The impact of climate change on morphological patterns of river floodplains in cryolithozone

Fluvial processes are highly variable and their dynamics under the influence of modern climate change are of both scientific and practical interest. The present work is an attempt to assess the impact of the modern climate change on the morphological pattern development in cryolithozone flood plains using modelling based on the methods of mathematical morphology of landscapes. The flood plains are territories of free channel meandering with topography formed by fluvial processes at different stages of development; so they represent a complex “patchwork” landscape morphological pattern occurring in the dynamic balance state. Our research involves fragments of the flood plains, for which there were two survey dates with a fairly large interval between them (about 50 years). As a climate change characteristic, the trends of surface air temperature anomalies for the same period (1956—2019) were calculated. An analysis of the calculated trends in surface temperature anomalies showed their heterogeneity both by seasons and by location, with a steady increase in surface temperature in general over the studied period. For all key sites, the mathematical model of the landscape morphological pattern of alluvial plains was tested. The analysis shows the correspondence of empirical data to theoretical ones, which allows us to obtain the model parameters to assess the change in the morphological pattern under the influence of climate change. It was suggested that climate change may lead to a change of the parameters of the corresponding distribution for the model variables due to the violation of dynamic balance. This statement was tested using the Smirnov test for two independent samples. The study of the relationship between distribution parameters and temperature trends includes assessing the correlation between them. Our analysis showed that the influence of modern temperature changes on the development of the morphological pattern of the flood plains over the past 40–50 years is manifested in a change of the distribution parameters for the forming flood plain segments, but it is not significant enough to change greatly the statistical distributions in the mathematical model of the morphological pattern of floodplains in general.