PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
October 2016
811
Spatial Patterns of Glacier Mass Change in the
Southern Andes
Pushkar Inamdar and Shrinidhi Ambinakudige
Abstract
The aim of this paper is to analyze the spatial patterns of
wastage trends of ice masses in the Southern Andes. The
study compared digital elevation models from Shuttle Radar
Topographic Mission (SRTM) (Year 2000) with the eleva-
tion footprints from the Geoscience Laser Altimeter System
(GLAS) campaign for the years 2004 through 2008 in the Dry
Central, North Wet, South Patagonia, and Cordillera Darwin
regions. Overall, the mean elevation differences on clean
ice were negative in all four regions. However, the higher
mass balance trends were observed in the Cordillera Darwin
(-0.126 ±0.05 m w.e.a
-1
) and the North Wet (–0.122 ±0.12 m
w.e.a
-1
) regions. In contrast, no major change in mass balance
trends was observed in Dry Central (-0.037 ± 0.13 m w.e.a
-1
) and South Patagonian Icefield (-0.037 ± 0.05 m w.e.a
-1
).
Introduction
The South American Cryosphere is composed of both trop-
ical and temperate ice masses. The Patagonian Icefields in
the Southern Andes is the major temperate ice mass in South
America (Warren and Sudgen, 1993). Although the retreat of
glaciers in the Southern Andes has been documented earli-
er (Rigot
et al
., 2003; Lopez
et al.
, 2010; Willis
et al
., 2012),
glacier of the Southern Andes have long been neglected for
mass-balance measurements. Due to the remoteness, inacces-
sibility, and tough weather conditions in the Andes, field-
based mass-balance studies are sparse (Aniya
et al.
, 1996). Be-
cause glaciers in this region have not been as closely studied,
there is an uncertainty in the estimation of the contribution
of these glacier-melts to the sea level rise (Rignot
et al.,
2003).
Similar to other regions of the world, the recession of the
glaciers and ice caps of the Andes is one of the most visible
indications of the effects of climate change (Ambinakudige,
2010 and 2014; Ambinakudige and Joshi, 2015; Bolch
et al.
,
2008; Lemke
et al.
, 2007; Lliboutry, 1998;Warren and Sud-
gen, 1993). Because the annual temperatures of temperate ice
masses are at the melting point, these glaciers respond very
rapidly to climatic changes (Fountain, 2011). Climate change
also affects the magnitude of the accumulation and ablation of
the glaciers and the length of the mass balance seasons (Kaser
et al.
, 2003; Pachauri
et al.
, 2014). In addition, glaciers are the
biggest wellsprings of fresh water in the Andes; therefore, the
lack of records of water balances in the region is of great con-
cern (Dixon and Ambinakudige, 2015). Hence, an estimation
of mass balance trends in the Andean glaciers has broader
impacts at the local, regional and global concerns on climate
change and water resource management. Our study will con-
tribute to the existing knowledge of the glacial conditions in
the Southern Andes. The study also contributes to the exist-
ing methodological approaches to use the sparingly available
remote sensing data to model temporal changes in the glacial
conditions in the region.
Status of Glaciers in the Andes
The annual trends of glacial length and area of many glaciers
in the Andes have fluctuated over time. Masiokas
et al.
(2009)
reviewed glacial fluctuations over the last 1,000 years and
found that in the Central Andes, glaciers retreated throughout
the twentieth century. They also found that after the little ice
age (
LIA
), most glaciers in Southern Patagonia retreated and
that has continued until today. Masiokas
et al.
(2009) also
noticed isolated advances during the first half of the past
millennium followed by a glacier reactivation between the
seventeenth and nineteenth centuries and widespread glacier
shrinkage afterward.
According to Rivera
et al.
(2006), a significant frontal
retreat trailed the glaciers located in the Central Andes.
Similarly, Espizua and Pitte (2009) using the historical data,
aerial photographs and satellite images, observed area loss
in Las Vacas, Güssfeldt, El Peñón, and El Azufre glaciers
between 1894 and 2007. They also noted contrasting behavior
of the glaciers in the Central Andes. Between 1894 and 1963,
there was a pronounced glacier retreat followed by the glacial
advance in 1963 to 1986, and nearly stationary conditions
during 2004 to 2007 (Espizua and Pitte, 2009). In addition, an
analysis of radiosonde data by Carrasco
et al.
(2005) over the
central Chile from 1975 to 2001 revealed that tropospheric
warming was the main cause of glacier retreat. Carrasco
et
al.
(2005) also noticed a rise in the equilibrium line altitude
(
ELA
) in the region during the study period. Furthermore,
the comparison study of Shuttle Radar Topographic Mission
(
SRTM
) digital elevation models with models generated from
aerial photographs between 1955 and 2000 in the Cipreses
glacier recorded a thinning rate of 1.06 ±0.45 m a
-1
(Rivera
et
al.
, 2006).
Most glaciers in the North Wet region of Andes are situated
on active volcanoes. Rivera and Bown (2013) analyzed the
contrasting morphology that glaciers adopt before and after
volcanic eruptions. Using historical documents and remote
sensing data, they studied the effects of volcanic events on
glaciers and detected significant frontal retreats and glacier ar-
eal change, with the maximum loss of -1.16 km
2
a
-1
in Volcán
Hudson. Rivera and Bown (2013) also concluded that the re-
covering capacity of glaciers was affected by the tropospheric
warming and the decrease in precipitation. Another study of
debris-covered ice at the Villarrica glacier showed an average
shrinking of -0.4 km
2
a
-1
, with an areal loss of 25 percent be-
tween 1961 and 2003 (Rivera
et al.
, 2006). Figure 1 depicts an
example of how glacier extents have changed in parts of the
Southern Andes. Change in the area of Jorge Montt (in South
Patagonian Icefield), Volcan Hudson (located in the North Wet
region) and Marinelli (located in the Cordillera Darwin Ice-
field) glaciers shown in Figure 1 is an example for the glacial
retreat in the region.
Mississippi State University, Department of Geosciences, 335
Lee Blvd., Mississippi State, MS 39759 (
.
Photogrammetric Engineering & Remote Sensing
Vol. 82, No. 10, October 2016, pp. 811–685.
0099-1112/16/811–685
© 2016 American Society for Photogrammetry
and Remote Sensing
doi: 10.14358/PERS.82.10.677
