# northamerica_usa_ak20 - Chitina (peat Bog) - 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.
#
#
# 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_ak20 - Chitina (peat Bog) - 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: Chitina (peat Bog)
#	Location:
#	Country: United States
#	Northernmost_Latitude: 61.67
#	Southernmost_Latitude: 61.67
#	Easternmost_Longitude: -144.67
#	Westernmost_Longitude: -144.67
#	Elevation: 150 m
#--------------------
# Data_Collection
#	Collection_Name: northamerica_usa_ak20B
#	Earliest_Year: 1801
#	Most_Recent_Year: 1986
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"moisture"}{"T1":"2.67279356182"}{"T2":"11.1820932308"}{"M1":"0.0234507026251"}{"M2":"0.647789921303"}
#--------------------
# Species
#	Species_Name: black spruce
#	Species_Code: PCMA
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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
1801	0.826
1802	0.871
1803	0.986
1804	0.98
1805	0.957
1806	1.052
1807	0.855
1808	0.98
1809	0.903
1810	0.689
1811	0.601
1812	0.774
1813	0.721
1814	0.645
1815	0.642
1816	0.595
1817	0.594
1818	0.585
1819	0.677
1820	0.697
1821	0.696
1822	0.641
1823	0.676
1824	0.675
1825	0.749
1826	0.736
1827	0.805
1828	0.76
1829	0.924
1830	0.795
1831	0.761
1832	1.049
1833	0.99
1834	0.958
1835	0.982
1836	0.977
1837	0.968
1838	1.152
1839	1.23
1840	1.09
1841	1.055
1842	1.157
1843	1.205
1844	1.117
1845	1.106
1846	1.039
1847	1.181
1848	1.192
1849	1.266
1850	1.494
1851	1.406
1852	1.244
1853	1.161
1854	1.166
1855	1.393
1856	1.292
1857	1.447
1858	1.255
1859	1.172
1860	1.343
1861	1.083
1862	1.074
1863	1.128
1864	1.03
1865	1.132
1866	1.013
1867	1.231
1868	0.933
1869	0.838
1870	0.889
1871	1.063
1872	1.256
1873	1.094
1874	1.39
1875	1.171
1876	0.995
1877	0.843
1878	1.023
1879	1.044
1880	0.883
1881	0.895
1882	1.022
1883	0.937
1884	1.02
1885	1.102
1886	1.208
1887	1.102
1888	1.088
1889	1.127
1890	1.411
1891	1.018
1892	0.997
1893	1.152
1894	1.192
1895	1.227
1896	1.411
1897	1.644
1898	1.51
1899	1.758
1900	1.454
1901	1.252
1902	1.178
1903	1.21
1904	1.105
1905	1.211
1906	1.35
1907	1.393
1908	1.206
1909	1.25
1910	1.159
1911	1.167
1912	1.052
1913	1.127
1914	1.028
1915	1.298
1916	0.986
1917	1.309
1918	1.299
1919	1.202
1920	1.344
1921	1.498
1922	1.381
1923	1.501
1924	1.387
1925	1.406
1926	1.421
1927	1.387
1928	1.486
1929	1.672
1930	1.357
1931	1.518
1932	1.349
1933	1.611
1934	1.376
1935	1.431
1936	1.294
1937	1.102
1938	1.05
1939	1.073
1940	0.988
1941	1.003
1942	1.158
1943	1.153
1944	1.104
1945	1.127
1946	1.029
1947	1.124
1948	1.167
1949	1.001
1950	1.049
1951	0.813
1952	0.836
1953	0.856
1954	0.834
1955	0.693
1956	0.728
1957	0.834
1958	0.788
1959	0.968
1960	0.767
1961	0.687
1962	0.649
1963	0.704
1964	0.744
1965	0.571
1966	0.782
1967	0.703
1968	0.775
1969	0.598
1970	0.572
1971	0.743
1972	0.536
1973	0.445
1974	0.479
1975	0.48
1976	0.451
1977	0.532
1978	0.419
1979	0.508
1980	0.518
1981	0.515
1982	0.391
1983	0.495
1984	0.555
1985	0.537
1986	0.593