# West Antarctic Ice Sheet (WAIS) Ice Core WDC-05A 1000 Year CO2 Data
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#                World Data Service for Paleoclimatology, Boulder 
#                                  and 
#                     NOAA Paleoclimatology Program 
#             National Centers for Environmental Information (NCEI)
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# Template Version 4.0
# Encoding: UTF-8
# NOTE: Please cite original publication, NOAA Landing Page URL, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, study title, NOAA Landing Page URL, and date accessed. 
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# Description/Documentation lines begin with #
# Data lines have no #
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# NOAA_Landing_Page:  https://www.ncei.noaa.gov/access/paleo-search/study/12949
#   Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata.
#
# Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-icecore-12949.json
#   Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata.
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# Data_Type: Ice cores
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# Dataset_DOI: 10.25921/rmrj-fp54
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# Science_Keywords:
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# Resource_Links
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# Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/icecore/antarctica/wais2012co2-noaa.txt
#   Data_Download_Description: NOAA Template File; Atmospheric Carbon Dioxide Data
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# Contribution_Date
#    Date: 2012-05-27
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# File_Last_Modified_Date
#     Date: 2025-06-27
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# Title
#   Study_Name: West Antarctic Ice Sheet (WAIS) Ice Core WDC-05A 1000 Year CO2 Data
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# Investigators
#   Investigators: Ahn, J.; Brook, E.J.; Mitchell, L.E.; Rosen, J.; McConnell, J.R.; Taylor, K.C.; Etheridge, D.M.; Rubino, M.
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# Description_Notes_and_Keywords
#   Description: Atmospheric CO2 data from the West Antarctic Ice Sheet (WAIS) Divide shallow core WDC05A.  We measured samples from 109 depth intervals of the WDC05A core. Each depth interval was usually less than 10 cm and 3 ~ 6 replicates (4 on average) were analyzed for each depth interval. The average standard deviation of replicates from the same depth interval was 1.6 ppm.
#--------------------
# Publication 
#   Authors: Ahn, J., E. J. Brook, L. Mitchell, J. Rosen, J. R. McConnell, K. Taylor, D. Etheridge, M. Rubino
#   Published_Date_or_Year: 2012-06-01
#   Published_Title: Atmospheric CO2 over the last 1000 years: A high-resolution record from the West Antarctic Ice Sheet (WAIS) Divide ice core
#   Journal_Name: Global Biogeochemical Cycles
#   Volume: 26
#   Edition: 
#   Issue: 2
#   Pages: 
#   Report_Number: GB2027
#   DOI: 10.1029/2011GB004247 
#   Online_Resource: 
#   Full_Citation:
#   Abstract: We report a decadally resolved record of atmospheric CO2 concentration for the last 1000 years, obtained from the West Antarctic Ice Sheet (WAIS) Divide shallow ice core. The most prominent feature of the pre-industrial period is a rapid ~7 ppm decrease of CO2 in a span of ~20-50 years at ~1600 A.D. This observation confirms the timing of an abrupt atmospheric CO2 decrease of ~10 ppm observed for that time period in the Law Dome ice core CO2 records, but the true magnitude of the decrease remains unclear. Atmospheric CO2 variations over the time period 1000-1800 A.D. are statistically correlated with northern hemispheric climate and tropical Indo-Pacific sea surface temperature. However, the exact relationship between CO2 and climate remains elusive due to regional climate variations and/or uneven geographical data density of paleoclimate records. We observe small differences of 0 ~ 2% (0 ~ 6 ppm) among the high precision CO2 records from the Law Dome, EPICA Dronning Maud Land and WAIS Divide Antarctic ice cores. However, those records share common trends of CO2 change on centennial to multicentennial time scales, and clearly show that atmospheric CO2 has been increasing above preindustrial levels since ~1850 A.D.
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# Funding_Agency 
#   Funding_Agency_Name: Gary Comer Science and Education Foundation
#   Grant: 
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# Funding_Agency 
#   Funding_Agency_Name: Korea Polar Research Institution (KOPRI)
#   Grant: PE 11090
#--------------------
# Funding_Agency 
#   Funding_Agency_Name: National Research Foundation of Korea (NRF)
#   Grant: 2011-0025242
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# Funding_Agency 
#   Funding_Agency_Name: US National Science Foundation
#   Grant: OPP-0739766, OPP 0538427, OPP 0739780
#--------------------
# Site_Information 
#   Site_Name: WAIS Divide WDC05A
#   Location: Antarctica
#   Northernmost_Latitude: -79.47
#   Southernmost_Latitude: -79.47
#   Easternmost_Longitude: -112.13
#   Westernmost_Longitude: -112.13
#   Elevation_m: 1759
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# Data_Collection  
#   Collection_Name: WDC05A2012CO2
#   First_Year: 993
#   Last_Year: 1939
#   Time_Unit: CE
#   Core_Length_m: 
#   Parameter_Keywords: atmospheric gas
#   Notes:
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# Chronology_Information
#   Chronology: 
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# Variables  
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# PaST_Thesaurus_Download_Resource:  https://www.ncei.noaa.gov/access/paleo-search/skos/past-thesaurus.rdf
#   PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format.
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# Variables format: Short_name <tab> what,material,error,units,seasonality,data_type,detail,method,data_format,additional_information
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## depth_m	depth,,,meter,,ice cores;climate forcing,,,N,
## gas_ageCE	age,,,year Common Era,,ice cores;climate forcing,,,N,
## CO2_mean	carbon dioxide,bulk atmosphere,,parts per million,,ice cores;climate forcing,averaged;corrected,gas chromatography - flame ionization detection,N,Corrections for gas solubility and blank and gravitational enrichment for the Oregon State University data
## CO2_1s	carbon dioxide,bulk atmosphere,one standard deviation,parts per million,,ice cores;climate forcing,corrected,gas chromatography - flame ionization detection,N,standard deviation of the mean for replicates
## num_rep	number of samples,,,count,,ice cores;climate forcing,,,N,number of replicates
#
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# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing_Values:
depth_m	gas_ageCE	CO2_mean	CO2_1s	num_rep
78.973	1939.9	311.6	1.6	6
80.095	1935.4	307.1	0.2	12
80.595	1933.2	306.5	1.3	5
82.588	1925.0	303.9	0.3	6
84.640	1916.4	298.8	1.2	4
86.385	1909.1	300.7	1.4	6
88.355	1900.7	295.9	0.6	5
90.153	1892.0	294.0	0.8	3
92.120	1882.8	292.1	0.3	2
94.671	1871.5	289.8	0.3	3
97.150	1861.6	288.3	1.5	3
98.394	1857.6	286.7	0.3	3
100.650	1848.4	286.9	1.1	3
102.702	1839.0	285.3	0.7	3
105.220	1828.4	285.9	0.2	3
106.328	1824.0	286.0	0.6	3
109.101	1812.0	284.4	0.3	5
110.575	1805.8	284.4	0.7	6
110.880	1805.0	282.6	0.7	4
113.160	1796.2	283.7	1.2	6
114.855	1786.8	281.7	0.6	3
115.100	1785.7	284.2	0.9	3
116.900	1777.6	281.8	0.3	3
118.740	1770.0	280.0	1.3	5
121.195	1759.0	281.7	0.6	4
123.220	1750.1	280.1	0.6	3
124.770	1743.2	280.6	1.4	3
126.795	1734.6	278.7	1.2	3
128.720	1726.2	281.4	0.4	4
130.850	1716.4	278.9	0.6	3
132.808	1707.1	279.0	1.8	7
134.695	1698.8	279.5	0.6	4
136.310	1693.0	278.9	0.5	4
138.878	1683.8	279.1	0.7	6
140.883	1675.2	277.7	0.5	5
142.426	1669.1	278.0	0.7	4
147.228	1644.1	279.2	0.6	4
149.073	1635.5	278.8	1.0	4
150.012	1631.5	281.3	0.5	6
152.717	1620.1	278.6	0.6	6
154.388	1613.1	282.2	0.5	9
157.129	1601.4	280.9	0.9	8
158.589	1595.5	279.9	0.7	4
160.499	1586.9	283.2	1.2	5
162.000	1580.2	283.9	0.9	3
163.476	1574.3	286.4	0.9	5
166.126	1564.1	285.5	0.6	5
168.623	1553.4	285.8	0.5	5
170.022	1547.5	283.9	1.5	6
172.690	1536.1	286.3	0.2	4
174.021	1530.4	284.7	0.4	4
176.355	1519.7	285.5	0.9	4
177.538	1513.8	285.3	0.8	4
180.373	1500.4	285.3	0.1	3
182.286	1491.5	282.2	0.5	10
184.430	1482.0	282.7	0.4	3
186.510	1472.1	283.3	0.7	3
187.745	1467.2	283.8	0.5	3
190.062	1456.9	281.1	0.3	4
192.474	1447.3	283.5	0.4	5
194.375	1439.4	281.9	1.7	4
196.528	1428.1	282.5	0.5	3
198.150	1421.3	284.6	0.3	4
200.148	1412.8	282.5	0.1	4
201.780	1406.5	284.8	1.4	4
204.990	1391.3	285.2	0.6	6
207.166	1381.4	283.5	0.6	4
207.825	1378.7	284.1	0.9	3
209.798	1369.2	285.3	0.5	3
212.656	1356.2	284.7	1.3	5
214.243	1348.3	283.7	0.7	3
216.507	1339.1	284.9	0.9	7
219.082	1329.0	284.5	0.7	8
220.999	1320.3	284.4	0.4	12
222.926	1312.0	285.4	0.3	3
224.870	1303.1	283.8	0.4	3
226.081	1297.7	284.4	1.3	3
228.310	1286.0	284.7	1.2	8
229.981	1278.9	283.7	1.3	4
232.095	1270.2	284.9	0.8	3
234.037	1261.6	286.1	1.1	3
235.770	1254.8	283.2	0.8	4
237.340	1248.4	284.3	0.8	3
240.495	1235.1	283.6	1.3	3
243.344	1224.2	286.2	1.9	9
245.020	1217.6	284.1	1.1	3
246.556	1211.9	284.2	0.6	3
248.256	1205.4	284.3	0.5	6
248.840	1203.2	287.5	1.2	6
251.708	1193.7	286.5	1.1	3
254.105	1179.5	285.1	0.8	4
256.315	1169.7	286.3	0.4	4
260.970	1150.0	287.4	1.2	4
262.425	1143.7	284.6	0.4	4
266.768	1126.3	286.1	0.6	5
269.153	1116.9	285.3	0.5	3
272.243	1103.0	286.5	1.4	4
275.252	1090.4	285.4	0.4	6
277.235	1082.5	285.4	0.6	4
278.567	1076.7	284.5	0.8	3
279.850	1072.2	283.3	0.3	3
285.196	1046.7	283.9	1.0	4
286.050	1042.6	282.1	1.2	4
286.271	1041.4	282.3	0.4	5
286.719	1039.0	280.6	1.2	3
288.830	1030.1	282.9	1.0	4
292.165	1015.9	284.0	1.4	3
295.590	1001.7	282.0	0.6	4
297.575	993.1	282.0	0.6	4
