Modeling Seasonality of River Discharge in Pan-Arctic Watersheds with
Ring Width and Tracheid Anatomical Parameters
Abstract
Polar regions are highly sensitive to climate change. In recent decades,
the Arctic has warmed twice as fast as the world average, which has led
to a significant loss of ice cover in the Arctic Ocean. The positive
feedback from continental hydrology to Arctic warming amplifies
perturbations in the climate system in response to changes in heat and
freshwater fluxes. As the surface warms and storm paths change,
precipitation and glacier melt have increased pan-Arctic runoff. Melting
permafrost adds even more water to river systems. Our research aims to
understand 1) whether this feedback impacts the river flow only in the
warm season, 2) whether the runoff change in the cold (winter) season
can amplify the initial warming, and 3) what is the spatiotemporal
pattern of seasonal variations in streamflow across pan-Arctic
watersheds. Tree rings serve as critical proxies for quantifying
hydrological responses to climate change. We are exploring the potential
of modeling seasonal flows, especially winter versus spring and summer
flows, and water temperature using intra-seasonal aggregation of climate
signals in subsets of ring chronologies derived from quantified tracheal
cell parameters: cell area, tangential cell diameter, radial cell
diameter, cell wall thickness. The preliminary results demonstrate
significant correlation of summer water temperature with cell area and
radial cell diameter, whereas the discharge correlates stronger with
cell wall thickness and tangential cell diameter. We emphasize the
importance of modeling intra-seasonal hydrological parameters versa the
hydrological year average to analyze the contribution of continental
hydrology to Arctic warming.