The Arctic Hydrological Cycle Monitoring, Modelling and Assessment Program

Project Description
Short Title: Arctic-Hydra
Proposal URL: http://classic.ipy.org/development/eoi/proposal-details.php?id=104

The scientific goals of the Arctic-HYDRA project are: To characterize variability in the Arctic Hydrological Cycle (AHC) and to examine linkages between atmospheric forcing and continental discharge to the ocean; to assess the historical response of the Arctic Ocean to variations in freshwater input from rivers and net precipitation over the ocean; to attribute to specific elements of the AHC or to external forcing the sources of observed spatial-temporal variability in the land-ocean-ice-atmosphere system; to detect emerging changes in the contemporary state of the AHC in near real time and to place such changes into a broader historical context.

Given the scope of these goals and the relatively short time-frame of the IPY, Arctic-HYDRA also forms part of the parallel longer term (10-15 yr) objectives of the ICARPII (International Conference on Arctic Research Planning) Working Group 7 (WG7) project "Terrestrial Cryospheric and Hydrologic Processes and Systems".

The Arctic-HYDRA project consists of a core network for observation of the AHC (Arctic-HYCOS) coupled with a suite of intensive, focused process studies that are based on in-depth measurements and modelling of the individual components of the AHC. Furthermore, hydrological models and data assimilation techniques will be developed to generate a comprehensive, integrated description of the AHC including the feedbacks between the atmosphere, cryosphere and the oceans. The project will have a data management and information system in accordance with IPY and WMO protocol. It will establish links with other relevant clusters, e.g. on meteorology, climatology, cryosphere, including permafrost, snow-cover and glaciers, biosphere and societal issues affected by the AHC.

The Arctic-HYCOS is the core network of the Arctic-HYDRA. This system is intended to provide hydrological information of a high quality, both historical as well as near real time data. It will provide an important benchmark for understanding future change to the AHC; information essential to the longer term ICARPII-WG7 program. The system will be based on the existing national data bases and observation systems in the Arctic countries that have historical long-term observation series on the large rivers discharging to the Arctic Ocean, as well as stations on tributaries and smaller rivers. The Arctic-HYCOS network will meet the requirements of WMO-HYCOS. During the International Polar Year (IPY) four test hydrological stations are to be established in the Mackenzie (Canada), Lena and Pechora (Russia) and Tana (Norway, Finland) river basins. It is envisaged that additional sites will be established in accordance with the broader plan of the Arctic-HYCOS and ICARPII-WG7 program.

To complement the core network, a set of Long Term Hydrological Observatories (LTHOs) will be established in Arctic North America and Eurasia. They will collect basic hydrologic data such as precipitation, stream flow, groundwater levels, etc. as well as meteorological and biogeochemical data. In Alaska a LTHO (the Kuparuk River) will serve as an international natural laboratory dedicated to understanding the dynamic interactions between hydrological, ecological and climatological processes. Another LTHO will be established in the Eurasian Continent with focus on the ocean/atmospheric interactions with the hydrological cycle, including radio-sonde observation, radar measurement, GPS and solid precipitation measurements. Similar LTHO or network of research basins will focus on advancing our understanding and description of land surface cryospheric processes in order to improve the predictive capacity of Arctic atmospheric, cryospheric and hydrological models at small to medium scales. This will include observations of snow accumulation, over-winter ablation processes, snowmelt, soil thermodynamics, infiltration and water redistribution in frozen and thawing soils and cold regions water balance components in non-frozen periods. Two additional LTHOs will focus on the impact of aerosols on the AHC with supplementary UAV measurements and enhanced surface observations. The LTHO observations will be used to improve atmospheric, hydrologic and cryospheric process representations and also to evaluate meso-scale representations in models and assess model performance and sensitivity in multi-criteria prediction. The LTHO network will form the platform for developing the "supersites" of monitoring and research activities identified for the ICARPII-program.

The Arctic-Hydra executes a strategy for synthesis and integration studies of the AHC based on the Arctic-RIMS project. It will produce time-varying aerological and land surface water budgets including river and ice melt inputs to the Arctic Ocean. All key elements of the terrestrial and ocean water balance will be provided, including an assessment of potential error. A guiding philosophy of the proposed research is to "stay close to the data" although both data assimilation and modelling systems will be used for generalizations. The use of observations, either by themselves or as model drivers, provides a "reality-based" framework to understand observed variability and change in the Arctic system.