Seminar by Cassie Wells Lumbrazo, University of Washington.
People love looking at snow in trees: how does this help hydrologists?
Abstract:
Snow and forest cover interact across at least 20% of the Northern Hemisphere land surface. One of the primary processes of this interaction is the interception of snowfall by forests. Depending on the climate, forests can intercept between 30-80% of snowfall. Once snow is intercepted, it can unload through meltwater drip, sublimate back to the atmosphere, or unload as solid snow to the snowpack below. Knowing exactly how much snow is intercepted, as well as when and how it is unloaded, is valuable for estimating both water and energy budgets. Modeling snow loading and unloading is extremely difficult due to the spatial and temporal complexity of the process, and validation of these models is almost impossible due to a lack of suitable data collection methods, both in the field and in laboratory environments.
Time-lapse photography is a unique tool that can capture forest-snow interception in remote areas and adverse weather conditions that has yet to be utilized for snow interception modelling. We leveraged time-lapse photography along with the online citizen science platform Zooniverse, involving > 8000 people, to create a dataset of snow interception observations at 15 field sites in the United States. With this unique interception dataset, we were able to evaluate the performance of three snow unloading parameterizations in the Structure for Unifying Multiple Modeling Alternatives (SUMMA) modular hydrologic modeling framework.
Our results show that the choice of unloading parameterization can result in 20% difference in SWE on the ground below the canopy and 10% difference in estimated average winter canopy albedo. Additionally, we were also able to show that site specific interception patterns, such as wind dominated unloading or riming, impact the transferability of unloading schemes.
These novel observations shed light on processes that are often overlooked in hydrology and prove that citizen science platforms, such as Zooniverse, can provide significant contributions to our scientific advancement. At the same time, these platforms can be valuable outreach tools, educating thousands of people on the importance of snow hydrology and snow water resources. We are working to expand the citizen science effort globally to continue our evaluation of different snow unloading regimes in multiple climates across the Northern Hemisphere.
It is possible to attend physically or to participate digitally at the seminar
Videolink to the lecture will be sent to the mailinglists alle@geo and geohyd-info@geo. If you want to subscribe to the geohyd-info@geo list send an email to Anita.
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About the seminar
This seminar is offered by the Section for Geography and Hydrology, Dept. of Geosciences, University of Oslo. The GEOHYD-seminars are announced as lunch seminars so bring your lunch if you want to.
The seminars are open for everyone interested, and especially students are welcome.
The Lunch Seminar Team
– Louise and Henning