A global synthesis of glacier mass balance data is proposed, which will include an evaluation and digitization of measured mass balance data . The mass balance data set will include three databases: I. annual specific mass balances of all measured mountain and subpolar glaciers; II. annual accumulation (or winter balance) and annual ablation (or summer balance); III. winter, summer and annual mass balance gradients will altitude. These data will be analyzed in several ways: statistical spatio-temporal analyses of individual glaciers, mountain ranges and countries, both hemispheric and global; analyses of annual fluctuations and determination of long-term mass-balance trends; and analyses of mass balance gradient changes. The main tasks include: (1) Assemble and check the annual specific mass balance data of all measured glaciers since 1945. (2) Determine the contribution of glacier changes to sea level, e.g., how much do different glacier regions contribute to sea-level change? (3) Estimate the variability of winter and summer balances (or annual accumulation and ablation) and their impact on annual mass balances in different geographical locations. (4) Determine the main causes for mass balance changes in different mountain regions. (5) Analyze mass balance gradients (activity indices) and their changes in connection with climate change. The end products of this research will include three mass balance data sets which will be produced at INSTAAR in a form accessible by the community, and the data report, "Mass balance of mountain and subpolar glaciers: data and syntheses" which will be published by World Data Center A Glaciology, University of Colorado, Boulder.
