# WAIS Divide Ice Core 9-23KYrBP CO2 Data 
#-----------------------------------------------------------------------  
#                World Data Center for Paleoclimatology, Boulder  
#                                  and  
#                     NOAA Paleoclimatology Program  
#-----------------------------------------------------------------------  
# NOTE: Please cite Publication, and Online_Resource and date accessed when using these data.  
# If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed.  
# 
# 
# Online_Resource: http://www.ncdc.noaa.gov/paleo/study/18636
# 
# Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2014co2.txt
#  
# Description/Documentation lines begin with # 
# Data lines have no # 
# 
# Archive: Ice Core 
#-------------------- 
# Contribution_Date 
#	Date: 2015-05-15 
#-------------------- 
# Title 
#	Study_Name: WAIS Divide Ice Core 9-23KYrBP CO2 Data    
#-------------------- 
# Investigators 
#       Investigators: Marcott, S.A.; Bauska, T.K.; Buizert, C.; Steig, E.J.; Rosen, J.L.; Cuffey, K.M.; Fudge, T.J.; Severinghaus, J.P.; Ahn, J.; Kalk, M.L.; McConnell, J.R.;  Sowers, T.; Taylor, K.C.; White, J.W.C.; Brook, E.J.
#-------------------- 
# Description_Notes_and_Keywords 
#	Description: Atmospheric Carbon Dioxide (CO2) concentration data from WAIS ice cores for the period 23,000 to 9,000 years before present. 
#-------------------- 
# Publication  
#       Authors: Shaun A. Marcott, Thomas K. Bauska, Christo Buizert, Eric J. Steig, Julia L. Rosen, Kurt M. Cuffey, T.J. Fudge, Jeffery P. Severinghaus, Jinho Ahn, Michael L. Kalk, Joseph R. McConnell, Todd Sowers, Kendrick C. Taylor, James W.C. White, and Edward J. Brook 
#       Published_Date_or_Year: 2014-10-14 
#       Published_Title: Centennial-scale changes in the global carbon cycle during the last deglaciation 
#       Journal_Name: Nature 
#       Volume: 515 
#       Edition:  
#       Issue: 7524 
#       Pages: 616-619 
#       DOI: 10.1038/nature13799 
#       Online_Resource: http://www.nature.com/nature/journal/v514/n7524/full/nature13799.html
#       Full_Citation:  
#       Abstract: Global climate and the concentration of atmospheric carbon dioxide (CO2) are correlated over recent glacial cycles. The combination of processes responsible for a rise in atmospheric CO2 at the last glacial termination  (23,000 to 9,000 years ago), however, remains uncertain. Establishing the timing and rate of CO2 changes in the past provides critical insight into the mechanisms that influence the carbon cycle and helps put present and future anthropogenic emissions in context. Here we present CO2 and methane (CH4) records of the last deglaciation from a new high-accumulation West Antarctic ice core with unprecedented temporal resolution and precise chronology. We show that although low-frequency CO2 variations parallel changes in Antarctic temperature, abrupt CO2 changes occur that have a clear relationship with abrupt climate changes in the Northern Hemisphere. A significant proportion of the direct radiative forcing associated with the rise in atmospheric CO2 occurred in three sudden steps, each of 10 to 15 parts per million. Every step took place in less than two centuries and was followed by no notable change in atmospheric CO2 for about 1,000 to 1,500 years. Slow, millennial-scale ventilation of Southern Ocean CO2-rich, deep-ocean water masses is thought to have been fundamental to the rise in atmospheric CO2 associated with the glacial termination, given the strong covariance of CO2 levels and Antarctic temperatures. Our data establish a contribution from an abrupt, centennial-scale mode of CO2 variability that is not directly related to Antarctic temperature. We suggest that processes operating on centennial timescales, probably involving the Atlantic meridional overturning circulation, seem to be influencing global carbon-cycle dynamics and are at present not widely considered in Earth system models.
#------------------ 
# Funding_Agency  
#       Funding_Agency_Name: US National Science Foundation 
#       Grant: 0739766-ANT, 1043518-ANT, 1043092-ANT, 0839093-ANT, 1142166-ANT
#------------------ 
# Site_Information  
#       Site_Name: West Antarctic Ice Sheet (WAIS) Divide 
#       Location: Antarctica 
#	Country:   
#	Northernmost_Latitude: -79.467 
# 	Southernmost_Latitude: -79.467 
# 	Easternmost_Longitude: -112.085 
# 	Westernmost_Longitude: -112.085 
# 	Elevation: 1766 m 
#------------------ 
# Data_Collection    
#	Collection_Name: WAIS2014CO2 
#	Earliest_Year: 23030 
#	Most_Recent_Year: 8893 
#	Time_Unit: Cal. Year BP 
#	Core_Length: 3405m 
#	Notes: 
#------------------ 
# Chronology: WDC06A-7  (Annual layer counting; Gas age modeling)
#  
# 
# 	 
#----------------	 
# Variables  
# 
# Data variables follow are preceded by "##" in columns one and two. 
# Data line variables format:  Variables list, one per line, shortname-tab-longname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data)  
# 
## depth_m	depth, , , m, , , , ,N 
## age_calBP	age, , , calendar years before present, , , WDC06A-7, ,N 
## co2_ppm	CO2 concentration, , , ppm, , ice cores, , ,N  
# 
#---------------- 
# Data: 
# Data lines follow (have no #) 
# Data line format - tab-delimited text, variable short name as header 
# Missing Values: 
# 
depth_m	age_calBP	CO2_ppm
1698.1650	8893.2	267.90
1708.1825	8985.5	265.45
1718.2305	9081.0	268.86
1728.2005	9176.9	263.95
1738.2113	9274.9	270.60
1748.2092	9370.1	269.23
1758.2252	9467.5	263.80
1768.2095	9561.4	265.55
1778.2425	9654.3	271.17
1788.9410	9759.9	264.97
1798.2455	9850.3	269.82
1808.7480	9953.1	265.92
1818.2703	10047.1	270.68
1828.2555	10147.8	268.05
1838.2470	10248.5	267.19
1848.2842	10352.7	267.44
1858.3193	10454.9	267.54
1868.3128	10555.8	271.28
1878.3400	10656.8	280.93
1888.3482	10758.4	268.11
1898.6095	10861.6	271.50
1908.4165	10957.4	271.81
1918.4123	11052.5	275.94
1928.6113	11151.2	268.06
1938.4485	11246.7	277.03
1948.3975	11339.4	268.81
1953.2441	11383.2	268.84
1955.2235	11399.9	272.16
1957.2365	11417.5	268.48
1959.3172	11435.9	274.14
1961.2375	11453.1	272.87
1963.3510	11472.8	273.10
1965.2388	11490.4	271.17
1967.2395	11507.2	271.66
1969.2385	11523.9	273.51
1971.4625	11543.6	270.90
1973.2420	11559.6	266.74
1975.2442	11576.4	271.09
1977.2528	11592.2	264.70
1979.2425	11611.3	265.30
1981.2495	11629.0	270.22
1983.3905	11647.9	261.13
1985.2445	11664.5	251.55
1987.2462	11682.8	258.62
1989.2525	11701.4	257.99
1991.2547	11719.7	260.04
1993.2590	11740.7	259.89
1995.2525	11759.2	262.74
1997.2535	11780.7	262.25
1999.4775	11802.8	262.53
2001.2615	11820.5	261.17
2003.3625	11843.3	258.31
2005.2635	11863.1	257.63
2007.2525	11883.2	255.56
2009.2535	11904.9	259.90
2011.2540	11927.0	262.57
2013.2735	11948.1	252.92
2015.2385	11969.6	257.99
2017.2585	11990.7	259.39
2019.2644	12015.9	251.85
2021.2575	12037.3	252.41
2023.3605	12058.8	257.10
2025.2655	12079.8	255.03
2027.2615	12105.2	259.66
2029.2575	12124.6	257.02
2031.2565	12146.5	255.14
2033.2783	12168.5	255.42
2035.2565	12190.4	254.97
2037.2565	12211.3	253.65
2039.2635	12232.9	253.23
2041.2135	12256.5	252.95
2043.3575	12280.8	253.38
2045.2595	12301.0	252.92
2047.2595	12321.3	254.73
2049.2645	12343.1	250.97
2051.2565	12365.3	248.31
2053.2635	12388.3	247.00
2055.2725	12409.4	250.40
2057.2591	12431.9	251.67
2059.2533	12454.8	249.83
2061.2515	12475.4	250.18
2063.2525	12495.8	248.42
2065.2555	12521.4	250.74
2067.2485	12543.7	253.92
2069.2578	12564.6	248.27
2071.2515	12586.6	251.02
2073.2590	12607.6	252.09
2075.2535	12629.9	250.94
2077.3745	12653.6	247.95
2079.2555	12673.9	246.53
2081.2565	12697.1	248.24
2083.3565	12719.8	245.59
2085.2555	12739.9	251.30
2087.2580	12762.6	244.02
2089.2535	12785.6	245.50
2091.2545	12809.3	246.23
2093.2867	12830.2	246.15
2095.2535	12852.7	243.35
2097.2545	12874.0	245.24
2099.2545	12893.4	243.44
2101.2595	12917.1	242.79
2103.2805	12939.2	242.18
2105.2545	12959.8	244.71
2107.2555	12980.9	241.15
2109.2545	13001.1	243.42
2111.2565	13021.9	238.68
2113.2270	13043.7	242.86
2115.2595	13066.6	241.91
2117.2670	13088.2	245.56
2121.2535	13128.4	238.82
2125.2565	13172.7	240.91
2129.2573	13216.2	243.41
2133.8752	13267.0	244.42
2137.2648	13304.1	240.86
2147.2505	13418.1	241.83
2153.2729	13486.7	244.25
2157.2485	13531.7	239.83
2163.3495	13600.8	247.86
2167.2485	13645.3	242.55
2173.2770	13712.8	245.59
2177.2592	13758.7	245.11
2183.3520	13827.2	243.08
2187.2425	13871.6	241.95
2193.2653	13940.2	244.57
2198.2420	14001.8	239.92
2200.2435	14022.9	241.87
2203.3643	14060.1	245.27
2205.2425	14084.5	236.88
2208.2405	14120.1	240.40
2211.2435	14156.6	243.24
2213.2710	14179.6	243.36
2215.2995	14205.6	242.36
2218.2468	14237.4	240.60
2221.2492	14273.0	244.21
2223.3485	14298.7	243.04
2224.2435	14308.6	239.80
2227.2435	14343.2	246.08
2228.3255	14354.5	242.39
2230.2445	14375.0	244.33
2233.2623	14410.6	246.55
2234.2530	14422.2	246.60
2236.2405	14443.3	244.95
2238.2195	14463.6	242.61
2241.2408	14497.2	246.06
2243.3590	14520.9	245.14
2244.2435	14531.3	247.17
2245.2415	14541.7	239.83
2246.2518	14552.9	245.73
2247.2450	14563.5	243.86
2248.3015	14575.9	243.77
2249.2445	14586.2	241.97
2250.2468	14595.5	239.31
2251.2422	14606.2	241.59
2252.2455	14619.4	241.97
2253.2640	14630.0	244.10
2254.7445	14645.2	242.12
2255.2465	14652.3	238.62
2256.2455	14664.1	237.42
2257.1955	14675.1	238.34
2258.1765	14686.4	241.49
2259.2425	14696.7	232.91
2260.2425	14707.0	232.18
2261.2415	14718.1	234.53
2262.2435	14730.9	238.54
2263.3603	14743.2	235.48
2264.7835	14758.5	231.90
2265.2452	14763.4	228.64
2266.2455	14776.3	231.39
2267.2455	14787.8	231.79
2268.2455	14799.1	232.50
2269.3095	14810.6	231.58
2270.2445	14822.4	230.51
2271.3298	14834.8	232.40
2272.2425	14844.8	231.87
2273.2757	14857.5	237.17
2274.2415	14869.2	236.22
2275.2415	14880.7	231.85
2276.2385	14892.5	234.63
2277.2398	14904.2	232.72
2278.2375	14915.9	232.36
2279.2648	14929.0	232.47
2281.3465	14953.7	232.89
2283.3697	14976.5	233.79
2284.2345	14987.3	231.65
2286.2345	15011.5	232.37
2288.2335	15034.8	229.38
2291.3342	15072.5	232.99
2293.2580	15095.8	238.47
2296.2647	15133.5	233.67
2298.2325	15156.5	232.81
2300.2295	15181.1	231.84
2303.3370	15218.9	234.18
2305.2305	15243.4	232.27
2308.2285	15280.7	229.77
2311.2475	15320.9	231.64
2313.2510	15345.2	232.92
2316.2285	15382.8	229.39
2318.2285	15410.1	228.74
2322.2493	15462.9	227.27
2328.2510	15546.4	227.53
2335.2835	15649.4	226.76
2339.2365	15704.8	226.16
2343.3590	15767.7	228.86
2348.2320	15845.0	226.36
2353.2520	15920.3	227.51
2354.2369	15936.5	227.77
2357.9995	15995.5	227.72
2358.2325	15999.0	228.41
2359.2325	16014.7	226.39
2360.2377	16033.8	228.48
2363.3385	16083.0	228.24
2365.2335	16114.1	226.41
2367.2405	16151.2	228.86
2368.2355	16166.7	230.19
2369.2342	16187.5	225.49
2370.4318	16208.7	231.32
2371.2365	16223.0	227.24
2372.2358	16240.6	224.49
2373.2552	16260.7	222.56
2374.2405	16278.7	218.22
2375.2415	16297.0	216.84
2376.2425	16317.4	218.60
2377.2425	16337.3	216.43
2378.2435	16354.2	218.83
2379.2435	16374.9	215.21
2380.2345	16391.9	213.51
2381.2445	16410.7	216.95
2382.2455	16431.3	215.79
2383.5690	16458.4	221.19
2384.2475	16472.0	217.94
2386.2475	16509.9	211.95
2388.2475	16553.5	212.65
2390.2045	16590.0	212.46
2393.4895	16655.9	217.15
2397.2550	16733.5	214.25
2400.2035	16797.5	209.53
2403.5565	16869.3	209.19
2406.2535	16928.8	206.93
2409.1631	16994.8	208.32
2413.3015	17091.8	206.10
2416.2597	17163.7	202.63
2419.2720	17236.2	202.29
2421.2740	17287.9	199.88
2422.2730	17311.9	198.65
2424.2585	17360.5	194.50
2425.2710	17385.3	197.02
2426.2585	17410.0	195.89
2427.2595	17435.0	194.76
2428.2585	17461.0	197.00
2429.2585	17485.3	195.48
2430.2595	17510.9	195.59
2431.2595	17534.6	196.37
2432.2751	17561.5	196.62
2433.2830	17586.3	200.96
2434.2730	17612.0	199.79
2435.2605	17637.9	197.21
2436.3425	17665.1	198.38
2437.2708	17691.2	195.52
2438.2615	17717.0	193.52
2439.3240	17743.8	194.41
2440.2718	17769.7	195.70
2441.2750	17797.6	191.25
2442.2718	17825.4	195.21
2443.3695	17854.6	193.52
2444.2790	17881.0	194.26
2445.2760	17907.2	195.72
2446.2748	17936.0	192.54
2447.2738	17965.8	192.66
2448.2665	17992.0	192.96
2449.3790	18024.5	191.79
2450.2758	18050.1	191.73
2451.2770	18081.6	192.64
2452.2778	18110.6	192.59
2453.2735	18139.8	188.88
2454.2820	18173.2	193.01
2455.2778	18201.8	189.65
2456.2789	18232.2	192.88
2457.2788	18264.7	192.52
2458.2778	18295.8	193.03
2459.2118	18324.4	191.12
2460.2808	18360.4	192.73
2461.2798	18391.2	192.21
2462.2820	18422.4	192.47
2463.3745	18457.8	191.45
2464.2685	18486.6	191.09
2465.2665	18520.0	191.67
2467.3138	18582.9	192.57
2470.2844	18677.4	197.90
2472.4465	18747.0	195.27
2474.2735	18803.6	196.97
2475.2818	18835.2	192.44
2476.2745	18866.9	192.50
2480.2870	18993.8	196.71
2485.2725	19152.8	195.09
2489.2826	19282.2	195.58
2494.2715	19442.7	195.52
2498.2840	19568.2	192.95
2500.2735	19629.5	195.42
2505.2735	19791.2	197.60
2508.1870	19883.9	200.06
2512.2900	20018.7	197.72
2518.2930	20213.3	194.47
2524.2855	20407.6	193.99
2528.3500	20536.8	197.93
2532.3965	20666.5	191.76
2537.3518	20828.4	196.66
2541.3038	20964.4	194.87
2544.2975	21067.7	192.40
2548.4970	21212.7	194.05
2552.3168	21345.2	191.24
2558.4380	21562.9	189.23
2564.8685	21790.6	191.96
2568.3410	21913.6	194.78
2572.3085	22055.6	191.38
2577.3035	22230.9	195.27
2581.3113	22367.7	196.08
2588.4165	22611.9	197.95
2590.3135	22677.4	193.97
2592.3142	22748.0	195.24
2594.9748	22840.6	200.00
2597.3165	22921.8	199.97
2598.4225	22962.3	198.94
2600.3175	23030.0	197.55