1,721,086 research outputs found
Replacing monitored glaciers undergoing extinction: A new measurement series on la Mare Glacier (Ortles-Cevedale, Italy)
Full text linkEffetto delle variazioni climatiche sulla criosfera e sull'idrologia dei bacini di alta quota
Full text linkThis work focuses on the cryosphere of the Ortles-Cevedale mountain group, which exhibit a high sensitivity to the ongoing climate change. The work is composed of four main parts: the first part introduces the research topic, the second part describes the study areas and field campaigns, the third part presents the results of field investigations and the final part describes the implementation and application of a model for the simulation of the mass balance on glaciers.Il lavoro di tesi è focalizzato sulla criosfera alpina del gruppo Ortles-Cevedale, che si dimostra molto sensibile alle variazioni climatiche globali in atto. La tesi consiste in quattro parti principali: una parte iniziale in cui si introduce la materia, una seconda parte in cui si descrive l'area di studio e le campagne di misura, una terza parte in cui si illustrano e commentano i risultati delle indagini di terreno e una parte finale in cui si propone l'implementazione di un modello per la simulazione del bilancio di massa glaciale
Comparison of the current behaviour of three glaciers in western Trentino (Italian Alps)
No full textSpring-water temperature from rock glaciers in the Val di Sole catchment (Easter Italian Alps)
No full textSpring-water temperature was measured at 131 springs with elevation ranging between 1698 and 3039 m a.s.l. in the Val di Sole catchment (Eaastern Italian Alps). Measurements were taken from mid-August to mid-October, after the end of the snowmelt. Most springs have been measured once per year from 2018 to 2020, and a small group of them was also measured in 2021. Spring-water temperature was used to investigate the spatial distribution of mountain permafrost in the study area, and in particular its occurrence in rock glaciers classified as relict
Recent mass balance results and morphological evolution of Careser glacier (Central Alps)
No full textThis paper presents the 2002 to 2005 and historical mass balance series for Careser glacier. The mass balance evolution since 1967 has been compared with the meteorological data from the local weather stations. The most recent morphological changes of the ice body are also described. In the last four years the mass balance was extremely negative, with an average value of -2008 mm we and a minimum value of –3317 mm we. The current mass loss rate is nearly twice the average of the 1981 to 2001 (–1195 mm we), whereas between 1967 and 1980 the glacier was near equilibrium conditions. This behaviour seems to be strictly connected with the ablation season temperatures. By contrast, the relationship with the accumulation season precipitation amounts is less clear. The strongly negative mass balances result in huge morphological changes (surface lowering, bedrock emersion, rapid fragmentation) and positive feedbacks contribute to accelerate the deglaciation process. At the present- day climatic conditions, the complete extinction of the glacier has to be expected within few decades
Variabilità spaziale dell'albedo sulle aree glaciali dell'Alta Val de La Mare (Gruppo Ortles-Cevedale)
No full textNell’ambito di un progetto di ricerca sulla criosfera e sugli effetti idrologici delle variazioni climatiche nei bacini di alta quota, è stato eseguito uno studio sulla va- riabilità spaziale dell’albedo in ghiacciaio. La campagna di rilievi è stata condotta nelle estati del 2007 e del 2008 sui ghiacciai dell’alta Val de La Mare (Gruppo Ortles-Cevedale, Trentino).
L’albedo regola la quantità di radiazione ad onde corte assorbita dalla superficie ed è quindi determinante nel modulare il bilancio energetico e il bilancio di massa glaciale. Le parametrizzazioni comunemente riportate nella letteratura scientifica sono generalmente orientate alla descrizione della variabilità spazio-temporale dell’albedo della neve, mentre l’albedo del ghiaccio è spesso assunto costante o parametrizzato in modo molto più semplice, ad esempio in funzione della quota. I rilievi eseguiti in alta Val de La Mare evidenziano un’elevata variabilità dell’albe- do del ghiaccio di ghiacciaio, che è funzione soprattutto della copertura detritica superficiale. Sulla base di queste osservazioni, si è cercato di mettere a punto un metodo speditivo che consente una valutazione semplice ed affidabile dell’albedo, basato su rilievi fotografici da terra. I risultati ottenuti confermano che il metodo proposto consente di cogliere in modo adeguato la variabilità spaziale dell’albedo sul ghiaccio di ghiacciaio
Estimation of winter precipitation in a high-altitude catchment of the eastern italian alps: validations by means of glacier mass balance observations
No full textThis work analyses the estimation of winter season (October 1 to May 31) precipitation over a high altitude catchment (Val di Peio) of the Eastern Italian Alps. The extrapolation of precipitation over un- gauged areas is problematic in this basin due to the combined effect of measurement errors and orographic effects. The study is based on the availability of long term series of weather data, snow observations and glacier mass balance measurements. The error in precipitation measure- ment at the uppermost weather station was assessed by comparison with snow water equivalent data. The error estimates were consistent with the outcomes of a precipitation correction model, with the aerodynamic correction as its main component. This correction procedure was used to compute correction factors for the entire precipitation gauge net- work. Both corrected and uncorrected precipitation data were used to estimate the spatial distribution of precipitation over the study area by means of a technique that accounts for the precipitation-altitude rela- tionship. Winter balance observations over Careser glacier (the longest mass balance series in Italy), which is within the study area, were used to assess the improvement given by the precipitation correction proce- dure, showing a reduction of bias from -38% to –2.5% and a reduction of the RMSE from 410 to 171 mm water equivalent. The use of correct- ed precipitation data led to a 31.7% (182 mm) increase of the winter season basin-averaged precipitation, whereas the winter season average vertical gradient increased from 4.0% km–1 to 21.9% km–1. Overall, these results highlight the need for precipitation correction in precipita- tion analyses over snow-dominated mountain areas. This paper also provides evidence of a considerable interannual variability in the cor- rection factors for snow at the uppermost weather station. Further im- provements in precipitation estimations would require an analysis of the dominant processes controlling this variability
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