INARCH is conducting a Common Observing Period Experiment (COPE) over the period 2022–2024 as a focal network activity.  The purpose of this is to collect high-quality measurements to the extent possible, along with supplementary observations and remote sensing campaigns, to produce a common, coherent, and well-documented and described data set of mountain meteorology and hydrology from INARCH basins over the two-year period at a minimum, and longer where possible.  We plan to take different models, apply them across our basins, examine the impact of different forcing data and process representations and model structures, calculate snow and ice dynamics and hydrological responses, and look at these diagnostically using observations.

Why have a COPE?  This initiative provides an opportunity for diagnostic model evaluations on INARCH basins, linking data orginators and the modelling community, and to coordinate data collection and data management activities.  By enhancing basin instrumentation and initiating this campaign, this can be a start for longer-term observations of higher quality that can be comparable.  The approach has been used in the past with various GEWEX initiatives (e.g., in western Canada some basins have stayed instrumented over time since the late-1990s).  This can also provide opportunities for comparing and evaluating various instruments, measurement techniques, or field methods, and thus developing best practices for cold region alpine hydrology.  

COPE will have tremendous scientific value in reducing the uncertainty of our understanding and ability to predict global change and water cycling and contributes directly to GEWEX; the World Meteorological Organization (WMO); the United Nations Educational, Scientific and Cultural Organization (UNESCO); Future Earth; the United Nations Framework Convention on Climate Change (UNFCC); and other global programs.  It will produce a valuable and unique set of observations, model simulations and intercomparisons, new process understanding and insights, and better prediction of the changing mountain water cycle in the headwaters of many of the world’s major river basins.