Data Correlating the Shallow GISP2 Dust Profile with the Wolf Sunspot Number Series

Summary

These data were collected for a research project that utilized the Greenland Ice Sheet Project 2 (GISP2) ice core. The project sought evidence of an 11-year sunspot cycle and whether the cycle correlated with dust that had been transported by global atmospheric circulation to the summit of Greenland and incorporated into the ice sheet. The dust profile was measured along the top 120 m of the GISP2 B-core using laser-light scattering (LLS) from meltwater. The profile has been dated using the established B-core depth-age scale and ranges from 1597 A.D. to 1988 A.D. It contains an average of 13 samples per year. There are significant gaps from 1698 A.D. to 1711 A.D. and from 1719 A.D. to 1727 A.D. where the ice was previously heavily sampled and therefore unavailable for analysis.

Based on previous evidence that the GISP2 deep (>1600 m) dust profile contains solar-type variability, investigators correlated the shallow dust profile with the Wolf Sunspot Number (SSN) series. The period under investigation ranges from 1752 to 1988 A.D.

For additional information on these data, please refer to the Ram Lab web site, Atmospheric Physics Group, Department of Physics, State University of New York (SUNY) at Buffalo.

This research project was funded by the Arctic System Sciences (ARCSS) Program, grant number OPP-9711609.

Data are available for ordering through NCAR.

Citing These Data:

Ram, M. 2003. Data Correlating the Shallow GISP2 Dust Profile with the Wolf Sunspot Number Series. Boulder, CO: National Center for Atmospheric Research, ARCSS Data Archive.

Overview Table

Table of Contents

1. Contacts and Acknowledgments:

Investigator(s) Name and Title:

Technical Contact:

2. Detailed Data Description:

These data were collected for a research project that utilized the GISP2 ice core to look for evidence of an 11-year sunspot cycle and whether the cycle correlated with dust that had been transported by global atmospheric circulation to the summit of Greenland and incorporated into the ice sheet.

Format:

The header of each data file includes the title, references to published use of the data, and a description of the data.

The data are in two tab-delimited columns. The first column contains the year A.D.; the second column contains the variable.

File Naming Convention:

The data descriptions for each data file are included below:

GISP2_Dust_raw.dat
Laser Light Scattering (LLS) from meltwater was used to obtain dust concentrations. The resulting dust profile was then converted from depth to age using the GISP2 depth-age scale.

GISP2_Dust_g10.dat
This data set is a smoothed version of the data in the file "GISP2_Dust_raw.dat." The data were smoothed in the time domain using a Gaussian-weighted moving average with a 50% cutoff period of 10 years. Each data point represents the center of the moving average window.

GISP2_Dust_s1_G8-15.dat
This data file contains a band-pass smoothed version of the data in the file "GISP2_Dust_raw.dat." The raw data were smoothed in the time domain using Gaussian-weighted moving averages with 50% cutoff periods of 8 and 15 years. The 8-year smoothed data were then subtracted from the 15-year smoothed data, and the results were resampled at 1-year intervals using an annual average.

SSN_Dust_w20_s1_G8-15.dat
This data file contains the results of a moving correlation between the files "GISP2_Dust_s1_G8-15.dat" and "SSN_s1_G8-15.dat," using a 20-point (20-year) correlation window. Each point represents the center of the moving correlation window.

SSN_s1_G8-15.dat
This is a band-pass smoothed version of the monthly SSN obtained from the Regional Warning Center (RWC) Belgium World Data Center for the Sunspot Index. The raw data were smoothed in the time domain using gaussian-weighted moving averages with 50% cutoff periods of 8 and 15 years. The 8-year smoothed data were then subtracted from the 15-year smoothed data, and the results were resampled at 1-year intervals using an annual average.

File Size:

File sizes range from 4 KB to 79 KB.

Spatial Coverage:

Data were collected at the Greenland Summit, 72.6 ºN and 38.5 ºW.

Temporal Coverage:

The dust profile has been dated using the established B-core depth-age scale and ranges from 1597 A.D. to 1988 A.D. There are significant gaps from 1698 A.D. to 1711 A.D. and from 1719 A.D. to 1727 A.D. where the ice was previously heavily sampled and therefore unavailable for analysis.

Please note the following:

• The investigative period for this dataset ranges from 1752 A.D. to 1988 A.D..
• The data analysis period ranged from August 1997 to January 1999.
• The data values contained in the file "SSN_s1_G8-15.dat" have been truncated by the filtering operations performed by the investigators. Even though the years 1989 to 1992 are reflected in the data, investigators were interested in analyzing only the time period covered by the beginning of the sunspot data and the end of the dust data, which is 1752 to 1988 A.D.

Temporal Resolution:

The dust profile data contain an average of 13 samples per year.

Parameters or Variables:

Parameter Description:

Please refer to the File Naming Convention section for a description of data parameters.

Unit of Measurement:

The dust profile is presented in units of relative scattering intensity. The raw data, a 10-year Gaussian-weighted average set, and an 8-year to 15-year bandpass-filtered set, are included. Also included are an 8-year to 15-year bandpass-filtered set of the Wolf SSN series, and a moving correlation between the bandpass-filtered dust profile and SSN.

Sample Data Record:

SSN_Dust_w20_s1_G8-15.dat

YearAD Moving_Correlation_Coefficient
1769 0.136311
1770 0.0615856
1771 0.0393264

3. Data Access and Tools:

Data Access:

Data are available for ordering through NCAR.

4. Data Acquisition and Processing:

Sensor or Instrument Description:

Data Acquisition Methods:

Laser Light Scattering (LLS) from meltwater was used to obtain dust concentrations along the top 120 m of the GISP2 B-core. In this technique, the intensity of light scattered at 90º from the meltwater sample is proportional to the amount of dust suspended in the meltwater. The resulting dust profile was then converted from depth to age using the GISP2 depth-age scale (Meese et al. 1997). Details of the LLS from meltwater technique are given in Ram and Illing (1994).

During data analysis, investigators identified a dust deposit in the GISP2 B-core that most likely originated from the central United States during the early 1930's Dust Bowl. The complete results are published in Donarummo et al. (2003).

5. References and Related Publications:

References Using Data

Donarummo, J. Jr., M. Ram, and M.R. Stolz. 2002. Sun/dust correlations and volcanic interference. Geophysical Research Letters 29(9): 75-1 to 75-4.

References About Data

Donarummo, J.Jr., M. Ram, and E.F. Stoermer. 2003. Possible deposit of soil dust from the 1930s U.S. Dust Bowl identified in Greenland ice. Geophysical Research Letters 30(6).

Meese, D.A., A.J. Gow, R.B. Alley, G.A. Zielinski, P.M. Grootes, M. Ram, K.C. Taylor, P.A. Mayewski, and J.F. Bolzan. 1997. The Greenland Ice Sheet Project 2 depth-age scale: Methods and results. Journal of Geophysical Research 102:26411-26423.

Ram, M., and M. Illing. 1994. Polar ice stratigraphy from laser-light scattering: scattering from meltwater. Journal of Glaciology 40:504-508.

Related Publications

The Greenland Summit Ice Cores CD-ROM. 1997. Available from the National Snow and Ice Data Center, University of Colorado at Boulder, and the World Data Center-A for Paleoclimatology, National Geophysical Data Center, Boulder, Colorado.

5. Document Information:

Document Creation Date:

2003-07-10

Document Review Date:

2003 September

Document URL:

http://data.eol.ucar.edu/codiac/dss/id=106.ARCSS113