SIBER SPIS sept 2011.pdf - IMBER
SIBER SPIS sept 2011.pdf - IMBER
SIBER SPIS sept 2011.pdf - IMBER
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<strong>SIBER</strong><br />
Science Plan and Implementation Strategy<br />
Comparative AS and BoB process studies should also include assessments of the benthos,<br />
benthic biogeochemical processes and fluxes, and benthic-pelagic coupling, across margins,<br />
OMZs and seasons.<br />
Existing mooring locations at key biogeochemical locations in the AS should be targeted as<br />
process study focal points. Two such sites are India’s time series station in the AS (17ºN 68ºE)<br />
at the core of the OMZ (see detailed description below) and the long-term Indo-German time<br />
series station (16ºN 60ºE) located within the upwelling zone off Oman. Known as the WAST<br />
site in the literature (Rixen et al., 1996), sediment trap observations dating back to 1986 were<br />
suspended in 1999, but were resumed again in November 2007 (Fig. 24). These sites should<br />
be maintained much like BATS and HOT for long-term measurements. They would also be<br />
appropriate sites for deployment of benthic landers in order to investigate benthic processes.<br />
Furthermore, deployment of sediment traps, benthic landers and time series samplers (e.g.<br />
cameras) below and in shelf/slope areas impacted by low OMZ waters would also be very<br />
valuable. Similar moorings should also be deployed in the central BoB for making physical and<br />
biogeochemical measurements. Both the central AS and BoB regions are currently targeted for<br />
deployment of moored instrumentation by IndOOS/RAMA (Fig. 24) and Indian investigators.<br />
Process studies could leverage on-going time series efforts as well as planned IndOOS/RAMA<br />
mooring array deployment activities. Moorings at these locations can potentially be deployed<br />
with biogeochemical sensors like those discussed above (see also Appendix IV).<br />
The IO Argo float program can also provide a physical context for carrying out comparative<br />
process studies in the AS and the BoB. The density of Argo floats in the IO is now sufficient<br />
to provide broad-scale characterization of physical variability on seasonal to interannual time<br />
scales; indeed the data density in the IO is now sufficient to allow for performing objective<br />
analyses on a weekly basis (cf., Gaillard et al., 2009). Differentiation between the two regions’<br />
stratification conditions can be characterized, as well as their response to climate-related<br />
variability (e.g. IOD and ENSO). Any comparative process study of the AS and the BoB should<br />
start with a focused comparative analysis of the physical characteristics of the two basins.<br />
This analysis could be augmented with the deployment of Argo floats with oxygen and optical<br />
sensors, focusing in particular on deployments in the OMZ in the AS and a comparable location<br />
in the central OMZ waters of the BoB.<br />
A comparative study of the AS and the BoB could be augmented with surface measurements<br />
from ships of opportunity. Potential routes include ferry services between Chennai and Port<br />
Blair, between Kolkatta and Port Blair, and between Lakshwadeep and Kochi. Glider surveys<br />
should also be carried out, focusing on the coastal OMZ in the AS and a comparable location<br />
in the BoB, e.g. off Visakhapatnam or on the IndOOS repeat XBT line in the BoB (Fig. 24).<br />
Deployment of only two gliders, one in each basin, would provide crucial information on<br />
subsurface processes including the OMZ, the deep chlorophyll maximum and subsurface<br />
productivity. For such glider deployments, data handling, storage and distribution issues need<br />
to be worked out to make these data widely available to the oceanographic community in a<br />
timely manner. CPR surveys should also be motivated. As discussed below, efforts are already<br />
underway to establish routine surveys from India to Oman. A comparable transect should also<br />
be considered for the BoB.<br />
The ongoing WAIMOS monitoring program along the coast of western Australia provides<br />
further opportunity for initiating an international <strong>SIBER</strong> process study. WAIMOS efforts focus<br />
on shore-based and remote observations using satellites, CODAR (Coastal Ocean Dynamics<br />
Applications Radar) and glider technologies along with high-resolution coastal modeling (OFAM/<br />
BLUELink), but ship time is limited. Establishing an offshore international time series station<br />
and process study would provide an ideal complement to these coastally-oriented observations,<br />
as well as endpoints for onshore-offshore transects and sustained measurements of the<br />
oceanic end-member properties. The maintenance of an international time series/monitoring<br />
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