Not logged in
PANGAEA.
Data Publisher for Earth & Environmental Science

Gunn, Grant E; Duguay, Claude R; Derksen, Chris; Lemmetyinen, Juha; Toose, Peter (2011): (Table 3) Air temperatures, and snow and ice characteristics of fresh and brackish water lakes in the Northwest Territories, Canada [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.810343, Supplement to: Gunn, GE et al. (2011): Evaluation of the HUT modified snow emission model over lake ice using airborne passive microwave measurements. Remote Sensing of Environment, 115(1), 233-244, https://doi.org/10.1016/j.rse.2010.09.001

Always quote citation above when using data! You can download the citation in several formats below.

RIS CitationBibTeX CitationShow MapGoogle Earth

Abstract:
The algorithms designed to estimate snow water equivalent (SWE) using passive microwave measurements falter in lake-rich high-latitude environments due to the emission properties of ice covered lakes on low frequency measurements. Microwave emission models have been used to simulate brightness temperatures (Tbs) for snowpack characteristics in terrestrial environments but cannot be applied to snow on lakes because of the differing subsurface emissivities and scattering matrices present in ice. This paper examines the performance of a modified version of the Helsinki University of Technology (HUT) snow emission model that incorporates microwave emission from lake ice and sub-ice water. Inputs to the HUT model include measurements collected over brackish and freshwater lakes north of Inuvik, Northwest Territories, Canada in April 2008, consisting of snowpack (depth, density, and snow water equivalent) and lake ice (thickness and ice type). Coincident airborne radiometer measurements at a resolution of 80x100 m were used as ground-truth to evaluate the simulations.
The results indicate that subsurface media are simulated best when utilizing a modeled effective grain size and a 1 mm RMS surface roughness at the ice/water interface compared to using measured grain size and a flat Fresnel reflective surface as input. Simulations at 37 GHz (vertical polarization) produce the best results compared to airborne Tbs, with a Root Mean Square Error (RMSE) of 6.2 K and 7.9 K, as well as Mean Bias Errors (MBEs) of -8.4 K and -8.8 K for brackish and freshwater sites respectively. Freshwater simulations at 6.9 and 19 GHz H exhibited low RMSE (10.53 and 6.15 K respectively) and MBE (-5.37 and 8.36 K respectively) but did not accurately simulate Tb variability (R= -0.15 and 0.01 respectively). Over brackish water, 6.9 GHz simulations had poor agreement with airborne Tbs, while 19 GHz V exhibited a low RMSE (6.15 K), MBE (-4.52 K) and improved relative agreement to airborne measurements (R = 0.47). Salinity considerations reduced 6.9 GHz errors substantially, with a drop in RMSE from 51.48 K and 57.18 K for H and V polarizations respectively, to 26.2 K and 31.6 K, although Tb variability was not well simulated. With best results at 37 GHz, HUT simulations exhibit the potential to track Tb evolution, and therefore SWE through the winter season.
Project(s):
International Polar Year (2007-2008) (IPY)
Coverage:
Median Latitude: 68.804250 * Median Longitude: -133.344500 * South-bound Latitude: 68.536000 * West-bound Longitude: -133.800000 * North-bound Latitude: 69.000000 * East-bound Longitude: -132.726000
Date/Time Start: 2008-04-06T00:00:00 * Date/Time End: 2008-04-06T00:00:00
Minimum Elevation: 2.0 m * Maximum Elevation: 33.0 m
Event(s):
Lake_Noel (Parsons Lake)  * Latitude: 68.948000 * Longitude: -133.630000 * Date/Time: 2008-04-10T00:00:00 * Elevation: 33.0 m * Location: Northwest Territories, Canada * Method/Device: Snow/ice sample (SNOW)
Lake_Sitidgi  * Latitude: 68.536000 * Longitude: -132.726000 * Date/Time: 2008-04-11T00:00:00 * Elevation: 2.0 m * Location: Northwest Territories, Canada * Method/Device: Snow/ice sample (SNOW)
Lakes_A-B  * Latitude: 69.000000 * Longitude: -133.800000 * Location: Northwest Territories, Canada * Method/Device: Snow/ice sample (SNOW)
Comment:
Note that the exact position of Lakes A and B could not be derived from the article. Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
1 Event labelEvent
2 Latitude of eventLatitude
3 Longitude of eventLongitude
4 Water bodiesWater bodiesGunn, Grant E
5 SiteSiteGunn, Grant E
6 DATE/TIMEDate/TimeGeocode
7 Date/time endDate/time endGunn, Grant E
8 Temperature, airTTT°CGunn, Grant E
9 Snow thicknessSnow thickmGunn, Grant E
10 Snow water equivalentSWEmmGunn, Grant E
11 Density, snowDensity snowkg/m3Gunn, Grant E
12 Snow grain sizeSnow grain sizemmGunn, Grant E
13 Sea ice thicknessEsEsmGunn, Grant Elake ice
14 Ice typeIce typeGunn, Grant E
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
250 data points

Data

Download dataset as tab-delimited text — use the following character encoding:

1 
Event		2 
Latitude		3 
Longitude		4 
Water bodies		5 
Site		6 
Date/Time		7 
Date/time end		8 
TTT [°C]		9 
Snow thick [m]		10 
SWE [mm]		11 
Density snow [kg/m3]		12 
Snow grain size [mm]		13 
EsEs [m]		14 
Ice type
Lakes_A-B 69.000-133.800FreshwaterA-12008-04-06T00:002008-04-15-13.40.22733151.61.21Clear with bubbles
Lakes_A-B69.000-133.800FreshwaterA-22008-04-06T00:002008-04-15-13.40.26783061.51.13Grey surface
Lakes_A-B69.000-133.800FreshwaterB-12008-04-06T00:002008-04-15-14.40.381072791.51.06Grey surface
Lakes_A-B69.000-133.800FreshwaterB-42008-04-06T00:002008-04-15-14.40.31902941.51.12White-grey
Lake_Noel 68.948-133.630FreshwaterTLF-122008-04-06T00:002008-04-15-7.10.30953202.41.32Grey surface
Lakes_Husky 68.733-133.222FreshwaterHusky-92008-04-06T00:002008-04-15-11.00.31822572.51.01Clear ice
Lakes_Husky68.733-133.222Brackish waterHusky-12008-04-06T00:002008-04-15-11.00.30792521.51.06Clear Ice
Lakes_Husky68.733-133.222Brackish waterHusky-22008-04-06T00:002008-04-15-11.00.371032712.41.02Clear Ice
Lakes_Husky68.733-133.222Brackish waterHusky-32008-04-06T00:002008-04-15-11.00.401172863.20.89Clear Ice
Lakes_Husky68.733-133.222Brackish waterHusky-42008-04-06T00:002008-04-15-11.00.36842322.70.85Clear Ice
Lakes_Husky68.733-133.222Brackish waterHusky-72008-04-06T00:002008-04-15-11.00.36802253.10.86Clear with Bubbles
Lakes_Husky68.733-133.222Brackish waterHusky-82008-04-06T00:002008-04-15-11.00.36912472.50.91Grey Surface
Lakes_Husky68.733-133.222Brackish waterTLF-072008-04-06T00:002008-04-15-7.10.31902832.40.94Rough-Rafted surface
Lakes_Husky68.733-133.222Brackish waterTLF-082008-04-06T00:002008-04-15-7.10.25843152.41.36Clear Ice
Lakes_Husky68.733-133.222Brackish waterTLF-092008-04-06T00:002008-04-15-7.10.31953112.40.99Clear Ice
Lakes_Husky68.733-133.222Brackish waterTLF-102008-04-06T00:002008-04-15-7.10.21683222.41.24Clear Ice
Lake_Sitidgi 68.536-132.726FreshwaterSitidgi-12008-04-06T00:002008-04-15-15.00.291053552.31.27Grey surface
Lake_Sitidgi68.536-132.726FreshwaterSitidgi-22008-04-06T00:002008-04-15-15.00.30933102.31.24Variable
Lake_Sitidgi68.536-132.726FreshwaterSitidgi-32008-04-06T00:002008-04-15-15.00.27772812.31.23Clear ice
Lake_Sitidgi68.536-132.726FreshwaterSitidgi-42008-04-06T00:002008-04-15-15.00.351002842.31.10Grey surface
Lake_Sitidgi68.536-132.726FreshwaterTLF-012008-04-06T00:002008-04-15-7.10.351052981.51.47Rough-rafted surface
Lake_Sitidgi68.536-132.726FreshwaterTLF-022008-04-06T00:002008-04-15-7.10.25853351.31.49Clear ice
Lake_Sitidgi68.536-132.726FreshwaterTLF-032008-04-06T00:002008-04-15-7.10.321113371.81.25Rough-rafted grey
Lake_Sitidgi68.536-132.726FreshwaterTLF-042008-04-06T00:002008-04-15-7.10.23683002.41.44Clear ice
Lake_Sitidgi68.536-132.726FreshwaterTLF-02.12008-04-06T00:002008-04-15-15.00.27873142.31.36Clear ice