# northamerica_usa_ak041 - Nome Creek treeline - 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_ak041 - Nome Creek treeline - 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: Nome Creek treeline
#	Location:
#	Country: United States
#	Northernmost_Latitude: 65.37
#	Southernmost_Latitude: 65.37
#	Easternmost_Longitude: -146.62
#	Westernmost_Longitude: -146.62
#	Elevation: 884 m
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# Data_Collection
#	Collection_Name: northamerica_usa_ak041B
#	Earliest_Year: 1810
#	Most_Recent_Year: 1997
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"temperature"}{"T1":"7.06357534574"}{"T2":"19.3839714179"}{"M1":"0.0220867662173"}{"M2":"0.235913531304"}
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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)
#
##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	0.926
1811	0.82
1812	0.837
1813	0.676
1814	0.447
1815	0.366
1816	0.353
1817	0.533
1818	0.619
1819	0.62
1820	0.712
1821	0.625
1822	0.644
1823	0.853
1824	0.787
1825	0.821
1826	1.007
1827	0.966
1828	1.296
1829	1.384
1830	1.639
1831	1.4
1832	1.419
1833	0.981
1834	0.881
1835	0.568
1836	0.787
1837	0.832
1838	1.241
1839	1.241
1840	1.244
1841	1.209
1842	1.255
1843	1.037
1844	1.181
1845	0.969
1846	1.451
1847	1.118
1848	1.135
1849	0.72
1850	0.699
1851	0.867
1852	1.047
1853	1.666
1854	1.657
1855	1.359
1856	0.923
1857	1.266
1858	0.894
1859	1.045
1860	0.944
1861	1.032
1862	1.086
1863	1.137
1864	1.008
1865	1.356
1866	1.053
1867	1.13
1868	0.958
1869	1.044
1870	1.128
1871	1.023
1872	0.857
1873	1.191
1874	1.033
1875	1.09
1876	0.888
1877	0.97
1878	0.951
1879	1.116
1880	0.831
1881	1.049
1882	1.113
1883	0.984
1884	1.05
1885	0.999
1886	1.16
1887	0.799
1888	0.61
1889	0.66
1890	0.804
1891	0.808
1892	0.716
1893	0.655
1894	0.649
1895	0.783
1896	0.821
1897	0.905
1898	0.752
1899	0.679
1900	0.7
1901	0.662
1902	0.717
1903	0.836
1904	0.671
1905	0.713
1906	0.934
1907	0.85
1908	1.214
1909	1.125
1910	0.915
1911	1.1
1912	0.545
1913	1.062
1914	1.067
1915	1.17
1916	0.741
1917	1.098
1918	1.259
1919	0.538
1920	0.877
1921	0.825
1922	0.532
1923	1.146
1924	0.495
1925	0.82
1926	1.115
1927	1.148
1928	0.878
1929	1.182
1930	1.094
1931	0.973
1932	1.237
1933	1.13
1934	1.49
1935	1.705
1936	1.577
1937	1.134
1938	0.922
1939	1.278
1940	0.717
1941	1.268
1942	1.143
1943	1.105
1944	0.959
1945	1.031
1946	1.427
1947	1.114
1948	1.107
1949	0.595
1950	1.15
1951	0.816
1952	1.219
1953	1.192
1954	1.104
1955	1.075
1956	0.888
1957	0.777
1958	0.833
1959	0.841
1960	1.21
1961	1.108
1962	1.159
1963	0.722
1964	1.195
1965	1.039
1966	1.111
1967	1.071
1968	0.934
1969	0.646
1970	0.446
1971	1.055
1972	0.64
1973	0.475
1974	0.725
1975	0.811
1976	0.879
1977	0.865
1978	0.67
1979	0.972
1980	1.043
1981	0.963
1982	1.395
1983	1.075
1984	1.027
1985	0.982
1986	0.9
1987	0.753
1988	0.626
1989	0.811
1990	0.825
1991	0.696
1992	0.77
1993	0.441
1994	0.608
1995	0.797
1996	0.936
1997	0.965