The methodology for assessing an integral indicator of the degree of favorable weather conditions for plants

The weather and climatic conditions of the periods under study significantly affect the response of biological systems to other environmental factors, including technogenic transformation of the environment. Having a complex of weather factors, it is difficult to unequivocally judge the favorable weather conditions of a particular year of observation. In this paper, an integral indicator of the degree of favorable weather conditions and a technology for its calculation are proposed. The degree of favorable weather is expressed in points on a five-point scale. The calculation uses a set of weather factors that potentially affect the biological object under study (organism, population, community). Weather factors and periods in which they can affect the objects under study are selected taking into account the biological characteristics of the object, for example, in our case, the period of the intrarenal phase (May of the previous year), the stage of active organogenesis, extrarenal growth until the period of collection of biological material (July of the current year). The method of principal components reduces hydrometeorological indicators and determines the factors that make the greatest contribution to weather variability in the periods under study. The absolute values of these factors are converted into points on the basis of a five-point scale for the correspondence of weather factors to the climatic norm and the optimal values of the HTC. Based on the average score for each year, the degree of favorable weather for a particular biological object is determined. The paper contains an example of a technology for calculating the integral indicator of favorable weather for silver birch (Betula pendula Roth), growing in six localities of the Tagil zone of the Middle Urals, in which the variability of leaf morphological features was studied in the period from 2016 to 2019. On the example of the Betula pendula leaf blade shape index, a statistically significant dependence of this feature on the integral indicator of the degree of favorable weather is shown.