UV climate over the Southern Ocean south of Australia, and its biological impact - 1994 data

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Identification_Information:

Citation:

Citation_Information:

Originator: Unknown

Publication_Date: Unknown

Title: UV climate over the Southern Ocean south of Australia, and its biological impact - 1994 data

Description:

Abstract:

Ozone depletion over Antarctica increases UVB irradiances reaching the Earth's surface in the region. Marine microbes, that support the Antarctic food web and play an integral part in carbon cycling, are damaged by UVB. This research determines Antarctic UV climate, biological responses to UV from the molecular to community level, and combines these elements to predict UV-induced changes in Antarctic marine microbiology. A season of field work was undertaken over November and December 1994 based from Davis Station with the intention of making field measurements of ultraviolet radiation in the fast ice environment, as well as some of the lakes in the Vestfold Hills. Instrumentation The instrument for the measurements was a Macam spectral radiometer, owned by Geography and Environmental Studies, University of Tasmania. Field personnel were Dr Kelvin Michael (IASOS) and Mr Michael Wall (Honours student, Geography and Environmental Studies, UTas). The radiometer was equipped with a 25-metre quartz light pipe, with a cosine sensor attachment at the end. To make a measurement of ultraviolet irradiance, the sensor would be oriented so that its sensing surface was horizontal, and it would collect light which was then transmitted along the light pipe to the radiometer - a suitcase-sized unit which ran on battery power in the field. The radiometer was encased in a wooden box lined with polystyrene foam to provide protection from the elements and heat insulation. The radiometer was controlled via a laptop PC and the data were stored on the hard disk of the PC. Measurements Measurements of the attenuation of ultraviolet and visible radiation as a function of wavelength in water were made at the ice edge and lake measurement sites. At the ice edge, the light pipe was spooled over a wheel and lowered to preset depths (typically 1,2,4,8,16 and 32 m below the water surface). On a lake, a 25-cm augur hole was drilled, and the light pipe was lowered by hand to various depths, the exact depths chosen depended on the depth of the lake. Where the lake ice conditions permitted, a frame was lowered through the hole and used to lever the light pipe against the underside of the ice and a measurement of the ultraviolet and visible transmission of the sea ice was collected. In all cases, measurements of the ultraviolet and visible surface irradiance were collected before and/or after the sub-surface measurements. When the sky conditions were sufficiently clear, the direct and diffuse components of the ultraviolet and visible irradiance values were estimated, via the use of a shading apparatus. This would ensure that the radiometer would measure the diffuse component of the radiation field, allowing the direct component to be estimated by subtraction of the diffuse from the global (unshaded) measurement. On some occasions, the upwelling irradiance from the snow or ice surface was also measured, providing information on the spectral albedo of the surface. At each measurement, spectral irradiance values were generally collected for two spectral ranges: UV-B (280 - 400 nm, in 1-nm steps) and visible (400 - 700 nm, in 5-nm steps). In some cases, the wavelength boundaries were different - eg 280 - 350 nm for the UV-B, or 550 - 680 nm in the visible (corresponding to channel 1 of the NOAA AVHRR sensor). The data were stored by the PC as raw data files. The names of these files are automatically defined from the time on the logging PC as 'hhmmss.dti'. Note that the PC was operating on Australian Eastern Summer Time, 4 hours ahead of DLT. These data files were later read into Excel spreadsheets for manipulation. See the linked report for further information. The measurements are all in units of watts per metre squared per nanometre (Wm^-2 nm_-1) The heading UV-B refers to the fact that the data are collected in the ultraviolet part of the spectrum (280 - 400 nm) The heading AVHRR refers to the fact that the data are collected in the visible part of the spectrum (400 - 700 nm) The fields in this dataset are: UV Radiation Wavelength Depth AVHRR

Purpose:

Not Available

Supplemental_Information:

REFERENCE: Nunez M., Michael K., Turner D., Wall M., Nilsson C. 1997 A satellite-based climatology of UV-B irradiance for Antarctic coastal regions. International Journal of Climatology 17 1029-1054

Supplemental_Information:

REFERENCE: Davidson A.T. 1998 The impact of UVB radiation on marine plankton. Mutation Research 422 119-129

Supplemental_Information:

REFERENCE: Davidson A.T., van der Heijden A. 2000 Exposure of natural Antarctic microbial communities to ambient UV radiation: effects on bacterioplankton Aquatic Microbial Aquatic Microbial Ecology 21 257-264

Supplemental_Information:

REFERENCE: Davidson A., Belbin L. 2002 Exposure of natural Antarctic marine microbial assemblages to ambient UV radiation effects on the marine microbial community Aquatic Microbial Ecology 27 159-174

Supplemental_Information:

REFERENCE: Thomson P.G, Nichols P., Wright S., Skerratt J., McMInn A. 2004 Molecular taxonomy, pigment and lipid composition and Antarctic distribution of the brine dinoflagellate, (Polarella glacialis Journal of Phycology. 40 867-873

Supplemental_Information:

REFERENCE: Davidson A.T 2006 Effects of ultraviolet radiation on microalgal growth, survival and production. In: Rao S.D.V. Algal Cultures Analogues of Blooms and Applications 2 715-767

Supplemental_Information:

REFERENCE: Nunez M., Davidson A.T., Michael K. 2006 Modelled effects of ambient UV radiation on a natural Antarctic marine microbial community Aquatic Microbial Ecology 42 75-90

Supplemental_Information:

REFERENCE: Buma A.G.J., Wright S.W., van den Enden R., van de Poll W.H., Davidson A.T. 2006 PAR acclimation and UVBR-induced DNA damage in Antarctic marine microalgae. Marine Ecology Progress Series 315 33-42

Supplemental_Information:

REFERENCE: Marchant H.J., Davidson A.T., Kelly G.J. 1991 UV-B protecting compounds in the marine alga Phaeocystis pouchetii from Antarctica. Marine Biology 109 391-395

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 19941101

Ending_Date: 19941231

Currentness_Reference:Unknown

Status:

Progress: Complete

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Description_of_Geographic_Extent:

Bounding_Coordinates:

West_Bounding_Coordinate: 77.0

East_Bounding_Coordinate: 79.0

North_Bounding_Coordinate: -66.0

South_Bounding_Coordinate: -68.0

Keywords:

Theme:

Theme_Keyword_Thesaurus: GCMD SCIENCE PARAMETERS

Theme_Keyword_Thesaurus: GCMD PLATFORM

Theme_Keyword_Thesaurus: GCMD INSTRUMENT

Theme_Keyword_Thesaurus: ANCILLARY KEYWORDS

Theme_Keyword_Thesaurus: ISO TOPIC CATEGORY

Theme_Keyword_Thesaurus: DATA SET LANGUAGE

Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > ULTRAVIOLET RADIATION

Theme_Keyword: EARTH SCIENCE > SPECTRAL/ENGINEERING > ULTRAVIOLET WAVELENGTHS > ULTRAVIOLET RADIANCE

Theme_Keyword: EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > PROTISTS

Theme_Keyword: EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > BACTERIA/ARCHAEA

Theme_Keyword: EARTH SCIENCE > BIOSPHERE > AQUATIC ECOSYSTEMS > PLANKTON

Theme_Keyword: FIELD SURVEYS

Theme_Keyword: GROUND-BASED OBSERVATIONS

Theme_Keyword: FIELD INVESTIGATION

Theme_Keyword: RADIOMETERS

Theme_Keyword: Uv

Theme_Keyword: Macam Spectral Radiometer

Theme_Keyword: Wavelength

Theme_Keyword: CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

Theme_Keyword: OCEANS

Theme_Keyword: ENGLISH

Place:

Place_Keyword_Thesaurus: GCMD

Place_Keyword: OCEAN > SOUTHERN OCEAN

Place_Keyword: CONTINENT > ANTARCTICA > VESTFOLD HILLS

Place_Keyword: GEOGRAPHIC REGION > POLAR

Access_Constraints: These data are publicly available for download from the URL given below.

Use_Constraints:

This data set conforms to the PICCCBY Attribution License (http://creativecommons.org/licenses/by/3.0/). Please follow instructions listed in the citation reference provided at the URL below when using these data.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: KELVIN MICHAEL

Contact_Position: INVESTIGATOR

Contact_Position: TECHNICAL CONTACT

Contact_Address:

Address_Type: Mailing and Physical Address

Address: Antarctic CRC

Address: GPO Box 252-80

City: Sandy Bay

State_or_Province: Tasmania

Postal_Code: 7005

Country: Australia

Contact_Voice_Telephone: +61 3 6226 2977

Contact_Facsimile_Telephone: +61 3 6226 2973

Contact_Electronic_Mail_Address: Kelvin.Michael@utas.edu.au

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Issues The University of Tasmania purchased the Macam radiometer in 1992 as a field instrument. It was marketed as a field-adapted version of an instrument that was originally designed for laboratory use. During this campaign (and subsequent deployments) a number of problems and shortcomings emerged with respect to the desired use of the Macam. a) Operation in cold conditions The specifications of the Macam suggested that it would not function reliably when used in an ice/snow environment without protection. A wooden box lined with polystyrene foam was manufactured to transport, protect and insulate the Macam. In addition, a heating unit was installed inside the Macam (via the bottom of its standard case) driven by a battery that could be recharged. These adaptations were on the whole very successful. b) Sensitivity to motion The Macam operated as a double grating spectral radiometer, so that light collected by the sensor and transferred along the light pipe was directed on to a diffraction grating. The angle of the grating was adjusted to direct the appropriate section of the UV/visible spectrum onto a second grating. This grating was also steered to direct a (finer) portion of the spectrum onto detectors. The problem that emerged with time was that, while the mounts and drive mechanisms for the gratings were designed to work reliably in a comfortable, stable laboratory environment, they were less able to cope with disturbances as a result of transport by ship, Hagglund and helicopter. The result was a lack of confidence in the wavelength stability of the instrument. c) Fragility of light pipe The field measurements used a quartz fibre light pipe, twenty-five metres in length, which transmitted light in the ultraviolet regions as well as visible / near-infrared (operating specifications of Macam: 240 - 820 nm). The light pipe could not be bent in a radius less than 20 cm. In order to protect the light pipe from bending and from other damage, a rubber hose was placed surrounding the light pipe along its whole length - this necessitated splitting the hose and then taping it back around the light pipe. The rigidity of the hose made it very difficult to bend the light pipe in too tight a curve. However, it became clear even in this first field deployment that the light pipe was deteriorating even when used with great care. The light pipe was composed of many small fibres of quartz glass, and small breaks in the fibres would have the effect of slightly reducing the transmission of the light pipe. The high cost of the quartz light pipe also precluded replacing the light pipe or having spares on hand (cost at time of purchase was ~ A$1000 per metre). d) Difficulty of calibration The measurements from the Macam were only useful when the instrument was well calibrated. The calibration process consisted of viewing a pair of standard lamps (one UV, one visible) and setting the gains at each wavelength. The gain values were stored on disk in a file called 25M.CAL for operation of the Macam with the 25-m light pipe. A set of calibrations was accurate only as long as nothing changed with the characteristics of the whole radiometer system. Therefore small changes in the transmissivity of the light pipe would introduce systematic underestimations of the spectral irradiance data. In the long term, the Macam radiometer became useless as a precision instrument in the UV-B because of highly reduced sensitivity in those wavelengths because of accumulated damage to the light pipe. Where a spreadsheet contains little or no data, it is a reflection of problems with data collection or subsequent data quality.

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Spatial_Reference_Information:

Distribution_Information:

Distributor:

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Contact_Organization_Primary:

Contact_Organization: AU/AADC > Australian Antarctic Data Centre, Australia

Contact_Person: DATA OFFICER AADC

Contact_Position: DATA CENTER CONTACT

Contact_Address:

Address_Type: Mailing and Physical Address

Address: Australian Antarctic Division

Address: 203 Channel Highway

City: Kingston

State_or_Province: Tasmania

Postal_Code: 7050

Country: Australia

Contact_Voice_Telephone: +61 3 6232 3244

Contact_Facsimile_Telephone: +61 3 6232 3351

Contact_Electronic_Mail_Address: metadata@aad.gov.au

Resource_Description: ASAC_2210_94

Distribution_Liability:

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Format_Name: excel, word

Transfer_Size: 936 kb

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http://data.aad.gov.au

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DATA CENTER URL

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http://data.aad.gov.au/aadc/portal/download_file.c...

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Download point for the data - excel spreadsheets and word documents

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https://secure3.aad.gov.au/proms/public/projects/r...

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Public information for ASAC project 2210

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http://data.aad.gov.au/aadc/metadata/citation.cfm?...

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Fees: Free

Metadata_Reference_Information:

Metadata_Date: 20070911

Metadata_Review_Date: 20110511

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: DAVE CONNELL

Contact_Position: DIF AUTHOR

Contact_Address:

Address_Type: Mailing and Physical Address

Address: Australian Antarctic Division

Address: 203 Channel Highway

City: Kingston

State_or_Province: Tasmania

Postal_Code: 7050

Country: Australia

Contact_Voice_Telephone: +61 3 6232 3244

Contact_Facsimile_Telephone: +61 3 6232 3351

Contact_Electronic_Mail_Address: dave.connell@aad.gov.au

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time