# northamerica_usa_ak2 - Yakutat  Near Glacier Bear Lodge - Breitenmoser Tree Ring Chronology 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.
#
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# Online_Resource:
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# Original_Source_URL:
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# Description/Documentation lines begin with #
# Data lines have no #
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# Archive: Tree Rings
#--------------------
# Contribution_Date
#	Date: 2016-01-07
#--------------------
# Title
#	Study_Name: northamerica_usa_ak2 - Yakutat  Near Glacier Bear Lodge - Breitenmoser Tree Ring Chronology Data
#--------------------
# Investigators
#	Investigators:  Breitenmoser, P.; Bronnimann, S.; Frank, D.
#--------------------
# Description_and_Notes
#	Description: Data from Breitenmoser 2014 Journal of past Climate supplementary, see publication for ARSTAN standardization details
#--------------------
# Publication
#	Authors: Breitenmoser, P.; Bronnimann, S.; Frank, D.
#	Published_Date_or_Year: 2014-03-11
#	Published_Title: Forward modelling of tree-ring width and comparison with a global network of tree-ring chronologies
#	Journal_Name: Climate of the Past
#	Volume: 10 
#	Edition:
#	Issue:
#	Pages: 437-449
#	DOI: 10.5194/cp-10-437-2014
#	Online_Resource: www.clim-past.net/10/437/2014/
#	Full_Citation:
#	Abstract: We investigate relationships between climate and tree-ring data on a global scale using the process-based Vaganov–Shashkin Lite (VSL) forward model of tree-ring width formation. The VSL model requires as inputs only latitude, monthly mean temperature, and monthly accumulated precipitation. Hence, this simple, process-based model enables ring-width simulation at any location where monthly climate records exist. In this study, we analyse the growth response of simulated tree rings to monthly climate conditions obtained from the CRU TS3.1 data set back to 1901. Our key aims are (a) to assess the VSL model performance by examining the relations between simulated and observed growth at 2287 globally distributed sites, (b) indentify optimal growth parameters found during the model calibration, and (c) to evaluate the potential of the VSL model as an observation operator for data-assimilation-based reconstructions of climate from tree-ring width. The assessment of the growth-onset threshold temperature of approximately 4–6 C for most sites and species using a Bayesian estimation approach complements other studies on the lower temperature limits where plant growth may be sustained. Our results suggest that the VSL model skilfully simulates site level treering series in response to climate forcing for a wide range of environmental conditions and species. Spatial aggregation of the tree-ring chronologies to reduce non-climatic noise at the site level yielded notable improvements in the coherence between modelled and actual growth. The resulting distinct and coherent patterns of significant relationships between the aggregated and simulated series further demonstrate the VSL model’s ability to skilfully capture the climatic signal contained in tree-ring series. Finally, we propose that the VSL model can be used as an observation operator in data assimilation approaches to reconstruct past climate.
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# Funding_Agency
#	Funding_Agency_Name: Swiss National Science Foundation
#	Grant:
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# Site_Information
#	Site_Name: Yakutat  Near Glacier Bear Lodge
#	Location:
#	Country: United States
#	Northernmost_Latitude: 59.52
#	Southernmost_Latitude: 59.52
#	Easternmost_Longitude: -139.7
#	Westernmost_Longitude: -139.7
#	Elevation: 15 m
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# Data_Collection
#	Collection_Name: northamerica_usa_ak2B
#	Earliest_Year: 1849
#	Most_Recent_Year: 1985
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"temperature"}{"T1":"5.68450083213"}{"T2":"17.9560021714"}{"M1":"0.0229076355745"}{"M2":"0.39068882095"}
#--------------------
# Species
#	Species_Name: Sitka spruce
#	Species_Code: PCSI
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# Chronology:
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# Variables
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# 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
##trsgi	tree ring standardized growth index, tree ring, ,percent relative to mean growth, , Tree Rings, , ,N
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# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing Values: nan
#
age	trsgi
1849	1.26
1850	1.352
1851	1.202
1852	1.075
1853	1.047
1854	1.174
1855	1.425
1856	1.067
1857	1.078
1858	1.138
1859	1.154
1860	1.446
1861	1.306
1862	0.84
1863	0.876
1864	0.87
1865	1.041
1866	1.482
1867	1.261
1868	1.046
1869	1.083
1870	1.394
1871	1.126
1872	1.316
1873	1.205
1874	1.232
1875	0.996
1876	0.69
1877	0.874
1878	0.861
1879	0.785
1880	0.784
1881	1.005
1882	0.866
1883	1.115
1884	1.24
1885	1.108
1886	1.083
1887	0.78
1888	1.253
1889	1.06
1890	1.243
1891	1.416
1892	1.528
1893	1.395
1894	1.064
1895	1.083
1896	1.068
1897	1.105
1898	1.272
1899	1.059
1900	1.063
1901	1.035
1902	1.387
1903	1.191
1904	1.071
1905	1.459
1906	0.959
1907	1.04
1908	1.085
1909	1.077
1910	0.852
1911	0.891
1912	1.024
1913	1.063
1914	1.284
1915	1.317
1916	0.952
1917	0.982
1918	1.149
1919	0.95
1920	0.995
1921	1.142
1922	0.77
1923	0.995
1924	0.826
1925	0.921
1926	0.918
1927	0.939
1928	0.938
1929	1.024
1930	0.907
1931	0.976
1932	0.892
1933	0.846
1934	0.915
1935	0.841
1936	0.808
1937	0.562
1938	0.652
1939	0.784
1940	0.905
1941	0.757
1942	0.815
1943	0.61
1944	0.633
1945	0.734
1946	0.806
1947	0.727
1948	0.728
1949	0.732
1950	0.814
1951	0.731
1952	0.843
1953	1.095
1954	1.04
1955	1.046
1956	0.972
1957	1.083
1958	0.898
1959	1.009
1960	1.136
1961	1.023
1962	1.051
1963	1.192
1964	1.113
1965	1.102
1966	1.073
1967	1.029
1968	1.117
1969	1.064
1970	0.995
1971	1.113
1972	0.913
1973	0.928
1974	1.078
1975	0.938
1976	0.862
1977	0.904
1978	0.855
1979	0.872
1980	0.968
1981	1.105
1982	1.086
1983	1.166
1984	1.074
1985	0.986