IEEE Geoscience and Remote Sensing Magazine - March 2023 - 79

been increasingly used to monitor rifts and crevasses, melting
ponds and ice dolines, windblown snow, sorted-stone circles,
ice velocity, ice and snow environment detection, and other
ice surface characteristics [7], [8], [14].
UNMANNED AERIAL VEHICLES IN
LANDFORM STUDIES
High-resolution orthomosaics and DEMs produced from
UAV-based aerial images provide an accurate dataset for identifying
and classifying landforms, constituting a new data
source for analyzing the connection among surface melting,
ice movement, and the supply of ice debris, as well as a
chance to investigate the relationship between landform processes
and the evolution of a study area's topography. The supraglacial
blue ice moraines in Antarctica record ice volume
fluctuations, and monitoring them can help in analyzing dynamic
changes in the ice sheet [68]. Analysis of their particle
size provides an understanding of their clast origin, transport
history, depositional mechanism, and processes of reworking
[27]. Particle size information of the blue ice moraine
complex can be recovered from high-resolution orthomosaics
created from UAV-based aerial images by using multiview
stereophotogrammetry. The accuracy of the patch- and sitescale
modeling is within 1.7 and 50 mm, respectively, which
is more accurate than the patch scale (1 m2) detected by traditional
methods, which contributes to the interpretation and
analysis of the glaciological process [27]. Short-term (annual
to intra-annual) changes in the dynamic surface topography
of glacial moraines can be detected using the differential fineresolution
terrain dataset obtained by UAV images, and DEM
differencing results show that the net uplift of the moraine
crests across the Patriot Hills region is ~0.07 m between season
1 (December 2012 and January 2013, respectively) and
season 2 (January 2014) [69]. Surveying, mapping, and spatial
analysis of periglacial landforms, such as solifluction landforms,
scarps, taluses, protalus ramparts, patterned ground,
coastal landforms, landslides and
mud flows, stone fields, and bedrock
outcrops, can also be performed using
UAV data that compensate for data
scarcity, low spatial resolution, and
the insufficient sensitivity of smallscale
landform observations in in situ,
airborne, and satellite observations
[21], [22], [70], [71]. High-resolution
DEMs generated by aerial images obtained
by repeated UAV surveys can
also be used to identify the specific
landforms of nival processes, which
provide an opportunity to study the
relationship among the processes related
to late-lying snow patches, topography
of the study area, and orientation
of the slopes in relation to the
prevailing wind direction [72]. The
ephemeral snow cover depicted based
Rifts
Blue Ice
MARCH 2023 IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE
on UAV images can also be used to study its influence on the
ground thermal regime, and the active layer thickness can be
studied [73]. In the visible spectrum of UAV-based orthomosaics,
several biological soil crust (BSC) variables and optical
signals of surface soil moisture can be observed (with documented
clusters of at least 100 m2), reflected by the color/
brightness parameters and morphological characteristics of
the soil surface [74]. DEMs and point clouds (with elevation
and red-green-blue color characteristics) can be applied in
spatial morphometric analysis and mapping. The slope map
created using DEMs and profile analysis can be utilized for
BSC classification and the investigation of soil organic matter
and organic layers in polar regions [74]. The dynamics of
cryotic features, such as frost blisters, and the surface changes
and sublimation rates in perennially frozen lakes have been
studied by Ponti et al. [75]. Calculations were made to determine
the extent and statistics (mean and standard deviation)
of the accretions and sublimation on the different surface
types. The results show that the temporal variability of frost
blister M1 is smaller than that of frost blister M2, with M1
decreasing 16.1 m2 from 2004 to 2011 while M2 increased
23.6 m2 from 2009 to 2018. The highest sublimation was recorded
between 11 and 22 November 2018, with a mean loss
of −1.7 cm for ice, −2.2 cm for snow, and −2 cm for ice/snow
[75]. Perennially frozen lakes carry important ecosystems,
and UAVs can be used to provide effective images. By combining
photogrammetry models, DEM differences, area changes,
pixel counting, timely analysis of frost blisters, and lake ice
elevation changes can be obtained, allowing the groundwater
recharge type of perennial frozen lakes to be understood [75].
UNMANNED AERIAL VEHICLES IN CREVASSE
AND RIFT STUDIES
The AIS contains rifts and crevasses in the sledge path, snow-
ice airfields, and human-accessible places, some of which
are more distinguishable while others are obscured by snow,
Glacial Microtopography Features Extracted From
UAV Images in the 35th and 36th CHINARE
Ice Doline
FIGURE 5. The microtopographic features of the AIS captured by UAVs. CHINARE: Chinese
National Antarctic Research Expedition.
79
Snow-Covered Rifts/
Crevasses
Melting Water
Crevasses
Windblown Snow
IEEE Geoscience and Remote Sensing Magazine - March 2023

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