Geoscience Reference
In-Depth Information
1965-1974. Since then, budget constraints and failure to maintain existing systems have
resulted in a general decline in monitoring, something that has been reported in several
studies (Brown
2002
; Fekete and V ¨r ¨smarty
2002
; Maurer
2003
; Hannerz
2008
; FAO
2009
).
The global trend of declining discharge monitoring is also evident in the Arctic
(Lammers et al.
2001
; Shiklomanov et al.
2002
; Hinzman et al.
2005
; Walsh et al.
2005
,
Arctic-HYDRA consortium
2010
). The particular situation in the Arctic has received
relatively much attention in the scientific community, partly due to the rapid changes and
the general scientific interest in the region. Also, the accessibility to discharge data has
been improved more in the Arctic than in many other parts of the world. These
improvements are mostly due to a few concentrated international collaborations, several of
which were coordinated from the University of New Hampshire. Nevertheless, some of
these efforts are now several years in the past, and the accessibility to recent discharge data
that they initially provided has not always been sustained.
In contrast to the situation for discharge monitoring, a clear picture of the status of water
chemistry data has been lacking. Previous efforts have tried to assess the state of affairs for
certain parameters (e.g., Holmes et al.
2000
,
2002
; Raymond et al.
2007
) and estimated the
quality of existing data (Zhulidov et al.
2000
,
2003
; Holmes et al.
2001
). Although specific
data sets have been made accessible for parts of the PADB (e.g., Holmes et al.
2000
;
Holmes and Peterson
2002
), and in at least one case for the wider PADB (McClelland et al.
2008
; data at
http://www.arcticgreatrivers.org
), no international repository and data host
exists for all accessible Arctic water chemistry data. Neither has any initiative yet been
launched to develop a common set of indicators, such as the Millennium Development
Goals-related UN Federated Water Monitoring System (FWMS) and its Key Water Indi-
cators Portal (KWIP).
The decline in station numbers and the lack of integrated hydrological and hydro-
chemical information, together with the grand challenge of improving Earth observation
systems, constitute an imperative to develop Arctic hydrological monitoring networks and
to
ensure
their
relevance
under
conditions
of
climate
change.
This
would
enable
improvements in both GCMs and hydro-climatic change understanding.
The importance of the continental water system in Arctic and global change means that
the hydrological drainage basin is a fundamental and relevant spatial scale unit, both for
water management and adaptation, and for basic research (Pahl-Wostl
2007
; UNECE
2009
). In this paper, we therefore survey and review several components required to
provide reliable water information, and to do this consistently at drainage basin scales.
Basin-scale water information also has ensuing applications in understanding coupled
changes across other terrestrial, atmospheric and marine systems (e.g., Karlsson et al.
2011
).
This review paper addresses the following three overarching topics:
•
The reliability of GCM projections on the scale of main Arctic river basins, as base
information for understanding and for societal adaptation to Arctic climate and water
change;
•
The recently observed changes to water flow and water budgets in the Arctic
hydrological cycle, and their potential consequences for both societal adaptation and
freshwater input to the Arctic Ocean; and
•
The representativeness, accessibility and relevance of hydrological and hydrochemical
observation systems for assessing changes to water, sediment and hydrochemical fluxes
in the Arctic hydrological cycle.
