Hydro-climatic and lake change patterns in Arctic permafrost and non-permafrost areas

•Opposite change direction found generally in runoff from that in precipitation.•This contrast and lake changes are explained by evapotranspiration changes.•Basin-scale permafrost thaw is clearly indicated in only one lake-change area.

SummaryThis paper investigates patterns of lake-area and hydro-climatic change in Arctic river basins, and possible influence of permafrost change reflected in such patterns. A salient change pattern, emerging across all investigated basins in both permafrost and non-permafrost areas, is an opposite change direction in runoff (R) from that in precipitation (P). To explain this change contrast, an increase (decrease) in relative water-balance constrained evapotranspiration ETwb/P is required where R decreases (increases). Increasing temporal variability of daily river discharge (sdQ) is found in all basins with spatially extensive lake decrease, which also exhibit decrease in ETwb/P. Clear indication of basin-wide permafrost thaw is found in only one basin, and is possible in two more, but unlikely in the largest of the total four investigated permafrost basins.