Project Funding: 2011 - 2014

NRA: 2010 NASA: Carbon Cycle Science   

Funded by NASA

Abstract:
In areas where deep water formation occurs, such as the Nordic Seas, a relatively rapid transmission of atmospheric gases to the deep ocean is expected. In the North Atlantic, one of the important regions of deep water formation is the Greenland Sea. Together with the Iceland and Norwegian Seas, the Arctic Ocean, and the Barents Sea, it makes up a region known as the northern limb of the Atlantic thermohaline circulation, which is estimated to give rise to a significant preindustrial inter-hemispheric transport of inorganic carbon directed from the northern to the southern hemisphere. Therefore, it is important to study the carbon dynamics in the Nordic Seas as they are an integral part of the global carbon cycle. Observational studies report significant variations of the ocean CO2 sink in the North Atlantic, and suggest a reduction of the atmospheric CO2 uptake during the last two decades, especially in the Subpolar and Nordic Seas. Modeling studies reveal that surface ocean water mass properties and CO2 system variables exhibit substantial multiannual variability on sub-basin scales in response to wind-driven reorganization in ocean circulation and surface warming/cooling. The temporal evolution of the CO2 system is influenced by anthropogenic trends and natural variability of the vertical inventory of carbon stocks. The phase of the North Atlantic Oscillation (NAO) plays a significant role in modulating the North Atlantic Current transport of subtropical waters into the eastern basin and thus impacting on surface ocean CO2 uptake. The intense spring-summer phytoplankton blooms that characterize the Nordic Seas not only support the commercially valuable fishing grounds through the foodweb via grazing by zooplankton, but also play a major role in the uptake of atmospheric CO2. Major changes in environmental conditions can significantly alter the physical-biogeochemical interactions in the region and consequently produce an impact on the carbon variability. We propose to use a combination of remote sensing data analysis, numerical model experiments, and in situ data to assess the impact of carbon variability in the Nordic Seas. We are already working with our European collaborators on a similar NASA-funded study with its major focus in waters south of Iceland. These collaborators have been providing, and will continue providing, invaluable carbon-related data sets and regional expertise for the proposed study. We propose to extend the scope of our work to other areas, such as the European Sub-Arctic, waters in the vicinity of Svalbard, and the Barents Sea. A 3D ice-ocean model, which covers the Arctic Ocean and the sub-polar North Atlantic, will be used to drive a 1D ecosystem/carbon model which will be applied to key biogeochemical provinces within the study regions. SeaWiFS and MODIS data analysis will include Chl-a, POC, PIC, CDOM (a proxy for DOC inputs from Arctic rivers), phytoplankton carbon (from backscatter), and derived products such as net primary production (NPP) and PIC production. While SeaWiFS and MODIS are primary sources of data, the Indian OCM-2 and VIIRS are also potential sources of data within the time frame of the investigation. The analysis will be linked to algorithm development/improvement (NPP, pCO2) and validation of model simulations. Recent studies have shown that satellite altimetry helps explain patchy changes in hydrographic carbon measurements. We will include satellite altimetry analysis in our study to address this issue. The proposed work addresses three of the five research themes solicited by NASA (items 2, 4, and 5, section 3 of A.5): (2) ocean acidification; (4) adaptation, mitigation, and vulnerability within the Earth system; and, (5) synthetic and integrative research to advance the carbon-related goals of ongoing research activities under the U.S. Carbon Cycle Science Program and the carbon-related goals and objectives of related national and international programs.

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Trends in the subpolar north atlantic carbon sink and ocean acidification: 1981-2008   --   (Sergio Signorini, Sirpa Häkkinen, Are Olsen, Nicolas Metzl, Kristinn Gudmundsson, Abdiraham Omar, Jón Olafsson, Gilles Reverdin, Stephanie Henson, Charles McClain)   [abstract]

More details may be found in the following project profile(s):

• NASA Ocean Biology & Biogeochemistry (OBB) Project Profile