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Anthony Arendt

Research Scientist/Engineer - Principal





Department Affiliation

Polar Science Center


B.S. Earth & Atmospheric Sciences, University of Alberta, 1995

M.S. Earth & Atmospheric Sciences, University of Alberta, 1997

Ph.D. Geophysics, University of Alaska, 2006


2000-present and while at APL-UW

Assimilation of citizen science data in snowpack modeling using a new snow data set: Community Snow Observations

Crumley, R.L., D.F. Hill, K.W. Jones, G.J. Wolken, A.A. Arendt, C.M. Aragon, and C. Cosgrove, "Assimilation of citizen science data in snowpack modeling using a new snow data set: Community Snow Observations," Hydrol. Earth Syst. Sci., 25, 4651-4680, doi:10.5194/hess-25-4651-2021, 2021.

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31 Aug 2021

A physically based snowpack evolution and redistribution model was used to test the effectiveness of assimilating crowd-sourced snow depth measurements collected by citizen scientists. The Community Snow Observations (CSO; https://communitysnowobs.org/, last access: 11 August 2021) project gathers, stores, and distributes measurements of snow depth recorded by recreational users and snow professionals in high mountain environments. These citizen science measurements are valuable since they come from terrain that is relatively undersampled and can offer in situ snow information in locations where snow information is sparse or nonexistent. The present study investigates (1) the improvements to model performance when citizen science measurements are assimilated, and (2) the number of measurements necessary to obtain those improvements. Model performance is assessed by comparing time series of observed (snow pillow) and modeled snow water equivalent values, by comparing spatially distributed maps of observed (remotely sensed) and modeled snow depth, and by comparing fieldwork results from within the study area. The results demonstrate that few citizen science measurements are needed to obtain improvements in model performance, and these improvements are found in 62% to 78% of the ensemble simulations, depending on the model year. Model estimations of total water volume from a subregion of the study area also demonstrate improvements in accuracy after CSO measurements have been assimilated. These results suggest that even modest measurement efforts by citizen scientists have the potential to improve efforts to model snowpack processes in high mountain environments, with implications for water resource management and process-based snow modeling.

Automated dynamic mascot generation for GRACE and GRACE-FO harmonic processing

Mohajerani, Y., D. Shean, A. Arendt, and T.C. Sutterley, "Automated dynamic mascot generation for GRACE and GRACE-FO harmonic processing," Remote Sens., 13, doi:10.3390/rs13163134, 2021.

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7 Aug 2021

Commonly used mass-concentration (mascon) solutions estimated from Level-1B Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On data, provided by processing centers such as the Jet Propulsion Laboratory (JPL) or the Goddard Space Flight Center (GSFC), do not give users control over the placement of mascons or inversion assumptions, such as regularization. While a few studies have focused on regional or global mascon optimization from spherical harmonics data, a global optimization based on the geometry of geophysical signal as a standardized product with user-defined points has not been addressed. Finding the optimal configuration with enough coverage to account for far-field leakage is not a trivial task and is often approached in an ad-hoc manner, if at all. Here, we present an automated approach to defining non-uniform, global mascon solutions that focus on a region of interest specified by the user, while maintaining few global degrees of freedom to minimize noise and leakage. We showcase our approach in High Mountain Asia (HMA) and Alaska, and compare the results with global uniform mascon solutions from range-rate data. We show that the custom mascon solutions can lead to improved regional trends due to a more careful sampling of geophysically distinct regions. In addition, the custom mascon solutions exhibit different seasonal variation compared to the regularized solutions. Our open-source pipeline will allow the community to quickly and efficiently develop optimized global mascon solutions for an arbitrary point or polygon anywhere on the surface of the Earth.

A changing hydrological regime: Trends in magnitude and timing of glacier ice melt and glacier runoff in a high latitude coastal watershed

Young, J.C., E. Pettit, A. Arendt, E. Hood, G.E. Liston, and J. Beamer, "A changing hydrological regime: Trends in magnitude and timing of glacier ice melt and glacier runoff in a high latitude coastal watershed," Water Resour. Res., 57, doi:10.1029/2020WR027404, 2021.

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1 Jul 2021

With a unique biogeophysical signature relative to other freshwater sources, meltwater from glaciers plays a crucial role in the hydrological and ecological regime of high latitude coastal areas. Today, as glaciers worldwide exhibit persistent negative mass balance, glacier runoff is changing in both magnitude and timing, with potential downstream impacts on infrastructure, ecosystems, and ecosystem resources. However, runoff trends may be difficult to detect in coastal systems with large precipitation variability. Here, we use the coupled energy balance and water routing model SnowModel–HydroFlow to examine changes in timing and magnitude of runoff from the western Juneau Icefield in Southeast Alaska between 1980 and 2016. We find that under sustained glacier mass loss (–0.57 ± 0.12 m w. e. a-1), several hydrological variables related to runoff show increasing trends. This includes annual and spring glacier ice melt volumes (+10% and +16% decade-1) which, because of higher proportions of precipitation, translate to smaller increases in glacier runoff (+3% and +7% decade-1) and total watershed runoff (+1.4% and +3% decade-1). These results suggest that the western Juneau Icefield watersheds are still in an increasing glacier runoff period prior to reaching "peak water." In terms of timing, we find that maximum glacier ice melt is occurring earlier (2.5 days decade-1), indicating a change in the source and quality of freshwater being delivered downstream in the early summer. Our findings highlight that even in maritime climates with large precipitation variability, high latitude coastal watersheds are experiencing hydrological regime change driven by ongoing glacier mass loss.

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In The News

The water future of Earth's 'third pole'

NASA Explores, Carol Rasmussen

The most comprehensive survey ever made of snow, ice, and water in the high mountains of Asian and how they are changing is now underway. NASA's High Mountain Asia Team (HiMAT), led by Anthony Arendt is charged with integrating the many, varied types of satellite observations and existing numerical models to create an authoritative estimate of the water budget of this region and a set of products local policy makers can use in planning for a changing water supply.

26 Jun 2019

How many glaciers are in Alaska? There's no easy answer.

Anchorage Daily News, Ned Rozell

Anthony Arendt notes that mapmakers tend to give different names to several branches of an ice mass, all of which, by a more scientific definition, form part of a single glacier.

1 Jun 2019

Scientists unravel the ocean's mysteries with cloud computing

UW Information Technology, Elizabeth Sharpe

The OOI Cabled Array is delivering data on a scale that was previously not possible. More than 140 instruments are working simultaneously.

That’s why oceanographers teamed up with data and research computing experts to organize a unique event at the University of Washington in late August 2018 to help ocean scientists learn the computational tools, techniques, data management and analytical skills needed to handle this massive amount of data.

8 Nov 2018

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Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center