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National Science Foundation Award #0538683

Solar Activity during the Last Millennium, Estimated from Cosmogenic in-situ 14C in South Pole and GISP2 Ice Cores

Investigator(s):

Devendra Lal (PI)

Sponsor:

University of California-San Diego Scripps Inst of Oceanography, CA 92093 8585341293

Start Date/Expiration Date

2006-02-15 to 2008-01-31 (amended 2006-02-04)

Awarded Amount to Date:

$225,000

Abstract: 0538683 Lal This award supports a project to continue development of a new method for estimating solar activity in the past. It is based on measurements of the concentrations of in-situ produced C-14 in polar ice by cosmic rays, which depend only on (i) the cosmic ray flux, and (ii) ice accumulation rate. This is the only direct method available to date polar ice, since it does not involve any uncertain climatic transfer functions as are encountered in the applications of cosmogenic C-14 data in tree rings, or of Be-10 in ice and sediments. An important task is to improve on the temporal resolution during identified periods of high/low solar activity in the past 32 Kyr. The plan is to undertake a study of changes in the cosmic ray flux during the last millennium (1100-1825 A.D.), during which time 4 low and 1 high solar activity epoch has been identified from historical records. Sunspot data during most of these periods are sparse. Adequate ice samples are available from ice cores from the South Pole and from Summit, Greenland and a careful high resolution study of past solar activity levels during this period will be undertaken. The intellectual merit of the work includes providing independent verification of estimated solar activity levels from the two polar ice records of cosmic ray flux and greatly improve our understanding of solar-terrestrial relationships. The broader impacts include collaboration with other scientists who are experts in the application of the atmospheric cosmogenic C-14 and student training. Both undergraduates and a graduate student will be involved in the proposed research. Various forms of outreach will also be used to disseminate the results of this project, including public presentations and interactions with the media.

NSF Org:

ANT - Antarctic Sciences Section

Award Number:

0538683

Award Instrument:

Standard Grant

Program Manager:

Julie Palais
ANT Antarctic Sciences Section
OPP Office of Polar Programs

NSF Program(s):

ANTARCTIC GLACIOLOGY

Field Application(s):

Polar Programs-Related

Program Reference Code(s):

UNASSIGNED, 0000

Program Element Code(s):

5116