Mapping of seasonal freeze‐thaw transitions across the pan‐Arctic land and sea ice domains with satellite radar

Mortin, Jonas; Schröder, Thomas; Hansen, Aksel Walløe; Holt, Benjamin; McDonald, K. C.

doi:10.1029/2012jc008001

Cited by 31 publications

(15 citation statements)

References 80 publications

(110 reference statements)

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“…Data from synthetic aperture radars (SARs), scatterometers and passive microwave radiometers have been used in previous studies to determine MO dates [8][9][10][11][12]. While data from both SARs and scatterometers can yield MO dates at reasonably high spatial resolution (100 m-5 km), the most commonly used MO retrieval methods use passive microwave data from the scanning multi-channel microwave radiometer (SMMR), and/or the special sensor microwave/imager (SSM/I), or the special sensor microwave imager/sounder (SSMIS).…”

Section: Introductionmentioning

confidence: 99%

Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago

2019

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The Canadian Arctic Archipelago (CAA) presents unique challenges to the determination of melt onset (MO) using remote sensing data. High spatial resolution data is required to discern melt onset among the islands and narrow waterways of the region. Current passive microwave retrievals use daily averaged 19 GHz and 37 GHz data from the multi-channel microwave radiometer (SMMR) and/or the special sensor microwave/imager (SSM/I). The development of a new passive microwave melt onset method capable of using higher resolution data is desirable. The new passive microwave melt onset method described here, named the Dynamic Threshold Variability Method (DTVM), uses higher resolution data from the 37 GHz vertically-polarized channel from the advanced microwave scanning radiometers (AMSR-E and AMSR-2). The DTVM MO detection methodology differs from previously presented passive microwave Arctic MO methods in that it does not use a fixed threshold of a brightness temperature parameter. Instead, the DTVM determines MO dates based on the distribution of dates corresponding to the exceedance of a range of brightness temperature variability thresholds. The method also uses swath data instead of daily averaged brightness temperatures, which is found to lead to improved melt detection. Two current passive microwave MO methods are compared and evaluated for applicability in the CAA alongside the DTVM. The DTVM provides MO dates at a higher spatial resolution than earlier methods in addition to higher correlation with MO dates from surface air temperature (SAT) reanalyses. It is found that, for some years, MO dates in the CAA exhibit a latitudinal dependence, while in other years the MO dates in the CAA are relatively uniform across the domain.

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Section: Introductionmentioning

confidence: 99%

Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago

2019

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“…The seasonal freeze/thaw (FT) state transition to predominantly non-frozen (FR) conditions in the spring initiates processes that are nearly dormant during the winter FR season and is related to seasonal snowmelt and soil thawing in high northern latitude (HNL) ecosystems (Kimball et al 2001, Euskirchen et al 2007, Mortin et al 2012. The FT signal and associated FR season metric obtained from satellite microwave remote sensing characterizes the predominant FR or non-FR status of the land surface and the duration of FR conditions within the sensor footprint, without distinguishing among individual landscape elements, including vegetation, snow cover and surface soil conditions (Zhang et al 2011, Kim et al 2012.…”

Section: Introductionmentioning

confidence: 99%

“…In a typical HNL seasonal snow cycle, snowmelt may last for several days to weeks in the spring until the snowpack is depleted and nighttime temperatures remain above freezing (Semmens et al 2013); surface air temperatures (SATs) may rise above freezing under daily solar radiation and thermal loading, while snow and underlying soil temperatures remain near 0.0°C or below freezing until the snow cover heat sink is gone. The seasonal transition from dry to wet snowpack conditions with spring snowmelt onset generally coincides with a rapid decline in land surface albedo (Ling andZhang 2003, Betts et al 2014), increased liquid water availability in the landscape (Kimball et al 2001, Mortin et al 2012 and a seasonal shift in the surface energy budget from predominantly sensible to latent energy, with commensurate increases in land surface evaporation (Chapin et al 2005, Ling and Zhang 2003, Zhang et al 2011. Prior to the beginning of the HNL snow cycle, FR ground conditions may occur in early to mid-fall before persistent snow cover (Kim et al 2014a).…”

Section: Introductionmentioning

confidence: 99%

New satellite climate data records indicate strong coupling between recent frozen season changes and snow cover over high northern latitudes

Kim

Kimball

Robinson

et al. 2015

Environ. Res. Lett.

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LETTERNew satellite climate data records indicate strong coupling between recent frozen season changes and snow cover over high northern latitudes Abstract We examined new satellite climate data records documenting frozen (FR) season and snow cover extent (SCE) changes from 1979 to 2011 over all northern vegetated land areas (⩾45°N). New insight on the spatial and temporal characteristics of seasonal FR ground and snowpack melt changes were revealed by integrating the independent FR and SCE data records. Similar decreasing trends in annual FR and SCE durations coincided with widespread warming (0.4°C decade −1 ). Relatively strong declines in FR and SCE durations in spring and summer are partially offset by increasing trends in fall and winter. These contrasting seasonal trends result in relatively weak decreasing trends in annual FR and SCE durations. A dominant SCE retreat response to FR duration decreases was observed, while the sign and strength of this relationship was spatially complex, varying by latitude and regional snow cover, and climate characteristics. The spatial extent of FR conditions exceeds SCE in early spring and is smaller during snowmelt in late spring and early summer, while FR ground in the absence of snow cover is widespread in the fall. The integrated satellite record, for the first time, reveals a general increasing trend in annual snowmelt duration from 1.3 to 3.3 days decade −1 (p < 0.01), occurring largely in the fall. Annual FR ground durations are declining from 0.8 to 1.3 days decade −1 . These changes imply extensive biophysical impacts to regional snow cover, soil and permafrost regimes, surface water and energy budgets, and climate feedbacks, while ongoing satellite microwave missions provide an effective means for regional monitoring.

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“…Therefore, snowmelt plays an important role in the mass and energy balance of the polar regions. The temporal and spatial distribution of snowmelt leads to the formation of different glacier facies, and the variations in glacier facies represent the changes of climate [2,3]. The Antarctic ice shelf snowmelt is particularly sensitive to climate change [4].…”

Section: Introductionmentioning

confidence: 99%

Mapping Radar Glacier Zones and Dry Snow Line in the Antarctic Peninsula Using Sentinel-1 Images

Zhou

Zheng

2017

Remote Sensing

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Surface snowmelt causes changes in mass and energy balance, and endangers the stabilities of the ice shelves in the Antarctic Peninsula (AP). The dynamic changes of the snow and ice conditions in the AP were observed by Sentinel-1 images with a spatial resolution of 40 m in this study. Snowmelt detected by the special sensor microwave/imager (SSM/I) is used to study the relationship between summer snowmelt and winter synthetic aperture radar (SAR) backscatter. Radar glacier zones (RGZs) classifications were conducted based on their differences in liquid snow content, snow grain size, and the relative elevations. We developed a practical method based on the simulations of a microwave scattering model to classify RGZs by using Sentinel-1 images in the AP. The summer snowmelt detected by SSM/I and Sentinel-1 data are compared between 2014 and 2015. The SSM/I-derived melting days is used to validate the winter dry snow line (DSL). RGZs derived from Sentinel-1 images suggest that snowmelt expanded from inland of the Larsen C Ice Shelf to the coastal area, whereas an opposite direction was found in the George VI Ice Shelf. The long melting season in the grounding zone of the Larsen C Ice Shelf may result from the adiabatically-dried föhn winds on the east side of the AP. As the uppermost limit of summer snowmelt, DSL was mapped based on the winter Sentinel-1 mosaic of the AP. Compared with the SSM/I-derived melting days, the winter DSL mainly distributed in the areas melted for one to three days in summer. DSL elevations on the Palmer Land increased from south to north.

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Mapping of seasonal freeze‐thaw transitions across the pan‐Arctic land and sea ice domains with satellite radar

Cited by 31 publications

References 80 publications

Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago

Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago

New satellite climate data records indicate strong coupling between recent frozen season changes and snow cover over high northern latitudes

Mapping Radar Glacier Zones and Dry Snow Line in the Antarctic Peninsula Using Sentinel-1 Images

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