Glaciers and freshwater resources in a changing climate
- Author(s): Lawrence, Collin
- Advisor(s): Famiglietti, James S.
- et al.
One of the most rapid transformations forced by recent global climate change is the recession of glaciers worldwide. The study of the fate of glacier meltwater lies at the intersection of the cryosphere and hydrologic cycle, making it a unique interdisciplinary study of the Earth system. A substantial body of research has focused on the how the changing volume of glaciers is contributing to sea level rise. However, comparatively fewer studies have investigated how glacier meltwater moves over the land surface to the oceans, impacting runoff and freshwater resources. Using models, in situ data, and remote sensing observations, this work seeks to quantify glacier contributions to runoff at large scales.
First, a temperature index melt model is developed to estimate mass balance for the Gulkana Glacier, Alaska, US. The model is forced with meteorological conditions taken near the surface of the glacier. Results from the model are compared with 40 years of glacier stake data recorded by the US Geological Survey.
Next, glacier contributions to streamflow are estimated for eight highly glaciated river basins in high mountain Asia (HMA). This work utilizes a new, globally complete glacier inventory along with remotely sensed estimates of glacier recession to quantify glacier storage change for 2003 - 2009. Results are integrated with the HydroSHEDS (Hydrological Data and Maps Based on Shuttle Elevation Derivatives at Multiple Scales) river network to simulate how glacier melt in this region moves downstream. Runoff data from previous literature and simulations from the Global Land Data Assimilation System (GLDAS) are used throughout the study region to quantify the fraction of streamflow due to glacier melt.
Finally, the combined land-atmosphere water balance is used to estimate basin runoff for the HMA region. Terrestrial water storage changes observed by the Gravity Recovery and Climate Experiment (GRACE) satellites are combined with atmospheric reanalysis from the ERA-Interim Project to provide a remote sensing estimate of runoff. These are compared with runoff simulations from the various GLDAS models.