The Arctic Environmental Problems - New Ecoinformatics Tools in Environmental Science: Applications and Decision-making - page 494

interactions and feedback of the land/cryosphere system and their adequate
parameterization within climate and hydrological models are still needed. Speci c

issues include the interactions and feedback of terrestrial snow and ice in the current
climate and their variability; in land surface processes; and in the hydrological
cycle. Improved knowledge is required of the amount, distribution, and variability
of solid precipitation on a regional and global scale, and its response to a changing
climate. Seasonally-frozen ground and permafrost modulate water and energy
fl

fluxes, and the exchange of carbon, between the land and the atmosphere. How do
changes of the seasonal thaw depth alter the land-atmosphere interaction, and what
will be the response and feedback of permafrost to changes in the climate system?
These issues require improved understanding of the processes and improved
observational and modeling capabilities that describe the terrestrial cryosphere in
the entire coupled atmosphere-land-ice-ocean climate system.
Over a considerable fraction of the high-latitude global ocean, sea ice forms a
boundary between the atmosphere and the ocean, and considerably in uences their

interaction. The details and consequences of the role of sea ice in the global climate
system are still poorly known. Improved knowledge is needed for the broad-scale
time-varying distributions of the physical characteristics of sea ice, particularly ice
thickness and the overlying snow-cover thickness, in both hemispheres, and the
dominant processes of ice formation, modi

fl

cation, decay, and transport which
influence and determine ice thickness, composition and distribution. We do not
know how are accurate the present model predictions of the sea ice responses to
climate change, since the representation of much of the physics is incomplete in
many models. It will be necessary to improve coupled models considerably to
provide this predictive capability.
Key issues on the global scale are: understanding the direct interactions between
the cryosphere and atmosphere, correctly parameterizing the processes involved in
models, and providing improved data sets to support these activities. In particular, it
is needed an improved interactive modeling of the atmosphere-cryosphere surface
energy budget and surface hydrology, including fresh-water runoff.
The scienti

c strategy for CliC project is similar in each of the areas of inter-
action: a combination of measurement, observation, monitoring and analysis, eld

process studies and modeling at a range of time and space scales. A CliC modeling
strategy must address improved parameterization in models of the direct interac-
tions between all components of the cryosphere, the atmosphere, and the ocean. It
will need to do this at a variety of scales from the regional to global; and with an
hierarchy of models ranging from those of individual processes to fully coupled
climate models. It will also be essential to provide the improved data sets needed for
validation of models and parameterization schemes. ”

Table 6.2 data characterizes major components of the cryosphere. It has been
mentioned in (Allison et al. 2001) that the processes in the coupled cryosphere-climate
system involve three time scales

—

intraseasonal-interannual, decadal-centennial, and
millennial or longer. The longest time scale is addressed through the IGBP PAGES
program, although abrupt climate shifts evidenced in ice core and ocean sediment
records (Heinrich events, involving extensive deposition of ice-rafted detritus in the