Sea Ice Melt Pond Fraction Derived From Sentinel‐2 Data: Along the MOSAiC Drift and Arctic‐Wide

Geophysical Research Letters, Journal Year: 2023, Volume and Issue: 50(5)

Published: March 4, 2023

Abstract Melt ponds forming on Arctic sea ice in summer significantly reduce the surface albedo and impact heat mass balance of ice. Therefore, their areal coverage, which can undergo rapid change, is crucial to monitor. We present a revised method extract melt pond fraction (MPF) from Sentinel‐2 satellite imagery, evaluated by MPF products higher‐resolution helicopter‐borne imagery. The analysis evolution during MOSAiC campaign 2020, shows split Central Observatory (CO) into level highly deformed part, latter exhibits exceptional early formation compared vicinity. Average CO MPFs are 17% before 23% after major drainage. Arctic‐wide for years 2017–2021 consistent seasonal cycle all regions years.

Language: Английский

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The MOSAiC Distributed Network: Observing the coupled Arctic system with multidisciplinary, coordinated platforms

Elementa Science of the Anthropocene, Journal Year: 2024, Volume and Issue: 12(1)

Published: Jan. 1, 2024

Central Arctic properties and processes are important to the regional global coupled climate system. The Multidisciplinary drifting Observatory for Study of Climate (MOSAiC) Distributed Network (DN) autonomous ice-tethered systems aimed bridge gaps in our understanding temporal spatial scales, particular with respect resolution Earth system models. By characterizing variability around local measurements made at a Observatory, DN covers both interactions involving ocean-ice-atmosphere interfaces as well three-dimensional ocean, sea ice, atmosphere. more than 200 instruments (“buoys”) were varying complexity set up different sites mostly within 50 km Observatory. During an exemplary midwinter month, observations captured atmospheric on sub-monthly time but less so monthly means. They show significant snow depth ice thickness, provide temporally spatially resolved characterization motion deformation, showing coherency scale smaller scales. Ocean data background gradient across dependent due mixed layer sub-mesoscale mesoscale processes, influenced by variable cover. second case (May–June 2020) illustrates utility during absence manually obtained providing continuity physical biological this key transitional period. We examples synergies between extensive MOSAiC remote sensing numerical modeling, such estimating skill drift forecasts evaluating modeling. has been proven enable analysis atmosphere-ice-ocean potential improve model parameterizations important, unresolved future.

Language: Английский

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Preconditioning of Summer Melt Ponds From Winter Sea Ice Surface Temperature

Geophysical Research Letters, Journal Year: 2023, Volume and Issue: 50(4)

Published: Feb. 22, 2023

Abstract Comparing helicopter‐borne surface temperature maps in winter and optical orthomosaics summer from the year‐long Multidisciplinary drifting Observatory for Study of Arctic Climate expedition, we find a strong geometric correlation between warm anomalies melt pond location following summer. Warm are associated with thinner snow ice, that is, depression refrozen leads, allow water accumulation during melt. January were 0.3–2.5 K warmer on sea ice later formed ponds. A one‐dimensional steady‐state thermodynamic model shows observed differences line thickness depth. We demonstrate potential seasonal prediction coverage observations. threshold‐based classification achieves correct 41%

Language: Английский

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Formation and fate of freshwater on an ice floe in the Central Arctic

˜The œcryosphere, Journal Year: 2025, Volume and Issue: 19(2), P. 619 - 644

Published: Feb. 7, 2025

Abstract. The melt of snow and sea ice during the Arctic summer is a significant source relatively fresh meltwater. fate this freshwater, whether in surface ponds or thin layers underneath leads, impacts atmosphere–ice–ocean interactions their subsequent coupled evolution. Here, we combine analyses datasets from Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition (June–July 2020) process study on formation freshwater floes Central Arctic. Our budget suggest that high fraction (58 %) derived melt. Additionally, contribution stored precipitation (snowmelt) outweighs by 5 times input situ (rain). magnitude rate local meltwater production are remarkably similar to those observed prior Surface Heat Budget Ocean (SHEBA) campaign, where cumulative totaled around 1 m both. A small (10 remains ponds, which higher more deformed second-year (SYI) compared first-year (FYI) later summer. Most drains laterally vertically, with vertical drainage enabling storage internally freshening brine channels. In upper ocean, can accumulate transient order 0.1 thick leads under ice. presence such substantially system reducing bottom allowing false growth; heat, nutrient, gas exchange; influencing ecosystem productivity. Regardless, majority inferred be ultimately incorporated into ocean (75 (14 %). Terms as annual could used future work diagnostics global climate models. For example, range values CESM2 model roughly encapsulate total production, while underestimated about 50 %, suggesting pond terms key investigation.

Language: Английский

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High-resolution repeat topography of drifting ice floes in the Arctic Ocean from terrestrial laser scanning

Scientific Data, Journal Year: 2024, Volume and Issue: 11(1)

Published: Jan. 13, 2024

Snow and ice topography impact are impacted by fluxes of mass, energy, momentum in Arctic sea ice. We measured the on approximately a 0.5 km

Language: Английский

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Seasonality of spectral radiative fluxes and optical properties of Arctic sea ice during the spring–summer transition

Elementa Science of the Anthropocene, Journal Year: 2024, Volume and Issue: 12(1)

Published: Jan. 1, 2024

The reflection, absorption, and transmittance of shortwave solar radiation by sea ice play crucial roles in physical biological processes the ice-covered Arctic Ocean atmosphere. These sea-ice optical properties, particularly during melt season, significantly impact energy fluxes within total budget coupled atmosphere-ice-ocean system. We analyzed data from autonomous drifting stations to investigate seasonal evolution spectral albedo, transmittance, absorptivity for different sea-ice, snow, surface conditions measured MOSAiC expedition 2019–2020. spatial variability these properties was small spring increased strongly after onset on May 26, 2020, when liquid water content increased, largely accounting enhanced variability. temporal albedo mostly event-driven, thus containing episodic elements. Melt ponds reduced local 31%–45%. Over melting single ponding events deposition 35% compared adjacent bare ice. Thus, may summer as much over 1 month. Absorptivity showed strong variabilities independently conditions, possibly due internal under-ice processes. differences shown impacted partitioning radiation. This study shows that formation development ponds, reducing a third sites, can notably increase heat deposition. vastly evolutions, timing duration need be considered comparing in-situ observations with large-scale satellite remote sensing datasets, which we suggest help improve numerical models.

Language: Английский

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Adaptive Clustering-Based Method for ICESat-2 Sea Ice Retrieval

IEEE Transactions on Geoscience and Remote Sensing, Journal Year: 2023, Volume and Issue: 61, P. 1 - 14

Published: Jan. 1, 2023

The great potential of NASA's Ice, Cloud and Land Elevation Satellite-2 (ICESat-2) to retrieve sea ice heights has been demonstrated. However, the presence a significant number noise photons in ICESat-2 data makes accurate monitoring changes challenging. This paper proposes an adaptive clustering kernel density estimation-based (AC-KDE) method for estimating photon clouds. First, effectively detects signal photons. method's input parameters are determined based on ATLAS LiDAR transmission equation. Then, adaptive-count aggregates used estimate heights, variable along-track resolution is obtained using estimation method. AC-KDE applied MABEL data, we compare it with other denoising algorithms, including HBM, DBSCAN, OPTICS, UMD_RDA, DDM, ILSM algorithms. results indicate that proposed outperforms these algorithms extracting higher accuracy scores F-scores, which 0.97 & 0.97, 0.92 0.90, 0.89 0.72 under high-medium-low signal-to-noise ratio conditions, respectively. Additionally, retrieved compared ATL07 heights. show correlation coincident ATM have lower RMSE value (0.066 m) (0.104 m). also demonstrates vertical height precision 0.01 m over flat leads. can extract accurately polar regions.

Language: Английский

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Melt pond fractions on Arctic summer sea ice retrieved from Sentinel-3 satellite data with a constrained physical forward model

˜The œcryosphere, Journal Year: 2024, Volume and Issue: 18(2), P. 933 - 956

Published: Feb. 29, 2024

Abstract. The presence of melt ponds on Arctic summer sea ice significantly alters its albedo and thereby the surface energy budget mass balance. Large-scale observations pond coverage are crucial to investigate role for amplification representation in global climate models. We present new Melt Pond Detection 2 (MPD2) algorithm, which retrieves pond, ice, open-ocean fractions as well from Sentinel-3 visible near-infrared reflectances. In contrast most other algorithms, our method uses neither fixed values spectral constituents nor an artificial neural network. Instead, it aims a fully physical reflective properties based their optical characteristics. state vector X, containing along with area open ocean, is optimized iterative procedure match measured reflectances describe state. A major problem unmixing compound pixel that mixture half water bright cannot be distinguished homogeneous darker ice. order overcome this, we suggest constraining retrieval priori information. Initial constraint derived empirical same implemented retrieval. snow grain size thickness change time, thus changes throughout season. Therefore, field used develop parameterization function temperature history With these data, optimization initialized constrained, resulting uncertainty below 8 % 9 compared reference dataset. As data evaluation, 10 m resolution product fraction Sentinel-2 imagery used.

Language: Английский

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Observing the evolution of summer melt on multiyear sea ice with ICESat-2 and Sentinel-2

˜The œcryosphere, Journal Year: 2023, Volume and Issue: 17(9), P. 3695 - 3719

Published: Aug. 31, 2023

Abstract. We investigate sea ice conditions during the 2020 melt season, when warm air temperature anomalies in spring led to early onset, an extended and second-lowest September minimum Arctic extent observed. focus on region of most persistent cover examine pond depth retrieved from Ice, Cloud, land Elevation Satellite-2 (ICESat-2) using two distinct algorithms concert with a time series fraction concentration derived Sentinel-2 imagery obtain insights about melting surface three dimensions. find study increased rapidly June, mean peaking at 16 % ± 6 24 June 2020, followed by slow decrease 8 3 July, remained below 10 for remainder season through 15 September. Sea was consistently high (>95 %) beginning until 4 as floes disintegrated, it decreased 70 30 July then became more variable, ranging 75 90 season. Pond steadily median 0.40 m 0.17 peaked 0.97 0.51 even had already started decrease. Our results demonstrate that combining high-resolution passive active remote sensing we now have ability track evolving observe changes throughout summer

Language: Английский

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Updated Arctic melt pond fraction dataset and trends 2002–2023 using ENVISAT and Sentinel-3 remote sensing data

˜The œcryosphere, Journal Year: 2025, Volume and Issue: 19(1), P. 83 - 105

Published: Jan. 10, 2025

Abstract. Melt ponds on Arctic sea ice affect the radiative balance of region as they introduce darkening during summer. The temporal extent and spatial ponding, well its amplitude, reflect state are important for our understanding change. Remote sensing retrievals melt pond fraction (MPF) provide information both present development change throughout years, which is valuable in context climate amplification. In this work, we transfer earlier published Pond Detector (MPD) remote retrieval to Ocean Land Colour Instrument (OLCI) data board Sentinel-3 satellite so complement existing Medium Resolution Imaging Spectrometer (MERIS) MPF dataset (2002–2011) from Environmental Satellite (ENVISAT) with recent (2017–present). To evaluate bias product, comparisons Sentinel-2 MultiSpectral (MSI) high-resolution imagery presented, addition validation studies. Both MERIS OLCI MPD tend overestimate small MPFs (ranging 0 0.2), can be attributed presence water-saturated snow before onset ponding. Good agreement middle-range (0.2–0.8) observed, areas exceptionally high = 100 % recognized well. were reprocessed using an improved cloud clearing routine together internally consistent dataset, allows past 20 years analyzed. Although total summer hemispheric trend moderate, at +0.75 per decade, regional weekly trends display a pronounced dynamic range −10 +20 depending region. We conclude following effects: global shifted towards spring by least 2 weeks, happening late May compared early June mid-June beginning dataset. There has been regime East Siberian Laptev Sea dominating not Beaufort Gyre before. central Arctic, north Greenland Canadian Archipelago (CAA) have shown signs increasing first-year (FYI) years. daily gridded averages available web page Institute Physics, University Bremen, historic ENVISAT ongoing operational processing data.

Language: Английский

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