International Polar Year 2007–2008 - WMO

2004 ITP 2
2005 ITP 1, ITP 3
Completed missions Active missions
2006 ITP 4, ITP 5 ITP 6
2007 ITP 7 ITP 8, ITP 9, ITP 10, ITP 11, ITP 12,
ITP 13, ITP 14, ITP 15, ITP 16, ITP 17,
ITP 18
2008 ITP 19, ITP 20, ITP 21, ITP 22, ITP 23,
ITP 24, ITP 25, ITP 26, ITP 27, ITP 28,
ITP 29, ITP 30
Altogether, the ITP array has now returned something
in excess of 20,000 CTD profiles between ~7 and
~750 m depth since the first unit was deployed in 2004
(pers. comm., John Toole WHOI, October 2009), transforming
the former data-desert into one of the mostdensely-observed
oceans on the planet. Though still
a work in progress (part of the data-set remains to be
calibrated), Fig. 2.2-5 by Ben Rabe, AWI Bremerhaven,
illustrates the barely believable progress that has been
made by combining the recent output of autonomous
profiling systems with conventional ship-based CTD-
hydrography (Rabe et al., in press). In fact, Fig. 2.2-5
illustrates three recent advances, all of them important
to the success of IPY. First (it goes almost without
saying), usefulness is linked to the extent and density
of coverage; the pan-Arctic distribution of ‘freshwater
content’ is an output of direct relevance to the
role of the Arctic in climate that could only have been
obtained by merging the full expanded sets of CTD
profiles, from all sources. Second, our ability to merge
these data sets stems from a quite new attitude to
the accessibility and availability of data. Thus the ITP
data are rapidly provided by the WHOI ITP Program
via www.whoi.edu/itp; the POPS data are provided by
EC-DAMOCLES and by JAMSTEC through the international
ARGO programme. Data can be found at www.
ipev.fr/damocles/ and ftp://ftp.ifremer.fr/ifremer/argo/
dac/jma/4900904/. The ship-based CTD data are courtesy
of AWI and were acquired during the RV Polarstern
cruises ARK- XXII/2 (Aug/Sep 2007) and ARK-XXIII/3
(September - October 2008); these data can be found
at www.pangea.de. Having merged the data, the third
comment made in Fig. 2. 2- 5 concerns the general
Fig. 2.2-5. The distribution of liquid
freshwater content in the upper
500m of the Arctic Ocean from ITP
(2006 to 2008), POPS (DAMOCLES
and JAMSTEC/ARGO, 2006 to
2008) and Polarstern cruises
ARK-XXII/2 (2007) and ARK-XXIII/3
(2008). The freshwater content is
expressed in metres. This analysis,
kindly provided by Ben Rabe AWI,
is not yet finalised; the ITPs (no. 6
to 18) have been salinity-corrected
using non-autonomous CTD
observations but the POPS data
have not yet been corrected in
this way. The Polarstern CTD data
have been fully post-processed
and corrected using in situ salinity
bottle samples and pre-/postcalibration
of the sensors.
(Map: Dickson and Fahrbach, 2010)
Table 2.2-3. Expansion
of the WHOI ITP
program between
2004 and 2008, from
www.whoi.edu/itp.
s C I e n C e P r o g r a m 161