ESTOC Service Activities

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SA Number: 17.1

Name of the SA: ESTOC– CENTRAL EAST ATLANTIC OCEAN ACIDIFICATION AND PRODUCTIVITY ASSESSMENT SERVICE

Institute: PLOCAN

Description:

Real-time / near real-time meteorological and oceanic observations at ESTOC observatory.

Buoy and mooring:

As stated in the first 30 months, the ESTOC observatory started to offer real-time / near real-time meteorological observations of atmospheric pressure, relative humidity, air temperature, wind speed and direction, as well as observations of surface oceanographic variables such as temperature, salinity, dissolved oxygen, chlorophyll a, pH, pCO2 and turbidity since 2nd June 2014. Subsurface monitoring in delayed mode includes physical (temperature, salinity) and biogeochemical (dissolved oxygen, current, Chlorophyll a, turbidity and nutrients) observations either at 100m or 150m. In situ data with CTD/rosette were also taken prior and post deployment. Since the FixO3 project started four cruises took place in the observatory area for deploying/recovering of the buoy and mooring. The ESTOC observatory will be serviced again this year 2016 in February and October. A temporal gap in the observations happened on 22th December 2014 when the mooring line broke and the subsurface equipment was lost, although the conductivity and temperature sensor located on the buoy was still taking data. The buoy was found the 23rd February 2015 by the Spanish Maritime Safety Agency in the northern coast of Gran Canaria Island, and recovered the 3rd March 2015 by a tug-boat; however, the frame with the sensors used at 100m depth was lost.

Upon checking the recovered parts, we hypothesise a potential break in the mooring line due to the wear of the shackle located immediately above the frame.

On May 19th 2015, a new buoy and mooring was deployed, adding to the aforementioned set-up an ADCP at 100m of depth and a nitrate sensor at 150m. A double system to measure meteorological and some surface oceanographic variables was also included to get a better quality of data. The system worked alright and was recovered on September 25th 2015. All the sensors were on board saved, however some mechanical problems which could affect the buoy security, prevented to deploy again at the observatory. Because of that, it was decided to return to land and repair it. Finally, the buoy/mooring deployment at the observatory took place on October 28th 2015, and it is currently working adequately and providing data in real-time mode. All data mentioned above as well as those obtained from the subsurface sensors once recovered is being quality controlled and distributed through the THREDDS (http://data.plocan.eu/thredds/catalog/aggregate/public/ ESTOCInSitu/catalog.html).

A malfunction occurred in the nitrate sensor (NAS) deployed at 150m as a consequence of a leakage which affected the colorimeter. The result was only five days of data. The sensor was replaced for another and deployed at the current mooring.

Gliders:

Supplementary to the buoy monitoring, five glider missions for measurements in the vicinity of the station have been carried out since the beginning of the project. Related data sets are available through THREDDS and graphs which show the variability of the parameters (temperature, salinity, dissolved oxygen, chlorophyll and turbidity) during the mission, are available at http://data.plocan.eu/thredds/catalog/aggregate/public/ESTOCInSitu /FixO3/GliderCampaigns/catalog.html.

At the beginning of the third mission carried out in August 2014, the glider showed an internal malfunction and the work had to be aborted. Because of the need to send the glider to the manufacturer for repairs, the missions had to stop for one year approximately.

Outputs:

Figure 1. THREEDS from PLOCAN web site with delayed mode files and real-time files.

Figure 1. THREDDS from PLOCAN web site with delayed mode files and real-time files.

 

Figure 2. THREEDS from PLOCAN web site with delayed mode files for Glider missions.

Figure 2. THREDDS from PLOCAN web site with delayed mode files for Glider missions.

On the other hand, temporal representations for all data (Real-time observations) are being updated to the web http://siboy.plocan.eu/ESTOC (Figure 3). In this web page it is always shown the last record of data received from the ESTOC observatory, obtained via the meteorological and oceanographic sensors fixed in the surface buoy; several figures which present the time variability (15 days and the whole deployment period) of the observed parameters are also made available. A table is also given to show how the current record and the last 15 days estimated averages of some core parameters compare to the average obtained from the historical records using the same resolution (Figure 2).

Figure 3. Real- time data visualization, comparative tables and figures showing how the real-  time data compares to the historical records.

Figure 3. Real- time data visualization, comparative tables and figures showing how the real-time data compares to the historical records.

Links:

Additionally, the link http://siboy.plocan.eu/plots/ESTOC/ includes figures which show the historical variability of some parameters measured at ESTOC. This is the list of the figures: