Preliminary results from antarctic albedo from remote sensing observations

The aim of the study is to analyse the surface albedo of the Ant-arctica and investigate eventual signals of variations in space and time between summer 2000/2001 and 2011/2012 by means of the GLASS albedo product. We followed a step-by-step procedure from micro- to macro-scale. At first, we analysed 95 glaciers around the continent, and we found limited temporal variability. Then, looking at spatial varia-tions, we divided Antarctica based on oceanic basins and by continen-tality. We found spatial signals, since mean albedo values range between 0.79 (Pacific and Atlantic basins) and 0.82 (Indian basin) and between 0.76 (along the shore) and 0.81 (inner continent). An increasing vari-ability was found from the inner continent to the shore, and heteroge-neous patterns among the basins, most likely due to meteorological and environmental conditions (mainly: temperature, precipitation, katabatic winds). Finally, the general patterns observed (considering the specific gla-ciers, the three basins and the three continentality sectors) were verified by the analysis of the whole continent and we did not find a significant change of summer averages over time, as they range between 0.79 and 0.80

Recent (1975-2003) changes in the Miage debris covere glacier tongue (Mont Blanc, Italy) from analysis of aerial photos and maps

The present study aims at identifying any changes in volume and thickness of the Miage Glacier tongue (Mont Blanc Massif, Italy) during the period 1975-2003. The Miage glacier developed the largest part of its debris cover over the last century, now found mostly between the glacier terminus (about 1850 m a.s.l.) and the upper ablation tongue (c. 2400 m a.s.l.) on a surface area of c. 4 km 2 The period examined (1975-2003) addresses climate conditions which were glacier-favourable (around the . 1980s), as well as glacier-unfavourable (since the early to mid-1990s), thus contributing to an understanding of the behaviour of debris covered glaciers under a changing climate. The analysis was based on the comparison between digital elevation models (DEMs), derived from historical records, specifically maps (1975; scale 1:10,000) and photogrammetric surveys (1991 and 2003, scale 1:15,000). The results show a general glacier volume loss (\u201316.640 x 10 6 m 3 ( from 1975 to 2003; nevertheless if we focus on the two time sub-windows (i.e.: 1975-1991 and 1991-2003) opposite trends are found: in the period 1975-1991 the volume variation of the Miage Glacier was about +19.25 710 6 m 3 , in the period 1991-2003, on the other hand, a volume decrease of about \u201336.2 710 6 m 3 occurred. Analysis shows that volume changes were strongly influenced by the supraglacial debris coverage which on Miage glacier tongue modulates the magnitude and rates of buried ice ablation

Post-Depositional Biodegradation Processes of Pollutants on Glacier Surfaces

Glaciers are important fresh-water reservoirs for our planet. Although they are often located at high elevations or in remote areas, glacial ecosystems are not pristine, as many pollutants can undergo long-range atmospheric transport and be deposited on glacier surface, where they can be stored for long periods of time, and then be released into the down-valley ecosystems. Understanding the dynamics of these pollutants in glaciers is therefore important for assessing their environmental fate. To this aim, it is important to study cryoconite holes, small ponds filled with water and with a layer of sediment, the cryoconite, at the bottom, which occur on the surface of most glaciers. Indeed, these environments are hotspots of biodiversity on glacier surface as they host metabolically active bacterial communities that include generalist taxa able to degrade pollutants. In this work, we aim to review the studies that have already investigated pollutant (e.g., chlorpyrifos and polychlorinated-biphenyls (PCBs)) degradation in cryoconite holes and other supraglacial environmental matrices. These studies have revealed that bacteria play a significant role in pollutant degradation in these habitats and can be positively selected in contaminated environments. We will also provide indication for future research in this field

2008-2011 snow covered area (SCA) variability over 18 watersheds of the central Chile through MODIS data

Snowmelt contributes largely to water budget of several Chilean mountain watersheds. To describe snow covered area (SCA) variability within 18 watersheds in Central Chile during 2008\u20132011 we used MODIS data (i.e. MOD10A2-V5 maximum snow cover extent in eight-day periods). The study area was divided into three different zones (Northern, Central, and Southern), due to its large extent (~205,000 km2), and according to former studies performed by the Direcc\uedon General de Aguas (DGA) of the Chilean Government covering the time window 2000\u20132007. After georeferencing our data to the WGS84 Datum (UTM Projection, zone 19S), the scenes were cropped to fit the study area. We selected and set a threshold for cloud coverage (<30%) in order to discard the images with too cloud cover, so losing only 2% of the sample. Hypsographic and aspect analyses were performed using the SRTM3 elevation model. We found largest values of SCA during 2008\u20132011 in the Central Zone, while the topographic and climatic features (i.e. lower altitudes in the South, and a drier climate in the North) limit snow deposition elsewhere. Similarly, snow line is higher in the Northern zone (due to the presence of the plateau), and lower moving southwards. In the North the minimum SCA is reached sooner than elsewhere, lasting for a longer period (November to March). West side showed the maximum of SCA in all zones throughout the study period. The present work extends in time the dataset of SCA in the Central Chile, adding information for statistic assessment, and trend analysis of snow cover in this area

Recent structural evolution of forni glacier tongue (Ortles-Cevedale Group, Central Italian Alps)

Structural glaciology yields important details about the evolution of glacier dynamics in response to climate change. The maps provided here document the occurrence and evolution of brittle and ductile structures on the tongue of Forni Glacier, Ortles-Cevedale Group, Central Italian Alps, between 2003 and 2014. Through the remote sensing-based analysis of structures, we found evidence of brittle fractures such as crevasses, faults and ring faults, and ductile structures such as ogives at the base of the icefall in the eastern glacier tongue. Although each of the three glacier tongues have evolved differently, a reduction in flow-related dynamics and an increase in the number of collapse structures occurred over the study period. Analysis of the glacier structural evolution based on the numbers and the locations of different structures, suggest a slowdown of glacier flow on the eastern tongue. The recent evolution of the glacier also suggests that the occurrence of a disintegration scenario is likely to worsen over the next decades

High-resolution mapping of glacier surface features. The UAV survey of the Forni Glacier (Stelvio National Park, Italy)

Fast, reliable and accurate methods for glacier mapping are necessary for understanding glacier dynamics and evolution and assessing their response to climate change. Conventional semi-automatic approaches are based on medium-resolution satellite images, but their use can cause significant loss of accuracy when analyzing small glaciers, which are predominant in the Alps. In this paper, we present a semi-automatic segmentation approach based on very high-resolution visible RGB images acquired from a UAV (Unmanned Aerial Vehicle) survey of the Fomi Glacier, in the Italian Alps, using an off-the-shelf digital camera. The method has the ability to map large-scale morphological features, i.e. bare ice and medial moraines, with better accuracy than methods relying on medium-resolution satellite imagery, with only slight misclassification at the margins. By using segmentation, we also mapped small-scale morphologies not discernible on satellite images, including epiglacial lakes and snow patches, in a semi-automatic way. On a small portion of the eastern ablation tongue, featuring homogeneous illumination conditions, we also investigated in finer detail the occurrence of fine and sparse debris and tested a texture filter technique for mapping crevasses, which showed promising results. Our analyses confirm that the glacier is undergoing intense dynamic processes, including darkening of the ablation tongue and increased surface instability, and show the potential of UAVs to revolutionize glaciological studies. We suggest that by using a combination of different payloads, mapping of glacier features via UAVs could reach high levels of accuracy and speed, making them useful tools for glacier inventories and geomorphological maps

Hydrology and potential climate changes in the Rio Maipo (Chile)

Glaciers of the central Andes have recently been retreating in response to global warming, with large consequences on the hydrological regime. We assessed here potential climate change impacts until 2100 upon the hydrologic regime of the largely snow-ice melt driven Maipo River basin (closed at El Manzano, ca. 4800 km2), watering 7 M people in the metropolitan region of Santiago de Chile. First, a weather-driven hydrological model including simplified glaciers\u2019 cover dynamics was set up and validated, to depict the hydrological regime of this area. In situ data from recent glaciological expeditions, ice thickness estimates, historical weather and hydrological data, and remote sensing data including precipitation from the Tropical Rainfall Measuring Mission (TRMM), and snow cover and temperature from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used for model set up. We subsequently forced the model with projections of temperatures and precipitations (plus downscaling) until 2100 from the GCM model ECHAM6, according to 3 different radiative concentration pathways (RCPs 2.6, 4.5, 8.5) adopted by the IPCC in its AR5. We investigated yearly and seasonal trends of precipitation, temperature and hydrological fluxes until 2100 under the different scenarios, in projection period (PR, 2014-2100), and we compared them against historically observed trends in control period (CP, 1980-2013). The results show potential significant increasing trends in temperature until 2100, consistently with observed historical trends, unless for Spring (OND). Precipitation varies more uncertainly, with no historically significant changes, and only few scenarios projecting significant variations. In the PR period, yearly flow decreases, significantly under RCP8.5 (-0.31 m3s-1). Flow decrease is expected especially in Summer (JFM) under RCP8.5 (-0.55 m3s-1). Fall (AMJ) flows would decrease slightly, while winter (JAS) flows are projected to increase, and significantly under RCP4.5 (+0.22 m3s-1), as due to sustained melting therein. Spring (OND) flows also would decrease largely under RCP8.5, down to -0.67 m3s-1, due to increased evapotranspiration for high temperatures

Bacterial diversity in snow from mid-latitude mountain areas: Alps, Eastern Anatolia, Karakoram and Himalaya

Snow can be considered an independent ecosystem that hosts active microbial communities. Snow microbial communities have been extensively investigated in the Arctic and in the Antarctica, but rarely in mid-latitude mountain areas. In this study, we investigated the bacterial communities of snow collected in four glacierized areas (Alps, Eastern Anatolia, Karakoram and Himalaya) by high-throughput DNA sequencing. We also investigated the origin of the air masses that produced the sampled snowfalls by reconstructing back-trajectories. A standardized approach was applied to all the analyses in order to ease comparison among different communities and geographical areas. The bacterial communities hosted from 25 to 211 Operational Taxonomic Units (OTUs), and their structure differed significantly between geographical areas. This suggests that snow bacterial communities may largely derive from 'local' air bacteria, maybe by deposition of airborne particulate of local origin that occurs during snowfall. However, some evidences suggest that a contribution of bacteria collected during air mass uplift to snow communities cannot be excluded, particularly when the air mass that originated the snow event is particularly rich in dust

Evidence of climate change within the Adamello Glacier of Italy

We analyze a daily series of rainfall, snowfall, air temperature, and snow water equivalent at fixed dates from 40 high-altitude stations on the Adamello Glacier area (Italian Alps), for the period 1965\u20132007. Purposes of the study are (1) to investigate significant variation in time, (2) to evaluate effect of temperature changes on cryospheric water cycle, and (3) to evaluate underlying climate patterns and the most significant variables for climate change studies. We detect the presence of a trend using linear regression, moving window average and Mann Kendall test. Linear dependence of water related variables on temperatures is assessed. We find substantially unchanged atmospheric water input along with increasing temperature and rainfall, decreasing snowfall and snow water equivalent at thaw, and shortening of snow cover extent and duration. We carry out a principal components analysis which highlights patterns of precipitation distribution resulting from local temperature and external forcing. A set of the most representative variables for climate and glacier studies is then assessed. A comparison with three nearby Southern Alpine glacierized areas in Italy and Switzerland shows substantial agreement. In spite of the relative shortness of the series, the results here are of interest and can be used as a benchmark for climate change impact assessment for the Adamello Glacier area and southern Alps