US - Chile Joint Commission for Environmental Cooperation

Chile - US Partnership on Monitoring the Glaciers of Chile

Bruce F. Molnia, Ph.D. (bmolnia@usgs.gov) U.S. Geological Survey, Reston, Virginia USA

Details of the U.S. - Chile Bilateral on Glacier Monitoring and Water Resources

The U.S. and Chile have had a Free Trade Agreement since 2003. A component, the Environmental Cooperation Agreement (ECA) focuses on bilateral environmental projects, such as environmental law and natural resources protection.

Typically, these bilateral agreements are linked to trade and productive sectors and their potential impact on the environment.

The ECA negotiated and signed in January 2010 stated that water resources are critical to productive sectors and that climate change will impact the availability of water in Chile.

The 2010 – 2012 ECA Workplan included sharing information and resources and developing cooperation as appropriate in constructing glacier inventories, installing monitoring networks, and generating glacier management strategies to support Chile’s National Climate Change Strategy.

The bilateral also mentioned building collaborative public-private relationships to implement and share research data, and to provide valuable input for global climate change models.

It continued that cooperation should involve information and technology exchange with an emphasis on the effects of glacial melt on available water resources, such as the impacts on agriculture and energy generation.

The implementation of the U.S. - Chile Bilateral on Glacier Monitoring and Water Resources began in January 2011. As formulated, it had three objectives.

Objective (1) - Meet with Chilean government officials, researches, and other public and private sector stakeholders to summarize and assess the state of Chile’s glacier and hydrological resources and technical capacity and to build consensus on Joint next steps.

Objective (2) - Conduct a technical workshop that brings together Chile’s leading glacier researchers (and many from other South American countries) to:

(A)characterize the current status of glacier

research and monitoring in Chile and adjacent countries;

(B) identify resources that the U.S. can contribute to Chile’s National glacier assessment; and

(C) identify innovative technological capabilities for field testing.

Objective (3) - Conduct a pilot project to test and implement glacier monitoring methodologies

Responsible Institution Glacier Latitude Longitude

DGA San Francisco -33.706 -70.036

DGA Olivares Beta -33.150 -70.183

UCHILE Universidad -34.678 -70.361

CECS Chillán -36.875 -71.385

CECS Mocho -39.929 -72.032

CECS N Patagonia IF -47.050 -73.250

Trier University Gran campo nevado -52.798 -73.093

INACH Isla rey Jorge -53.369 -71.460

Glacier Monitoring

A Technological Approach

Cortaderal Glacier – Photo courtesy of Pablo Zenteno

Typically, ablation measurements are made with stakes inserted vertically into the ice; the difference between the exposed length of the stake at the beginning and end of the melt season is used to estimate the loss at that point. A network of these stakes along the length of the glacier can provide measurements that can be converted into volume lost during an ablation season. In practice, these stakes are measured infrequently; due to the remoteness of most glaciers and the effort involved.

At Bering Glacier, it was not feasible to make measurements more than two or three times during the ablation season. More frequent measurements were needed. For this reason, a joint Michigan Tech Research Institute (MTRI), USGS, and Bureau of Land Management (BLM) project designed an instrument to be left on the glacier, recording a variety of parameters (in addition to ablation) on an hourly basis.

The Michigan Tech Research Institute (MTRI) Custom Glacier Ablation Sensor System (GASS) Unit

Since 2005, MTRI’s custom Glacier Ablation Sensor System (GASS) units have been deployed at Bering Glacier. Each year, the GASS method becomes more sophisticated and capable of more diverse and comprehensive measurements. Initial GASS units had radiance, irradiance, ambient temperature, and wind speed sensors. They were also equipped with an acoustic beam that measures the amount of ice that has melted from the surface of the glacier.

These measurements are conducted with the intention of supporting other remote sensing and hydrological measurements of melt and for the purpose of extrapolating total annual melt from the Bering Glacier using a regression model.

Using a steam drill, a 10m-deep hole is made, into which an aluminum or PVC pipe is inserted. The GASS is installed on the top section of the pipe, and activated.

INSTALLATION

3-Glacier Runoff Summary

3-Glacier Runoff Summary

Light

CPU

GPS

Iridium Antenna

Iridium Antenna

Solar Panel

Iridium Modem

Anemometer

Ultrasonic Ranger

Solar Panel

Beginning in 2008 selected GASS units were upgraded to record data describing the horizontal and vertical (melt) movement of a glacier, as well as corresponding meteorological parameters on a hourly basis. For the 2008 and 2010 field seasons, one of the GASS sensors was equipped to transmit data using the ARGOS satellite service.

For the 2011 season, the ARGOS hardware was replaced with an Iridium Satellite modem. The Iridium network has 66 satellites in polar orbits, with excellent worldwide coverage. Two GASS units, B01 (near the terminus) and B02 (up-glacier), were equipped to transmit collected data in real time. The data from the other units (B03, B04, B06, and T01) must still be manually downloaded at the end of the melt season.

While conventional mass balance methods required the distance to the ice be measured by hand, GASS uses a sonar pulse to measure the distance to the ice. The time delay between the emitted pulse and the received signal is converted to distance, and recorded. The other sensors in the 2011 GASS include temperature, wind speed, and upward and downward-looking light intensity. The GASS unit is powered by a rechargeable battery coupled with a solar panel to provide extra power. A sophisticated embedded microprocessor manages the power, data collection and storage.

A WAAS-enabled GPS records position and time for each measurement, and an acoustic sensor (sonar) is used to measure absolute distance between the GASS unit and glacier to derive the required melt information.

A sonar that “pings” the ice surface, measuring the distance from the GASS to the ice surface. As the surface melts, the range increases. A GPS, which provides time and location information. Light sensors that measure both incident and reflected light, allowing continuous measurements of the albedo (which in turn is related to how much sunlight the ice is absorbing). An anemometer for measuring wind speed A temperature sensor

2012 GASS Sensors

One GASS Site Became the Location of a Supraglacial Blue Water

Lake

Ablation Time Series A zero phase offset 3rd-order Bessel filter with a cutoff of 0.07 Hz was applied to the ablation data

Migration Time Series

USGS Glacier Monitoring Strategy

Benchmark Glaciers

A 1997 Report by Andrew Fountain, Bob Krimmel, and Dennis Trabant 19 p.

Glaciers are important features in the hydrologic cycle and affect the volume, variability, and water quality of runoff. Assessing and predicting the effect of glaciers on water resources requires a monitoring program to provide basic data for this understanding. The monitoring program of the U.S. Geological Survey employs a nested approach whereby an intensively studied glacier is surrounded by less intensively studied glaciers and those monitored solely by remote sensing.

Ideally, each glacierized region of the United States would have such a network of glaciers. The intensively studied glacier provides a detailed understanding of the physical processes and their temporal changes that control the mass exchange of the glaciers in that region. The less intensively studied glaciers are used to assess the variability of such processes within the region.

The concept behind measuring glacier mass balance is quite simple-sum the mass losses and gains; however, in practice, it becomes complex. Generally, the main source of mass input is snow accumulation from snowfall and avalanches. Other sources include the freezing of rain within the snow, condensation of water vapor, and rockfall events.

Processes of ablation (all forms of mass loss) include melting from the surface and interior of the glacier, evaporation, and calving of ice from the glacier margin. Another consideration is the redistribution of mass, such as the refreezing of surface mass balance.

The U.S. Geological Survey (USGS) operates a long-term "benchmark" glacier program to monitor climate, glacier geometry, glacier mass balance, glacier motion, and stream runoff. The data collected are used to understand glacier-related hydrologic processes and improve the quantitative prediction of water resources, glacier-related hazards, and the consequences of climate change.

The approach has been to establish long-term mass balance monitoring programs at three widely spaced glacier basins in the United States that clearly sample different climate-glacier-runoff regimes. From north to south, the three basins are Gulkana and Wolverine Glaciers in Alaska and South Cascade Glacier in Washington State.

The approach has been to establish long-term mass balance monitoring programs at three widely spaced glacier basins in the United States that clearly sample different climate-glacier-runoff regimes. From north to south, the three basins are Gulkana and Wolverine Glaciers in Alaska and South Cascade Glacier in Washington State.

The observations and calculations associated with glaciers in the Benchmark Network are summarized as follows: Mass balance Point measurements/calculations of mass balance on the glacier Seasonal mass balance, summer and winter Net and annual mass balance Mass balance as a function of elevation Equilibrium-line elevation Accumulation-area ratio

Geometry Glacier area Terminus position Surface elevation Meteorology and streamflow Precipitation Air temperature and humidity Wind speed and direction Solar radiation Stream discharge

Supplementary data Glacier-bed topography Glacier velocity Water-quality data-suspended sediment, electrical conductivity

USGS

Benchmark

Glaciers

Measurements began on Gulkana Glacier during the early 1960's with the University of Alaska Gulkana Glacier Project (Péwé and Reger, 1983). For several years this project measured the energy budget, mass balance, meteorology, foliation, flow, and glacier bottom topography (from gravity anomalies). In 1966, a continuing series of meteorological, snow and ice balance, and runoff measurements was begun by the USGS as part of the U.S. contribution to the International Hydrologic Decade (IHD) study of mass balances on selected glaciers. Detailed results from 1966 and 1967 are reported by Meier and others (1971) and Tangborn and others (1977), respectively.

Measured winter snow balances and annual balances from 1966-77 are reported by Meier and others (1980). Balance studies were relatively intensive until the mid-1970's, after which spatial sampling was reduced to three sites used as indices for mass balance. Measurements at the three remaining sites were expanded to include ice-motion and surface-altitude observations (for determining glacier-volume change) in addition to the balance, runoff, and meteorological observations already in progress. .

Since 1966, part of the Gulkana data set (net balance, accumulation, ablation, accumulation area ratio (AAR), and equilibrium line altitude (ELA)) has been published by the World Glacier Monitoring Service (Kasser, 1967; Muller, 1977; Haeberli, 1985; Haeberli and Müller, 1988; Haeberli and Hoelzle, 1993). Index-site glacier-surface and summer-surface altitudes, measured winter balance, and net firn and ice balance from 1975 to 1983 are reported by Mayo and Trabant (1986). Data for 1992 and 1993 were published by March and Trabant (1996 and 1997) and for 1994 by March (1998). Interpretations of regional climate-glacier relations using the Gulkana data include papers by Fahl (1973), by Walters and Meier (1989), and by Letréguilly and Reynaud (1989).

During 1997–2001, Gulkana Glacier showed a continued and accelerated negative mass balance trend, especially below the equilibrium line altitude where thinning was pronounced. Ice motion also slowed, which combined with the negative mass balance, resulted in glacier retreat under a warming climate.

The Most Recent

Publication

Cumulative Net Mass Balance

3-Glacier Runoff Summary

US - Chile Joint Commission for Environmental Cooperation

Chile-US Partnership on Monitoring the Glaciers of Chile

For Additional Information: Bruce F. Molnia, Ph.D. bmolnia@usgs.gov 703-648-4120 - phone U.S. Geological Survey Reston, Virginia USAFo