# northamerica_usa_ak15 - Gulkana  Glenallen - 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_ak15 - Gulkana  Glenallen - 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: Gulkana  Glenallen
#	Location:
#	Country: United States
#	Northernmost_Latitude: 62.28
#	Southernmost_Latitude: 62.28
#	Easternmost_Longitude: -145.37
#	Westernmost_Longitude: -145.37
#	Elevation: 500 m
#--------------------
# Data_Collection
#	Collection_Name: northamerica_usa_ak15B
#	Earliest_Year: 1879
#	Most_Recent_Year: 1985
#	Time_Unit: y_ad
#	Core_Length:
#	Notes: {"sensitivity":"moisture"}{"T1":"3.09733279407"}{"T2":"14.442210911"}{"M1":"0.0229341745515"}{"M2":"0.541120111709"}
#--------------------
# Species
#	Species_Name: Sitka spruce
#	Species_Code: PCSI
#--------------------
# 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
1879	0.701
1880	0.886
1881	1.1
1882	1.113
1883	0.989
1884	0.719
1885	0.779
1886	0.848
1887	0.824
1888	0.713
1889	0.702
1890	0.859
1891	0.793
1892	1.0
1893	0.967
1894	0.925
1895	0.981
1896	1.038
1897	1.02
1898	0.96
1899	1.119
1900	0.763
1901	0.623
1902	0.837
1903	0.77
1904	0.854
1905	0.875
1906	0.951
1907	0.975
1908	0.952
1909	0.932
1910	0.783
1911	0.74
1912	0.774
1913	0.866
1914	0.852
1915	0.824
1916	0.88
1917	0.932
1918	0.992
1919	1.032
1920	1.09
1921	1.061
1922	1.156
1923	1.032
1924	0.885
1925	1.017
1926	0.969
1927	0.908
1928	1.112
1929	1.112
1930	1.351
1931	1.141
1932	1.449
1933	1.448
1934	1.281
1935	1.252
1936	1.425
1937	1.188
1938	1.692
1939	1.497
1940	1.598
1941	1.415
1942	1.384
1943	1.358
1944	1.251
1945	1.231
1946	1.475
1947	1.071
1948	0.932
1949	1.048
1950	0.973
1951	0.815
1952	0.95
1953	0.974
1954	0.696
1955	0.889
1956	0.995
1957	0.986
1958	1.126
1959	1.235
1960	1.261
1961	1.252
1962	1.245
1963	1.035
1964	0.901
1965	1.02
1966	1.102
1967	0.99
1968	1.031
1969	0.546
1970	0.336
1971	0.639
1972	0.674
1973	0.687
1974	1.007
1975	0.968
1976	0.741
1977	0.766
1978	0.686
1979	0.908
1980	0.68
1981	0.773
1982	0.993
1983	0.643
1984	0.716
1985	0.744