ENSO influence on surface energy and mass balance at Shallap Glacier, Cordillera Blanca, Peru
Summary: Using a newly developed open-source tool, we downscale the glacier surface energy and mass balance fluxes at Shallap Glacier. This allows an unprecedented quantification of the ENSO influence on a tropical glacier at climatological time scales (1980-2013). We find a stronger and steadier anti-correlation between pacific sea surface temperature (SST) and glacier mass balance than previously reported and provide keys to understand its mechanism.
The Cryosphere Discuss., 9, 2999-3053, doi:10.5194/tcd-9-2999-2015, 2015
A prognostic model of the sea ice floe size and thickness distribution
Summary: Sea-ice cover is composed of floes of different sizes and thicknesses whose distribution varies in space and time and may affect the interaction between sea ice and the ocean and atmosphere, yet is not represented in climate models. We develop and demonstrate a model for the evolution of the joint distribution of floe sizes and thicknesses, subject to melting and freezing, mechanical interactions between floes, and the fracture of floes by waves, forced by atmospheric and ocean forcing fields.
The Cryosphere Discuss., 9, 2955-2997, doi:10.5194/tcd-9-2955-2015, 2015
The relative contributions of calving and surface ablation to ice loss at a lake-terminating glacier
Summary: Calving and surface melt is estimated for Bridge Glacier, a lake-terminating glacier in British Columbia, Canada. Estimates suggest that calving was a relatively minor contributor of ice loss until the terminus began to float in 1991. Since then, calving has accounted for 10-25% of total ice loss. However, as the glacier retreats into shallower water, and eventually onto dry land, calving losses are expected to decrease, and the glacier is expected to respond more readily to regional climate.
The Cryosphere Discuss., 9, 2915-2953, doi:10.5194/tcd-9-2915-2015, 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
CryoSat-2 delivers monthly and inter-annual surface elevation change for Arctic ice caps
Summary: We show that the Cryosat (CS) radar altimeter can measure elevation change on a variety of Arctic ice caps. With the frequent coverage of Cryosat it is even possible to track summer surface height loss due to extensive melt; no other satellite altimeter has been able to do this. However, we also show that under cold conditions there is a bias between the surface and Cryosat detected elevation which varies with the conditions of the upper snow and firn layers.
The Cryosphere Discuss., 9, 2821-2865, doi:10.5194/tcd-9-2821-2015, 2015
Monitoring ice break-up on the Mackenzie River using MODIS data
Summary: This study involves the analysis of MODIS Level 3 500-m snow products, complemented with 250-m Level 1B data, to monitor ice cover during the break-up period on the Mackenzie River, Canada. Results from the analysis of data for 13 ice seasons (2001-2013) show that first day ice-off dates is observed between days of year (DOY) 115-125 and end DOY 145-155, resulting in average melt durations of about 30-40 days and concluded that MODIS can for monitoring ice break-up.
The Cryosphere Discuss., 9, 2783-2820, doi:10.5194/tcd-9-2783-2015, 2015
Satellite observations of changes in snow-covered land surface albedo during spring in the Northern Hemisphere
Summary: Snow cover explained most of the spring surface albedo changes in the Northern Hemisphere in the years 2000−2012. However, there are vast areas where albedo changed up to ±0.2 under full snow covered conditions. We found that if in these areas mean monthly air temperature exceeds −15°C, albedo decreases with increase of the temperature. Vegetation and precipitation changes affects albedo in Chukotka and Eastern Siberia. Complexity of processes involved into surface albedo changes are discussed.
The Cryosphere Discuss., 9, 2745-2782, doi:10.5194/tcd-9-2745-2015, 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
Reducing uncertainties in projections of Antarctic ice mass loss
Summary: Projections of Antarctic dynamics and contribution to sea level rise are evaluated in the light of intercomparison exercices dedicated to evaluate models' ability to represent coastal changes. Uncertainties in projections can be substantially decreased if a selection of models is made and unqualified models for coastal dynamics representation are excluded.
The Cryosphere Discuss., 9, 2625-2654, doi:10.5194/tcd-9-2625-2015, 2015
Revealing glacier flow and surge dynamics from animated satellite image sequences: examples from the Karakoram
Summary: This study uses high-speed animations of freely available Landsat images (acquired over 15 years) to reveal glacier flow and surge dynamics in the central Karakoram. The animations provide a holistic view on the timing and variability of glacier dynamics that is hard to recognize by other, more quantitative methods. Among others, the study reveals that most surging glaciers in this region are comparably small, steep and debris free, and have a wide range of surge durations and characteristics.
The Cryosphere Discuss., 9, 2597-2623, doi:10.5194/tcd-9-2597-2015, 2015
Ice sheet mass loss caused by dust and black carbon accumulation
The Cryosphere Discuss., 9, 2563-2596, doi:10.5194/tcd-9-2563-2015, 2015
The benefit of using sea ice concentration satellite data products with uncertainty estimates in summer sea ice data assimilation
The Cryosphere Discuss., 9, 2543-2562, doi:10.5194/tcd-9-2543-2015, 2015
Microwave scattering coefficient of snow in MEMLS and DMRT-ML revisited: the relevance of sticky hard spheres and tomography-based estimates of stickiness
Summary: The paper establishes a theoretical link between two widely used microwave models for snow. The scattering formulations from both models are unified by reformulating their microstructure models in a common framework. The results show that the scattering formulations can be considered equivalent, if exactly the same microstructure model is used. The paper also provides a method to measure a hitherto unknown input parameter for the microwave models from tomography images of snow.
The Cryosphere Discuss., 9, 2495-2542, doi:10.5194/tcd-9-2495-2015, 2015
Evolution of Ossoue Glacier (French Pyrenees) since the end of the Little Ice Age
Summary: Pyrenean glaciers are currently the southernmost glaciers in Europe. Using an exceptional archive of historical datasets and recent accurate observations, we propose the reconstruction of the length, area, elevation and mass balance of Ossoue Glacier (French Pyrenees) since the Little Ice Age. We show that its evolution is in good agreements with climatic data. Assuming that the current ablation rate stays constant, Ossoue Glacier will disappear midway through the 21st century.
The Cryosphere Discuss., 9, 2431-2494, doi:10.5194/tcd-9-2431-2015, 2015
Temporal variations in the flow of a large Antarctic ice-stream controlled by tidally induced changes in the subglacial water system
Summary: We use a full-Stokes model to investigate the long period modulation of Rutford Ice Stream flow by the ocean tide. We find that using a nonlinear sliding law cannot fully explain the measurements and an additional mechanism, whereby tidally induced subglacial pressure variations are transmitted upstream from the grounding line, is also required to match the large amplitude and decay length scale of the observations.
The Cryosphere Discuss., 9, 2397-2429, doi:10.5194/tcd-9-2397-2015, 2015
Numerical simulation of formation and preservation of Ningwu ice cave, Shanxi, China
The Cryosphere Discuss., 9, 2367-2395, doi:10.5194/tcd-9-2367-2015, 2015
Assimilating high horizontal resolution sea ice concentration data into the US Navy's ice forecast systems: Arctic Cap Nowcast/Forecast System (ACNFS) and the Global Ocean Forecast System (GOFS 3.1)
Summary: This study presents the improvement in the U.S. Navy's operational sea ice forecast systems gained by assimilating high horizontal resolution satellite-derived ice concentration products. A method of blending ice concentration observations from AMSR2 along with a sea ice mask has been developed resulting in an ice concentration product with high spatial resolution. A significant improvement in the ice edge location has been shown in the operational system assimilating this new product.
The Cryosphere Discuss., 9, 2339-2365, doi:10.5194/tcd-9-2339-2015, 2015
Simulated high-latitude soil thermal dynamics during the past four decades
Summary: Soil temperature change is a key indicator of the dynamics of permafrost. Using nine process-based ecosystem models with permafrost processes, large spread of soil temperature trends across the models. Air temperature and longwave downward radiation are the main drivers of soil temperature trends. Based on an emerging observation constraint method, the total boreal near-surface permafrost area decrease comprised between 39 ± 14 ×10^3 and 75 ± 14 ×10^3 km2 yr-1 from 1960 to 2000.
The Cryosphere Discuss., 9, 2301-2337, doi:10.5194/tcd-9-2301-2015, 2015
Impact of debris cover on glacier ablation and atmosphere-glacier feedbacks in the Karakoram
Summary: We investigate the impact of surface debris on glacier energy and mass fluxes and on atmosphere-glacier feedbacks in the Karakoram range, by including debris in an interactively coupled atmosphere-glacier model. The model is run from 1 May to 1 October 2004, with a simple specification of debris thickness. We find an appreciable reduction in ablation that exceeds 2.5m w.e. on glacier tongues, as well as significant alterations to near-surface air temperatures and boundary layer dynamics.
The Cryosphere Discuss., 9, 2259-2299, doi:10.5194/tcd-9-2259-2015, 2015
Precipitation measurement intercomparison in the Qilian Mountains, Northeastern Tibetan Plateau
Summary: 1. It is the first precipitation measurement intercomparison in Tibet Plateau. 2. Pit gauge gets the most local precipitation in rainy season and in total. 3. The pit gauge could be used as reference in the most regions of China.
The Cryosphere Discuss., 9, 2201-2230, doi:10.5194/tcd-9-2201-2015, 2015
21st century changes in snow water equivalent over Northern Hemisphere landmasses due to increasing temperature, projected with the CMIP5 models
The Cryosphere Discuss., 9, 2135-2166, doi:10.5194/tcd-9-2135-2015, 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
Impact of model developments on present and future simulations of permafrost in a global land-surface model
Summary: In this paper we use a global land-surface model to study the dynamics of Arctic permafrost. We examine the impact of new and improved processes in the model, namely soil depth and resolution, organic soils, moss and the representation of snow. These improvements make the simulated soil temperatures and thaw depth significantly more realistic. Simulations under future climate scenarios show that permafrost thaws more slowly in the new model version, but still a large amount is lost by 2100.
The Cryosphere Discuss., 9, 1965-2012, doi:10.5194/tcd-9-1965-2015, 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
Century-scale simulations of the response of the West Antarctic Ice Sheet to a warming climate
Summary: We used a high resolution ice sheet model capable of resolving grouding line dynamics (BISICLES) to compute responses of the major West Antarctic ice streams to projections of ocean and atmospheric warming. This is computationally demanding, and although other groups have considered parts of West Antarctica, we think this is the first calculation for the whole region at the sub-kilometer resolution that we show is required.
The Cryosphere Discuss., 9, 1887-1942, doi:10.5194/tcd-9-1887-2015, 2015
Diagnostic and model dependent uncertainty of simulated Tibetan permafrost area
Summary: We use a model-ensemble approach for simulating permafrost on the Tibetan Plateau. We identify the uncertainties of across-models (state-of-the-art land surface models) and across-methods (most commonly used methods to define permafrost). We differentiate between uncertainties stemming from climatic driving data or from physical process parameterization, and show how these uncertainties vary seasonally and inter-annually, and how estimates are subject to the definition of permafrost used.
The Cryosphere Discuss., 9, 1769-1810, doi:10.5194/tcd-9-1769-2015, 2015
Area, elevation and mass changes of the two southernmost ice caps of the Canadian Arctic Archipelago between 1952 and 2014
Summary: In this study, we used multiple datasets, in particular some Pléiades stereo-pairs, to measure the first historical and recent mass balances of Grinnell and Terra Nivea ice caps, as well as area and elevation changes for both ice caps. Results show that rates of area, elevation and mass changes strongly accelerated in the last years. At -1.68 ± 0.36 m a-1 w.e. between 2007 and 2014, Terra Nivea mass balance is among the most negative multi-annual glacier-wide mass balances measured to date.
The Cryosphere Discuss., 9, 1667-1704, doi:10.5194/tcd-9-1667-2015, 2015
Albedo reduction caused by black carbon and dust accumulation: a quantitive model applied to the western margin of the Greenland ice sheet
The Cryosphere Discuss., 9, 1345-1381, doi:10.5194/tcd-9-1345-2015, 2015
Summer snowfall on the Greenland Ice Sheet: a study with the updated regional climate model RACMO2.3
Summary: We compare Greenland ice sheet surface mass balance (SMB) from the updated polar version of the regional climate model RACMO2.3 and the previous version 2.1. RACMO2.3 has an adjusted rainfall-to-snowfall conversion favouring summer snowfall over rainfall. Enhanced summer snowfall reduce melt rates in the ablation zone by covering dark ice with highly reflective fresh snow. This improves the modelled SMB-elevation gradient and surface energy balance compared to observations in west Greenland.
The Cryosphere Discuss., 9, 1177-1208, doi:10.5194/tcd-9-1177-2015, 2015
Microscale variability of snow depth using U.A.S. technology
Summary: We investigate the capabilities of photogrammetry-based surveys with Unmanned Aerial Systems (U.A.S.) to retrieve the snow depth distribution at cm resolution over a small alpine area. Results show that the U.A.S. technique provides an accurate estimation of point snow depth values, and a distributed evaluation of the snow accumulation patterns.
The Cryosphere Discuss., 9, 1047-1075, doi:10.5194/tcd-9-1047-2015, 2015
Cloud effects on the surface energy and mass balance of Brewster Glacier, New Zealand
Summary: Clouds are shown to force a fundamental change in the surface energy and mass balance of Brewster Glacier, New Zealand. Greater melt during cloudy periods was associated with enhanced emission of longwave radiation by clouds and increased atmospheric vapour pressure, rather than a minimal change in mean air temperature and wind speed. Surface mass balance was more sensitive to changes in air temperature during cloudy periods due to more frequent melt and a strong precipitation – albedo feedback.
The Cryosphere Discuss., 9, 975-1019, doi:10.5194/tcd-9-975-2015, 2015
Role of rainwater induced subsurface flow in water-level dynamics and thermoerosion of shallow thermokarst ponds on the Northeastern Qinghai–Tibet Plateau
The Cryosphere Discuss., 8, 6117-6146, doi:10.5194/tcd-8-6117-2014, 2014