Vena W. Chu

Vena W. Chu
University of California, Los Angeles | UCLA · Department of Geography

About

30
Publications
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843
Citations
Introduction
I am interested in Arctic climate change and impacts on hydrology, particularly for the Greenland ice sheet. Currently, my work deals with understanding the spatial and temporal dynamics of the Greenland ice sheet hydrologic system from snow to sea using geospatial technologies and field techniques.

Publications

Publications (30)
Article
Full-text available
Recent work has identified complex perennial supraglacial stream and river networks in areas of the Greenland Ice Sheet (GrIS) ablation zone. Current surface mass balance (SMB) models appear to overestimate meltwater runoff in these networks compared to in-channel measurements of supraglacial discharge. Here, we constrain SMB models using the hills...
Article
Full-text available
In situ river discharge estimation is a critical component of studying rivers. A dominant method for establishing discharge monitoring in situ is a temporary gauge, which uses a rating curve to relate stage to discharge. However, this approach is constrained by cost and the time to develop the stage‐discharge rating curve, as rating curves rely on...
Preprint
Full-text available
Recent work has identified complex perennial supraglacial stream/river networks in areas of the Greenland Ice Sheet (GrIS) ablation zone. Current surface mass balance (SMB) models appear to overestimate meltwater runoff in these networks compared to in-channel measurements of supraglacial discharge. Here, we constrain SMB models using the Hillslope...
Article
Full-text available
Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolu...
Article
Supraglacial rivers on the Greenland Ice Sheet (GrIS) transport large volumes of surface meltwater toward the ocean, yet have received relatively little direct research. This study presents field observations of channel width, depth, velocity, and water surface slope for nine supraglacial channels on the south-western GrIS collected between July 23...
Article
Extensive, complex supraglacial river networks form on the southwest Greenland ice sheet (GrIS) surface each melt season. These networks are the dominant pathways for surface meltwater transport on this part of the ice sheet, but their fluvial morphometry has received little study. This paper utilizes high-resolution (2 m) WorldView-1/2 images, dig...
Article
Full-text available
Digital elevation models (DEMs) of ice surface topography are often used for hydrologic analysis of the Greenland Ice Sheet (GrIS), but their suitability for this purpose has received little quantitative assessment. We compare remotely sensed maps of supraglacial lakes, rivers, and moulins with their DEM-modeled counterparts, using two moderate-res...
Article
Full-text available
River systems in remote environments are often challenging to monitor and understand where traditional gauging apparatus are difficult to install or where safety concerns prohibit field measurements. In such cases, remote sensing, especially terrestrial time-lapse imaging platforms, offer a means to better understand these fluvial systems. One such...
Article
Full-text available
River systems in remote environments are often challenging to monitor and understand where traditional gauging apparatus are difficult to install or where safety concerns prohibit field measurements. In such cases, remote sensing, especially terrestrial time lapse imaging platforms, offer a means to better understand these fluvial systems. One such...
Article
Full-text available
Thermally incised meltwater channels that flow each summer across melt-prone surfaces of the Greenland ice sheet have received little direct study. We use high-resolution WorldView-1/2 satellite mapping and in situ measurements to characterize supraglacial water storage, drainage pattern, and discharge across 6,812 km(2) of southwest Greenland in J...
Article
Full-text available
Understanding Greenland ice sheet (GrIS) hydrology is essential for evaluating response of ice dynamics to a warming climate and future contributions to global sea level rise. Recently observed increases in temperature and melt extent over the GrIS have prompted numerous remote sensing, modeling, and field studies gauging the response of the ice sh...
Article
Full-text available
Greenland ice sheet mass losses have increased in recent decades with more than half of these attributed to sur-face meltwater runoff. However, the magnitudes of englacial storage, firn retention, internal refreezing and other hydro-logic processes that delay or reduce true water export to the global ocean remain less understood, partly due to a sc...
Article
Full-text available
Improved understanding of Greenland ice sheet hydrology is critically important for assessing its impact on current and future ice sheet dynamics and global sea level rise. This has motivated the collection and integration of in situ observations, model development, and remote sensing efforts to quantify meltwater production, as well as its phase c...
Article
Full-text available
Greenland ice sheet mass losses have increased in recent decades with approximately half of these attributed to increased surface meltwater runoff. However, controls on ice sheet water release, and the magnitude of englacial storage, firn densification, internal refreezing and other hydrologic processes that delay or reduce true water export to the...
Article
Full-text available
Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datas...
Article
Full-text available
Rising sea levels and increased surface melting of the Greenland ice sheet have heightened the need for direct observations of meltwater release from the ice edge to ocean. Buoyant sediment plumes that develop in fjords downstream of outlet glaciers are controlled by numerous factors, includ- ing meltwater runoff. Here, Moderate Resolution Imaging...
Data
Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datas...
Article
Increased mass loss of the Greenland Ice Sheet and subsequent global sea level rise has amplified the need to understand Greenland's hydrology and melt patterns. Drainage basins for Greenland's land surface and ice sheet were produced using the GLAS/IceSat 1km surface DEM and a hydrostatic surface pressure grid over the ice sheet. The pressure grid...
Article
Modeling studies show that ice sheet mass loss in the form of meltwater runoff constitutes a large fraction of the total mass loss of the Greenland ice sheet. However, the controls on Greenland ice sheet runoff to the ocean are not well understood in part because few direct observations of ice sheet meteorological conditions and meltwater runoff in...
Article
Full-text available
Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datas...
Article
Full-text available
Rising sea levels and increased surface melting of the Greenland ice sheet have heightened the need for direct observations of meltwater release from the ice edge to ocean. Buoyant sediment plumes that develop in fjords downstream of outlet glaciers are controlled by numerous factors, including meltwater runoff. Here, Moderate Resolution Imaging Sp...
Article
Ongoing changes at the ice sheet margin of Greenland's land terminating glaciers can be inferred from terrestrial river discharge because these rivers are dominated by ice sheet meltwater export. Meltwater export inferred from discharge has the unique feature of providing an integrated signal of ice sheet melt processes by quantifying exported melt...
Article
Addressing the declining health of the inland Salton Sea in southern California requires an understanding of the nature of water quality features that pervade the Sea and their drivers. Such features as phytoplankton blooms and gypsum precipitates are explored in response to wind-driven upwelling events that have been related to massive fish kills....
Article
Full-text available
Increased mass losses from the Greenland ice sheet and inferred contributions to sea-level rise have heightened the need for hydrologic observations of meltwater exiting the ice sheet. We explore whether temporal variations in ice-sheet surface hydrology can be linked to the development of a downstream sediment plume in Kangerlussuaq Fjord by compa...
Article
Observations and models indicate that the Greenland ice sheet is and will continue to increase in both melt area and intensity. The impact of the increased inland surface melt on ice sheet dynamics remains an outstanding question that relates both to ablation losses at the ice margin and internal ice sheet hydrology and dynamics. Here, we combine P...
Article
Full-text available
Recent decreases in Arctic sea ice and increases in Greenland ice sheet surface-melt may have global impacts, but the interactions between these two processes are unknown. Using microwave satellite data, we explore the spatial and temporal covariance of sea ice extent and ice sheet surface-melt around Greenland from 1979 to 2007. Significant covari...
Article
Quantifying the mass balance of the Greenland ice-sheet in a warming climate intensifies the need for hydrologic observations of meltwater exiting the ice-sheet. Traditional observational methods such as stream discharge measurements are sparse due to the remoteness of Greenland, therefore alternative methods must be explored. We hypothesize that h...
Article
Continued reduction of Arctic sea ice may significantly alter the climate of the northern high latitudes and the mass balance of the Greenland ice-sheet. While sea ice loss and Greenland ice-surface melting both increased in the late-20th/early-21st century, the influence of sea ice on Greenland surface melt is unknown. In this presentation, we stu...

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