Metadata Report for BODC Series Reference Number 1012489

• Metadata Summary

• Problem Reports

• Data Access Policy

• Narrative Documents

• Project Information

• Data Activity or Cruise Information

• Fixed Station Information

• BODC Quality Flags

• SeaDataNet Quality Flags

Metadata Summary

Problem Reports

No Problem Report Found in the Database

Data Quality Report

The data originator reported that data collection began in earnest on 23/05/07. Prior to this the Aerosol Mass Spectrometer was being set up and calibrated. Electrical problems, leading to partial data coverage, were reported during the set-up period. Data coverage was interrupted on the return leg of the cruise, from 06/06/07, when the AMS was being used to support bubble tank experiments.

A number of minor interruptions to normal data logging were identified during BODC screening. During these periods each AMS parameter "stuck" at a single value for periods of up to two hours. These data have been flagged as suspect.

Data Access Policy

Public domain data

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

Instrumentation Description

Aerodyne High Resolution Aerosol Mass Spectrometer

The Aerodyne High Resolution Aerosol Mass Spectrometer (AMS, Aerodyne Research Inc, Billerica, MA, USA) measures online aerosol particle composition.

The AMS impacts a focussed particle beam onto a porous, tungsten vapouriser under ultra high vacuum. The non refractory components of the particles are vapourised, then ionised using 70 eV electron impact ionisation. The resultant ions are analysed by a quadrupole mass spectrometer with unit mass to charge (m/z) resolution. Non refractory components are defined, operationally, as those species that evaporate rapidly (< 5 s) under instrument conditions.

Aerosol Properties Sampling

The University of Manchester deployed a suite of instruments to measure aerosol properties on D319. Wet and dry aerosol size spectra were measured by a combination of Differential Mobility Particle Sizers and an Optical Particle Counter. Online aerosol particle composition was determined by Aerodyne Aerosol Mass Spectrometer, and by Multi Angle Aerosol Photometer. Aerosol particle growth factors were measured by a Hygroscopicity Tandem Differential Mobility Analyser. A combination of samplers was used for the offline analysis of aerosol particle composition: a four stage Harvard compact cascade impactor, and an Anderson high-volume sampler.

Atmospheric aerosols were sampled throughout the D319 cruise through a 10 m vertical inlet stack mounted on the forecastle deck. Air was drawn in though a 2.5 µm cutoff cyclone, and distributed to the instruments listed above through a horizontal manifold, using isokinetic sampling ports.

BODC Data Processing

Data were received by BODC in tab separated ASCII format (D319_online_aerosol_comp_v1_1.txt). This file included date and time, the AMS parameters (nitrate, sulphate, ammonium and organic matter), and black carbon equivalent measured by Multi Angle Aerosol Photometer (MAAP). The MAAP black carbon data have been banked by BODC as a separate data set.

No position data were supplied with the online aerosol composition data. Latitude and longitude position were merged into the data file, by BODC, from the screened and processed cruise navigation file, matching on time.

Parameter codes defined in the BODC parameter dictionary were mapped to the variables as follows:

The data were banked according to BODC standard procedures for series data. Nitrate, sulphate and ammonium concentration data were converted to BODC standard units. The unit conversions applied, given in the table above, were derived using published relative atomic mass values (Manahan, 1994). No averaging or other data processing was applied. Once tagged with the appropriate parameter code, the data were loaded into BODC Series Database.

References

Manahan S.E. (Ed.), 1994. Environmental Chemistry, 6th Edition. ISBN: 1-566670-088-4.

Originator's Data Processing

Online aerosol composition was measured using an Aerodyne High Resolution Aerosol Mass Spectrometer (hereafter AMS). Standard methods were used for sampling, calibration and data analysis (Allan et al., 2004). The ionisation efficiency calibration was performed using a 350 nm ammonium nitrate particle standard. The collection efficiency was assumed to be 0.5, validated against offline sulphate measurements from the colocated compact cascade impactor.

Instrument output was decomposed arithmetically (Allan et al., 2004) into mass spectra for sulphate, nitrate, ammonium and organic matter.

Further details of sampling strategy and methodology for this, and other D319 data sets, are available from the D319 cruise report, and from Allan et al. (2009).

References

Allan J.D., Delia A.E., Coe H., Bower K.N., Alfarra M.R., Jimenez J.L., Middlebrook A.M., Drewnick F., Onasch T.B., Canagaratna M.R., Jayne J.T., Worsnop D.R., 2004. A generalised method for the extraction of chemically resolved mass spectra from Aerodyne aerosol mass spectrometer data, Aerosol Science, 35, 909-922.

Allan J.D., Topping D.O., Good N., Irwin M., Flynn M., Williams P.I., Coe H., Baker A.R., Martino M., Niedermeier N., Wiedensohler A., Lehmann S., Muller K., Herrmann H., McFiggans G., 2009. Composition and properties of atmospheric particles in the eastern Atlantic and impacts on gas phase uptake rates, Atmospheric Chemistry and Physics, 9, 9299-9314.

Project Information

Surface Ocean Lower Atmosphere Study

The Surface Ocean-Lower Atmosphere Study (SOLAS) is an international research initiative comprising over 1500 scientists in 23 countries. Its central goal is to understand the biogeochemical-physical interactions between the ocean and atmosphere, and how their coupling affects, and is affected by climate change.

UK SOLAS, Reactive Halogens in the Marine Boundary Layer (RHaMBLe)

This project was run by the University of Manchester, aiming to quantify the impacts of marine halogens on atmospheric composition. Emphasis was placed on the roles of halogens in oxidative processes, and on aerosol formation and transformations. Observations were made of a range of reactive halogen species in the marine atmosphere.

Fieldwork included open ocean and coastal campaigns:

• Intensive field campaign at the Cape Verde observatory
• Simultaneous ship transect through the Mauretanian Upwelling region (D319)
• Coastal field project to diagnose links between particle formation and reactive halogen species

These observations provide a comprehensive characterisation of halogen compounds in the marine atmosphere. New understanding of halogen chemistry enables development of parameterisations for model tuning. RHaMBLe has extensive links with UK SOLAS funded projects, and with other UK and internationally funded projects.

More detailed information on this project may be found in the official cruise report for the RHaMBLe cruise, D319.

Weblink: http://www.nerc.ac.uk/research/programmes/solas/

UK SOLAS, Aerosol Characterisation and Modelling in the Marine Environment (ACMME)

This project was run by the University of Manchester, with the following principal aims:

• To characterise the chemical and hygroscopic properties of marine aerosol as a function of size
• To quantify the cloud-forming potential of the aerosol
• To predict the effect of marine aerosol on cloud droplet number
• To study meridional variation in aerosol properties

ACMME made use of the fieldwork activities of other UK SOLAS projects. Sampling was carried out on the RHaMBLe cruise, D319, and at the Cape Verde observatory. Key measurements included aerosol size spectra, chemical composition, and hygroscopicity. The data will be used in conjunction with the models developed by the NERC-funded Aerosol Properties, Processes And InfluenceS on the Earth's climate (APPRAISE) programme. The model study will examine the relationships between aerosol characteristics and cloud formation.

More detailed information on this project may be found in the official cruise report for D319.

Weblinks

http://www.nerc.ac.uk/research/programmes/solas/

http://ncasweb.leeds.ac.uk/appraise/

UK Surface Ocean Lower Atmosphere Study

The UK Surface Ocean Lower Atmosphere Study (UK SOLAS) is the UK's contribution to the international SOLAS programme.

UK SOLAS formed interdisciplinary teams to address three primary aims

• To determine the mechanisms controlling rates of chemical transfer and improve estimates of chemical exchanges
• To evaluate the impact of these exchanges on the biogeochemistry of the surface ocean and lower atmosphere and on feedbacks between the ocean and atmosphere
• To quantify the impacts of these boundary layer processes on the global climate system

UK SOLAS started in 2003, to run for seven years. The programme was funded by the Natural Environment Research Council.

Funded projects

In total, 19 projects have been funded by UK SOLAS, over four funding rounds.

UK SOLAS has also supported ten tied studentships, and two CASE studentships.

Fieldwork

UK SOLAS fieldwork has included eight dedicated research cruises in the North Atlantic Ocean. Continuous measurements were made aboard aboard the Norwegian weather ship, Polarfront, until her decommission in 2009. Time series have been established at the SOLAS Cape Verde Observatory, and at the Plymouth Marine Laboratory L4 station. Experiments have taken place at the Bergen mesocosm facility.

A series of collaborative aircraft campaigns have added complementary atmospheric data. These campaigns were funded by UK SOLAS, African Monsoon Multidisciplinary Analyses (AMMA-UK), Dust and Biomass Experiment (DABEX) and the Facility for Airborne Atmospheric Measurements (FAAM).

Weblink: http://www.nerc.ac.uk/research/programmes/solas/

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

No Fixed Station Information held for the Series

BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: