Ã¯Â»Â¿# HuascarÃÂ¡n Ice Core, Core 2 Data
#-----------------------------------------------------------------------
#               World Data Center for Paleoclimatology, Boulder
#                                  and
#                     NOAA Paleoclimatology Program
#-----------------------------------------------------------------------
# NOTE: Please cite original reference when using these data,
# If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed
#
#
#
# Online_Resource: https://www.ncdc.noaa.gov/cdo/f?p=519:1:::::P1_STUDY_ID:2447
#
# Online_Resource: https://www.ncdc.noaa.gov/paleo/study/24611
#
# Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/trop/huascaran/readme_huascaran.txt
#
# Description/Documentation lines begin with #
# Data lines have no #
#
# Archive: Ice Cores
# --------------------
# Contribution_date
#	Date: 2014
# --------------------
# Title 
#	Study_Name: HuascarÃÂ¡n Ice Core, Core 2 Data
# --------------------
# Investigators
#	Investigators:  Thompson, L.G.; Mosley-Thompson, E.; Davis, M.E.; Lin, P-N.; Henderson, K.A.; Cole-Dai, J.; Bolzan, J.F.; Liu, K-b. 
# --------------------
# Description_and_Notes
#	Description: Site Description and Analysis
#	In July-August 1993, two ice cores to bedrock were recovered from the col 
#	between the north and south peaks of Nevado HuascarÃÂ¡n, Peru (9ÃÂ¸S, 77ÃÂ¸30'W, col 
#	elevation 6050 m) and were subsequently transported back to the cold room facility at the 
#	Byrd Polar Research Center (BPRC).  Core 1 (HSC1, 160.40 m) was sectioned in the 
#	field into 2677 samples decreasing in thickness from 13 cm at the top to 3 cm at the base, 
#	which were then melted and poured into 2 or 4 oz. plastic (HDPE) bottles, and sealed 
#	with wax.  Core 2 (HSC2, 166.08 m), drilled approximately 100 m from the HSC1 site, 
#	was returned frozen in 1 m sections.  Ice motion vectors determined from stake 
#	movements from 1991-93 indicate that the drill sites are proximal to the divide between 
#	ice flow towards the east and west outlets of the col.  Visible observations and borehole 
#	temperatures indicate that the glacier is 'polar' type, i.e., it remains frozen to the bed 
#	(Thompson et al., Science, v.269, 1995, p. 46-50).
#	Each ice sample from HSC2 was prepared in a Class 100 clean room 
#	environment, and analyzed for major anion concentrations (Cl-, NO3-, and SO42-) on a 
#	Dionex 2010i ion chromatograph, d18O on a Finnigan Mat mass spectrometer (Craig, 
#	1957), and for particulate concentration and size distribution using a Coulter TA-II 
#	particle counter (Thompson, OSU IPS Report 46, 1973).  A complete d18O profile was 
#	also produced from the bottled samples from HSC1.  Contamination during field 
#	preparation and transport of these samples precluded the development of a second 
#	complete record of particles and anion concentrations.
#	For display purposes, variable averaging on the core depth scale was utilized to 
#	show the major large-scale events in the record without the confusion of the large annual 
#	variations superimposed upon the upper portion.  Hence, for HSC2, 5-m integrated 
#	averages were calculated for between the surface and 140 meters depth and then 50-cm 
#	averages were generated between 140 and 160 meters.  Between 160 and 166 meters, 
#	every sample value was plotted.  A similar scheme was used for HSC1 (all values plotted 
#	for 155-160.4 m).  These data are included in hs12-5m.txt in this data archive, and the 
#	graph can be seen in Thompson et al., 1995 (Fig. 3).
#
#	Development of the time/depth relationship
#	Tropical South American climate is marked by annual dry seasons (July-October) 
#	which were identifiable in the ice core record as elevated values in all relevant 
#	measurements.  The nitrate (NO3-) record from the HuascarÃÂ¡n ice core provided the most 
#	definitive seasonal marker, but the final time scale was constructed from a comparison of 
#	four major parameters (NO3-, d18O, dust and SO42-).  Each annual maximum corresponds 
#	to the middle of the dry season, assumed to occur on the 1st of August.  The rapid layer-
#	thinning below 120 m limited annual resolution to the most recent 270 years.  However, 
#	the high accumulation and strong preservation of seasonal cycles also made possible the 
#	subannual resolution of d18O variations for a period of at least 100 years (1894-1993).
#	The accuracy of the time scale is of paramount importance in the development of 
#	relationships between ice core proxy data and tropical climate conditions.  Several 
#	horizons in recent times were useful for confirming the layer counting as a reliable 
#	method, and indicate almost certain ages for the uppermost 50 years.  In 1980, during the 
#	original reconnaissance expedition to HuascarÃÂ¡n, a 10 m firn core was extracted and 
#	analyzed for d18O at BPRC (Thompson et al., JGR, v. 89d3, 1984, p. 4638-4646). Aside 
#	from minor accumulation variation and slight signal attenuation, the 1993 cores 
#	duplicated the earlier stable isotope profile over the common portion, and confirmed the 
#	layer counting to 1980 as absolute.  Additionally, a magnitude 7.7 earthquake struck 
#	coastal Peru in May 1970, generating large mud flows following the collapse of a large 
#	portion of the HuascarÃÂ¡n glacier from the north peak. The event was recognized in the ice 
#	core by a sharp two-year rise in particulates from the newly-created sediment source.  A 
#	third time horizon was provided by the HSC2 36Cl profile (Synal et al., Glaciers From the 
#	Alps, Paul Scherrer Inst., 1997, p. 99-102), a substance produced by neutron activation 
#	during the explosion of atomic devices in the presence of a 35Cl source, such as sea water.  
#	An abrupt >100-fold rise in 36Cl concentration occurred at ~54 m depth, which dates (by 
#	layer counting) to 1951-53.  This was in direct response to the October 31, 1952 U.S. 
#	'Ivy' surface test of an experimental nuclear device on the Eniwetok Atoll in the Pacific 
#	Ocean (11N, 162E) (Carter and Moghissi, Health Physics, v. 33, 1977, p. 55-71).  
#	Finally, in both HSC1 and HSC2, the 1883 eruption of Krakatau, Indonesia (6S, 
#	10530'E) was identified by an anomalous sulfate concentration of ~400 ppb at 110 m 
#	depth, more than twice the level of any other local (within 10 m) event.  A date of mid-
#	year 1884 was thus considered to be an absolute time marker for both cores within the 
#	error of the time lag (less than one year).
#
# --------------------
# Publication
#	Authors: L.G. Thompson, E. Mosley-Thompson, M.E. Davis, P-N. Lin, K.A. Henderson, J. Cole-Dai, J.F. Bolzan and K-b. Liu
#	Published_Date_or_Year: 1995
#	Published_Title:  Late Glacial Stage and Holocene tropical ice core records from HuascarÃÂ¡n, Peru. 
#	Journal_Name: Science
#	Volume: 269
#	Edition: 	
#	Issue: 
#	Pages: 46-50
#	DOI: 
#	Online_Resource: 
#	Full_Citation: 
#	Abstract: Two ice cores from the col of HuascarÃÂ¡n in the north-central Andes of Peru contain a paleoclimatic history extending well into the Wisconsinan (WÃÂ¼rm) Glacial Stage and include evidence of the Younger Dryas cool phase. Glacial stage conditions at high elevations in the tropics appear to have been as much as 8 degrees to 12 degrees C cooler than today, the atmosphere contained about 200 times as much dust, and the Amazon Basin forest cover may have been much less extensive. Differences in both the oxygen isotope ratio zeta(18)O (8 per mil) and the deuterium excess (4.5 per mil) from the Late Glacial Stage to the Holocene are comparable with polar ice core records. These data imply that the tropical Atlantic was possibly 5 degrees to 6 degrees C cooler during the Late Glacial Stage, that the climate was warmest from 8400 to 5200 years before present, and that it cooled gradually, culminating with the Little Ice Age (200 to 500 years before present). A strong warming has dominated the last two centuries.
# --------------------
#	Authors: Anderson, D.M., Tardif, R., Horlick, K., Erb, M.P., Hakim, G.J., Noone, D., Perkins, W.A., and E. Steig
#	Published_Date_or_Year: 2018
#	Published_Title: Additions to the last millennium reanalysis multi-proxy database
#	Journal_Name: Data Science Journal
#	Volume:
#	Edition:
#	Issue:
#	Pages:
#	Report_Number:
#	DOI:
#	Online_Resource:
#	Full_Citation: Anderson, D.M., Tardif, R., Horlick, K., Erb, M.P., Hakim, G., J., Noone, D., Perkins, W.A., and E. Steig, submitted. Additions to the last millennium reanalysis multi-proxy database. Data Science Journal.
#	Abstract: Progress in paleoclimatology increasingly occurs via data syntheses. We describe additions to a collection prepared for use in paleoclimate state estimation, specifically the Last Millennium Reanalysis (LMR).  The 2290 additional series include 2152 tree ring chronologies and 138 other series.  They supplement the collection used previously and together form a database titled LMRdb 1.0.0. The additional data draws from lake core, ice core, coral, speleothem, and tree ring archives, using published data primarily from the NOAA Paleoclimatology archive and a set of tree ring width chronologies standardized from raw International Tree Ring Data Bank ring width series. In contrast to many previous paleo compilations, the data were not selected (screened) on the basis of their environmental correlation, multi-century length, or other attributes. The inclusion of proxies sensitive to moisture and other environmental variables expands their use in data assimilation.  A preliminary calibration using linear regression with mean annual temperature reveals characteristics of the proxy series and their relationship to temperature, as well as the noise and error characteristics of the records. The additional records are structured as individual files in the NOAA Paleoclimatology format and archived at NOAA Paleoclimatology (Anderson et al. 2018) and will continue to be improved and expanded as part of the LMR Project.  The additions represent a four-fold increase in the number of records available for assimilation, provide expanded geographic coverage, and add additional proxy variables.  Applications include data assimilation, proxy system model development, and paleoclimate reconstruction using climate field reconstruction and other methods.
#------------------
# Funding_Agency
#	Funding_Agency_Name: 
#	Grant: 
# --------------------
#	Funding_Agency_Name: National Science Foundation
#	Grant:AGS-1304263
#	Funding_Agency_Name: National Oceanic and Atmospheric Administration
#	Grant:NA14OAR4310176
#------------------
# Site_Information
#	Site_Name: Huascaran glacier
#	Location: South America>Bolivia
#	Country: Bolivia
#	Northernmost_Latitude: -9.183
#	Southernmost_Latitude: -9.183 
#	Easternmost_Longitude: -77.5
#	Westernmost_Longitude: -77.5
#	Elevation: 6050 m
# --------------------
# Data_Collection
#	Collection_Name: 95Huas02
#	Earliest_Year: 1900
#	Most_Recent_Year: 1992
#	Time_Unit: y_ad
#	Notes: {"database":"LMR"} 
#
# --------------------
# Variables
#
# Data variables follow that 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) 
#
##age	age,,,years AD,,,,,N
##d18O	delta 18 oxygen,,,permil SMOW,,Ice Cores,,,N
#
# --------------------
# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing values: NAN
#
age	d18O
1992.5	-12.81
1991.5	-16.82
1990.5	-14.63
1989.5	-18.07
1988.5	-16.47
1987.5	-16.24
1986.5	-18.22
1985.5	-16.5
1984.5	-21.2
1983.5	-14.6
1982.5	-16.78
1981.5	-18.11
1980.5	-15.37
1979.5	-17.26
1978.5	-16.14
1977.5	-16.94
1976.5	-19.91
1975.5	-18.63
1974.5	-18.52
1973.5	-19.78
1972.5	-18.9
1971.5	-17.82
1970.5	-17.67
1969.5	-13.79
1968.5	-15.37
1967.5	-17.77
1966.5	-15.69
1965.5	-16.21
1964.5	-14.02
1963.5	-14.96
1962.5	-18.55
1961.5	-18.8
1960.5	-16.91
1959.5	-16.82
1958.5	-17.49
1957.5	-15.08
1956.5	-14.38
1955.5	-19.75
1954.5	-18.56
1953.5	-18.55
1952.5	-18.19
1951.5	-18.86
1950.5	-19.76
1949.5	-19.08
1948.5	-15.93
1947.5	-15.94
1946.5	-14.73
1945.5	-18.41
1944.5	-16.94
1943.5	-17.31
1942.5	-19.17
1941.5	-15.76
1940.5	-17.18
1939.5	-15.75
1938.5	-17.23
1937.5	-15.5
1936.5	-15.71
1935.5	-14.86
1934.5	-16.15
1933.5	-19.24
1932.5	-20.3
1931.5	-16.32
1930.5	-18.67
1929.5	-17.04
1928.5	-14.65
1927.5	-15.38
1926.5	-17.48
1925.5	-16.64
1924.5	-17.99
1923.5	-16.58
1922.5	-21.28
1921.5	-18.33
1920.5	-18.02
1919.5	-18.41
1918.5	-17.57
1917.5	-18.92
1916.5	-17.07
1915.5	-18.48
1914.5	-15.79
1913.5	-17.99
1912.5	-17.59
1911.5	-18.33
1910.5	-18.41
1909.5	-15.86
1908.5	-18.77
1907.5	-21.37
1906.5	-17.83
1905.5	-17.52
1904.5	-14.53
1903.5	-15.93
1902.5	-21.17
1901.5	-15.02
1900.5	-19.54