here - CEOP-HE

undertaken by both groups, which largely comprised similar scientists engaged in analogous
projects. In particular, it coordinates the plan and the focus of scientific issues relating to the
development and implementation of Regional Hydroclimate Projects (RHPs) and oversees all
GEWEX regional hydroclimate and land-surface projects.
‘CEOP’ began as part of the initial GHP strategy to help coordinate the activities of diverse GEWEX
Continental Experiments (CSEs), aimed at understanding and modeling the influence of
continental hydroclimate processes on the predictability of global atmospheric circulation and
changes in water resources. Efforts are now required to address regional climate prediction, which
is reflected in a major new initiative of the WCRP. Adequate attention should also be devoted to
biogeochemical aspects, an issue within the realm of the International Geosphere-Biosphere
Programme (IGBP).
The overall goal of CEOP is “to understand and predict continental to local-scale hydroclimates for
hydrologic applications”, with the commitment to attaining skill in predicting changes in water
resources and soil moisture on time scales up to seasonal and annual as an integral part of the
climate system. The Strategic Implementation Plan (SIP) of CEOP is available at
http://monsoon.t.u-tokyo.ac.jp/ceop2/implementationplan.html.
In broad terms, CEOP allows a global synthesis of the water cycle, bringing together surface,
satellite and model data with the ultimate aim of evaluating model skill and accelerate model
development. CEOP is the largest cross-cutting global scale project of GEWEX and has grown to
include 52 reference sites (CEOP Phase II: begun 2007), product generation by more than 10
numerical weather prediction centres (e.g. NCEP, UKMO, JMA , etc.), and a large archive of
satellite data with contributions from five major space agencies (e.g. NASA, ESA, JAXA, etc.).
The HE initiative is a recent element (March 2007) of the CEOP “Regional Foci”, identified by
Regional Studies in the CEOP SIP. CEOP-HE is a concerted, interoperative and interdisciplinary
effort geared toward obtaining further knowledge on physical and dynamical processes at high
elevations, providing a contribution to global climate and water cycle studies.
1.2 Why focus on high elevation areas?
The world’s high elevation mountainous areas form an alpine environment characterized by severe
climate conditions, the presence of glaciers and permafrost, specific alpine geomorphology,
vegetation, soils, and fauna. People need to adapt to live in such conditions.
High mountains are the Earth’s water towers (Viviroli et al., 2007). Water accumulation in
mountain snow and glacier ice forms a hydrologic regime that is favorable to agriculture, due to
increased runoff during the growing season. Mountains are the only renewable clean water source
in many regions and a significant contributor to the hydroelectric potential. Snow, glaciers and
frozen soil at high elevations are a reserve for maintaining the river flows in dry years. An improved
understanding of alpine hydrology will allow a more precise estimation of fresh water resources in
regions where the demand for water is forecast to rise progressively, even if seasonal snow cover,
glaciers and permafrost cannot be clearly guaranteed.
Hydro-meteorological phenomena in the lower atmosphere, such as precipitation (rain, snow, hail),
evaporation and vapour condensation, cloud development , evolution of hydrological cycle, floods
and droughts, are strongly modulated by mountain ranges and plateaus with elevations over 2500
m above sea level (Barry, 2003). A the same time, mountains in many parts of the world are
fundamentally characterized sub-continental scale climate conditions and susceptible to impacts of
the rapidly changing climate system, thus constituting interesting locations for the early detection
of climate change signals and their impacts on hydrological, ecological and societal systems
(Beniston, 2000).
Climate models predict that a substantial warming will occur in continental interiors, such as
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