Channel Network Control on Seasonal Lake Area Dynamics in Arctic Deltas

Area of Science:

• Environmental science
• Remote sensing
• Arctic research

Background:

• Arctic deltas feature numerous lakes, which are significant sources of methane emissions and centers of biogeochemical activity.
• Seasonal changes in lake extent introduce uncertainties in estimating carbon emissions from lakes, especially when using annual or longer timescales.
• Understanding lake dynamics is crucial for accurate climate modeling and carbon budget assessments in the Arctic.

Purpose of the Study:

• To analyze the seasonal variability of lake area loss (shrinkage) on Arctic deltas over the past 20 years.
• To investigate the spatial patterns of lake shrinkage in relation to the channel network.
• To identify the key factors driving observed lake shrinkage patterns and their implications for methane emissions and permafrost depth.

Main Methods:

• Analysis of Landsat-derived water masks to quantify summertime lake area loss over two decades.
• Statistical analysis of monthly shrinkage rates in relation to proximity to the channel network.
• Correlation of shrinkage patterns with environmental factors such as active layer depth and vegetation density.

Main Results:

• A structured variability in monthly lake shrinkage rates was observed, decreasing systematically with distance from the channel network.
• Deeper active layers near channels enhance near-surface connectivity and storage, while increased vegetation density promotes higher evapotranspiration rates.
• These findings highlight a distinct spatial pattern in lake shrinkage driven by hydrological and ecological factors.

Conclusions:

• The identified lake shrinkage patterns can be effectively monitored using remote sensing data.
• These shrinkage signals offer a valuable method for constraining estimates of lacustrine methane emissions.
• The study provides a basis for developing process-based estimates of permafrost depth on Arctic deltas.