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Computer assisted quality control in tree ring dating and measurement amanda diva dating

Agricultural production across eastern Australia and New Zealand is highly vulnerable to drought, but there is a dearth of observational drought information prior to CE 1850.Using a comprehensive network of 176 drought-sensitive tree-ring chronologies and one coral series, we report the first Southern Hemisphere gridded drought atlas extending back to CE 1500.

The CROSSDATE program focuses on comparing multiple tree-ring samples for growth pattern matching.Here we report the development of an eastern Australia and New Zealand Drought Atlas (ANZDA), a seasonally resolved gridded spatial reconstruction of drought and wet periods over the past 500 years, derived from a network of 176 tree-ring chronologies from both countries and Indonesia as well as a coral record from Queensland (177 records in total).The region in general was chosen due to common climate influences linked to droughts—predominantly the interdecadal Pacific oscillation (IPO, Power 2003).Once the samples have been pattern matched in time, a composition tool is provided to create a master chronology from component samples or other chronology files.The three-sample composition limit is bypassed through the use of hierarchical composition.The correlation tool provides a quick and effective numeric tool for finding the "best" match position between two tree-ring series.The tool is based on statistical covariance theory and is efficiently implemented using Fast Fourier Transforms (FFT).The 2013 drought in New Zealand was estimated to have caused GDP to fall by 0.6% (Mc Donald 2013).There is thus an urgent need to quantify and improve understanding of past natural climatic variations, through accurate, quantified, and absolutely-dated reconstructions that capture variation over annual, decadal and multi-decadal timescales, which in turn can be used to test and refine global climate models.The master chronology is also checked year-by-year for sample component ring widths that are statistical outliers.The CROSSDATE program additionally performs sample and file date checking for each sample component of the master chronology.


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