Many CO₂-related proceedings, reports, and other documents are available from CDIAC while supplies last. A complete list of these publications can be requested with the order form at the back of this newsletter. Documents that are no longer available from CDIAC may be purchased from the National Technical Information Service in microfiche or hard copy; prices may vary with the number of pages.

V. N. Razuvaev and S. G. Sivachok

This report presents abstracts in English and Russian of Russian-language literature related to aerosols and climate change (such as the aerosol optical thickness of the atmosphere, modeling the climate effects of atmospheric aerosols, spatial and temporal variability of aerosol distributions in the atmosphere, volcanic eruptions' climatic effects, and characterization of atmospheric aerosols). This literature has never before been translated into English, so this bibliography and the informative abstracts serve both as an English-language announcement of the availability of this literature and as a surrogate for those for whom the literature is otherwise inaccessible.

The entries are arranged alphabetically by first author, the English and Russian versions appear side by side, and the entries are indexed (in English) by author and by title.

D. N. Williams, R. L. Mobley, R. S. Drach, and T. J. Phillips

This brochure describes the VCS software package developed by DOE's Program for Climate Model Diagnosis and Intercomparison. This package allows climate scientists (and others) to analyze and display large (gigabyte+) data files. With VCS, the user can browse data directories and read various file formats, quickly display variables, create template attributes and graphics methods, perform grid transformations, save a display for recovery, zoom into a specified portion of a display, vary the orientation or size of a display, and animate data displays.

VCS handles many common data-file formats; and with VCS, data can easily be displayed as color maps, line graphs, text, lists, and other methods.

VCS runs on UNIX-based platforms, like Sun (with SunOS 4.1.3 or Solaris 2.4 operating systems), Silicon Graphics (with IRIX 5.2 or 5.3), and Hewlett Packard (with HP-UX 9.0.5), and is available free of charge to qualified licensees who complete a collaborative agreement. Instructions on filing such an agreement are included in the brochure.

R. S. Turner and F. M. O'Hara, Jr.

A workshop on integrated assessment was sponsored by the U.S. Department of Energy in June 1994. It reviewed the importance of integrated assessment and presented a framework for characterizing its key policy issues. Discussion groups analyzed hundreds of issues about the process of integrated assessment and identified 77 key issues, which are listed in the report.

The discussants recognized that there is no one way to perform integrated assessments. Instead, the assessment process must respond to specific groups that have a unique set of information needs, values, and motivating interests.

From this perspective, the 77 key issues were analyzed, and five major conclusions were drawn:

• The most important aspect of assessment is the process of communication, review, stakeholder involvement, broadening of perspectives, balancing of needs, bartering of support, discovery of common goals, gradual understanding, and evolutionary resolution that occurs.

• An assessment must use a variety of approaches with fundamentally different assumptions, with a wide range in focus, and with differing levels of analytical sophistication.

• Perceived ecological, social, and economic consequences of global climate change (including extreme events) will determine the most pressing needs for integrated assessments' support of policy decisions.

• The assessment process and its results should be viewed in the context of the policy issues at hand, the broader social and environmental policy issues, the availability of information, and the experience and background of the stakeholders and decisionmakers.

• Uncertainty must be considered in a meaningful way and communicated to lay audiences in an understandable manner.

L. R. Leung, M. S. Wigmosta, S. J. Ghan, D. J. Epstein, and L. W. Vail

DHSVM, a watershed/meteorology model, was developed at Pacific Northwest Laboratory in collaboration with the University of Washington. It treats surface hydrologic processes at the topographic scale (down to 90 m in resolution), is driven by meteorology that is observed or simulated by a climate model, and features a subgrid oro- graphic precipitation scheme. It includes a two-layer canopy model for evapotranspiration, an energy-balance model for snow accumulation and melting, a two-layer rooting-zone model, and a saturated-subsurface flow model. Digital elevation data are directly used to model topographic influences on absorbed solar radiation and downslope water movement. At each timestep, the model provides a simultaneous solution to the energy- and water-balance equations for every grid cell in the watershed. Individual grid cells are hydrologically linked through a saturated-subsurface transport scheme.

In assessing the effects of climate change on a watershed, the discharge rate is perhaps the most important variable from a water-resources perspective. Evaluations of the prediction of discharge by the DHSVM model and its subgrid orographic precipitation scheme indicate that the predicted values agree quite well with observed data.

This watershed model can be applied to any number of watersheds and the discharges from each linked and cumulated. Thus, the modeling of the effects of greenhouse warming on entire river systems should be possible.

R. C. J. Somerville, C. Gautier, S. J. Hassol, and P. Norris

Cloud-radiation parameterizations are responsible for most of the global mean differences in climate models' sensitivities to greenhouse-gas increases. That uncertainty in model responses is directly caused by a lack of fundamental understanding of the physical processes involved. Therefore, 25 participants were invited to contribute presentations at the Aspen Global-Change Institute 1994 summer science session on Climate-Radiation Feedbacks: The Current State of the Science to thoroughly examine the key issues in the parameterization of clouds. This report contains the papers presented at that session and a summary discussion of the ideas presented by the participants.

The presentations were largely accounts of personal research involving (1) field observations of cloud, radiation. and/or atmospheric phenomena or (2) modeling efforts and comparisons. The papers dealt with cloud dynamics and microphysics, atmosphere-surface interactions, parameterization, radiative transfer, multifractal and stochastic cloud analysis and modeling, and ground- and space-based observations. Those papers and the discussions that followed elicited a number of key observations: The climate-modeling community now realizes that cloud-feedback processes are not limited to macrophysical cloud properties like cloud amount and cloud altitude.

Because we cannot account theoretically for such observed properties of the present climate as the large-scale upper bound of about 304K on the sea-surface temperature, we are at a loss to explain convincingly how those properties might change in some future climate.

The different GCMs take noticeably similar approaches in their parameterizations. Modern developments, such as the advances made in fractal and multifractal representations of variability, have not yet found their way into common practice in GCMs.

New formalisms are slowly emerging to facilitate radiative-transfer computations in three dimensions; a main thrust of this research is the use of Monte Carlo models and of approximate radiative-transfer methods.

Three characteristics can describe the statistical nature of the highly intermittent cloud liquid-water fields: (1) how nonconservative the mean field is, (2) how fractal it is, and (3) how multifractal it is.

Phase diagram of the heating and cooling of the ocean surface and upper ocean as a function of wind speed. The numbers in the figure reflect elapsed days. From Elements of Change, 1994; originally from P. Webster, Rev. Geophys. 32:427476, 1994.

During October 1993, scientists specializing in various aspects of plant science met to discuss how our predictive capabilities could be improved by developing a more rational, mechanistic approach to relating photosynthetic processes to environmental factors. This report is a summary of that workshop.

At the meeting, a consensus emerged that achieving the stated goal requires multidisciplinary research efforts that combine tools and techniques of genetics, molecular biology, biophysics, biochemistry, and physiology to understand the principles, mechanisms, and limitations of evolutional adaptation and physiological acclimation of photosynthetic processes. Many of these basic tools and techniques, often developed in other fields of science, are already available but have not yet been applied in a coherent, coordinated fashion to ecological research.

This multidisciplinary research is related to developing more-realistic prognostic models to forecast climate change that include photosynthetic responses and feedbacks at regional and ecosystem levels. The workshop identified scientific issues that must be undertaken:

• An understanding of the basic mechanisms of the environmental factors that determine or limit photosynthesis

• The effects of increased atmospheric CO₂ on plant productivity and storage allocation in the short and long terms

• The limitations on the realized quantum yield of photosynthesis

• The effects of increased UV-B radiation on photosynthetic responses

• The methods by which plants adapt to environmental extremes of temperature, water, nutrients, and energy supply

The workshop recommended that the scientific problems be addressed by small teams of researchers with a high degree of individual independence, backed by basic research efforts in ecology, photosynthesis, molecular genetics, and biophysics.