Rick Lee Wessels

Global Land Ice Measurements from Space (GLIMS): remote sensing and GIS investigations of the Earth's cryosphere

Abstract Concerns over greenhouse‐gas forcing and global temperatures have initiated research into understanding climate forcing and associated Earth‐system responses. A significant component is the Earths cryosphere, as glacier‐related, feedback mechanisms govern atmospheric, hydrospheric and lithospheric response. Predicting the human and natural dimensions of climate‐induced environmental change requires global, regional and local information about ice‐mass distribution, volumes, and fluctuations. The Global Land‐Ice Measurements from Space (GLIMS) project is specifically designed to produce and augment baseline information to facilitate glacier‐change studies. This requires addressing numerous issues, including the generation of topographic information, anisotropic‐reflectance correction of satellite imagery, data fusion and spatial analysis, and GIS‐based modeling. Field and satellite investigations indicate that many small glaciers and glaciers in temperate regions are downwasting and retreating, although detailed mapping and assessment are still required to ascertain regional and global patterns of ice‐mass variations. Such remote sensing/GIS studies, coupled with field investigations, are vital for producing baseline information on glacier changes, and improving our understanding of the complex linkages between atmospheric, lithospheric, and glaciological processes.

Recent and future warm extreme events and high-mountain slope stability

The number of large slope failures in some high-mountain regions such as the European Alps has increased during the past two to three decades. There is concern that recent climate change is driving this increase in slope failures, thus possibly further exacerbating the hazard in the future. Although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied, the impacts of short-term, unusually warm temperature increases on slope stability in high mountains remain largely unexplored. We describe several large slope failures in rock and ice in recent years in Alaska, New Zealand and the European Alps, and analyse weather patterns in the days and weeks before the failures. Although we did not find one general temperature pattern, all the failures were preceded by unusually warm periods; some happened immediately after temperatures suddenly dropped to freezing. We assessed the frequency of warm extremes in the future by analysing eight regional climate models from the recently completed European Union programme ENSEMBLES for the central Swiss Alps. The models show an increase in the higher frequency of high-temperature events for the period 2001–2050 compared with a 1951–2000 reference period. Warm events lasting 5, 10 and 30 days are projected to increase by about 1.5–4 times by 2050 and in some models by up to 10 times. Warm extremes can trigger large landslides in temperature-sensitive high mountains by enhancing the production of water by melt of snow and ice, and by rapid thaw. Although these processes reduce slope strength, they must be considered within the local geological, glaciological and topographic context of a slope.

ASTER measurement of supraglacial lakes in the Mount Everest region of the Himalaya

Abstract We demonstrate an application of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images to detect and monitor supraglacial lakes on glaciers in the Mount Everest region in Tibet (Xizang) and Nepal. ASTER offers powerful capabilities to monitor supraglacial lakes in terms of (1) surface area, growth and disappearance (spatial resolution =15m), (2) turbidity (15m resolution), and (3) temperature (90m resolution). Preliminary results show an overall similarity of supraglacial lakes on three glaciers. Lakes have widely varying turbidity as indicated by color in visible/near-infrared bands 1–3, the largest lakes being bright blue (highly turbid), cold (near 0°C) and hydraulically connected with other lakes and supraglacial streams, while small lakes are mostly darkblue (relatively clear water), warmer (>4°C), and appear hydraulically isolated. High levels of turbidity in supraglacial lakes indicate high rates of meltwater input from streams or erosion of ice cliffs, and thus are an indirect measure relating to the activity and hydraulic integration of the lake with respect to other lakes and streams in the glacier.

Rapid ASTER Imaging Facilitates Timely Assessment of Glacier Hazards and Disasters

Glacier- and permafrost-related hazards increasingly threaten human lives, settlements, and infrastructure in high-mountain regions. Present atmospheric warming particularly affects terrestrial systems where surface and sub-surface ice are involved. Changes in glacier and permafrost equilibrium are shifting beyond historical knowledge. Human settlement and activities are extending toward danger zones in the cryospheric system. A number of recent glacier hazards and disasters underscore these trends. Difficult site access and the need for fast data acquisition make satellite remote sensing of crucial importance in high-mountain hazard management and disaster mapping.

Eruption of Alaska volcano breaks historic pattern

In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (∼2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud “thunder,” lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

The reawakening of Alaska's Augustine volcano

Augustine volcano, in south central Alaska, ended a 20-year period of repose on 11 January 2006 with 13 explosive eruptions in 20 days. Explosive activity shifted to a quieter effusion of lava in early February, forming a new summit lava dome and two short, blocky lava flows by late March (Figure 1). The eruption was heralded by eight months of increasing seismicity, deformation, gas emission, and small phreatic eruptions, the latter consisting of explosions of steam and debris caused by heating and expansion of groundwater due to an underlying heat source.

Recent Extreme Avalanches: Triggered by Climate Change?

On 25 September 2008, seismo meters operated by the Alaska Volcano Observatory (AVO) registered strong ground shaking. On the basis of previous experience with such large seismic signals, AVO personnel were able to rapidly identify the seismic event as an avalanche. Two days later, an AVO overflight of Iliamna volcano, near Alaskas Cook Inlet, confirmed that a massive chunk of glacial ice and rock had broken free from its position on the upper flanks of the volcano, generating a massive avalanche that could have buried an entire town had it occurred in a more populated area. Rapidly moving rock, ice, or debris avalanches, such as the one that occurred on Iliamna, can be highly destructive and deadly. Similar events have caused the deaths of hundreds to thousands of people [Keefer and Larsen, 2007]. In general, avalanches that move more than 1 million cubic meters of material are rare. However, a remarkable series of large avalanches recently occurred in Alaska and the Caucasus, providing a new opportunity to better understand this type of hazard. All events initiated in steep mountain slopes, involved rock and significant amounts of ice, and traveled for 10–35 kilometers.

Surface textures and dynamics of the 2005 lava dome at Shiveluch volcano, Kamchatka

Shiveluch is one of the largest and most active andesitic volcanoes of the Kuril-Kamchatka arc. It commonly alternates between Vulcanian explosive eruptions and periods of dome growth and subsequent dome collapse–driven block-and-ash flows. The volcano was in an extended period of heightened activity for most of the period 2004–2010. We examined this activity in detail using thermal infrared (TIR) remote sensing as part of the urgent request protocol (URP) program of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument and confirmed the results with ground-based photography and airborne TIR camera data. High-spatial-resolution TIR images were collected during both daytime and nighttime satellite overpasses prior to and following the large explosive event/eruption of 27 February 2005 and the dome growth that followed. During a field campaign in August 2005, a helicopter overflight designed to acquire visible and TIR data of the active dome was performed. This was a nadir-looking, low-altitude overflight and the first ever of Shiveluch volcano involving non-Russian scientists. The image data revealed an active crease structure in the center of the dome with a distinctly different, crescent-shaped, high-temperature (>380 °C) zone roughly perpendicular to the crease. In order to provide a time context and estimate extrusion rates, the airborne data were compared to the spaceborne ASTER data and long-distance ground-based photography of the dome acquired by our Russian colleagues. The presence of a crease structure and the complex thermal pattern on the surface were both unexpected discoveries that reveal the way in which exogenous dome growth was occurring at the time. This highly active period at Shiveluch provides a unique example to better understand silicic lava dome growth using TIR data. The results also demonstrate a straightforward approach for fusing ground, air, and spaceborne image data, which could be applied to other active domes around the world.

Applications of high-resolution satellite remote sensing for northern Pacific volcanic arcs

There has been a dramatic increase in the remote-sensing data volume being acquired from Earth orbit over the past two decades. Although none of these satellite instruments were designed specifically to monitor volcanic eruptions, many government agencies and university partnerships are currently utilizing them for this task. Most rely on high temporal/moderate spatial resolution instruments (e.g., MODIS, AVHRR, GOES) to monitor transient and temporally variable anomalies such as eruption clouds and hot spots. The uses of these instruments for such purposes are detailed in Chapters 3, 4 and 6. However, in order to better develop a quantitative scientific basis from which to model transient geological and meteorological hazards as well as map small-scale phenomena, higher spatial/spectral resolution datasets are commonly needed. Whereas moderate-resolution data may be frequently received directly from the satellite at many institutes globally, access to, and temporal frequency of, coverage from high-resolution instruments has been limited because much of the data must be specially acquired and purchased using a few government (e.g., ASTER, ETM+) and commercial (e.g., IKONOS, QuickBird) providers. Despite this, high-resolution data use has increased greatly as their capabilities have become recognized. The data from these sensors are particularly useful for numerous aspects of volcanic remote sensing. For example, high spatial resolution/multispectral thermal infrared data are critical for monitoring low-temperature anomalies and mapping both chemical and textural variations on volcanic surfaces. The data can also be integrated into a near-real time monitoring effort that is based primarily on high temporal/moderate spatial resolution orbital data. This synergy allows small-scale activity to be targeted for science and response, and the establishment of a calibration baseline between each sensor. The focus of this chapter is to highlight how these high spatial resolution (<100 m/pixel) data, commonly with more spectral capabilities, are being used for volcanic mapping and monitoring in the North Pacific region. A review of volcanic remote-sensing research using these data is presented with attention paid to case studies of new research. These studies showcase the capabilities of higher resolution sensors to map pyroclastic flows and detect changes over time in those flows (Mt. Augustine Volcano), and to document detection of volcanic terrains using a fusion approach of data from the visible to the radar wavelengths (Westdahl Volcano).

Monitoring volcanic threats using ASTER satellite data

This document summarizes ongoing activities associated with a research project funded by the national aeronautics and space administration (NASA) focusing on volcanic change detection through the use of satellite imagery. This work includes systems development as well as improvements in data analysis methods. Participating organizations include the NASA land processes distributed active archive center (LP DAAC) at the U.S. geological survey (USGS) center for earth resources observation and science (EROS), the Advanced spaceborne thermal emission and reflection radiometer (ASTER) science team, the Alaska volcano observatory (AVO) at the USGS Alaska science center, the jet propulsion laboratory/California Institute of Technology (JPL/CalTech), the University of Pittsburgh, and the University of Alaska Fairbanks.