# northamerica_usa_ak050 - Nutirwik Creek - 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_ak050 - Nutirwik Creek - 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: Nutirwik Creek
#	Location:
#	Country: United States
#	Northernmost_Latitude: 67.15
#	Southernmost_Latitude: 67.15
#	Easternmost_Longitude: -149.13
#	Westernmost_Longitude: -149.13
#	Elevation: 100 m
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# Data_Collection
#	Collection_Name: northamerica_usa_ak050B
#	Earliest_Year: 1803
#	Most_Recent_Year: 2000
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"moisture"}{"T1":"6.02399939859"}{"T2":"16.0517028499"}{"M1":"0.0223519415734"}{"M2":"0.424454637406"}
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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
1803	0.906
1804	0.609
1805	0.695
1806	0.765
1807	1.09
1808	0.978
1809	0.875
1810	0.857
1811	0.701
1812	0.609
1813	0.577
1814	0.521
1815	0.526
1816	0.58
1817	0.669
1818	0.712
1819	0.681
1820	0.752
1821	0.924
1822	0.798
1823	0.905
1824	0.95
1825	1.145
1826	1.065
1827	0.777
1828	1.255
1829	1.227
1830	1.15
1831	1.07
1832	1.345
1833	0.968
1834	0.897
1835	0.642
1836	0.575
1837	0.691
1838	0.858
1839	0.642
1840	0.719
1841	0.651
1842	0.788
1843	0.77
1844	0.703
1845	0.591
1846	0.674
1847	0.851
1848	1.159
1849	1.011
1850	0.844
1851	1.218
1852	1.064
1853	1.151
1854	1.232
1855	1.291
1856	0.945
1857	1.092
1858	0.967
1859	0.935
1860	0.907
1861	1.048
1862	1.073
1863	1.027
1864	0.795
1865	0.877
1866	0.869
1867	0.918
1868	0.621
1869	0.497
1870	0.658
1871	0.575
1872	0.571
1873	0.83
1874	0.913
1875	0.955
1876	1.237
1877	1.24
1878	1.044
1879	1.259
1880	1.219
1881	1.281
1882	1.393
1883	0.98
1884	1.092
1885	1.431
1886	1.265
1887	0.977
1888	1.051
1889	1.128
1890	1.142
1891	1.317
1892	1.064
1893	0.793
1894	0.648
1895	0.989
1896	0.839
1897	1.022
1898	0.672
1899	0.556
1900	0.477
1901	0.67
1902	0.867
1903	0.738
1904	0.709
1905	0.635
1906	0.938
1907	0.835
1908	0.932
1909	0.987
1910	0.856
1911	1.031
1912	0.715
1913	0.883
1914	0.797
1915	0.717
1916	0.697
1917	0.889
1918	0.962
1919	0.414
1920	0.775
1921	1.043
1922	0.668
1923	1.31
1924	0.804
1925	0.951
1926	0.926
1927	0.904
1928	0.87
1929	1.037
1930	1.074
1931	0.859
1932	0.942
1933	0.675
1934	0.922
1935	1.213
1936	1.201
1937	1.086
1938	0.939
1939	1.169
1940	0.834
1941	1.067
1942	1.281
1943	1.544
1944	1.615
1945	1.311
1946	1.392
1947	1.055
1948	0.978
1949	0.806
1950	1.018
1951	0.902
1952	1.227
1953	1.183
1954	1.4
1955	1.349
1956	1.072
1957	1.129
1958	1.238
1959	1.069
1960	1.456
1961	1.171
1962	1.153
1963	0.99
1964	1.114
1965	1.026
1966	0.905
1967	0.996
1968	1.037
1969	0.608
1970	0.526
1971	0.872
1972	0.908
1973	0.594
1974	0.608
1975	0.852
1976	0.77
1977	1.063
1978	0.828
1979	0.947
1980	1.194
1981	0.888
1982	1.308
1983	1.081
1984	1.191
1985	1.147
1986	1.052
1987	0.781
1988	0.864
1989	0.848
1990	0.945
1991	0.934
1992	0.955
1993	0.563
1994	0.503
1995	0.713
1996	1.006
1997	1.149
1998	1.024
1999	0.984
2000	1.039