SPECMAP Archive #2: Specmap2.readme
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               World Data Center A- Paleoclimatology
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NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!!


NAME OF DATA SET:  SPECMAP Archive #2
LAST UPDATE:  12/92  (Original receipt date by WDC-A Paleo) 
CONTRIBUTORS: J. Imbrie, et al., Brown University
IGBP PAGES/WDCA Data Contribution Series #:  92-017
SUGGESTED DATA CITATION: 
Imbrie, J. et al, 1992, SPECMAP Archive #2.  IGBP PAGES/
World Data Center-A for Paleoclimatology Data Contribution Series # 92-017.
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

ORIGINAL REFERENCE:
'ON THE STRUCTURE AND ORIGIN OF MAJOR GLACIATION 
CYCLES. , 1. LINEAR RESPONSES TO MILANKOVITCH 
FORCING', Paleoceanography, Dec, 1992 (Imbrie et al.,1992).

GEOGRAPHIC REGION: Global
PERIOD OF RECORD: 0 - 400,000 YBP
LIST OF FILES: please see FILELIST and archive2.con for detailed descriptions.

DESCRIPTION:

The purpose of this archive is to make widely available in digital form 
the climatic time series which form the basis for the research 
presented in the original reference.  Users of the archive should have a 
copy in hand to identify the files which follow.  Imbrie et al.,1992, 
references the papers where the data was first published.  These 
references contain important information, such as species corrections, 
etc., which can not be included in this archive.  Files which appeared 
in Archive 1 are not repeated here.  These files are K708-1 (O-18, 
SST), V19-30 (delta del 13C), Curry -Crowly stack (delta del 13C).  
The version of SPECMAP stack included in Archive 2 is in units of 
ppm rather than standard deviations.  A file erroneously omitted from 
Archive 1, the planktonic foram counts for V25-56 is included here 
(see Archive 1 for details of formatting, etc.)  For several of the time 
series new age models were developed.  The ages assigned in cores 
RC11-120, E49-18, AII 107, CHN 82, RC13-229, and K-11 differ 
slightly from the previously published ones.  (The ages for RC11-120, 
E49-18 are as published in Howard and Prell, 1992).  Also included 
are files which are not data.  The mid-month insolation for June at 65 
deg N (from Berger, 1978a) is given, as well as a listing of thorium 
ages corresponding to C-14 dates for the interval 5ka to 29.3 ka (thor), 
based on an equation provided by Edouard Bard of the University of 
Marseille, France.  All long time series were filtered in the three 
principal Milankovitch frequency bands.  Bandpass filters with Tukey 
cosine tapers were used.  For all three frequencies, the bandwidth was 
0.01/ky.  The central frequencies were 1/100ky, 1/41ky, and 1/23ky.  
For those using the ARAND statistical package, the number of 
triangles was 1 for all three filters.  The number and value of the 
weights making up the filters depend on the interpolation interval of 
the time series.  In this archive, filter weights are given for 
delta-t's of 2ky, 3ky, and 5ky. A convolution program, such as SMOOTH 
in the ARAND package, is required to perform the filtering.