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CHEMICAL COMPOSITION OF FRESH SNOW IN HIMALAYAS AND KARAKORUM S. Polesello, M. Comi, A. Marinoni, M. Pecci, G. Tartari,S. Valsecchi and G. Tartari, S.

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Presentation on theme: "CHEMICAL COMPOSITION OF FRESH SNOW IN HIMALAYAS AND KARAKORUM S. Polesello, M. Comi, A. Marinoni, M. Pecci, G. Tartari,S. Valsecchi and G. Tartari, S."— Presentation transcript:

1 CHEMICAL COMPOSITION OF FRESH SNOW IN HIMALAYAS AND KARAKORUM S. Polesello, M. Comi, A. Marinoni, M. Pecci, G. Tartari,S. Valsecchi and G. Tartari, S. Valsecchi and E. Vuillermoz “That pure congealed white, high Taurus snow, fanne’d with the eastern wind,...” Shakespeare, A Midsummer Night Dream

2 Why should we study fresh snow? To characterise atmospheric depositions and estimate chemical loads in high altitude areas To understand the sources of contaminants on local and regional scale To give information on atmospheric pollution (can it act as “passive sampler”?) To interpret glaciochemical records in ice core

3 Scientific development of snow studies in Central Asia high altitude sites ’80 – Characterisation of the spatial and temporal distribution of snow chemistry in Central Asia ’90 – how far does snow chemistry represent atmospheric chemistry? Last decade – Ice coring for past atmosphere reconstruction

4 CHARACTERIZATION OF MONSOONIC DEPOSITION AT PYRAMID SITE , summer – Intensive sampling of wet and dry deposition [ Valsecchi et al., Sci. Total Environ., 226 (1999) 187] 1998, September – Extensive fresh snow sampling in Khumbu valley [ Marinoni et al. Atmos. Environ., 35 (2001) 3183 ] SAMPLING OF SNOW DURING CLIMBING EXPEDITIONS 1992, September – EVEREST (Southern slope) [Valsecchi et. al., 1999] 1998, May – ISLAND PEAK (Southern slope) [Marinoni et al. 2001] 2000, September – CHO OYU (Northern slope) [Balerna et al. Atmos. Environ., 37 (2003) 1573] 2000, October – PUMORI (Southern slope) [unpublished results] 04: K YEARS LATER PROJECT 2004: K YEARS LATER PROJECT [unpublished results] April-May – EVEREST (Northern slope) June-July – K2 (Southern slope) June-July – K2 (Northern slope) 2005, May – ANNAPURNA [work in progress] Activities of Water Research Institute (IRSA-CNR)

5 INDIA C H I N A P A K I S T A N NE P A L EVEREST K2 Determination of ion composition, nutrients, light carboxylic acids, trace metals, persistent organic pollutants, in situ radioactivity in the sub-surfacial snow layer CHO OYU ANNAPURNA

6 SAMPLING Storage in special freezer to keep the snow frozen during the transport to Italy Field determination of pH and conductivity Collection of fresh snow samples at different altitudes by trained climbers

7 Analytical methods ION CHROMATOGRAPHY (with preconcentration or large volume injection): – –Ionic macrocostituents: Cl -, NO 3 -, SO 4 2-, NH 4 +, Na +, K +, Mg 2+, Ca 2+ – –Carboxylic acids (oxalate, acetate, formate, metansulphonate, etc..) SPECTROPHOTOMETRY: – –Nutrients: Total Nitrogen (TN), Total Phosphorus (TP) pH Conductivity

8 Ev-K2-CNR PYRAMID Snow sampling in Khumbu valley PUMORI EVEREST ISLAND PEAK

9 Characterization of air mass sources in Khumbu valley by Principal Component Analysis 2° Component: Marine source 1° Component: Continental source Monsoon samples Extra-monsoon samples

10 COMPARISON BETWEEN MEAN VALUES OF EVEREST REGION, DURING MONSOON AND EXTRA-MONSOON SEASON, ALPS AND INTERNAL ANTARTICA Data sources: Alps: Nikus et al., 1997; our unpublished results Himalaya : Marinoni et al., 2001; Balerna et al., 2003; Kang et al., 2004 Antartic Region: Whitlow et al., 1992; Legrand,1987. µeq/L

11 CHEMICAL COMPOSITION OF FRESH SNOW SAMPLES FROM NORTHERN AND SOUTHERN SLOPES OF HIMALAYA DURING SUMMER MONSOON SEASON Data sources: Valsecchi et al., 1999; Shresta et al., 1997; Marinoni et al., 2001; Balerna et al., 2003

12 CHEMICAL COMPOSITION OF FRESH SNOW SAMPLES FROM NORTHERN AND SOUTHERN SLOPES OF HIMALAYA DURING EXTRAMONSOON SEASON Data sources: Jenkins et al., 1983; Marinoni et al., 2001; Balerna et al., 2003

13 COMPARISON BETWEEN EVEREST 2004 CAMPAIGN AND PREVIOUS CAMPAIGNS IN THE SAME AREA DURING EXTRA-MONSOON SEASON Data sources: Jenkins et al., 1983; Marinoni et al., 2001; Balerna et al., 2003 µeq/L

14 K YEARS LATER PROJECT: RESULTS K2 RESULTS µeq/L 43

15 Sampling during climbing expeditions Concentrations vs Altitude: Is there a relationship?

16 TOTAL PHOSPHORUS (TP) K YEARS LATER PROJECT: RESULTS

17 PUMORI October 2000: 7 sites from 5800 to 7160 m a.s.l. ClNO3SO4C2O4NaNH4KMgCaAltitude Cl 1,00 NO3 0,951,00 SO4 0,990,971,00 C2O4 -0,09-0,22-0,121,00 Na 0,960,840,940,091,00 NH4 0,950,940,950,050,931,00 K 0,980,96 -0,070,920,961,00 Mg 0,990,950,98-0,080,950,960,991,00 Ca 0,960,980,95-0,190,860,950,980,971,00 Altitude 0,110,010,16-0,010,210,03-0,060,01-0,091,00 Correlation matrix

18 EVEREST 27 April- 18 May 2004: 6 sites from 5200 to 7300 m a.s.l. Correlation matrix ?

19 Carboxylic acids Data source for ice cores: Lee et al., 2002; Lee et al., 2001; Kang et al., 2001

20 Samples can be classified in two main classes: summer monsoon and extra-monsoon samples In the Everest region, concentrations on both slopes (Northern and Southern) are very similar in both periods Monsoon depositions in central Himalayas are not substantially influenced by anthropogenic inputs (NO3 ~ µeq/l ; SO4 ~ µeq/l) In extra-monsoon period high concentrations of crustal ions, sulphate and nitrate are measured The concentration alternances is confirmed in ice core records and can be used for dating MAIN FEATURES OF HIMALAYAN FRESH SNOW CHEMICAL COMPOSITION

21 Open issues: Source of sulphate particularly in extra-monsoon period Origin of crustal particles in extra-monsoon period (Central Asia dust storm or westernly driven Saharian air masses?) Formation mechanisms and sources of organic acids Relantionship between snow chemistry and aerosol chemistry

22 FUTURE AIMS Integration of deposition chemistry with aerosol chemistry in order to obtain complementary information on atmospheric processes involved in Atmospheric Brown Cloud Sulphate: 32% Organics: 26%

23 Thank you ! “et eunt homines admirari alta montium et ingentis fructus maris et latissimos lapsus fluminum et ocean ambitum et giros siderum, et reliquunt se ipsos” “And men go about to wonder at the heights of the mountains, and the mighty waves of the sea, and the wide sweep of rivers, and the circuit of ocean, and the revolution of the stars, but they do not consider themselves” Augustinus, Confessiones


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