# northamerica_usa_ak010 - Eureka Summit - 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:
#
# Original_Source_URL:
#
# Description/Documentation lines begin with #
# Data lines have no #
#
# Archive: Tree Rings
#--------------------
# Contribution_Date
#	Date: 2016-01-07
#--------------------
# Title
#	Study_Name: northamerica_usa_ak010 - Eureka Summit - 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.
#--------------------
# Funding_Agency
#	Funding_Agency_Name: Swiss National Science Foundation
#	Grant:
#--------------------
# Site_Information
#	Site_Name: Eureka Summit
#	Location:
#	Country: United States
#	Northernmost_Latitude: 61.83
#	Southernmost_Latitude: 61.83
#	Easternmost_Longitude: -147.33
#	Westernmost_Longitude: -147.33
#	Elevation: 960 m
#--------------------
# Data_Collection
#	Collection_Name: northamerica_usa_ak010B
#	Earliest_Year: 1735
#	Most_Recent_Year: 1983
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"temperature"}{"T1":"4.61059734778"}{"T2":"16.8860594611"}{"M1":"0.0222982798536"}{"M2":"0.402473943861"}
#--------------------
# Species
#	Species_Name: white spruce
#	Species_Code: PCGL
#--------------------
# Chronology:
#
#
#
#--------------------
# Variables
#
# 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
#
#--------------------
# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing Values: nan
#
age	trsgi
1735	1.14
1736	0.851
1737	1.282
1738	1.113
1739	0.988
1740	0.884
1741	1.023
1742	1.17
1743	0.955
1744	0.861
1745	0.987
1746	0.966
1747	1.055
1748	1.044
1749	1.276
1750	1.293
1751	1.183
1752	1.228
1753	1.087
1754	1.059
1755	0.968
1756	1.011
1757	0.739
1758	0.99
1759	1.029
1760	0.792
1761	1.126
1762	1.046
1763	1.074
1764	0.866
1765	0.904
1766	0.94
1767	1.089
1768	0.955
1769	0.971
1770	1.056
1771	0.894
1772	0.88
1773	0.914
1774	0.894
1775	0.987
1776	0.943
1777	1.041
1778	0.967
1779	1.009
1780	0.835
1781	1.048
1782	0.988
1783	1.112
1784	1.12
1785	1.306
1786	1.167
1787	1.334
1788	1.107
1789	1.089
1790	0.993
1791	1.052
1792	1.247
1793	1.084
1794	1.047
1795	1.245
1796	1.009
1797	1.272
1798	1.118
1799	1.115
1800	0.97
1801	1.301
1802	1.187
1803	1.058
1804	1.153
1805	1.025
1806	1.005
1807	0.862
1808	1.049
1809	0.892
1810	0.802
1811	0.755
1812	0.804
1813	0.96
1814	0.645
1815	0.59
1816	0.809
1817	0.585
1818	0.898
1819	0.882
1820	0.895
1821	0.886
1822	0.85
1823	0.973
1824	0.885
1825	0.915
1826	0.816
1827	0.83
1828	0.996
1829	1.144
1830	0.815
1831	0.782
1832	0.974
1833	1.082
1834	0.841
1835	0.698
1836	0.851
1837	0.752
1838	1.048
1839	0.82
1840	0.896
1841	1.053
1842	0.953
1843	0.945
1844	1.195
1845	0.97
1846	1.133
1847	0.93
1848	1.256
1849	0.948
1850	0.879
1851	0.94
1852	1.036
1853	0.89
1854	1.122
1855	1.178
1856	0.905
1857	1.045
1858	1.225
1859	1.331
1860	1.249
1861	1.071
1862	1.219
1863	1.239
1864	1.21
1865	1.271
1866	1.136
1867	1.435
1868	1.094
1869	1.011
1870	1.11
1871	0.899
1872	1.191
1873	1.118
1874	1.027
1875	1.149
1876	1.244
1877	0.919
1878	0.872
1879	0.873
1880	0.978
1881	1.169
1882	1.097
1883	0.934
1884	1.291
1885	1.137
1886	1.168
1887	0.834
1888	1.127
1889	1.039
1890	1.071
1891	1.185
1892	1.071
1893	1.13
1894	1.136
1895	1.031
1896	1.172
1897	1.323
1898	1.353
1899	1.215
1900	1.101
1901	1.088
1902	1.281
1903	1.121
1904	0.76
1905	1.078
1906	0.969
1907	0.82
1908	0.936
1909	0.783
1910	0.776
1911	1.039
1912	0.849
1913	1.228
1914	0.948
1915	1.08
1916	0.711
1917	0.845
1918	1.058
1919	0.681
1920	0.875
1921	0.854
1922	0.904
1923	0.973
1924	0.724
1925	0.636
1926	0.775
1927	0.797
1928	0.799
1929	0.828
1930	0.804
1931	0.862
1932	0.766
1933	1.004
1934	0.915
1935	1.08
1936	1.2
1937	0.905
1938	0.77
1939	1.039
1940	0.959
1941	1.098
1942	1.243
1943	1.255
1944	1.302
1945	1.031
1946	1.275
1947	1.059
1948	1.141
1949	0.803
1950	1.044
1951	0.81
1952	0.835
1953	0.847
1954	0.738
1955	0.72
1956	0.595
1957	0.877
1958	0.899
1959	0.9
1960	0.787
1961	0.839
1962	1.01
1963	0.687
1964	1.043
1965	0.71
1966	0.983
1967	0.902
1968	0.943
1969	0.912
1970	0.646
1971	1.04
1972	0.808
1973	0.48
1974	0.749
1975	0.829
1976	0.857
1977	0.844
1978	0.768
1979	1.014
1980	0.915
1981	0.91
1982	1.141
1983	0.987