Fresh water stored on and beneath land helps people and ecosystems survive dry periods, but GRACE satellite records begin only in 2002. We tested whether tree rings can extend water storage records further back in time. Across western North America, tree growth often tracked yearly storage changes, especially in dry regions. These findings provide a new way to place recent droughts and water shortages in a much longer historical context.

This study addresses the challenge of accurately representing mountain observations in Atmospheric Transport Models and inverse modeling studies. We introduce a new varying release height method based on potential temperature to better represent mountain observations in the ATM. We evaluated three release height methods at three mountain sites and the results show that the model performance strongly depends on the release height choice, meteorological resolution, and atmospheric conditions.