Dust Logging at Dome C for Abrupt Climate Changes, Large Volcanic Eruptions and Bolide Impacts

Federal Geographic Data Committee (FGDC) Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Reference_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Unknown

Publication_Date: Unknown

Title: Dust Logging at Dome C for Abrupt Climate Changes, Large Volcanic Eruptions and Bolide Impacts

Description:

Abstract:

This award supports a project to make high-resolution logs of dust and ash in the Dome C borehole using an optical dust logger. The dust logger employs a temperature-regulated diode laser at 404 nm wavelength near the absorption minimum for glacial ice, a photon counting detector, onboard computer control and DSL telemetry to the surface. The logger shines light into the ice surrounding a borehole; photons scatter off of bubbles and impurities to be eventually absorbed; a small fraction return to be detected. Annular black nylon brushes sweep ice crystals and debris from the source beam, and intercept stray light to ensure that all detected photons have exited and re-entered the borehole. Depth resolution is determined mainly by the focus of the source and the logger probes into the ice of order one effective scattering length. In bubbly ice the logger signal responds strongly to absorption by thin volcanic ash layers; in clear deep ice the back-scattering signal is a tracer of both ash and continental mineral dust. Logging at 20-50 cm/sec, in a matter of hours, mm-scale depth resolution of dust concentration and volcanic ash layers over the entire 3270 m borehole back to ~800 ka can be obtained The logger probes an area of order m2 of the horizon compared to the ~0.02 m2 core, greatly suppressing depositional noise and making the technique immune to core damage or loss. The method achieves unprecedented resolution of climate variations for matching or comparing ice core records, can detect particulate layers from explosive fallout which are invisible or missing in the core, and often reveals subtle trend changes which can elude standard core analyses. With the highly resolved dust record, it is expected to find new synchronous age markers between East Antarctica, West Antarctica and Greenland. The data could be instrumental in unifying global climate records, or resolving mysteries such as the transition from 41-kyr glacial cycles to apparent 100-kyr cycles. The project will extend previous finding, which make the most convincing case to date for a causal relationship between explosive volcanic events and abrupt climate change on millennial timescales. A search will also be made for evidence that some of the worldwide explosive fallout events that have been identified may have resulted from impacts by comets or asteroids. The investigators will evaluate the reliability of terrestrial impact crater records and the possibility that Earth impacts are considerably more frequent than is generally appreciated. Better understanding of the factors which force abrupt climate changes, the recurrence rate and triggering mechanisms of large volcanic eruptions, and the frequency of Gt to Tt-energy bolide impacts are of vital interest for civilization.

Purpose:

Not Available

Supplemental_Information:

REFERENCE: R. C. Bay, R. A. Rohde, P. B. Price, and N. E. Bramall, "South Pole paleowind from automated synthesis of ice core records," J. Geophys. Res. 115 (2010). Price, P. B.; Rohde, R. A.; Bay, R. C. "Fluxes of microbes, organic aerosols, dust, sea-salt Na ions, non-sea-salt Ca ions, and methanesulfonate onto Greenland and Antarctic ice," Biogeosciences 6 (2009). Rohde, R. A.. "Development and use of the Berkeley Fluorescence Spectrometer to characterize microbial content and detect volcanic ash in glacial ice," Ph.D. thesis, UC Berkeley (2009). Rohde, R. A.; Price, P. B.; Bay, R. C.; Bramall, N. E. "In situ microbial metabolism as a cause of gas anomalies in ice," of the National Academy of Sciences of the USA, 2008.

Status:

Progress: In Work

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Description_of_Geographic_Extent:

Bounding_Coordinates:

West_Bounding_Coordinate: 123.35

East_Bounding_Coordinate: 123.35

North_Bounding_Coordinate: -75.1

South_Bounding_Coordinate: -75.1

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 > CRYOSPHERE > GLACIERS/ICE SHEETS

Theme_Keyword: EARTH SCIENCE > CRYOSPHERE > SNOW/ICE

Theme_Keyword: EARTH SCIENCE > PALEOCLIMATE > ICE CORE RECORDS

Theme_Keyword: EARTH SCIENCE > PALEOCLIMATE > ICE CORE RECORDS > PARTICULATE MATTER

Theme_Keyword: EARTH SCIENCE > PALEOCLIMATE > ICE CORE RECORDS > VOLCANIC DEPOSITS

Theme_Keyword: FIELD INVESTIGATION

Theme_Keyword: FIELD SURVEYS

Theme_Keyword: LABORATORY

Theme_Keyword: OPTICAL DUST LOGGERS > DOWNHOLE OPTICAL DUST AND ASH LOGGERS

Theme_Keyword: Climate

Theme_Keyword: Climate Change

Theme_Keyword: Ice Cores

Theme_Keyword: Borehole

Theme_Keyword: Paleoclimate

Theme_Keyword: Volcanic

Theme_Keyword: Ash Layer

Theme_Keyword: Bolides

Theme_Keyword: Antarctica

Theme_Keyword: CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

Theme_Keyword: ENGLISH

Place:

Place_Keyword_Thesaurus: GCMD

Place_Keyword: GEOGRAPHIC REGION > POLAR

Place_Keyword: CONTINENT > ANTARCTICA

Access_Constraints: Not Available

Use_Constraints:

Not Available

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: RYAN C. BAY

Contact_Position: INVESTIGATOR

Contact_Address:

Address_Type: Mailing and Physical Address

Address: Physics Department

Address: University of California

City: Berkeley

State_or_Province: CA

Postal_Code: 94720

Country: USA

Contact_Voice_Telephone: 510-459-4954

Contact_Facsimile_Telephone: 510-643-7809

Contact_Electronic_Mail_Address: bay@berkeley.edu

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Not Available

Logical_Consistency_Report:

Not Available

Completeness_Report:

Not Available

Lineage:

Process_Step:

Process_Description:

Not Available

Process_Date: Unknown

Spatial_Reference_Information:

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NSIDC_AGDC > NSIDC Antarctic Glaciological Data Center

Contact_Person: NSIDC AGDC USER SERVICES

Contact_Position: DATA CENTER CONTACT

Contact_Address:

Address_Type: Mailing and Physical Address

Address: National Snow and Ice Data Center

Address: CIRES, 449 UCB

Address: University of Colorado

City: Boulder

State_or_Province: CO

Postal_Code: 80309-0449

Country: USA

Contact_Voice_Telephone: +1 (303) 492-6199

Contact_Facsimile_Telephone: +1 (303) 492-2468

Contact_Electronic_Mail_Address: nsidc@nsidc.org

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: NSIDC > National Snow and Ice Data Center

Contact_Person: NSIDC USER SERVICES

Contact_Position: DATA CENTER CONTACT

Contact_Address:

Address_Type: Mailing and Physical Address

Address: National Snow and Ice Data Center

Address: CIRES, 449 UCB

Address: University of Colorado

City: Boulder

State_or_Province: CO

Postal_Code: 80309-0449

Country: USA

Contact_Voice_Telephone: +1 (303) 492-6199

Contact_Facsimile_Telephone: +1 (303) 492-2468

Contact_Electronic_Mail_Address: nsidc@nsidc.org

Resource_Description: bay_0739743

Distribution_Liability:

Not Available

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: Not Available

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

http://nsidc.org/agdc/

Access_Instructions:

DATA CENTER URL

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

http://nsidc.org

Access_Instructions:

DATA CENTER URL

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

http://icecube.berkeley.edu/~bay/edc99/

Access_Instructions:

This webpage makes all of our Dome C optical logging data available for other researchers. The data are fully processed and depths have been corrected to the core using known features. We also include a working list of optical anomalies that suggest the presence of thin opaque fallout layers, typically from volcanic eruptions.

Fees: Not Available

Metadata_Reference_Information:

Metadata_Date: 20120627

Metadata_Review_Date: 20120629

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: GCMD User Support Office

Contact_Organization: NASA Global Change Master Directory

Contact_Address:

Address_Type: Mailing and Physical Address

Address: Not Available

City: Lanham

State_or_Province: MD

Postal_Code: 20706

Country: USA

Contact_Voice_Telephone: Not Available

Contact_Electronic_Mail_Address: gcmduso@gcmd.gsfc.nasa.gov

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time