The Ocean Sciences Division of the National Science Foundation (NSF) issued a “Dear Colleague letter” on 18 February to encourage wider use of the OOI data by supporting workshops, conferences or other training events to introduce researchers and educators to available data and community tools.

NSF is encouraging researchers or educators to propose workshops, conferences or other training events to 1) teach other researchers or educators how to use available tools and data; 2) develop additional community tools or instructional material to use the OOI data; or 3) create communities of practice that use the data for multi-investigator, community-driven research purposes. The goal of such activities is to promote development and dissemination of the OOI data tools and research opportunities.

Two- and four-year U.S. institutions of higher education and U.S. non-profit non-academic organizations are eligible to submit relevant proposals.

NSF intends to support about 15-20 awards in FY2020. Proposals may be submitted at any time, but at least six months prior to the planned event. To be considered for FY2020 funding, proposals should be submitted before May 15th. Submission details are available here.

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[media-caption type="image" path="" link="#"]Fig. 1. Irminger-5 surface buoy after deployment in June 2018. Damage to the direct covariance flux sensor (center of tower) is evident.[/media-caption]

The recently completed OOI mooring service cruise on the R/V Neil Armstrong (2-25 Aug 2019) established a significant milestone – the Irminger Sea Global Surface Mooring was sustained for over a year and returned high quality data. To our knowledge, this is the first surface mooring with instrumentation to compute bulk air-sea fluxes of heat, moisture and momentum that has operated through a full annual cycle in this region.

It is now recognized (e.g. de Jong and de Steur, 2016, Geophys. Res. Lett., 43, 7106–7113, DOI: 10.1002/2016GL069596) that extreme heat loss in the Irminger Sea results in deep water formation, which ultimately influences the strength of the Atlantic Meriodonal Overturning Circulation and has important climate implications. The strong heat loss in the region is largely driven by episodic cold-air outbreaks from the southern tip of Greenland (Josey et al., 2019, Geophys. Res. Lett., 46. DOI: 10.1029/2018GL080956).

[media-caption type="image" path="" link="#"]Fig. 2. Satellite scatterometer winds (QuikSCAT) during a cold-air outbreak (right; from Vage et al., 2008))[/media-caption]

Cold-air outbreaks are associated with high winds, sub-freezing temperatures, and large, steep waves (Vage et al., 2008, J. Phys. Oceanogr., 38(3), DOI: 10.1175/2007JPO3678.1), which create very difficult conditions for sustained observations at the air-sea interface.  The situation is further complicated by the occasional passage of icebergs, which could impact the buoy. The lack of continuous time series data through the winter season capable of identifying episodic events has hindered understanding of air-sea interaction in the Irminger Sea.

The biggest risks to sustained operation of the OOI Irminger Sea mooring were determined to be icing on the buoy tower & freezing of sensitive instrument components.  Icing could not be controlled, but potential impacts could be mitigated, for example by shutting down the wind turbines to reduce the likelihood of broken blades. However, a turbine shut-down also meant reduced power generation.  Freezing of the precipitation sensor was controllable using a built-in heater, but at the cost of additional power.

[media-caption type="image" path="" link="#"]Fig. 3a. Buoy cam pictures showing tower icing.[/media-caption]

The CGSN operations team took on the challenge by monitoring weather forecasts for conditions conducive to icing, adding cameras to the buoy tower to detect icing, and implementing a power management strategy during storms. When icing conditions were forecast, the wind turbines were shut down to reduce the likelihood of damage, while some mooring components were simultaneously shut down to save power. Power to high priority instruments (including the bulk meteorology system) and the precipitation sensor heaters was maintained. The strategy was effective, but the difficulty of sustained observations was still evident: The direct-covariance flux package was damaged upon deployment and did not return useful data. The buoy sustained damage to the wind vane, a solar panel and a wind turbine during the winter storms. This compromised power generation capability eventually led to an eight-day data gap in June 2019 due to sustained low wind and overcast skies.

[media-caption type="image" path="" link="#"]Fig. 4. Time series of METBK meteorological parameters spanning the full deployment period. Left panel: Air (red) and sea surface (blue) temperature, relative humidity and barometric pressure. Right panel: East (red) and north (blue) wind, shortwave (red) and longwave radiation, and precipitation.[/media-caption] [media type="image" path="" link="#"][/media]

Despite the challenges, the buoy bulk meteorology system operated for 420 days of the 428-day deployment (8 June 2018 – 9 Aug 2019) and returned a wealth of scientific data. One-minute records from the bulk meteorology sensors show wind speeds up to 25 m/s and air temperatures as low as -5 C associated with cold -air outbreaks that likely dominate the cumulative wintertime heat loss, as described by Josey et al. (2019).  The availability of the first annual cycle of surface meteorology, in conjunction with subsurface data from the OOI Irminger Sea array and the Overturning in the Subpolar North Atlantic Program (OSNAP) array, provide the potential for new insights into the nature of deep mixing, carbon sequestration and deep-water formation in the region.

[media-caption type="image" path="" link="#"]Fig. 5. Photo of the Irminger-5 buoy about to be recovered from the R/V/ Armstrong in August 2019. A close look shows damage to the wind turbine and solar panel on the left side.[/media-caption] Read More
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Data from the Ocean Observatories Initiative (OOI) Global Irminger Sea Array contributed to the longest continuous record of total volume transport of water in the Deep Western Boundary Current. This current, in the subpolar North Atlantic, travels southwest along the continental slope off of Greenland and is considered a significant part of the global climate system.

In a recent Journal of Geophysical Research Letters: Oceans paper, Dr. Joanne Hopkins at the National Oceanography Center in Southampton, U.K., and collaborators used data from two U.S. OOI flanking moorings, along with three U.S. Overturning in the Subpolar North Atlantic Program (OSNAP) East Greenland Current array moorings, and five U.K. OSNAP moorings to study the total amount of water moved by the current over a period of two years, as well as its daily and seasonal variability.

The data used for this paper was gathered over 22 months between 2014 and 2016, while all 10 of the moorings were in the water for the same period. Previous research to determine transport estimates at this latitude have been limited by a sparse number of direct and sustained measurements, relying instead on measurements over 9.5 months, 60 days, and “snapshot” or repeated summertime hydrographic sections.

Hopkins et al estimate that the Deep Western Boundary Current transports an average of 10.8 × 106 m3 of water per second with variation in time. In addition, the transport variability shifts from high to low frequencies with distance down slope. While the results did suggest an increase in transport since 2005-2006, they did not conclude that there was a significant long-term trend, given the limitations of previous data sets.

The location of the OOI Global Irminger Sea array was selected as part of an effort by the scientific community to place moorings in areas that have been historically under-sampled and subject to high winds and sea states that make frequent ship-based measurements difficult. The OOI Data Portal provides access to data from the Irminger Sea Array dating back to the initial installation in September 2014.

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NOTE: Video of this event available here. Fast forward to about 52:00 to get past the distorted audio.

The National Science Foundation will host “Science in the Deep,” a Facebook Live event with researchers aboard R/V Atlantis on Wednesday, June 26, from 1:00-2:00 p.m. Eastern. The Atlantis team will be off the coast of Oregon servicing parts of the Ocean Observatories Initiative Regional Cabled Array using the remotely operated vehicle (ROV) Jason, which is expected to be 800 meters deep at Southern Hydrate Ridge, where methane bubbles from the seafloor and life flourishes.

Join NSF host Deena Headley as she speaks with OOI Research Scientist Michael Vardaro and Research Scientist/Eng2 Katie Bigham, both from the University of Washington, about their work on the recent cruises off the U.S. Northwest Coast, live views from Jason on the seafloor, and life at sea.

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