# northamerica_usa_ak018 - Kenai Lowlands - 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_ak018 - Kenai Lowlands - 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: Kenai Lowlands
#	Location:
#	Country: United States
#	Northernmost_Latitude: 59.68
#	Southernmost_Latitude: 59.68
#	Easternmost_Longitude: -151.42
#	Westernmost_Longitude: -151.42
#	Elevation: 20 m
#--------------------
# Data_Collection
#	Collection_Name: northamerica_usa_ak018B
#	Earliest_Year: 1753
#	Most_Recent_Year: 1988
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"moisture"}{"T1":"2.11722292186"}{"T2":"12.0405251232"}{"M1":"0.0238767000966"}{"M2":"0.59820925731"}
#--------------------
# Species
#	Species_Name: Sitka spruce
#	Species_Code: PCSI
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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
1753	0.595
1754	0.613
1755	0.525
1756	0.415
1757	0.5
1758	0.458
1759	0.611
1760	0.878
1761	0.784
1762	0.785
1763	0.575
1764	0.588
1765	0.666
1766	0.817
1767	0.721
1768	0.803
1769	0.785
1770	0.402
1771	0.544
1772	1.126
1773	1.179
1774	1.414
1775	1.141
1776	1.62
1777	1.491
1778	1.279
1779	1.407
1780	1.237
1781	1.252
1782	1.613
1783	1.254
1784	1.602
1785	1.606
1786	1.724
1787	1.424
1788	1.31
1789	0.932
1790	0.877
1791	0.979
1792	1.064
1793	1.184
1794	1.651
1795	2.021
1796	1.821
1797	1.975
1798	1.636
1799	1.409
1800	1.058
1801	1.128
1802	1.07
1803	1.076
1804	0.886
1805	0.972
1806	0.97
1807	0.887
1808	0.978
1809	0.812
1810	0.698
1811	0.645
1812	0.625
1813	0.432
1814	0.416
1815	0.456
1816	0.488
1817	0.547
1818	0.637
1819	0.873
1820	0.972
1821	1.208
1822	1.108
1823	0.997
1824	1.124
1825	0.94
1826	0.865
1827	0.949
1828	0.955
1829	1.086
1830	0.854
1831	0.845
1832	1.009
1833	0.7
1834	0.758
1835	1.024
1836	0.952
1837	0.842
1838	1.042
1839	1.004
1840	1.114
1841	1.191
1842	0.653
1843	0.793
1844	0.736
1845	0.855
1846	0.983
1847	0.851
1848	0.715
1849	0.728
1850	0.56
1851	0.528
1852	0.627
1853	0.593
1854	0.63
1855	0.583
1856	0.45
1857	0.465
1858	0.474
1859	0.554
1860	0.532
1861	0.483
1862	0.414
1863	0.539
1864	0.449
1865	0.382
1866	0.358
1867	0.383
1868	0.364
1869	0.312
1870	0.356
1871	0.317
1872	0.386
1873	0.339
1874	0.323
1875	0.368
1876	0.302
1877	0.346
1878	0.448
1879	0.358
1880	0.527
1881	0.588
1882	0.579
1883	0.962
1884	1.266
1885	1.253
1886	1.674
1887	1.595
1888	1.605
1889	1.255
1890	1.56
1891	1.908
1892	1.593
1893	1.722
1894	1.022
1895	0.824
1896	0.764
1897	0.825
1898	0.82
1899	0.995
1900	1.218
1901	1.087
1902	1.126
1903	0.911
1904	0.858
1905	0.963
1906	0.895
1907	0.989
1908	1.055
1909	1.085
1910	0.936
1911	1.047
1912	1.097
1913	1.275
1914	1.237
1915	1.425
1916	1.263
1917	1.265
1918	1.346
1919	1.165
1920	1.142
1921	1.114
1922	1.143
1923	1.518
1924	1.357
1925	1.448
1926	1.52
1927	1.204
1928	1.403
1929	1.643
1930	1.474
1931	1.543
1932	1.489
1933	1.56
1934	1.41
1935	1.528
1936	1.372
1937	0.922
1938	1.209
1939	1.139
1940	1.325
1941	1.239
1942	1.269
1943	1.455
1944	1.344
1945	1.158
1946	1.098
1947	1.028
1948	1.094
1949	1.043
1950	0.738
1951	0.712
1952	0.609
1953	0.673
1954	0.499
1955	0.602
1956	0.635
1957	0.746
1958	0.656
1959	0.811
1960	0.747
1961	1.089
1962	1.067
1963	0.913
1964	0.849
1965	0.761
1966	0.809
1967	0.653
1968	0.774
1969	0.65
1970	0.613
1971	0.694
1972	0.521
1973	0.528
1974	0.577
1975	0.476
1976	0.504
1977	0.598
1978	0.598
1979	0.78
1980	0.75
1981	1.117
1982	0.954
1983	1.101
1984	0.913
1985	0.984
1986	1.108
1987	0.859
1988	1.018