# northamerica_usa_ak013 - Willow Island - 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_ak013 - Willow Island - 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: Willow Island
#	Location:
#	Country: United States
#	Northernmost_Latitude: 64.83
#	Southernmost_Latitude: 64.83
#	Easternmost_Longitude: -148.17
#	Westernmost_Longitude: -148.17
#	Elevation: 99 m
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# Data_Collection
#	Collection_Name: northamerica_usa_ak013B
#	Earliest_Year: 1810
#	Most_Recent_Year: 1983
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"moisture"}{"T1":"2.89977135303"}{"T2":"15.6762141077"}{"M1":"0.0223416454423"}{"M2":"0.486667807596"}
#--------------------
# 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)
#
##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
1810	0.999
1811	0.943
1812	0.972
1813	0.913
1814	0.904
1815	0.767
1816	0.83
1817	0.678
1818	0.594
1819	0.514
1820	0.687
1821	0.871
1822	0.786
1823	1.186
1824	1.29
1825	1.059
1826	1.22
1827	0.971
1828	1.301
1829	1.382
1830	1.552
1831	1.31
1832	1.251
1833	1.047
1834	1.02
1835	1.029
1836	0.736
1837	0.825
1838	0.833
1839	0.823
1840	0.794
1841	0.777
1842	0.842
1843	1.108
1844	0.956
1845	1.134
1846	1.162
1847	1.101
1848	1.113
1849	1.01
1850	1.16
1851	1.134
1852	1.095
1853	1.357
1854	1.295
1855	1.132
1856	1.063
1857	1.306
1858	1.155
1859	1.186
1860	1.153
1861	1.144
1862	1.055
1863	0.878
1864	0.688
1865	0.636
1866	0.762
1867	0.597
1868	0.806
1869	0.727
1870	0.777
1871	0.756
1872	0.717
1873	0.815
1874	1.085
1875	1.03
1876	0.896
1877	0.731
1878	0.639
1879	0.795
1880	1.05
1881	1.036
1882	1.091
1883	0.969
1884	1.029
1885	0.816
1886	1.056
1887	1.12
1888	0.911
1889	0.749
1890	0.881
1891	1.052
1892	0.651
1893	0.745
1894	0.836
1895	0.935
1896	0.741
1897	0.9
1898	0.684
1899	0.681
1900	0.744
1901	0.813
1902	0.763
1903	0.753
1904	0.528
1905	0.66
1906	0.839
1907	0.844
1908	1.041
1909	0.859
1910	0.558
1911	0.756
1912	0.658
1913	0.93
1914	1.069
1915	1.349
1916	1.447
1917	1.569
1918	1.665
1919	1.229
1920	1.323
1921	1.498
1922	1.259
1923	1.792
1924	1.255
1925	1.328
1926	1.443
1927	1.192
1928	1.027
1929	1.267
1930	1.204
1931	1.288
1932	1.209
1933	1.315
1934	1.353
1935	1.415
1936	1.412
1937	1.101
1938	1.236
1939	1.259
1940	0.834
1941	0.733
1942	0.648
1943	1.073
1944	1.097
1945	1.016
1946	1.198
1947	1.061
1948	1.116
1949	0.973
1950	1.124
1951	0.883
1952	1.064
1953	0.812
1954	0.663
1955	0.861
1956	0.978
1957	0.948
1958	0.522
1959	0.641
1960	0.818
1961	0.809
1962	0.996
1963	0.921
1964	1.026
1965	0.989
1966	0.874
1967	0.824
1968	0.966
1969	0.75
1970	0.508
1971	0.82
1972	0.893
1973	0.746
1974	0.859
1975	0.615
1976	0.809
1977	0.708
1978	0.706
1979	0.8
1980	0.797
1981	0.705
1982	1.205
1983	1.428