Evaluation of passive microwave snow water equivalent retrievals across the boreal forest/tundra transition of western Canada

Derksen, Chris; Walker, Anne; Goodison, B.

doi:10.1016/j.rse.2005.02.014

Cited by 161 publications

(114 citation statements)

References 33 publications

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“…This result is in agreement with recent studies (Brown et al, 2007(Brown et al, , 2010Frei and Lee, 2010) which find that over the last decade or so the timing of spring ablation over North America is later, by up to several weeks in the central Canadian Arctic, according to IMS in comparison to other observations. The reasons for these discrepancies, which are found during the entire spring ablation season (April, May, and June; May and June not shown here) over the boreal forest as well as the tundra, are not understood, but may be related to geographic factors such as the forest type and/or the presence of numerous lakes in this (Derksen et al, 2005a;Rees et al, 2006). Investigations into the cause of this problem continue.…”

Section: Disagreement Between Amsr-e and The Other Two Productsmentioning

confidence: 75%

“…Sources of error include: surface heterogeneity within a passive microwave footprint; temporal and spatial variability in grain size and snow density; obscuration of snow by forests; masking of the passive microwave signal by liquid water in the snow pack; and effects of atmospheric attenuation. The persistent underestimation by AMSR-E with respect to CMC over some regions can be partially explained by considering that snow depth over many of those areas is above the 'saturation' depth to which the passive microwave algorithm is sensitive Markus et al, 2006;Matzler, 1994;Schanda et al, 1983); the presence of a high fraction of lakes over the north east of North America is also believed to be a source of error (Derksen et al, 2005a;Rees et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

“…Of particular relevance to the monitoring of high latitude snow is the presence of numerous frozen lakes in Arctic regions, which may contribute to the overestimation of snow covered area from visible and infrared based imagery during periods when lakes remain frozen after the snow has melted on adjacent land surfaces (Derksen et al, 2005a;Frei and Lee, 2010), at least when high resolution land surface data sets are not used to filter out the signal from lake surfaces. Passive microwave based estimates of SWE may be underestimated due to the presence of lakes (Derksen et al, 2005a;Rees et al, 2006). On the other hand, surface heterogeneity may assist in the interpretation of snow-covered versus snow-free ground, and of snow-covered versus cloud-covered scenes, when trained analysts are mapping snow extent using visible imagery.…”

Section: Visible and Near-infraredmentioning

confidence: 99%

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A review of global satellite-derived snow products

Frei

Tedesco

Lee

et al. 2012

Advances in Space Research

264

184

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Snow cover over the Northern Hemisphere plays a crucial role in the Earth's hydrology and surface energy balance, and modulates feedbacks that control variations of global climate. While many of these variations are associated with exchanges of energy and mass between the land surface and the atmosphere, other expected changes are likely to propagate downstream and affect oceanic processes in coastal zones. For example, a large component of the freshwater flux into the Arctic Ocean comes from snow melt. The timing and magnitude of this flux affects biological and thermodynamic processes in the Arctic Ocean, and potentially across the globe through their impact on North Atlantic Deep Water formation.Several recent global remotely sensed products provide information at unprecedented temporal, spatial, and spectral resolutions. In this article we review the theoretical underpinnings and characteristics of three key products. We also demonstrate the seasonal and spatial patterns of agreement and disagreement amongst them, and discuss current and future directions in their application and development. Though there is general agreement amongst these products, there can be disagreement over certain geographic regions and under conditions of ephemeral, patchy and melting snow.

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Section: Disagreement Between Amsr-e and The Other Two Productsmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Visible and Near-infraredmentioning

confidence: 99%

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A review of global satellite-derived snow products

Frei

Tedesco

Lee

et al. 2012

Advances in Space Research

264

184

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“…GlobSnow is a hybrid product which assimilates passive microwave satellite 212 measurements, as well as records from climate stations to derive daily SWE 213 maps with a spatial resolution of 25 km (Takala et al, 2011 lakes and rivers (Foster et al, 2005;Derksen et al, 2005Derksen et al, , 2011 …”

mentioning

confidence: 99%

Satellite-based modeling of permafrost temperatures in a tundra lowland landscape

Langer

Westermann

Heikenfeld

et al. 2013

Remote Sensing of Environment

105

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Remote sensing offers great potential for detecting changes of the thermal state of permafrost and active layer dynamics in the context of Arctic warming. This study presents a comprehensive feasibility analysis of satellite-based permafrost modeling for a typical lowland tundra landscape in the Lena River Delta, Siberia. We assessed the performance of a transient permafrost model which is forced by time series of land surface temperatures (LSTs) and snow water equivalents (SWEs) obtained from MODIS and GlobSnow products. Both the satellite products and the model output were evaluated on the basis of long-term field measurements from the Samoylov permafrost observatory. The model was found to successfully reproduce the evolution of the permafrost temperature and freeze-thaw dynamics when calibrated with ground measurements. Monte-Carlo simulations were performed in order to evaluate the impact of inaccuracies and in model forcing and uncertainties in the parameterization. The sensitivity analysis showed that a correct SWE forcing and parameterization of the snow's thermal properties are essential for reliable permafrost modeling. In the worst case, the bias in the modeled permafrost temperatures can amount to 5 • C. For the thaw depth, a maximum uncertainty of about ±15 cm is found due to possible uncertainties in the soil composition.

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“…Prohibitive costs of manual snow course observations have led to the reduction of these measurements by many agencies, including Environment and Climate Change Canada, where operational snow course numbers have decreased from over 100 in the 1980s to less than 30 (Barry, 1995;Brown et al, 2000). Since the early 1990s, manual SWE measurements have been augmented or replaced by remote sensing techniques such as passive microwave retrievals (Goodison and Walker, 1995) but these techniques still require accurate and reliable in situ measurements for ground truthing and retrieval development (Derksen et al, 2005;Takala et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

An assessment of two automated snow water equivalent instruments during the WMO Solid Precipitation Intercomparison Experiment

et al. 2017

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Abstract. During the World Meteorological Organization (WMO) Solid Precipitation Intercomparison Experiment (SPICE), automated measurements of snow water equivalent (SWE) were made at the Sodankylä (Finland), Weissfluhjoch (Switzerland) and Caribou Creek (Canada) SPICE sites during the northern hemispheric winters of 2013/14 and 2014/15. Supplementary intercomparison measurements were made at Fortress Mountain (Kananaskis, Canada) during the 2013/14 winter. The objectives of this analysis are to compare automated SWE measurements with a reference, comment on their performance and, where possible, to make recommendations on how to best use the instruments and interpret their measurements. Sodankylä, Caribou Creek and Fortress Mountain hosted a Campbell Scientific CS725 passive gamma radiation SWE sensor. Sodankylä and Weissfluhjoch hosted a Sommer Messtechnik SSG1000 snow scale. The CS725 operating principle is based on measuring the attenuation of soil emitted gamma radiation by the snowpack and relating the attenuation to SWE. The SSG1000 measures the mass of the overlying snowpack directly by using a weighing platform and load cell. Manual SWE measurements were obtained at the intercomparison sites on a bi-weekly basis over the accumulation-ablation periods using bulk density samplers. These manual measurements are considered to be the reference for the intercomparison. Results from Sodankylä and Caribou Creek showed that the CS725 generally overestimates SWE as compared to manual measurements by roughly 30-35 % with correlations (r 2 ) as high as 0.99 for Sodankylä and 0.90 for Caribou Creek. The RMSE varied from 30 to 43 mm water equivalent (mm w.e.) and from 18 to 25 mm w.e. at Sodankylä and Caribou Creek, which had respective SWE maximums of approximately 200 and 120 mm w.e. The correlation at Fortress Mountain was 0.94 (RMSE of 48 mm w.e. with a maximum SWE of approximately 650 mm w.e.) with no systematic overestimation. The SSG1000 snow scale, having a different measurement principle, agreed quite closely with the manual measurements at Sodankylä and Weissfluhjoch throughout the periods when data were available (r 2 as high as 0.99 and RMSE from 8 to 24 mm w.e. at Sodankylä and from 56 to 59 mm w.e. at Weissfluhjoch, where maximum SWE was approximately 850 mm w.e.).

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Evaluation of passive microwave snow water equivalent retrievals across the boreal forest/tundra transition of western Canada

Cited by 161 publications

References 33 publications

A review of global satellite-derived snow products

A review of global satellite-derived snow products

Satellite-based modeling of permafrost temperatures in a tundra lowland landscape

An assessment of two automated snow water equivalent instruments during the WMO Solid Precipitation Intercomparison Experiment

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