Metadata Report for BODC Series Reference Number 1224548

• 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

AMT19 RRS James Cook (JC039) Surface UV Measurements Data Quality Report

The clocks changed on AMT19 from GMT to GMT -1 on 25th October 2009 at 02:00. This effects the raw data but not the processed UVA and UVB calculations.

The data were calibrated by Trios in March 2009.

Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."

Narrative Documents

AMT19 RRS James Cook (JC039) Surface UV Instrumentation

TriOS RAMSES-ACC-UV radiometer

Basic Information

This is a spectral radiometer measuring over the UV band range (280-500 nm) with a cosine-response to measure irradiance. It is fitted with a 256 channel silicon photodiode array with channels giving 2.2 nm/pixel and a spectral accuracy of 02 nm. Typical saturation (4ms integration time) is 20 W m-2 nm-1 sr-1 (at 300 nm), 17 W m-2 nm-1 sr -1 (at 360nm), 18W m-2 nm-1 sr -1 (at 500nm). Typical NEI (8ms integration time) is 0.85 µW m-2 nm-1 sr -1 (at 300nm), 0.75 µW m-2 nm-1 sr -1 (at 360nm), 0.80 µW m-2 nm-1 sr -1 (at 500nm). Acuuracy is quoted as being better than 6-10 per cent depending on spectral range.

Performance Specifications

Optics

Detection

Electrical

Physical

* specifications from Carl ZEISS, Germany

Further information may be found in the TriOS RAMSES brochure.

AMT19 RRS James Cook (JC039) Surface UV Measurements Data Processing Document

Originator's Processing

The UV hyperspectral measurements were taken on the superstructure of the RRS James Cook during AMT-19. The measurements were taken every 5 minutes during daylight hours for the duration of the cruise.

The individual acquisitions with filenaming 224d_yyyy-mm-dd_HH-MM-SS_nnn_nnn.dat (where yyyy is the year, mm the month, dd the day, HH the hour, MM the month, SS the second and nnn an obsolete identifier from the Trios database. Within the file there is a header describing the data (first 43 lines) followed by the hyperspectral data. The nominal wavelength interval is around 2 nm but varies. The first column is the wavelength (nm) and the second UV light intensity (mW/(m^2 nm)). The third and fourth columns are measures of error and sensor status (not used in general).

The data were fully calibrated using a calibration carried out by Trios in March 2009.

Using the idl routine trios_uv_deck.pro the hyperspectral data were split into UVA and UVB components and put into daily files with the naming convention yymmdd_uva_uvb.txt. These text files were subsequently submitted to BODC alongside the raw .dat files.

N.B. The clocks changed on AMT-19 erroneously from GMT to GMT - 1 on 25th October 2009 at 02.00. This effects the raw data files but not the UVA and UVB calculations.

BODC Processing

The data were received and archived to the BODC system. Due to the lack of longitude and latitude in the originator's files the underway latitude and longitude in the BODC bank were concatenated with the UV files. No data existed in the files on the 23/10/2009, 24/10/2009, 25/10/2009 and 29/11/2009. The data were then transferred to the BODC format and loaded to the database.

Parameters

Parameter codes defined in the BODC parameter dictionary were assigned to the variables as shown in the table below:

Screening

The data was screened using the BODC in-house software, Edserplo. The data was screened with no flags applied.

Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 1: The Atlantic Meridional Transect (AMT)

The Atlantic Meridional Transect has been operational since 1995 and through the Oceans 2025 programme secures funding for a further five cruises during the period 2007-2012. The AMT programme began in 1995 utilising the passage of the RRS James Clark Ross between the UK and the Falkland Islands southwards in September and northwards in April each year. Prior to Oceans 2025 the AMT programme has completed 18 cruises following this transect in the Atlantic Ocean. This sustained observing system aims to provide basin-scale understanding of the distribution of planktonic communities, their nutrient turnover and biogenic export in the context of hydrographic and biogeochemical provinces of the North and South Atlantic Oceans.

The Atlantic Meridional Transect Programme is an open ocean in situ observing system that will:

• give early warning of any fundamental change in Atlantic ecosystem functionng
• improve forecasts of the future ocean state and associated socio-economic impacts
• provide a "contextual" logistical and scientific infrastructure for independently-funded national and international open ocean biogeochemical and ecological research.

The specific objectives are:

• To collect hydrographic, chemical, ecological and optical data on transects between the UK and the Falkland Islands
• To quantify the nature and causes of ecological and biogeochemical variability in planktonic ecosystems
• To assess the effects of variability in planktonic ecosystems on biogenic export and on air-sea exchange of radiatively active gases

The measurements taken and experiments carried out on the AMT cruises will be closely linked to Themes 2 and 5. The planned cruise track also allows for the AMT data to be used in providing spatial context to the Sustained Observation Activities at the Porcupine Abyssal Plain Ocean Observatory (SO2) and the Western Channel Observatory (SO10).

More detailed information on this Work Package is available at pages 6 - 9 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/

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: