 |
| Titel |
Impact of Po Valley emissions on the highest glacier of the Eastern European Alps |
| VerfasserIn |
J. Gabrieli, L. Carturan, P. Gabrielli, N. Kehrwald, C. Turetta, G. Cozzi, A. Spolaor, R. Dinale, H. Staffler, R. Seppi, G. Dalla Fontana, L. Thompson, C. Barbante |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 15 ; Nr. 11, no. 15 (2011-08-09), S.8087-8102 |
| Datensatznummer |
250009993
|
| Publikation (Nr.) |
 copernicus.org/acp-11-8087-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
In June 2009, we conducted the first extensive glaciological survey of Alto
dell'Ortles, the uppermost glacier of Mt. Ortles (3905 m a.s.l.), the
highest summit of the Eastern European Alps. This section of the Alps is
located in a rain shadow and is characterized by the lowest precipitation
rate in the entire Alpine arc. Mt. Ortles offers a unique opportunity to
test deposition mechanisms of chemical species that until now were studied
only in the climatically-different western sector. We analyzed snow samples
collected on Alto dell'Ortles from a 4.5 m snow-pit at 3830 m a.s.l., and we
determined a large suite of trace elements and ionic compounds that comprise
the atmospheric deposition over the past two years.
Trace element concentrations measured in snow samples are extremely low with
mean concentrations at pg g−1 levels. Only Al and Fe present median values of
1.8 and 3.3 ng g−1, with maximum concentrations of 21 and 25 ng g−1. The median
crustal enrichment factor (EFc) values for Be, Rb, Sr, Ba, U, Li, Al, Ca,
Cr, Mn, Fe, Co, Ga and V are lower than 10 suggesting that these elements
originated mainly from soil and mineral aerosol. EFc higher than 100 are
reported for Zn (118), Ag (135), Bi (185), Sb (401) and Cd (514),
demonstrating the predominance of non-crustal depositions and suggesting an
anthropogenic origin.
Our data show that the physical stratigraphy and the chemical signals of
several species were well preserved in the uppermost snow of the Alto
dell'Ortles glacier. A clear seasonality emerges from the data as the summer
snow is more affected by anthropogenic and marine contributions while the
winter aerosol flux is dominated by crustal sources. For trace elements, the
largest mean EFc seasonal variations are displayed by V (with a factor of
3.8), Sb (3.3), Cu (3.3), Pb (2.9), Bi (2.8), Cd (2.1), Zn (1.9), Ni (1.8),
Ag (1.8), As (1.7) and Co (1.6).
When trace species ratios in local and Po Valley emissions are compared
with those in Alto dell'Ortles snow, the deposition on Mt. Ortles is clearly
linked with Po Valley summer emissions. Despite climatic differences
between the Eastern and Western Alps, trace element ratios from Alto
dell'Ortles are comparable with those obtained from high-altitude glaciers
in the Western Alps, suggesting similar sources and transport processes at
seasonal time scales in these two distinct areas. In particular, the large
changes in trace element concentrations both in the Eastern and Western Alps
appear to be more related to the regional vertical structure of the
troposphere rather than the synoptic weather patterns. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|