A PARAMETERIZATION ALGORITHM FOR THE VAGANOV–SHASHKIN MODEL OF SEASONAL GROWTH AND TREE-RING FORMATION

Abstract

In order to simulate the Vaganov–Shashkin model for seasonal growth and tree-ring formation, a solution algorithm for the parameterization problem of the model is being proposed in cases, when a modulation is possible. The algorithm is realized as dll-library (or as a text file), tested on extensive data. A concept of difference in criterion between the actual tree-ring chronology and its model is introduced. Two new difference criteria are developed.

Full Text

The Vaganov- Shashkin model of seasonal growth and tree-ring formation [1–3] (hereinafter referred to as VSmodel) describes the influence of climatic conditions on the cellular structure of annual rings. The main destination of the model consists in using it as a tool permitting any individual or generalized tree-ring chronology (TRC) during a set of years with available meteorological station data (see below description of the VS-model input): 1) extracting the climate-driven component of the TRC under consideration; 2) pointing, if modeling quality of the involved TRC by the VS-model is satisfactory, for arbitrary day of the given years set, what of two factors – air temperature or precipitation – had limited the growth of woody plant which corresponds to the TRC. TRC is a time series of values of some numerical characteristic of tree/trees of this TRC [4]. The main destination of the VS-model, in particular, is that it makes possible to use it as a quality tester for individual and generalized TRCs which will be used as mediators, carrying information about climatic data [2]. A TRC is considered to be suitable for using for the purpose of a mediator for carrying climatic information if and only if its climate-driven component had been extracted by the VS-model conforms with the TRC satisfactorily enough. The VS-model is a deterministic dynamic simulation model. Its input data consist of two blocks. The first block is the climatic data of daily resolution at air temperature, precipitation, and doses of solar radiation coming down to the Earth’s surface.