!Rosel, Kaleschke, Birnbaum, 2011
Rösel, A., Kaleschke, L., and Birnbaum, G.: Melt ponds on Arctic sea ice determined from MODIS satellite data using an
artificial neural network, The Cryosphere Discuss., 5, 2991-3024, doi:10.5194/tcd-5-2991-2011, 2011.
Arctic-wide melt pond fractions and sea ice concentrations are derived from the level 3 MODIS
surface reflectance product. The validation of the MODIS melt pond data set was conducted with
aerial photos from the MELTEX campaign 2008 in the Beaufort Sea, data sets from the National
Snow and Ice Data Center (NSIDC) for 2000 and 2001 from four sites spread over the entire Arctic,
and with ship observations from the trans-Arctic HOTRAX cruise in 2005.
Furthermore, the MODIS results are used to estimate the influence of melt ponds on retrievals of sea
ice concentrations from passive microwave data. Results from a case study comparing sea ice
concentrations from ASI-, NASA Team 2-, and Bootstrap-algorithms with MODIS sea ice
concentrations indicate an underestimation of around 40 % for sea ice concentrations retrieved with
microwave algorithms.
Fetterer & Untersteiner, 1998a
Fetterer, F.; Untersteiner, N.; , "Melt pond coverage statistics from classified satellite data," Geoscience and Remote Sensing
Symposium Proceedings, 1998. IGARSS '98. 1998 IEEE International , vol.4, no., pp.1954-1956 vol.4, 6-10 Jul 1998, doi:
10.1109/IGARSS.1998.703706
Melt pond development over one summer in the Beaufort Sea was monitored with high resolution
satellite data. These data resolve individual melt ponds, and were used to obtain pond coverage
measurements for ice floes. If pond coverage is known, floe albedo can be estimated. Pond coverage
ranged from 30 to 40% at the beginning of melt to about 15% at freezeup. The range in coverage from
floe to floe on any day was about 10%.
Fontana et al, 2010
Godoy ?
Laine, 2004
Laine, V. (2004), Arctic sea ice regional albedo variability and trends, 1982–1998, J. Geophys. Res., 109, C06027,
doi:10.1029/2003JC001818.
Whole-summer and monthly sea ice regional albedo averages for June, July, and August from 1982 to
1998 have been processed from advanced very high resolution radiometer data. Time series for albedo,
sea ice concentration, sea ice extent, and surface air temperature have been calculated for the sea ice
cover for the Northern Hemisphere as a whole and for six subregions: the Arctic Ocean, the Kara and
Barents Seas, the Greenland Sea, the Labrador Sea, Hudson Bay, and the Canadian archipelago. The
highest albedo values are mainly found in the Arctic Ocean north of Greenland. The lowest albedo
(0.2–0.3) occurs in the fringe area of the Arctic Ocean, e.g., on the coasts of Alaska and Siberia. Low
albedo values also exist on the east coast of Greenland and in Hudson Bay.
Lindsay & Rothrock, 1994
Lindsay, R. W.; Rothrock, D. A., Arctic Sea Ice Albedo from AVHRR. Journal of Climate, vol. 7, Issue 11, pp.1737-1749
The seasonal cycle of surface albedo of sea ice in the Arctic is estimated from measurements made
with the Advanced Very High Resolution Radiometer (AVHRR) on the polar-orbiting satellites
NOAA-10 and NOAA-11. The albedos of 145 200-km-square cells are analyzed. Cloud masking is
performed manually. Corrections are applied for instrument calibration, nonisotropic reflection,
atmospheric interference, narrowband to broadband conversion, and normalization to a common solar
zenith angle. The estimated albedos are relative, with the instrument gain set to give an albedo of 0.80
for ice floes in March and April. The mean values for the cloud-free portions of individual cells range
from 0.18 to 0.91. Monthly averages of cells in the central Arctic range from 0.76 in April to 0.47 in
August.
Mainen et al, ?
Moody et al., 2007
Moody, EG, King, MD, Schaaf, CB, Hall, DK, Platnick, S (2007). Northern Hemisphere five-year average (2000-2004) spectral
albedos of surfaces in the presence of snow: Statistics computed from Terra MODIS land products. REMOTE SENSING OF
ENVIRONMENT, 111(3-Feb), 337-345.
In this paper, we present five-year (2000-2004) climatological statistics of Northern Hemisphere
spectral white-sky albedo for the 16 International Geosphere-Biosphere Program (IGBP) ecosystem
classes when accompanied by the presence of snow on the ground. These statistics are obtained using
validated, high quality Moderate Resolution Imaging Spectroradiometer (MODIS) land surface albedo
(MOD43B3) data flagged as snow in the associated Quality Assurance (QA) fields. Near Real-Time
Ice and Snow Extent (NISE) data are used as an additional discriminator of snow extent. Statistics are
provided for the first seven MODIS bands, ranging from 0.47 to 2.1 mu m, and for three broadbands,
0.3-0.7, 0.3-5.0 and 0.7-5.0 mu m. The statistics demonstrate that each ecosystem classification has a
discernible spectral albedo signature when accompanied by snow on the ground. This indicates that
winter canopy and the underlying surface radiative properties are impacted by the presence of snow
overlying these surfaces.
Roesel, Kaleschke 2011
Roesel, A. Kaleschke L., Comparison of different retrieval techniques for melt ponds on Arctic sea ice from Landsat and
MODIS satellite data, Annals of Glaciology 52(57) 2011
An algorithm based on a principal component analysis (PCA) of two spectral channels has been
developed in order to determine the melt-pond fraction from Landsat and MODIS. PCA allows
differentiation of melt ponds and other surface types such as snow, ice or water. Spectral bands 1 and
4 with central wavelengths at 480 and 770 nm, respectively, are used as they represent the differences
in the spectral albedo of melt ponds. A Landsat 7 ETM+ scene from 19 July 2001 was analysed using
PCA. The melt-pond fraction determined by the PCA method yields a different spatial distribution of
the ponded areas from that developed by others. A MODIS subset from the same date and area is also
analysed. The classification of MODIS data results in a higher melt-pond fraction than both Landsat
classifications.
Sneed, Hamilton, 2007
Sneed, W. A., and G. S. Hamilton (2007), Evolution of melt pond volume on the surface of the Greenland Ice Sheet,
Geophys. Res. Lett., 34, L03501, doi:10.1029/2006GL028697.
The paper describes an algorithm for estimating the depth and hence volume of surface melt ponds
using multispectral ASTER satellite imagery. The method relies on reasonable assumptions about the
albedo of the bottom surface of the ponds and the optical attenuation characteristics of the ponded
meltwater. We apply the technique to sequences of satellite imagery acquired over the western margin
of the Greenland Ice Sheet to derive changes in melt pond extent and volume during the period 2001–
2004. Results show large intra- and interannual changes in ponded water volumes, and large volumes
of liquid water stored in extensive slush zones.
Tschudi abstract
Tschudi et al., 2008
Tschudi, M.A., Maslanik, J.A. & Perovich, D.K., 2008. Derivation of melt pond coverage on Arctic sea ice using MODIS
observations. Remote Sensing of Environment, 112(5), p.2605-2614.
MODIS surface reflectance product is used to derive the daily melt pond cover over sea ice in the
Beaufort/Chukchi Sea region through the summer of 2004. For this region, the estimated pond cover
increased rapidly during the first 20 days of melt from 10% to 40%. Fluctuations in pond cover
occurred through summer, followed by a more gradual decrease through late August to 10%. The
rapid initial increase in pond cover occurred later as latitude increased and melt progressed northward.
A surface campaign at Barrow in June 2004 provided pond and ice spectral reflectance needed by the
MODIS algorithm to deduce pond coverage. Although individual pond and ice reflectance varies
within the comparatively small region of measurement, the mean values used within the algorithm
ensured that relevant values (i.e. concurrent with satellite observations) were being applied.
Wang, Zender, 2011
Wang,X., Zender,C.: MODIS snow albedo bias at high solar zenith angles relative to
theory and to in situ observations in Greenland, Remote Sensing of Environment,
Volume 114, Issue 3, 15 March 2011
In situ measurements of snow albedo at five stations along a north–south transect in the dry-snow
facies of the interior of Greenland follow the theoretically expected dependence of snow albedo with
solar zenith angle (SZA). Greenland Climate Network (GC-Net) measurements from 1997 through
2007 exhibit the trend of modest surface brightening with increasing SZA on both diurnal and
seasonal timescales. SZA explains up to 50% of seasonal albedo variability. The two other
environmental factors considered, temperature and cloudiness, play much less significant roles in
seasonal albedo variability at the five stations studied. Compared to the 10-year record of these GCNet measurements, the five-year record of MODIS satellite-retrieved snow albedo shows a systematic
negative bias for SZA larger than about 55°. The discrepancy of MODIS albedo with in situ albedo
and with theory is determined mainly by two related factors, SZA and retrieval quality.