# northamerica_usa_ak069 - Ptarmigan Hill - 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_ak069 - Ptarmigan Hill - 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: Ptarmigan Hill
#	Location:
#	Country: United States
#	Northernmost_Latitude: 65.07
#	Southernmost_Latitude: 65.07
#	Easternmost_Longitude: -162.23
#	Westernmost_Longitude: -162.23
#	Elevation: 244 m
#--------------------
# Data_Collection
#	Collection_Name: northamerica_usa_ak069B
#	Earliest_Year: 1790
#	Most_Recent_Year: 2002
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"temperature"}{"T1":"5.09359023208"}{"T2":"17.0395318984"}{"M1":"0.0232548733433"}{"M2":"0.440615662779"}
#--------------------
# 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
1790	0.898
1791	1.001
1792	1.053
1793	1.206
1794	1.224
1795	1.333
1796	1.14
1797	0.925
1798	0.857
1799	0.764
1800	0.792
1801	0.731
1802	0.732
1803	0.921
1804	0.795
1805	0.726
1806	0.687
1807	0.667
1808	0.753
1809	0.569
1810	0.734
1811	0.78
1812	0.805
1813	0.858
1814	0.981
1815	0.914
1816	0.837
1817	0.874
1818	1.125
1819	1.067
1820	1.332
1821	1.292
1822	0.975
1823	1.37
1824	1.205
1825	1.074
1826	1.141
1827	1.251
1828	1.057
1829	1.278
1830	1.204
1831	1.084
1832	0.944
1833	0.907
1834	0.772
1835	0.812
1836	0.721
1837	0.92
1838	1.124
1839	1.009
1840	1.164
1841	0.893
1842	0.905
1843	0.964
1844	1.116
1845	1.179
1846	1.132
1847	1.333
1848	1.321
1849	1.041
1850	1.207
1851	1.254
1852	1.329
1853	1.332
1854	1.091
1855	1.282
1856	0.943
1857	1.555
1858	1.383
1859	1.172
1860	1.144
1861	1.071
1862	1.154
1863	1.085
1864	0.985
1865	1.093
1866	0.85
1867	1.054
1868	0.853
1869	0.908
1870	1.085
1871	0.816
1872	1.113
1873	1.17
1874	1.297
1875	1.252
1876	1.292
1877	1.409
1878	1.484
1879	1.376
1880	1.391
1881	1.447
1882	1.674
1883	1.207
1884	1.376
1885	1.329
1886	1.009
1887	1.14
1888	0.821
1889	0.989
1890	1.145
1891	1.267
1892	1.04
1893	0.959
1894	1.102
1895	1.001
1896	0.872
1897	1.1
1898	0.819
1899	0.499
1900	0.801
1901	0.642
1902	0.752
1903	0.71
1904	0.616
1905	0.621
1906	0.788
1907	0.738
1908	0.628
1909	0.569
1910	0.572
1911	0.872
1912	0.558
1913	0.87
1914	1.037
1915	1.224
1916	1.149
1917	0.894
1918	1.105
1919	0.73
1920	1.071
1921	1.07
1922	0.591
1923	0.908
1924	0.891
1925	1.078
1926	1.197
1927	1.069
1928	1.072
1929	1.083
1930	0.92
1931	0.8
1932	1.053
1933	0.917
1934	0.842
1935	1.017
1936	0.888
1937	0.903
1938	0.707
1939	0.907
1940	0.551
1941	0.862
1942	0.973
1943	1.02
1944	0.751
1945	0.688
1946	0.863
1947	0.678
1948	0.87
1949	0.712
1950	0.79
1951	0.863
1952	1.164
1953	1.136
1954	1.233
1955	1.388
1956	1.322
1957	1.296
1958	1.364
1959	1.305
1960	1.464
1961	1.025
1962	1.297
1963	1.048
1964	1.047
1965	0.844
1966	1.093
1967	0.942
1968	0.69
1969	0.638
1970	0.818
1971	0.998
1972	0.825
1973	0.648
1974	0.83
1975	0.77
1976	0.707
1977	0.928
1978	0.549
1979	0.914
1980	0.823
1981	0.781
1982	1.019
1983	0.809
1984	0.968
1985	1.047
1986	0.817
1987	0.898
1988	0.785
1989	0.954
1990	0.997
1991	0.778
1992	0.883
1993	0.784
1994	0.829
1995	0.835
1996	0.899
1997	1.086
1998	1.001
1999	1.123
2000	1.128
2001	1.217
2002	1.165