Automatic measurement of glacier ice ablation using thermistor strings

In this work we tested the suitability of thermistor strings as automatic tools for the continuous measurement of glacier ice ablation. Experimental data collected in summer 2017 over an Italian glacier provided ice ablation readings with accuracy similar to manual measurements with ablation stakes and other automatic systems, like the draw-wire method and the B\uf8ggild ablatometer. Thermistor strings have potential for future applications in remote glacier monitoring, thanks to their flexibility, simple construction, and robustness

GROUND TEMPERATURE REGIMES OF A DOLOMITIC AREA CHARACTERIZED BY CRYOGENIC LANDFORMS

The studied area corresponds to the so-called Basin of Vauz, located between 1840 m and 2250 m of elevation. It lies between the Pordoi Pass (Dolomites) and the village of Arabba (BL). There are several landforms related to frost action and solifluction in this area, such as patterned ground, terracettes and lobes. This research aims at i) studying the processes involved in the slow movement of the ground and in the development of the landforms of the area, and ii) understanding the role of water circulation inside the slope. Analogous phenomena are present in many areas of the Dolomites, especially on the passes and in several locations where pelitic and volcano-clastic formations crop out (i.e. S. Cassiano Fm. and Wengen Fm.). Indeed, the movements usually develop within the detrital deposits generated from the degradation of the two previously mentioned geological formations. The particle sizes of debris involved in the movements are between coarse sand and fine silt, with a predominance of medium sand and coarse silt (from 4mm to 0,002mm). Measurements of the thermal state of the soil were recently undertaken in the study area, using thermometric probes (PB-5001-1M5; accuracy \ub10.2\ub0C) connected to specific data loggers (TGP-4520 TINYTAG PLUS 2). They allow to store hourly minimum, maximum and average temperature. Measurements were collected at 1874 m, 1935 m, 2190 m and 2365 m of altitude, at sites exposed to the south and with an inclination of respectively 23 \ub0, 14 \ub0, 11 \ub0 and 36 \ub0. In order to analyze the trend of temperature with depth, in one of the monitoring sites (at 1935 m) three thermometers were placed at different depth (5 cm, 25 cm and 50 cm from the ground level). Data on air temperatures and snow thickness are provided by the weather stations of Arabba and Passo Pordoi - Belvedere (data supplied by the ARPAV Meteorological Centre of Arabba and Meteotrentino). Data series between November 2009 and September 2010 have been already collected, while a second set of data spanning from autumn 2010 to spring 2011 are going to be collected. The first data show that in autumn 2009, in absence of snow cover, soil temperatures fluctuated in connection the daily air temperature cycles but the ground temperature remained above 0\ub0C. After the first snowfall, this connection weakened and the ground temperatures developed independently from the air temperature variations. The soil temperatures at the various monitoring sites reached stable values above 0\ub0C during winter, until the snow cover disappeared. Thermometers placed at different depths show an attenuation of the thermal wave with increasing depth. The thermal cycles are visible at a depth of 5 cm, while at 25 cm depth they are more attenuated (only when snow cover is absent, e.g. autumn and late spring). Moreover, higher temperatures were recorded at 50 cm than at 5 cm and at 25 cm in autumn and in winter, the opposite in spring and in summer. During winter, with the presence of snow cover, generally an almost stable value of temperature is reached at every depth without temperature oscillations. The collected temperatures indicate the absence of freeze conditions during the full year at all the monitoring sites. Actually, soil temperatures never fell below 0\ub0C, even if air temperatures reached values well below 0\ub0 C (- 15\ub0, -18\ub0 C). The lowest temperatures are not recorded at the highest monitoring sites, indicating that not only the altitude but also the steepness and the exposure of the slopes exert a strong control on the thermal regime of the soil. The results obtained so far suggest that the thermal regime of the ground controls in a complicated way the solifluction phenomena affecting the slopes of this area

A new database for reconstructing the spatial-temporal evolution of the glacial resource in the Italian Alps

Long-term glacier observation series represent the basis for reconstructing secular trends and for investigating the physical processes driving the response of glaciers to ongoing climatic changes. Since its origin, the Italian Glaciological Committee (CGI) recognized the relevance of systematic monitoring of Italian glaciers and, in particular, started from the measurement of frontal variations. Annual surveys are regularly conducted since the end of the 19th Century and were never interrupted since 1911, with the only exception of war periods. Glaciological surveys from the CGI supply therefore one of the longest series of observations of the glacial front variations in the world. Furthermore, large amount of data and a precious photographic documentation were collected during the annual glaciological surveys. The photographic archive of the CGI holds tens of thousands of images related to Italian glaciers imprinted on various media (negatives, black and white, and colour print, slides, DVDs and precious as delicate glass plates). The results obtained in the framework of the glaciological campaigns (http://www.glaciologia.it/i-ghiacciai-italiani/le-campagne-glaciologiche/) are regularly published since 1927 in a dedicated section of the CGI Bulletin, today known as Geografia Fisica e Dinamica Quaternaria http://gfdq.glaciologia.it/issues/). At present, approximately 150 glaciers are monitored every year by a large number of surveyors, also linked to other volunteers associations. In the framework on the Nextdata Project, we collected all the data related to frontal variation surveyed by the CGI during the last 100 years. all the data have been validated and storaged in a spread sheet to perform analysis of glaciological data of the Italian Alps. The Italian glaciers, since the end of the maximum Holocene advance have experienced a phase of generalized retreat, accentuated in the 50s of the 20th Century, which was followed by a slight advancing stage culminated in the late '70s and early '80s. Since the '90s there was a general withdrawal of almost all the Italian glaciers. The mean annual snow line rose about 100 m, as a mean. About a dozen of glaciers are presently monitored for measuring the glaciological mass balance. All the collected data related to the monitoring of frontal variations and annual mass balances measured in the Italian Alps contribute to the World Glacier Monitoring Service (WGSM) database (www.geo.uzh.ch/microsite/wgms/). Annual mass balance of selected Italian glaciers is measured since 1967 (e.g. Careser Glacier). The cumulative net mass balance of the Careser Glacier calculated by direct glaciological surveys registers about – 50 m w.e. from 1967 to 2012 (Carturan et al., 2013). The longest mass balance series show an increase of mass loss rates, mainly induced by longer and warmer ablation seasons. In the decade from 2004 to 2013 the mean annual mass balance varied from - 1788 to -763 mm w.e. yr-1 (Carturan et al, 2016). The combination of October– May precipitations and June–September temperatures are responsableresponsible of negative glaciers mass balance but an important role is played by rapid geometric adjustments in driving the accelerated responceresponse of glacial bodies

Analysis of long-term mass balance series of the glaciers in the Italian Alps

Mass balance measurements on glaciers are a key source of quantitative information for early detection of environmental changes, process understanding, model development and prediction of possible future developments. The Comitato Glaciologico Italiano and the World Glacier Monitoring Service regularly collect standardized observations on glacier mass balance, based on the ‘direct glaciological’ method. We analyzed mass balance series of the glaciers in the Italian Alps which are still being regularly measured and which have at least ten years of continuous data. The longest series started in 1967 on Careser glacier. Measurements began on Fontana Bianca and Sforzellina in the 1980s, and on Ciardoney and Pendente in the 1990s. Other observation series started in the 2000s on Grand Etret, Lunga, La Mare and Malavalle. Two glaciers are located in the Western Alps, the other seven in the Eastern Alps. Measurements results indicate that average mass balances agree well with a sample of glaciers representative of the entire European Alps. Among the longest series, however, Careser and Ciardoney glaciers are losing mass at significantly higher rates. However, given the high correlation of their series with the other Italian glaciers, they enable recognizing mountainrange- scale temporal trends in the seasonal components of mass balance. In particular, the Careser series shows a sharply negative trend in the annual mass balance, almost entirely due to increasing summer ablation. Most monitored glaciers display strongly imbalanced conditions and nearly complete absence of accumulation area, with the exception of few years in the last two decades. Consequently, as their survival and the prosecution of mass balance measurements are at risk, there is the need to i) evaluate their spatial representativity by means of regional-scale geodetic mass balance assessments based on DTM differencing, and ii) start parallel measurements on neighboring larger and higher-reaching glaciers, which should replace them in the future