Spatiotemporal Trends in Changes in the River Water Contents in the Sakha Republic (Yakutia)

Studies of long-term fluctuations of the river flow are of interest with regard to causal relationships and associations between the climate changes and water regimen of the rivers. It is important to minimize the negative effects associated with fluctuations in the river flow based on long-term predictions of the water contents. Long-term and very long-term predictions of the water contents require understanding of the nature of the long-term changes in the water contents of the rivers. Investigation of the spatial trends in changes in the river water contents is important. It was established that there was an increasing straight-line trend of change in water content for the majority of the rivers on the territory of the Republic of Sakha (Yakutia) during the period from 1964 till 2015. Mapping of the slope factor of the linear trends allowed to determine the main regularities of the spatial breakdown of the type of perennial change in river flows. Besides, smoothing of the time series of the river flow by the method of 20–year sliding linear trend in a span of twenty years allowed to establish the types of perennial change in water content for each water body with further zoning.