# northamerica_usa_ak011 - Mount Billy Mitchell - 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
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# Contribution_Date
#	Date: 2016-01-07
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# Title
#	Study_Name: northamerica_usa_ak011 - Mount Billy Mitchell - 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: Mount Billy Mitchell
#	Location:
#	Country: United States
#	Northernmost_Latitude: 61.33
#	Southernmost_Latitude: 61.33
#	Easternmost_Longitude: -145.25
#	Westernmost_Longitude: -145.25
#	Elevation: 300 m
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# Data_Collection
#	Collection_Name: northamerica_usa_ak011B
#	Earliest_Year: 1817
#	Most_Recent_Year: 1983
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"temperature"}{"T1":"4.56180841852"}{"T2":"16.489841419"}{"M1":"0.0225349330703"}{"M2":"0.400281250062"}
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# Species
#	Species_Name: white spruce
#	Species_Code: PCGL
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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)
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##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
1817	0.907
1818	0.882
1819	0.96
1820	1.051
1821	1.139
1822	1.151
1823	1.27
1824	1.091
1825	1.141
1826	0.982
1827	0.988
1828	0.884
1829	1.111
1830	0.95
1831	0.783
1832	1.01
1833	0.852
1834	1.026
1835	1.215
1836	1.034
1837	1.17
1838	1.185
1839	1.146
1840	1.034
1841	1.212
1842	1.09
1843	1.202
1844	1.194
1845	1.226
1846	1.248
1847	1.116
1848	1.07
1849	0.821
1850	0.938
1851	1.061
1852	1.05
1853	1.203
1854	0.947
1855	0.969
1856	0.911
1857	0.943
1858	0.945
1859	1.138
1860	1.155
1861	1.021
1862	1.125
1863	1.364
1864	1.072
1865	1.01
1866	0.953
1867	1.033
1868	0.963
1869	0.925
1870	0.931
1871	0.914
1872	0.957
1873	0.97
1874	1.147
1875	1.099
1876	0.858
1877	0.73
1878	0.776
1879	0.731
1880	0.744
1881	0.858
1882	0.767
1883	0.748
1884	0.693
1885	0.631
1886	0.586
1887	0.695
1888	0.724
1889	0.78
1890	0.918
1891	1.271
1892	1.043
1893	0.997
1894	1.049
1895	0.958
1896	0.92
1897	1.023
1898	0.956
1899	1.148
1900	0.874
1901	0.788
1902	0.859
1903	0.878
1904	0.832
1905	1.04
1906	1.016
1907	1.168
1908	1.162
1909	1.229
1910	1.036
1911	0.993
1912	0.814
1913	0.961
1914	0.831
1915	1.129
1916	0.743
1917	0.84
1918	0.879
1919	0.932
1920	1.137
1921	1.255
1922	0.827
1923	1.006
1924	0.703
1925	0.96
1926	1.018
1927	0.746
1928	1.01
1929	1.034
1930	0.932
1931	0.85
1932	0.906
1933	1.056
1934	0.891
1935	0.902
1936	1.143
1937	0.719
1938	0.844
1939	1.156
1940	1.212
1941	1.29
1942	1.295
1943	1.357
1944	1.311
1945	1.283
1946	1.498
1947	1.144
1948	0.983
1949	1.053
1950	1.145
1951	0.84
1952	0.789
1953	1.066
1954	0.967
1955	0.855
1956	0.931
1957	0.914
1958	0.887
1959	1.008
1960	1.112
1961	1.199
1962	1.129
1963	1.167
1964	1.301
1965	1.124
1966	1.041
1967	0.934
1968	1.048
1969	0.951
1970	0.877
1971	1.08
1972	0.855
1973	0.625
1974	1.058
1975	0.962
1976	0.87
1977	0.891
1978	0.945
1979	1.112
1980	0.934
1981	1.114
1982	1.239
1983	1.242