# northamerica_usa_ak045 - Usibelli 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_ak045 - Usibelli 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: Usibelli treeline
#	Location:
#	Country: United States
#	Northernmost_Latitude: 63.9
#	Southernmost_Latitude: 63.9
#	Easternmost_Longitude: -148.67
#	Westernmost_Longitude: -148.67
#	Elevation: 762 m
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# Data_Collection
#	Collection_Name: northamerica_usa_ak045B
#	Earliest_Year: 1809
#	Most_Recent_Year: 1996
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"temperature"}{"T1":"6.12604358168"}{"T2":"18.5289631259"}{"M1":"0.0216727779048"}{"M2":"0.250115431384"}
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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
1809	0.797
1810	0.853
1811	0.939
1812	0.68
1813	0.849
1814	0.78
1815	0.808
1816	0.934
1817	0.903
1818	0.892
1819	1.085
1820	0.929
1821	0.769
1822	0.768
1823	0.771
1824	0.676
1825	0.612
1826	0.778
1827	0.879
1828	1.18
1829	1.333
1830	1.146
1831	1.111
1832	1.131
1833	0.66
1834	0.815
1835	0.93
1836	0.719
1837	0.809
1838	0.791
1839	1.143
1840	1.221
1841	1.286
1842	1.23
1843	0.996
1844	1.135
1845	1.254
1846	1.251
1847	1.04
1848	0.794
1849	0.805
1850	0.887
1851	0.84
1852	0.779
1853	0.908
1854	0.835
1855	0.781
1856	0.911
1857	0.762
1858	0.949
1859	0.812
1860	0.848
1861	0.83
1862	0.746
1863	0.827
1864	0.836
1865	0.949
1866	0.951
1867	0.893
1868	0.793
1869	0.865
1870	0.887
1871	0.797
1872	0.903
1873	1.078
1874	1.014
1875	1.15
1876	1.283
1877	1.159
1878	1.015
1879	0.988
1880	0.86
1881	0.894
1882	0.634
1883	0.809
1884	0.681
1885	0.692
1886	0.712
1887	0.667
1888	0.755
1889	0.658
1890	1.0
1891	1.012
1892	0.946
1893	0.663
1894	0.672
1895	0.911
1896	0.827
1897	0.671
1898	0.693
1899	0.768
1900	0.862
1901	0.835
1902	0.838
1903	0.696
1904	0.799
1905	0.831
1906	0.81
1907	0.786
1908	0.84
1909	0.678
1910	0.982
1911	0.667
1912	0.799
1913	0.808
1914	0.941
1915	0.638
1916	0.65
1917	0.85
1918	0.668
1919	0.544
1920	0.797
1921	0.778
1922	0.602
1923	0.751
1924	0.82
1925	0.825
1926	0.862
1927	0.771
1928	0.521
1929	0.72
1930	0.663
1931	0.863
1932	0.975
1933	1.155
1934	1.416
1935	1.225
1936	1.291
1937	0.724
1938	0.574
1939	0.712
1940	0.771
1941	1.071
1942	1.127
1943	1.205
1944	0.933
1945	0.984
1946	1.059
1947	0.903
1948	0.874
1949	1.097
1950	1.057
1951	1.048
1952	1.15
1953	1.54
1954	1.303
1955	1.347
1956	1.478
1957	0.919
1958	0.83
1959	1.026
1960	1.118
1961	1.215
1962	0.924
1963	0.964
1964	0.995
1965	0.854
1966	0.916
1967	0.873
1968	0.763
1969	0.728
1970	0.682
1971	1.001
1972	0.974
1973	0.651
1974	1.001
1975	1.019
1976	1.24
1977	0.965
1978	0.638
1979	0.995
1980	1.004
1981	0.971
1982	1.048
1983	0.877
1984	0.86
1985	1.055
1986	1.287
1987	1.337
1988	1.291
1989	0.906
1990	0.79
1991	0.723
1992	0.882
1993	0.627
1994	0.635
1995	0.898
1996	1.298