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

Federal Geographic Data Committee (FGDC) Metadata:


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
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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
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Spatial_Reference_Information:
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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
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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
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