The vertical atmospheric structure of the partially glacierised Mittivakkat valley, southeast Greenland

Hansche, Iris; Shahi, Sonika; Abermann, Jakob; Schöner, Wolfgang

doi:10.1017/jog.2022.120

Cited by 4 publications

(5 citation statements)

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“…A more reliable procedure to account for the thermal drift and atmospheric impacts would be the concurrent sounding of the atmospheric boundary layer above the glacier surface (see e.g. Hansche et al, 2023) during thermal UAV surveys and the use of a portable lightweight calibrator that can be attached to a TIR camera to enable consistent thermal measurements and increase the accuracy of absolute temperature recordings (e.g. Virtue et al, 2021).…”

Section: Accuracy Of Uav-based Thermal Imagingmentioning

confidence: 99%

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A low-cost and open-source approach for supraglacial debris thickness mapping using UAV-based infrared thermography

Messmer,

Groos

2024

The Cryosphere

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Abstract. Debris-covered glaciers exist in many mountain ranges and play an important role in the regional water cycle. However, modelling the surface mass balance, runoff contribution and future evolution of debris-covered glaciers is fraught with uncertainty as accurate observations on small-scale variations in debris thickness and sub-debris ice melt rates are only available for a few locations worldwide. Here we describe a customised low-cost unoccupied aerial vehicle (UAV) for high-resolution thermal imaging of mountain glaciers and present a complete open-source pipeline that facilitates the generation of accurate surface temperature and debris thickness maps from radiometric images. First, a radiometric orthophoto is computed from individual radiometric UAV images using structure-from-motion and multi-view-stereo techniques. User-specific calibration and correction procedures can then be applied to the radiometric orthophoto to account for atmospheric and environmental influences that affect the radiometric measurement. The thermal orthophoto reveals distinct spatial variations in surface temperature across the surveyed debris-covered area. Finally, a high-resolution debris thickness map is derived from the corrected thermal orthophoto using an empirical or inverse surface energy balance model that relates surface temperature to debris thickness and is calibrated against in situ measurements. Our results from a small-scale experiment on the Kanderfirn (also known as Kander Neve) in the Swiss Alps show that the surface temperature and thickness of a relatively thin debris layer (ca. 0–15 cm) can be mapped with high accuracy using an empirical or physical model. On snow and ice surfaces, the mean deviation of the mapped surface temperature from the melting point (∼ 0 ∘C) was 0.6 ± 2.0 ∘C. The root-mean-square error of the modelled debris thickness was 1.3 cm. Through the detailed mapping, typical small-scale debris features and debris thickness patterns become visible, which are not spatially resolved by the thermal infrared sensors of current-generation satellites. The presented approach paves the way for comprehensive high-resolution supraglacial debris thickness mapping and opens up new opportunities for more accurate monitoring and modelling of debris-covered glaciers.

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Section: Accuracy Of Uav-based Thermal Imagingmentioning

confidence: 99%

“…Khadka et al, 2022). The ideal solution would be to equip the deployed UAVs with meteorological sensors (see for example Hansche et al, 2023) and collect the necessary data for determining spatio-temporal variations of individual meteorological variables over the debris area in parallel with the thermal imagery.…”

Section: Model Sensitivity and Limitationmentioning

confidence: 99%

A low-cost and open-source approach for supraglacial debris thickness mapping using UAV-based infrared thermography

Messmer,

Groos

2024

The Cryosphere

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show abstract

“…A more reliable procedure to account for the thermal drift and atmospheric impacts would be the concurrent sounding of the atmospheric boundary layer above the glacier surface (see e.g. Hansche et al, 2023) during thermal UAV surveys and the use of a portable light-weight calibrator that can be attached to a TIR camera to enable consistent thermal measurements and increase the accuracy of absolute temperature recordings (e.g. Virtue et al, 2021).…”

Section: Thermal Imaging Of Debris-covered Glaciers With Uavsmentioning

confidence: 99%

“…In an ideal setup, a weather station on the glacier in conjunction with atmospheric profiling (e.g. Hansche et al, 2023) during the thermal UAV surveys would provide the necessary data to model the spatial and temporal distribution of the individual meteorological variables accurately across the debris-covered area (Bisset et al, 2022;Gök et al, 2022). Two highly sensitive debris parameters in surface energy balance models are typically albedo and effective thermal conductivity (e.g.…”

mentioning

confidence: 99%

A low-cost and open-source approach for supraglacial debris thickness mapping using UAV-based infrared thermography

Messmer

Groos

2023

Preprint

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Abstract. Debris-covered glaciers exist in many mountain ranges and play an important role in the regional water cycle. However, modelling the surface mass balance, runoff contribution and future evolution of debris-covered glaciers is fraught with uncertainty as accurate information on small-scale variations in debris thickness and sub-debris ice melt rates is only available for a few locations worldwide. Here we present a customised low-cost UAV for high-resolution thermal imaging of mountain glaciers and a complete open-source pipeline that facilitates the generation of accurate surface temperature and debris thickness maps from radiometric images. First, a thermal orthophoto is computed from individual radiometric UAV images using structure-from-motion and multi-view-stereo techniques. User-specific calibration and correction procedures can then be applied to the raw thermal orthophoto to account for atmospheric and environmental influences that affect the radiometric measurement. The corrected thermal orhthophoto reflects spatial variations in surface temperature across the surveyed debris-covered area. Finally, a high-resolution debris thickness map is derived from the corrected thermal orthophoto using in-situ measurements in conjuction with an empirical or inverse surface energy balance model that relates surface temperature to debris thickness. Our results from a small-scale experiment on the Kanderfirn in the Swiss Alps show that the surface temperature and thickness of a relatively thin debris layer (ca. 0–15 cm) can be mapped with high accuracy. On snow and ice surfaces, the mean deviation of the mapped surface temperature from the melting point (∼0 °C) was 0.4 ±1.0 °C. The root-mean-square error of the modelled debris thickness was 1.2 cm. Through the detailed mapping, typical small-scale debris features and debris thickness patterns become visible, which are not spatially resolved by the thermal infrared sensors of current-generation satellites. The presented approach paves the way for glacier-wide high-resolution debris thickness mapping and opens up new opportunities for more accurate monitoring and modelling of debris-covered glaciers.

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“…Despite the opening of new sea routes at high latitudes, fog will continue to be a logistic barrier to marine navigation (Dawson et al, 2017; Teufel & Sushama, 2022). Fog occurrence is also important for the surface energy budget of Arctic cryospheric components (Cox et al, 2019; Eastman & Warren, 2010b; Hansche et al, 2023; Shupe & Intrieri, 2004; Tjernström et al, 2015) and the moisture supplied by fog can be ecologically beneficial to Arctic plant communities (Gould et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

A climatology of Arctic fog along the coast of East Greenland

Gilson,

Jiskoot,

Gueye

et al. 2023

Quart J Royal Meteoro Soc

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This study presents a comprehensive climatology of coastal fog from four synoptic weather stations operated by the Danish Meteorological Institute along the entire East Greenland coast between 1958 and 2016. Elements investigated include fog frequency, daily timing, temperature, wind, visibility and radiosonde profiles during fog. The spatiotemporal patterns in fog from the low‐ to high‐Arctic locations were related to varying regional seasonal temperatures, surface and upper‐air wind and sea ice conditions, and to correlations with the North Atlantic Oscillation (NAO) and the Greenland Blocking Index (GBI). Results indicate that ~70–80% of East Greenland fog occurs in summer (MJJA), and yearly fog onset is near‐coincident with the start of sea ice break‐up. This warm‐season fog has the typical characteristics of advection fog, as shown in the radiosonde profiles and the association with a gentle sea breeze. More than 95% of warm‐season fog is warmer than –10°C, and peaks close to 0°C and, therefore, consists of liquid or supercooled water droplets. In the cold season, mixed‐phase fog prevails in the high‐Arctic locations, accounting for ~70% of observations. Ice fog (T < –30°C) occurs in only 2% of observations and is limited to Northeast Greenland during the cold season. The cold‐season composite radiosonde fog profiles in the high Arctic locations are characterized by deep (~1000 m) and strong (~6°C) surface‐based temperature inversions. Visibility during most fog conditions is lowest during the warm season (< 500 m) and higher during the cold season (< 800 m). In Northeast Greenland, visibility during warm‐season fog has decreased by ~50 m dec‐1 between 1981 and 2016. In Southeast Greenland, fog visibility is high during low GBI and a positive phase of NAO, but no other correlations with climate indices were found.This article is protected by copyright. All rights reserved.

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The vertical atmospheric structure of the partially glacierised Mittivakkat valley, southeast Greenland

Cited by 4 publications

References 53 publications

A low-cost and open-source approach for supraglacial debris thickness mapping using UAV-based infrared thermography

A low-cost and open-source approach for supraglacial debris thickness mapping using UAV-based infrared thermography

A low-cost and open-source approach for supraglacial debris thickness mapping using UAV-based infrared thermography

A climatology of Arctic fog along the coast of East Greenland

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