CONTRIBUTION TO THE COMPREHENSION OF CLIMATE CHANGE TOWARDS CRYOSPHERE AND ATMOSPHERIC ANALYSIS: THE CASES STUDY OF CHANGRI NUP GLACIER, NEPAL HIMALAYAS AND OF FORNI GLACIER, ITALIAN ALPS.
Tesi di Dottorato
Data di Pubblicazione:
2013
Citazione:
CONTRIBUTION TO THE COMPREHENSION OF CLIMATE CHANGE TOWARDS CRYOSPHERE AND ATMOSPHERIC ANALYSIS: THE CASES STUDY OF CHANGRI NUP GLACIER, NEPAL HIMALAYAS AND OF FORNI GLACIER, ITALIAN ALPS / E.m. Vuillermoz ; tutore: C. Smiraglia ; co-tutore: G. Diolaiuti, P. Bonasoni ; coordinatore: E. Erba. UNIVERSITA' DEGLI STUDI DI MILANO, 2013 Feb 05. 25. ciclo, Anno Accademico 2012. [10.13130/vuillermoz-elisa-maria_phd2013-02-05].
Abstract:
In this PhD Thesis are reported the main results from an interdisciplinary research focused on evaluating impacts and effects of black carbon (BC) on glacier snow and ice melting. With this purpose we selected two glaciers: the Changri Nup glacier (Nepal, Himalaya) and the Forni glacier (Italian Alps). The glaciers have been chosen due to their representativity (geographical setting, size, morphology) and the availability of meteorological and energy data collected at the glacier surface through Automatic Weather Stations (AWSs).
In fact on both the glaciers AWSs have been installed in the recent years and they have been running without meaningful interruptions thus permitting to analyze glacier micrometeorology and to evaluate glacier surface energy balance and its variability (data are sampled with a hourly frequency all over the year). Moreover we planned and performed field campaigns to collect snow samples for describing chemical and physical features of soot and dust present in the glacier snow.
More precisely, since the Autumn 2005 and AWS has been running at the melting surface of the Forni Glacier (Italian Alps). The AWS is property of UNIMI and it attends the international network SHARE (Stations at High Altitude for Research on the Environment) promoted and managed by EVK2CNR Committee. Within the Ev-K2-CNR Project SHARE on February 2010 an AWS has been installed on the debris-free surface of the Changri Nup Glacier (Nepal, Himalayas, Sagarmatha Nationa Park) at 5,700 m asl to acquire meteorological data and energy fluxes (incoming and outgoing) at the glacier surface. The AWS is property of EvK2CNR Committee. The acquired data permit the calculation of glacier energy balance and high resolution analysis of glacier albedo. In the present study more than 85.000 meteorological parameters, related to the time window 2010-2012 and collected by The Changri Nup AWS, have been analyzed, processed and validated. Average daily parameters estimated at glacier surface have been: temperature: -4.61 °C, relative humidity: 78.47%, atmospheric pressure: 505.6 hPa, SWin: 220 W m-2, SWout:136 W m-2, LWin: 240 W m-2, LWout: 280 W m-2, wind speed: 1.48 m s-1, prevalent wind direction: 183°.
Yearly albedo, deriving from SWout/SWin was 0.7, with an average of 0.75 for snow and 0.26 for glacier ice. Instead data from Forni AWS were already available thanks to another PhD research presently on line at the University of Milan.
Ablation season at the Changri Nup glacier occurred in summer period, in the monsoon season, when the temperature conditions (T>0°C) and radiation and rain precipitation increase the melting process. Results have been compared with the Alpine site of Forni glacier, the largest Italian valley glacier, located in the Stelvio National Park and characterized by a “strategic” location on the Central-Eastern Alpine sector, able to be reached by southern fluxes and close to the northern Alpine Italian boundary. This part of the research was performed within the SHARE STELVIO project aiming at detecting and quantifying climate change evidences and effects on a sensible area located in the Stelvio National Park – Lombardy sector (600 km2 of area). This project will permit to evaluate composition, quality and variability of high elevation atmosphere and effects on the alpine water resource (i.e. snow, glaciers and meltwater rivers).
In both sites the main component deterring melting are positive temperature and shortwave radiation, this latter higher in the Himalaya due to the difference of latitude, altitude and incident direction. Melting season in the Alps is longer than in the Himalaya and in both sites the effect of latent and sensible heat fluxes have a minor effect in driving melting processes.
Tipologia IRIS:
Tesi di dottorato
Keywords:
climate change ; glacier ; albedo ; black carbon ; himalya
Elenco autori:
E.M. Vuillermoz
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