Margulis Research Group

Department of Civil and Environmental Engineering

UCLA

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"Investigating SWE and glacial variability in the Chilean Andes" (student fellowship) and "Advancing drought and avalanche preparedness through multiscale snow measurements and modeling" (multi-year field campaign)

(Sponsor: Chilean National Science and Technology Commission; Student Fellow: Gonzalo Cortes, Collaborator/s: James McPhee, U. Chile; Noah Molotch, U. Colorado)

The Andes snowpack plays a vital role in providing key water resources to many high-population centers in South America. These two projects involve an effort to extend remote sensing reanalysis schemes to the estimation of snowpack characteristics in the Andes. As a key first step they involve gathering in situ data for validation and developing remote sensing and modeling methods. The focus is on remotely sensed fractional snow covered area using Landsat data for use in the assimilation and seasonal snow campaigns to gather intensive data within test watersheds. If successful, the methods could be extended to the entire Andes where operational in situ sensors are scarce. An auxiliary aim of this work is to use the remote sensing data to investigate Andean glaciers and how they are changing.

Study region for development/testing/validation of fSCA retrieval algorithm. Maps showing the general location of the preliminary study areas, their relation to Santiago, and specific validation sites.

 

Example data from Landsat showing falsecolor map (left panel) and a derived glacial mask (right panel).

 

DEM of Andean study region. Watersheds shown in red are the basis of preliminary testing of the SWE reanalysis methods.

Example of the fractional snow covered area over northern region of domain shown to the left. The red dots indicate locations of operational snow data collection, which incidentally do not show snow despite significant snow remaining at higher elevations.

 

Preliminary results:

Trends in glacial area diagnosed with full Landsat 5 record using the fractional and binary classification scheme.

 

Maps of posterior estimates of fSCA (left two panels) and SWE (right two panels) for the Ojos de Agua watershed for day of water year 191 and 239.

 

Time series of prior and posterior fSCA (left panel) and SWE (right panel) for a particular pixel in Ojos de Aqua where in situ SWE measurements were available near peak SWE. Left panel shows the update of fSCA to fit the Landsat measurements and the right panel shows the corresponding updated SWE. Colored ranges represent uncertainty of the estimate in terms of (ensemble) interquartile range.

Datasets: All datasets generated as part of this project will be released publically upon publication and completion of the project. Please contact the PI about expected release dates, preliminary data availability and consult this site for ftp links when they become available.