The marine troposphere plays important roles in the global geochemical cycles of many elements, in the global radiation budget, and in the global distribution of organic compounds, nutrients, microbes, and pollutants. Our ability to sample this space between the atmosphere and the sea is central to improving our understanding of this dynamic zone. By virtues of its location in the western North Atlantic Ocean, Bermuda has been a key location for numerous field studies on the marine troposphere.
With support through this grant, researchers at the Bermuda institute of Ocean Sciences (BIOS) will continue to maintain and operate a state-of-the-art Tudor Hill facility for three more years (September, 2011 through August, 2014). Operations will include the collection of continuous meteorological data and weekly bulk aerosol samples and rainwater samples. These data and samples will be archived at BIOS and made freely available to the scientific community, as well as the collection of samples and data for a variety of external research projects funded variously by NSF, NOAA, NASA, and other agencies. Modest user fees will be requested for the collection of samples or data in addition to those specified above or for other research use of the facility. Anticipated net revenue from these user fees (ca. $10,000 per year) will be used to defray costs of site maintenance, equipment replacement, and additional technician support.
Broader Impacts: In general terms, the continued operation of the Tudor Hill facility will facilitate and augment research into the physics and chemistry of the lower marine troposphere and ocean-atmosphere exchange processes in the North Atlantic Ocean Basin -- topics that are of central importance to international research initiatives such as GEOTRACES, COLAS, and IGAC. Regionally, this facility will complement other ongoing time-series research in the Sargasso Sea, including the Bermuda Atlantic Time Series (BATS), Hydrostation S, and the Ocean Flux Program (OFP). As in the past, data and samples will be made available to support graduate student research as well as undergraduate educational activities and research.
The BIOS Tudor Hill Marine Atmospheric Observatory (NSF Grant # 1130395) Owing to its remote geographic location in the western North Atlantic, Bermuda has been a key sampling location for numerous studies of the marine atmosphere. Measurements of various chemicals in the atmosphere have been made on Bermuda since the mid-1970s. Longer term measurements of air and rain chemistry began in the early 1980’s under the Western Atlantic Ocean Experiment (WATOX) program, and in 1988 a 70’ walk-up research tower (see Figure 1) was erected at Tudor Hill as part of the Atmosphere/Ocean Chemistry Experiment (AEROCE), an international long-term study of the atmospheric transport of aerosols and gases in the North Atlantic region. Since March 2003, with support from the US National Science Foundation (NSF), the Bermuda Institute for Ocean Sciences (BIOS) has been operating the Tudor Hill observatory as a research site for research activities conducted by BIOS and visiting US and international scientists. From September 2011 to August 2014 it was supported by funding through NF grant # 1130395 from the Divisions of Ocean Sciences (OCE) and Atmospheric Sciences (ATM). This award allowed us to maintain an important resource that is available to researchers and students for studies of the marine atmosphere, in the form of an operational, state-of-the-art atmospheric sampling facility. It is of great value to the disciplines of marine and atmospheric chemistry, and has been used for US university research funded by NSF, many involving the participation of undergraduate and graduate students and post-doctoral scientists. Research was also conducted at the facility by the National Oceanic and Atmospheric Administration (NOAA), the National Aeronautic and Space Administration (NASA), and various international research organizations. This facility is one of only a few marine atmospheric observatories that exist worldwide and it provides the ability to make year-round, complex measurements of the atmosphere over the ocean without the use of a research ship or buoy mooring. The work supported by this grant has resulted in the continued maintenance and operational capability of the Tudor Hill tower and site laboratories, thus providing the only permanent, instrumented atmospheric-sampling platform in the western subtropical North Atlantic. The facility is located on the shoreline at the western end of the island and is equipped to undertake sectored air sampling, whereby air is sampled only when the wind is blowing directly from the ocean in the sector 210-315° (approximately SSW to NW) when wind speeds are greater than 1m/s. This ensures that air is sampled which is representative of the marine boundary layer over the open ocean, and is not affected by local and/or anthropogenic sources. Routine activities at the site include continuous recording of meteorological data (e.g., wind speed and direction, air temperature and humidity) and sampling of bulk aerosol (airborne particulate) and rainwater, providing archived samples available for a range of chemical analyses. The following research projects were undertaken at the facility during the grant period: Princeton and Brown Universities and BIOS: Isotopic and compositional investigation of the sources and interactions of reactive nitrogen in the marine atmosphere at Bermuda; Arizona State University: Source apportionment of iron in the marine atmosphere - application of stable iron isotopic measurements; Florida State University and University of Miami: A novel tracer approach to estimate the atmospheric input of trace elements into the global ocean; Plymouth University, UK: The role of the marine atmosphere in the transport of trace metals; Laboratoire des Sciences du Climat et de l'Environnement, Paris, France: Measurement of the isotopic composition of water vapor in the marine environment. Additionally, there are a number of on-going, long-term routine sampling activities at the facility: Continuous measurements of ozone concentrations in the lower atmosphere for NOAA's Earth Systems Research Laboratory; Sampling for CO2 and other greenhouse gases for NOAA's Earth Systems Research Laboratory (see Figure 2); Continuous data on air column properties, including the aerosol optical depth, for NASA’s AERONET Program; Sampling for the Global Atmosphere Passive Sampler (GAPS) Network, operated by Environment Canada to monitor persistent organic pollutants on a global scale. During project year 3 (1 September 2013 - 31 August 2014), a major clean-up of the site was conducted. A large amount of obsolete or broken equipment and surplus materials had accumulated at the site, some dating from the 1980’s, and had become an eye-sore and litter threat. A dumpster and two truck loads of trash (see Figure 3) were collected and disposed of at the local municipal waste handling facility.
