IEEE Geoscience and Remote Sensing Magazine - March 2023 - 74

a series of UAV-related studies on the cryosphere have been
published. However, a thorough review that explicitly details
the scientific progress and possibilities of using UAVs in Antarctic
polar research is lacking. In this era of rapid global and
regional climate change, it is becoming increasingly necessary
to employ UAVs to investigate the finer changes in the Antarctic
ice sheet (AIS) and ice shelves. This work investigates the
use of UAVs in the monitoring of the glacial microtopography
(including rifts and crevasses, surface subsidence, and melting
ponds), ice surface landforms, atmosphere, flora and fauna,
sea ice, subglacial environment, and other aspects of Antarctic
glaciology investigation, and it speculates on their future use
in multidisciplinary research.
INTRODUCTION
The AIS is currently the largest continental ice sheet on Earth
and one of the most vulnerable to climate change. Antarctica
holds 70% of the global fresh water and 91% of the global
ice mass; if the ice melts, the global sea level will rise by 58 m
[1], [2]. The mass budget and stability of the AIS substantially
influence global climate change and sea level rise as
well as water and atmospheric thermodynamic cycles [3],
[4], [5]. Therefore, tracking the progress of the AIS is critical
for assessing its contribution to global climate change and
sea level rise [5], [6].
Restricted by the adverse environment of Antarctica, in
situ data are extremely rare and can be obtained only at specific
times under specific conditions, mostly during Antarctic
expeditions, and they are concentrated in the vicinity of the
research stations of various countries [7]. Optical and radar
satellite remote sensing are effective methods for regularly
monitoring the Antarctic continent. They can obtain large
amounts of data quickly and efficiently and have excellent
temporal and geographical coverage, which satisfies the demand
for long-time and frequent investigations into the evolution
of glacier surfaces [8]. This significantly compensates
for the scarcity of in situ observations. Different processing
techniques for these two types of data have been developed,
and the applications of the data are various [9], [10], [11],
[12]. These data are currently the most widely used information
source and monitoring technology in polar research
[1], [13]. The temporal and spatial resolutions, however, are
limitations of satellite remote sensing. The cost of gathering
data via optical and radar satellite observations is also very
high, especially for commercial satellites [8]. Data collection
depends on the temporal resolution of a satellite; therefore,
it is impossible to guarantee that data will be collected at a
particular date and time [8], [14]. Increased spatial resolution
will result in smaller pixel sizes, but the cost of obtaining submeter-resolution
data is too expensive for large-scale monitoring.
Clouds, wind, and other weather conditions can also
interfere with satellite remote sensing data (except synthetic
aperture radar) [8]. Furthermore, ground-based platforms are
rigid and cannot function securely in locations with rifts and
crevasses [15]. Similarly, mandated airborne operations are
limited owing to safety and resource constraints [16], [17].
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The use of UAVs can readily bypass these restrictions.
UAVs, also known as unmanned aerial systems (UASs), such as
drones, remotely piloted aircraft, and aerial robots, rely on
air for lift and are controlled remotely from the ground [18].
Such systems are equipped with a variety of sensors to capture
high-resolution terrain data for processing (such as photogrammetry)
and applications. UAVs are simple to set up
and can work with multitype sensors, for instance, visible, infrared,
microwave, and purpose-designed cameras [8]. Their
flight altitude can be flexibly adjusted to obtain high-spatialresolution
images. The data received from them can reach
a centimeter-scale spatial resolution, which is substantially
higher than standard satellite remote sensing, while the cost
involved in the data acquisition is much lower than the latter.
Therefore, researchers can obtain images according to their
schedule and convenience [8], [14], [19]. UAV flying operations
include visible line of sight (VLOS) and beyond VLOS
(BVLOS), depending on the horizontal distance between a
UAV and the pilot [20]. VLOS requires UAVs to operate within
a range where the pilot maintains direct visual contact with
them and keeps the drones from hitting people and things in
the surrounding environment. BVLOS refers to the operation
of UAVs beyond the VLOS. Extended VLOS operation is another
sort of BVLOS that involves using additional observers
and remote pilots to maintain visual contact with UAVs [20].
In comparison to VLOS operation, BVLOS operation enhances
environmental monitoring by
◗ covering a larger area and acquiring more images in one
flight by allowing UAVs to fly at higher altitudes and faster
speeds
◗ improving safety and enabling multifaceted environmental
analysis in remote inaccessible locations
◗ reducing human footprints and having less impact on
nearby wildlife
◗ increasing precision, saving time, and providing logistics
support [21], [22].
However, BVLOS is also much more demanding than VLOS.
BVLOS operations are more complicated than VLOS, which
requires pilots to have greater training and experience as well
as more detailed planning and risk analysis. In addition, in
some locations, BVLOS operations require special flight conditions
and exceptional approvals [20].
UAVs have rapidly become popular owing to their advantages
over traditional satellite remote sensing. In 2004, UAVs
were used for the first time for scientific research in the Antarctic
during the 17th Italian Antarctic Expedition [23]. Following
that, they have been increasingly used in scientific expeditions
and research in the Antarctic, owing to their small size,
ease of transport, simple operation, high spatial and temporal
resolution of acquired data, and low cost, making it possible
to survey and map an area in the adverse environment of
polar glaciers and ice sheets [8], [24], [25]. Centimeter-scale
digital orthophoto maps (DOMs) and digital elevation models
(DEMs) generated from high-resolution remote sensing
images from UAVs are also used to track the geomorphological
and topographical evolution of the Antarctic ice surface
IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE MARCH 2023
IEEE Geoscience and Remote Sensing Magazine - March 2023

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