AK CASC Fellow Thesis Defense

IARC 501
Monday, May 1, 2017 - 11:00am to 12:00pm AKDT

AK CASC Fellow Abraham Endalamaw will have his thesis defense on Monday, May 1st titled "Improved Mesoscale Hydrologic Modeling of the Interior Alaska Boreal Forest Ecosystem".

The Interior Alaska boreal forest ecosystem is one of the largest ecosystems on earth and lies between the warmer southerly temperate and colder arctic regions. The ecosystem is underlain by discontinuous permafrost. The presence or absence of permafrost primarily controls water pathways and ecosystem composition. As a result, the region hosts two distinct ecotypes that transition over a very short spatial scale – often on the order of meters. Incorporating these spatial ecosystem and their hydraulic and thermal properties into meso-scale hydrologic model is very challenging, but critical as the region is experiencing unprecedented ecological and hydrological changes that have regional and global implications. However, the issue of accurate representation of the landscape heterogeneity and mesoscale hydrological modeling has remained a big challenge. In this study, this grand challenge has been addressed by developing a simple landscape model from the hill-slope studies and in situ measurements over the past several decades. The new approach developed in this study significantly improved the meso-scale prediction of several hydrological processes including streamflow and evapotranspiration (ET).

The impact of climate induced landscape change on hydrology is also investigated. In the projected climate scenario, Interior Alaska is projected to undergo a major landscape shift including transitioning from a coniferous-dominated to deciduous-dominated ecosystem and from discontinuous permafrost to either a sporadic or isolated permafrost region. This major landscape shift is predicted to have a larger and complex impact in the predicted runoff, evapotranspiration, and moisture deficit (precipitation minus evapotranspiration). Overall, a large increase in runoff, evapotranspiration, and moisture deficit is predicted under future climate. Most hydrological climate change impact studies do not usually include the change in landscape. In this study we found that ignoring the potential ecosystem change could lead to an inaccurate conclusion. Hence, hydrological climate change impact studies must take the climate induced vegetation and permafrost changes into account to fully account for the overall changes.