195 (USA); tel: 1-206-543-1353; fax: 1-206-543-6785; telex: 910.444.1345; Omnet: M.GREGG; e-mail: firstname.lastname@example.org.
Co-convener: Thomas E. Van Zandt (USA).
This symposium will focus on interactions among the different regions of the equatorial atmosphere, from the troposphere to the ionosphere. Dynamical, electrodynamical, radiational, and chemical processes produce these interactions, contributing to unique features of equatorial regions (e. g. equatorial waves, the quasi-biennial oscillation, the semiannual oscillation, the equatorial electrojet, the equatorial ionospheric anomaly and equatorial ionospheric irregularities). This symposium will examine how results of recent coordinated studies of the equatorial region (e.g., TOGA/COARE, CADRE, ALOHA, IEEY, MISETA) can be used to understand better the coupling between phenomena at different altitudes as well as between phenomena at equatorial and higher latitudes.
Lead Convener: R. A. Vincent, Department of Physics, University of Adelaide, Adelaide 5005, AUSTRALIA; tel: +61-8-303-5758; fax: +61-8-303-4380, e-mail: email@example.com.
Co-conveners: A. D. Richmond (USA), S. Kato (JAPAN).
The Middle Atmosphere Sciences Symposia are concerned with the physics and chemistry of the Earth's atmosphere from the tropopause to the lower thermosphere (100 km). They include four individual symposia:
A. Dynamics of the Middle Atmosphere
This symposium will address all aspects of the dynamics of the middle atmosphere, with emphasis on tropical dynamics, excitation of vertically propagating waves (including planetary waves and small-scale gravity waves), mesospheric tides and their variability, mechanisms of interannual variability of the large-scale circulation, and wave forcing and transports in the stratosphere and mesosphere.
B. Chemistry, Radiation, and Transport in the Middle Atmosphere
This symposium will address all aspects of chemistry, radiation, and transport, and their interactions in the middle atmosphere. Areas of special interest include observational, theoretical and modelling studies of recent changes in ozone and related chemicals; new findings on the possible impacts of ozone change on climate and UV-B radiation in the troposphere; theoretical and observational studies of heterogeneous chemical processes (with emphasis on the role of sulphate aerosols); radiative response of the middle atmosphere to changes in composition; the thermal budget of the mesosphere; and the influence of transport processes on chemical distributions in the middle atmosphere (including the role of transport from the polar vortex on ozone depletion at middle latitudes in the stratosphere).
C. The Polar Mesosphere
This symposium will focus on the dynamics and photochemistry of the polar regions between 50 and 90 km. Contributions are solicited on coupling of the neutral and ionized atmosphere with aerosols, solar UV radiation, and dynamical and chemical influences originating at lower levels; secular changes in the occurrence of polar mesospheric clouds; theoretical modelling of polar mesospheric structure, chemistry, cloud microphysics, and dynamics; and ground-based observations of winds and density by radar, lidar, spectroscopy, polarimetry, etc.
D. Solar-Terrestrial Interactions
This symposium will address the effects of temporally variable solar ultraviolet radiation and solar and magnetospheric energetic particle fluxes on the middle atmosphere. Contributions are solicited on the response of the mesosphere and stratosphere to 27-day variations of solar ultraviolet flux; the solar cycle variation of ozone, temperature, and zonal wind in the upper stratosphere and mesosphere; and observational and theoretical studies of dynamical changes at lower levels occurring over a solar cycle.
Lead Convener: Rolando R. Garcia, NCAR, P.O. Box 3000, Boulder, CO 80307-3000; tel: 1-303-497-1446 or 497-1434; fax: 1- 303-497-1400, e-mail: firstname.lastname@example.org.
Co-conveners: B. A. Boville (USA), D. Fritts (USA), M Shiotani (JAPAN), S. Solomon (USA), J. Russell (USA), L. Gray (UK), G. Thomas (USA), G. Witt (SWEDEN), R. Goldberg (USA), L. Hood (USA), J. Lastovicka (CZECH REP).
This symposium will concentrate on the atmospheric effects caused by the June 15, 1991, eruption of Mount Pinatubo (15.14oN, 120.35oE) in the Philippines. Enormous amounts of SO2 spewed from the volcano created over 30 megatonnes of stratospheric sulphuric acid aerosol which dispersed globally over the ensuing months, warming stratospheric temperatures and cooling the troposphere. In addition, with human-derived chlorine, record low levels in lower stratospheric ozone have been recorded. Papers are requested which deal with characterization of the formation, dispersal, and removal of aerosols, and the influence of these aerosols on radiative and chemical processes, clouds, dynamics, and remote sensing.
Lead Convener: P. Mc Cormick, NASA Langley Research Center, Mail Stop 475, Hampton, VA 23665-5225 (USA); tel: 1-804-864-2669; fax: 1-804-864-2671.
Co-conveners: G. Brasseur
The terrestrial biosphere plays an important role in atmospheric CO2 variations on seasonal and interannual timescales. The purpose of this symposium is to provide a forum for scientists from different disciplines to bring together their different approaches to the problem area of biosphere-atmosphere interaction and how that is affected by global change. The main focus will be to define concrete ways to better assess the role of the terrestrial biosphere in the global carbon cycle.
Lead Convener: Ingeborg Levin, Institut fur Umweltphysik, Universitat Heidelberg, Im Neuenheimer Feld 366, D-69120, Heidelberg (GERMANY); tel: +49-221-56-3330; fax: +49-221-56-3405.
Co-conveners: P. Tans, D. Schimel
This joint symposium invites presentations describing the climate of the past millennium, including its natural variations and changes induced by natural forcing and by human activities. The symposium will cover the means and techniques for reconstruction of the climate and climate forcings over this period, the spatial and temporal patterns of the climate and its variations, the explanations for and causes of these variations, the extent to which natural and human influences can be distinguished over the past two centuries, and the implications of these findings for distinguishing anthropogenic and natural changes in climate in the future. Session themes are planned to include: methods for reconstructing climate, high-resolution records of volcanism and other forcing factors, the Medieval Climate Optimum, the Little Ice Age, the Industrial Period, and the implications of past climate relationships for the future climate.
Lead Convener: Michael MacCracken, Office of the U.S. Global Change Research Project, c/o National Science Foundation 300 D Street, S.W., Suite 840, Washington, DC 20024 (USA); tel: 1- 202-651-8250; fax: 1-202-554-6715; e-mail: email@example.com.
Co-conveners: C. Folland (UK), P. D. Jones (UK), H. Pollack (USA), A. Robock (USA), S. Self (USA), G. Zielinski (USA), U. Mikolajewicz (GERMANY).
This symposium will address all aspects of observational, theoretical and modelling studies on the distribution of ozone throughout the troposphere and the physical and chemical processes contributing to its production and destruction, with emphasis on (1) trends in the northern and southern hemispheres; (2) effects of tropospheric aircraft; (3) ozone and climate; (4) polar ozone distribution mechanisms; (5) measurements of free radicals involved in ozone production and destruction (e. g. peroxy radicals, nitrate radicals and halogen radicals); and (6) ozone production from biomass burning. The main purpose of this symposium is to provide a forum for researchers with various different expertise to bring together their views and approaches to the advancement of the current state of knowledge on tropospheric ozone issues from the standpoint of global change.
Lead Convener: H. Niki, Centre for Atmospheric Chemistry, York University, 4700 Keele Street, North York, Ontario M3J 1P3 (CANADA); tel: 1-416-736-5410 fax: 1-416-736-5411.
Co-conveners: S. Penkett (UK) and W. Chameides (USA).
This symposium will address processes which affect the transfer of radiation through the atmosphere and which play an important role in climate forcing. Papers describing studies of the radiation budget, either global or local in scope, as well as those discussing processes which affect the budgets, are encouraged. Papers based on the International Satellite Cloud Climatology Project should be directed to Symposium HJS1. A major theme will be the direct and indirect role of aerosol in the radiation budget and papers in this area are particularly encouraged, as are those addressing the impact of clouds and cloud systems. It is the intention that papers should address processes relevant to climate, rather than to the problem of climate change.
Lead Convener: G. Stephens, Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523 (USA); tel: 1-303-491-8330; fax: 1-303-491-8449.
Co-conveners: S. Warren, J. Ogren, A. Slingo.
With the recent optical measurements that confirm the existence of upward vertical lightning above the clouds up to the mesosphere, this year's atmospheric electricity sessions promise to be exciting. Sessions will be convened on topics including cloud electrification, lightning, global circuits, and middle atmosphere electrodynamics.
Lead Convener: Robert Holzworth, Geophysics Program, AK-40, University of Washington, Seattle, WA 98195 (USA); tel: 1-206-685-7410; fax: 1-206-685-3815.
Co-convener: C. Saunders
Strong interactions between the planetary boundary layer and mesoscale weather systems are important in many contexts, including flow over inhomogeneous terrain, orographic effects, tropical cyclones, and explosive cyclogenesis events. However, much work in these areas focuses either on the boundary layer effects or on the mesoscale meteorology. The aim of this symposium is to bring together boundary layer and mesoscale studies and to develop a coherent account of these various phenomena. Papers devoted to observational, modelling, or theoretical studies are invited.
Lead Convener: Roger Smith, Meteorologisches Institut, Universitat Munchen, Theresienstrasse 37, D-80333 Munchen (GERMANY); fax: +49-89-280-5508.
Observational and numerical studies have provided significant advances in our knowledge of the structure, dynamics, and climatology of the atmospheric systems found in the Arctic and Antarctic, resulting in greater understanding of the role of the polar regions in the general circulation. This symposium seeks to assess our knowledge of polar weather systems and draw attention to areas where further work is needed. In particular, the symposium will address representation of synoptic and mesoscale disturbances in operational NWP systems, climatological studies of the variability of systems on seasonal and interannual time scales, diagnostic and numerical investigations of individual disturbances, comparative studies of Arctic and Antarctic weather systems, and work examining the links with the tropical and mid-latitude circulation and ocean forcing.
Lead Convener: John Turner, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, (UK).
Co-convener: E. Rasmussen (DENMARK)
This symposium will consist of two parts: one about the atmosphere of Mars, and the other about the atmosphere of Jupiter. The Mars portion of the symposium will focus on the questions of composition and structure of the present atmosphere; circulation; transport of dust and water; surface-atmosphere interaction; and the evolution and stability of the Martian atmosphere. The Jupiter portion of the symposium will have as its theme "Jupiter on the Eve of Galileo," and will consist mostly of a series of invited talks on the state of Jupiter's atmosphere as we know it just before the observations of this planet by Galileo orbiter and probe instruments in late 1995, and on predictions for Galileo.
Lead Convener: Sushil K. Atreya, Department of Atmospheric Oceanic and Space Science, The University of Michigan, 2455 Hayward Avenue, Ann Arbor, MI 48109-2143, (USA); tel: 1-313-764-3335; fax: 1-313-764-4585.
Co-conveners: J. R. Barnes, D. McCleese, T. C. Owen, F. W. Taylor.
Within the next 10 years, implementation of operational satellite systems of advanced sounders in the infrared and in the microwaves will complement existing techniques to address global change problems. Expected improvements from such sounders are enhanced accuracy, and improved vertical and spatial resolution in the retrieval of surface and atmospheric variables. Achieving such improvements at global scale requires more and more accurate, tractable, and rapid modelling of the forward and inverse radiative transfer processes, and highly reliable spectroscopic parameters. Contributions (refined or new methods, results) that deal with these requirements and emphasize the associated quality assurance and quality controls are solicited.
Lead Convener: Noelle Scott, Ecole Polytechnique, LMD/ARA, 91128 Palaiseau cedex (FRANCE); tel: +33-1-6933-4532; fax: +33-1-6933-3005.
This symposium offers the opportunity to present relevant SPARC results. The topics should deal with results concerning the impact of stratospheric changes on the troposphere-stratosphere system and on climate. Papers related to the six SPARC initiatives will be particularly welcomed: i.e.; modelling the stratosphere in GCMs and intercomparison of models, gravity wave climatology leading to improved parameterization, climatology of water vapour in the high troposphere and stratosphere, assessment of stratospheric temperature trends, stratosphere-troposphere exchange and quantification of these exchanges, and UV-B impact due to ozone depletion on atmospheric chemistry and climate.
Lead Convener: Marie-Lise Chanin, Service d'Aeronomie du CNRS, B. P. 3, F-91371 Verrieres-le-Buisson (FRANCE); tel: +33-1-6920-0794; fax: +33-1-6920-2999.
Co-convener: M. Geller (USA)
The symposium will deal with all aspects of the variability of ocean, atmosphere, and the coupled atmosphere-ocean system on timesscales of one year to centuries. Topics will be empirical analyses of observational records, representative of the global or regional climates, empirical analyses of the output of extended (global or regional) climate model "control" runs, theoretical analyses of low-frequency variability, sensitivity experiments of the effect of anomalous boundary conditions on the state of the atmosphere or the ocean, and sensitivity experiments on the effect of anomalous forcing mechanisms on the coupled atmosphere-ocean system (aerosols, greenhouse gases, solar forcing).
Lead Convener: Hans von Storch, Max-Planck-Institut fur Meteorologie, Bundesstrasse 55, D-20146 Hamburg (GERMANY); tel: +49-40411-73-232; fax: +49-40-44-1787.
M W2: New Technology and Mesoscale Forecasting
Traditional synoptic observations have insufficient resolution in time or space for use in forecasting meteorological phenomena on the mesoscale. Increasingly reliance is placed on the integration of satellite-borne and surface-based remote sensing techniques with the forecasting system. This workshop will survey the available remote sensing techniques, including novel techniques and their integration within a forecasting system.
Lead Convener: Keith Browning, Joint Centre for Mesoscale Meteorology, University of Reading, Reading RG6 2AU, (UK); tel: +44-734-318425; fax: +44-734-318316.
This workshop will focus on studies of the solar cycle variation of stratospheric chemistry (especially ozone), temperature, and dynamics. The primary goal of the workshop is to establish the basic properties of the solar cycle variation of the stratosphere as derived from available satellite and ground-based remote sensing data sets. A secondary goal is to determine the extent of agreement/disagreement of the observed variation with available two- and three-dimensional model simulations that incorporate the observed solar cycle variation of ultraviolet spectral irradiance. The workshop will consist of invited oral presentations and contributed oral and/or poster presentations.
Lead Convener: L. Hood, University of Arizona, Lunar and Planetary Laboratory, 85721 Tucson, AZ (USA);
tel: 1-602-621-6936; fax: 1-602-621-4933.
Considerable progress has been made in recent years in defining gravity wave source variability and propagation conditions. As a result, we are now in a position to begin to define more quantitatively how these variable sources and the gravity waves they excite influence the atmosphere at greater altitudes. The intent of this workshop is to provide a forum in which our knowledge of source conditions and variability can be used to improve descriptions of these processes in large-scale models. Contributions on all aspects of gravity wave excitation, propagation, spectral evolution, and parameterization are encouraged.
Lead Convener: David Fritts, Laboratory for Atmospheric and Space Physics, University of Colorado, Campus Box 425, Boulder, CO 80309 (USA); tel: 1-303-492-2806; fax: 1-303-492-6946, e-mail: firstname.lastname@example.org.
The workshop will discuss and compare the formulation and performance of comprehensive global climate-middle atmosphere models in simulating the present-day climate and its possible response to various forcing mechanisms. Emphasis will be placed on modelling the thermal and dynamical structure of the high-latitude low stratosphere and the quasi-biennial oscillation in the tropics, both of which are known to present problems in such models. Particular attention will be devoted to problems of modelling the exchange of energy and trace constituents between the troposphere and stratosphere, an objective of the SPARC program of the WMO.
Lead Convener: Steven Pawson, Institut fur Meteorologie Freie, Universitat Berlin, Carl-Heinrich-Becker Weg 6 - 10, D-12165 Berlin (GERMANY); tel: +49-30-838-71165; fax: +49-30-793-1785, e-mail: email@example.com.
Co-convener: R. Rood
There is clear evidence that the observed long-term ozone decreases in the recent past are associated with increases in the UV-B flux reaching the ground. Long-term changes in UV-B are still uncertain, however, mainly because of uncertainties of broadband instruments and our limited knowledge of interference caused by a wide range of environmental factors, both natural and anthropogenic. This workshop will focus on specific topics relating total ozone changes to the accompanying UV-B changes. Topics will include modelling and observations of spectral UV transfer through representative atmospheres, consequences of UV-B changes and measurements, and calibration practices.
Lead Convener: Christos S. Zerefos, Laboratory of Atmospheric Physics, Campus Box 149, University of Thessaloniki, Thessaloniki 54006 (GREECE); fax: +30-31-248-602.
Co-convener: J. Kerr
A major goal of the International Global Aerosol Program (IGAP) is to improve understanding of the role of atmospheric aerosols in forcing mechanisms and prediction of change in global climate and in geospheric-biospheric processes. To achieve this goal IGAP has initiated eight international science projects on cloud-aerosol interaction studies, sulfur and carbonaceous aerosols in the arctic and their radiative forcing, the biological component of the atmospheric aerosol, biomass burning aerosols in the tropics: impact on radiation budget and climate, atmospheric impact of the 1991 Pinatubo eruption, radiative properties of aerosols, and tropospheric aerosol radiative forcing observational experiment. Progress on each of these projects will be reviewed and further activities planned. Plenary sessions of the workshop are open to all interested parties.
Lead Convener: Peter V. Hobbs, Department of Atmospheric Sciences, AK-40, University of Washington, Seattle, WA 98195 (USA); tel: 1-206-543-6027; fax: 1-206-543-0308.
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IUGG XXI General Assembly