Long-term coastal-polynya dynamics in the Southern Weddell Sea from MODIS thermal-infrared imagery
Summary: We established a 13 year long MODIS-derived thin-ice thickness data set from which we derived information about polynya dynamics in the Southern Weddell Sea. In contrast to other studies, we do not focus on a single region, but discuss polynya dynamics for the complete coastal area. The higher spatial resolution of MODIS compared to passive-microwave sensors enables us to resolve even very narrow coastal polynyas that would remain otherwise undetected.
The Cryosphere Discuss., 9, 3959-3993, doi:10.5194/tcd-9-3959-2015, 2015
The global land Cryosphere Radiative Effect during the MODIS era
Summary: Our work quantifies the effect of snow/ice cover on Earth's top of atmosphere solar energy budget. We used higher resolution MODIS data, combined with microwave retrievals of snow presence and radiative kernels produced from 4 different models for Cryosphere Radiative Effect (CrRE) estimation. We have estimated a global land-based CrRE of about -2.6Wm-2 during 2001-2013, with about 59% of the effect originating from Antarctica. We were also be able to resolve contribution from Mountain glaciers.
The Cryosphere Discuss., 9, 3925-3957, doi:10.5194/tcd-9-3925-2015, 2015
Climatic controls and climate proxy potential of Lewis Glacier, Mt Kenya
The Cryosphere Discuss., 9, 3887-3924, doi:10.5194/tcd-9-3887-2015, 2015
The influence of a model subglacial lake on ice dynamics and internal layering
Summary: This paper explores the influence of a subglacial lake on ice dynamics and internal layers by means of numerical modelling as well as simulating the effect of a subglacial drainage event on isochrones. We provide an explanation for characteristic dip and ridge features found at the edges of many subglacial lakes and conclude that draining lakes can result in travelling waves at depth within isochrones, thus indicating the possibility of detecting past drainage events with ice penetrating radar.
The Cryosphere Discuss., 9, 3859-3886, doi:10.5194/tcd-9-3859-2015, 2015
Improved Arctic sea ice thickness projections using bias corrected CMIP5 simulations
Summary: Projections of Arctic sea ice thickness have the potential to inform stakeholders about accessibility to the region, but are currently rather uncertain. We present a new method to constrain GCM simulations of SIT to narrow projection uncertainty via a statistical bias correction technique.
The Cryosphere Discuss., 9, 3821-3857, doi:10.5194/tcd-9-3821-2015, 2015
Brief Communication: Global glacier mass loss reconstructions during the 20th century are consistent
The Cryosphere Discuss., 9, 3807-3820, doi:10.5194/tcd-9-3807-2015, 2015
Glaciers change over the last century, Caucasus Mountains, Georgia, observed by the old topographical maps, Landsat and ASTER satellite imagery
Summary: The article presents the percentage and quantitative changes in the number and area of the glaciers of Georgia (Caucasus) in the years of 1911-1960-1975-2014, according to the individual river basins. The air temperature course of the Georgia’s high mountain weather stations has been studied. The river basins have been revealed, where there are the highest indices of the reduction in area and number of the glaciers and the reasons have been explained.
The Cryosphere Discuss., 9, 3777-3806, doi:10.5194/tcd-9-3777-2015, 2015
Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia
The Cryosphere Discuss., 9, 3741-3775, doi:10.5194/tcd-9-3741-2015, 2015
Inconsistency in precipitation measurements across Alaska and Yukon border
Summary: The bias corrections are very significant due to the windy and cold environment in the northern regions. Monthly precipitation is more closely correlated for the warm months than for cold month between the station pairs. Bias corrections of the gauge data slightly alter precipitation relationship across the border. Double mass curves indicate changes in the cumulative precipitation over the study periods. These changes lead to a smaller and inverted precipitation gradient across the border.
The Cryosphere Discuss., 9, 3709-3739, doi:10.5194/tcd-9-3709-2015, 2015
Investigation of a deep ice core from the Elbrus Western Plateau, the Caucasus, Russia
The Cryosphere Discuss., 9, 3661-3708, doi:10.5194/tcd-9-3661-2015, 2015
A new methodology to simulate subglacial deformation of water saturated granular material
Summary: This paper details a new algorithm for performing computational experiments of subglacial granular deformation. The numerical approach allows detailed studies of internal sediment and pore-water dynamics under shear. Feedbacks between sediment grains and pore water can cause rate-dependent strengthening, which additionally contributes to the plastic shear strength of the granular material. Hardening can stabilise patches of the subglacial beds with implications for landform development.
The Cryosphere Discuss., 9, 3617-3660, doi:10.5194/tcd-9-3617-2015, 2015
Intercomparison of snow density measurements: bias, precision and spatial resolution
Summary: Density is a fundamental property of porous media such as snow. During the MicroSnow Davos 2014 workshop different approaches (box, wedge and cylinder type density cutters, micro computed tomography) to measure snow density were applied in a controlled laboratory environment and in the field. In general, result suggests that snow densities measured by different methods agree within 9%. However, the density profiles resolved by the measurement methods differed considerably.
The Cryosphere Discuss., 9, 3581-3616, doi:10.5194/tcd-9-3581-2015, 2015
Elevation change of the Greenland ice sheet due to surface mass balance and firn processes, 1960–2013
The Cryosphere Discuss., 9, 3541-3580, doi:10.5194/tcd-9-3541-2015, 2015
Debris-covered energy balance model for Imja-Lhotse Shar Glacier in the Everest region of Nepal
Summary: A debris-covered energy balance was used to model debris temperatures and sub-debris ablation rates on Imja-Lhotse Shar glacier during the 2014 melt season. Field measurements were used to assess model performance. A novel method was also developed using Structure from Motion to estimate the surface roughness. Lastly, the effects of temporal resolution, i.e., 6h and daily time steps, and various methods for estimating the latent heat flux were also investigated.
The Cryosphere Discuss., 9, 3503-3540, doi:10.5194/tcd-9-3503-2015, 2015
On the substantial influence of the treatment of friction at the grounding line
Summary: In this paper we present three different methods to apply the friction in the very close vicinity of the grounding line and show that the results are very sensitive to the chosen method. Because all previous results using Elmer/Ice were published using only one of these three methods, we here honestly inform the community about the impact of this choice. The new results obtained in this work are made available to the community as Supplementary Materials.
The Cryosphere Discuss., 9, 3475-3501, doi:10.5194/tcd-9-3475-2015, 2015
Measurements and modelling of snow particle size and shortwave infrared albedo over a melting Antarctic ice sheet
Summary: We illustrate a method to measure the size distribution of a snow particle metric from macro-photos of snow particles. This snow particle metric corresponds well to the optically equivalent effective radius. Our results evidence the impact of grain shape on albedo, indicate that more than just one particle metric distribution is needed to characterize the snow scattering properties at all optical wavelengths, and suggest an impact of surface roughness on the shortwave infrared albedo.
The Cryosphere Discuss., 9, 3405-3474, doi:10.5194/tcd-9-3405-2015, 2015
Effect of soil property uncertainties on permafrost thaw projections: a calibration-constrained analysis
Summary: This paper investigates the uncertainty associated with permafrost thaw projections at an intensively monitored site. Permafrost thaw projections are simulated using a thermal hydrology model forced by a worst case scenario carbon emission scenario. The uncertainty associated with active layer depth, saturation state, thermal regime, and thaw duration are quantified and compared with the effects of climate model uncertainty on permafrost thaw projections.
The Cryosphere Discuss., 9, 3351-3404, doi:10.5194/tcd-9-3351-2015, 2015
Snow and albedo climate change impacts across the United States Northern Great Plains
Summary: We used 60 years of daily meteorological data from 20 stations across the United States Northern Great Plains to examine climate trends focusing on the winter climate. Besides standard climate trends, we computed trends in snowfall amounts, days with precipitation, days with snow, and modeled winter albedo (surface reflectivity). Daily minimum temperatures and days with precipitation increased at most locations, while winter albedo decreased at many stations. There was much spatial variability.
The Cryosphere Discuss., 9, 3331-3349, doi:10.5194/tcd-9-3331-2015, 2015
Comparison of a coupled snow thermodynamic and radiative transfer model with in-situ active microwave signatures of snow-covered smooth first-year sea ice
The Cryosphere Discuss., 9, 3293-3329, doi:10.5194/tcd-9-3293-2015, 2015
Estimating supraglacial lake depth in western Greenland using Landsat 8 and comparison with other multispectral methods
Summary: Liquid water stored on the surface of ice sheets and glaciers, such as that in surface (supraglacial) lakes, plays a key role in the glacial hydrological system. Multispectral remote sensing can be used to detect lakes and estimate their depth. Here, we use in situ data to assess lake depth retrieval using the recently launched Landsat 8. We validate Landsat 8-derived depths and provide suggestions for future applications. We apply our method to a case study are in Greenland for summer 2014.
The Cryosphere Discuss., 9, 3257-3292, doi:10.5194/tcd-9-3257-2015, 2015
Improving a priori regional climate model estimates of Greenland ice sheet surface mass loss through assimilation of measured ice surface temperatures
Summary: An Ensemble Batch Smoother was used to assess the feasibility of generating a reanalysis estimate of the Greenland Ice sheet (GrIS) surface mass fluxes (SMF) via integrating measured ice surface temperatures with a regional climate model estimate. The results showed that assimilation of IST were able to overcome uncertainties in meteorological forcings that drive the GrIS surface processes. We showed that the proposed methodology is able to generate posterior reanalysis estimates of the SMF.
The Cryosphere Discuss., 9, 3205-3255, doi:10.5194/tcd-9-3205-2015, 2015
From Doktor Kurowski's Schneegrenze to our modern glacier equilibrium line altitude (ELA)
Summary: Kurowski suggested in 1891 that ELA is equal to the mean altitude of the glacier when the glacier is in balance. I compare mean altitude with balanced budget ELA for 103 modern glaciers. Kurowski’s mean altitude is significantly higher (at 95% level) than balanced budget ELA for 19 outlet and 42 valley glaciers, but not significantly higher for 34 mountain glaciers. The error in Kurowski mean altitude as a predictor of balanced budget might be due to nonlinearity in balance gradients.
The Cryosphere Discuss., 9, 3165-3204, doi:10.5194/tcd-9-3165-2015, 2015
The importance of a surface organic layer in simulating permafrost thermal and carbon dynamics
The Cryosphere Discuss., 9, 3137-3163, doi:10.5194/tcd-9-3137-2015, 2015
Evaluation of the CMIP5 models in the aim of regional modelling of the Antarctic surface mass balance
Summary: Estimates of the Antarctic surface mass balance with regional climate models (RCMs) require appropriate fields for forcing. Here we evaluate 41 climate models from CMIP5 over Antarctica, including 5 reanalyses in the inter-comparison. ACCESS1-3 seems to be the most pertinent choice for RCM forcing and we show that climate change is much more dependent on the initial state of sea-ice and on the local feedback between air temperature increase and sea-ice decrease than on the global warming signal.
The Cryosphere Discuss., 9, 3113-3136, doi:10.5194/tcd-9-3113-2015, 2015
Soot on snow experiment: bidirectional reflectance factor measurements of contaminated snow
The Cryosphere Discuss., 9, 3075-3111, doi:10.5194/tcd-9-3075-2015, 2015
Photopolarimetric retrievals of snow properties
The Cryosphere Discuss., 9, 3055-3074, doi:10.5194/tcd-9-3055-2015, 2015
Changing surface–atmosphere energy exchange and refreezing capacity of the lower accumulation area, west Greenland
The Cryosphere Discuss., 9, 2867-2913, doi:10.5194/tcd-9-2867-2015, 2015
Correction of albedo measurements due to unknown geometry
Summary: Diurnal albedo variation of glaciers on clear sky days are high due to geometric effects caused by tilt errors, which are corrected where tilts of sensors and slopes are unknown. With a reference measurement using a horizontally levelled sensor a model is developed and fitted to the measured data to determine tilts and directions which vary daily due to changing atmospheric conditions and snow cover. The results show an under- or overestimation of albedo depending on the direction of the slope.
The Cryosphere Discuss., 9, 2709-2744, doi:10.5194/tcd-9-2709-2015, 2015
Verification of the multi-layer SNOWPACK model with different water transport schemes
Summary: A verification of the physics based SNOWPACK model with field observations showed that typical snowpack properties like density and temperature are adequately simulated. Also two water transport schemes were verified, showing that although Richards equation improves snowpack runoff and several aspects of the internal snowpack structure, the bucket scheme appeared to have a higher agreement with the snow microstructure. The choice of water transport scheme may depend on the intended application.
The Cryosphere Discuss., 9, 2655-2707, doi:10.5194/tcd-9-2655-2015, 2015
Overview on radon measurements in Arctic glacier waters
Summary: We present a study of the subglacial component in waters using the natural radioisotope radon. The paper is the result of several years of investigations on a Svalbard glacier and constitutes a first overview on this new technique. The paper is innovative as we are the first to use radon as a tracer for the system of glacier drainage, hydrology and glacier dynamics.
The Cryosphere Discuss., 9, 2013-2052, doi:10.5194/tcd-9-2013-2015, 2015
First Sentinel-1 detections of avalanche debris
Summary: During an avalanche cycle in January 2015 in northern Norway we used repeat pass Sentinel-1 images to map avalanches. Avalanche debris shows up as increased backscatter in repeat pass images. We detected 489 avalanches in a single scene. Results were validated using high resolution SAR data and field reconnaissance. The results are very promising, and pave the way for operational avalanche monitoring using SAR. Sentinel-1 grant frequent coverage with high quality to monitor avalanches.
The Cryosphere Discuss., 9, 1943-1963, doi:10.5194/tcd-9-1943-2015, 2015