Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Chemical composition of monsoon deposition in the Everest region |
| Abstract | Between 1990 and 1994 a campaign for sampling summer depositions was carried out in the Everest region Khumbu Valley, Nepal. in order to understand the physical, chemical and transport processes responsible for the ion chemistry in the deposition of this region. Wet and bulk depositions at 5050 m a.s.l. and snow samples from 5515 to 7400 m altitude were collected. Conductivity, pH, alkalinity, the major inorganic ions and carboxylic acids were measured and the seasonal loads were estimated. The analytical results show that the monsoon contribution dominated up to 5050 m of elevation, but it was not a source of acidifying species; the transport of chemical compounds at higher altitude was due to the local breezes. At this altitude 5050 m a.s.l.. relatively high levels of nitrate and ammonium must be due to local or regional biogenic and anthropogenic inputs; non-sea-salt sulphate concentration was of the same order of magnitude of tropospheric sulphate background. An intense oxidative photochemical activity of locally emitted precursors NOx and VOC. is probably responsible for the high levels of carboxylic acids and nitrate. Above 6000 m altitude no monsoon or regional influences were found and the measured concentration should be indicative of background tropospheric levels. |
| Source | Science of the total environment 226, pp. 187–199 |
| Keywords | Monsoon depositionEverest regionIon chemistry |
| Journal | Science of the total environment |
| Editor | Elsevier, Lausanne ;, Paesi Bassi |
| Year | 1999 |
| Type | Articolo in rivista |
| Authors | Valsecchi S., Smiraglia C., Tartari G. and Polesello S. |
| Text | 235556 1999 Monsoon deposition Everest region Ion chemistry Chemical composition of monsoon deposition in the Everest region Valsecchi S., Smiraglia C., Tartari G. and Polesello S. IRSA CNR, Brugherio Universita degli Studi di Milano, Dipartimento di Scienze della Terra Between 1990 and 1994 a campaign for sampling summer depositions was carried out in the Everest region Khumbu Valley, Nepal. in order to understand the physical, chemical and transport processes responsible for the ion chemistry in the deposition of this region. Wet and bulk depositions at 5050 m a.s.l. and snow samples from 5515 to 7400 m altitude were collected. Conductivity, pH, alkalinity, the major inorganic ions and carboxylic acids were measured and the seasonal loads were estimated. The analytical results show that the monsoon contribution dominated up to 5050 m of elevation, but it was not a source of acidifying species; the transport of chemical compounds at higher altitude was due to the local breezes. At this altitude 5050 m a.s.l.. relatively high levels of nitrate and ammonium must be due to local or regional biogenic and anthropogenic inputs; non sea salt sulphate concentration was of the same order of magnitude of tropospheric sulphate background. An intense oxidative photochemical activity of locally emitted precursors NOx and VOC. is probably responsible for the high levels of carboxylic acids and nitrate. Above 6000 m altitude no monsoon or regional influences were found and the measured concentration should be indicative of background tropospheric levels. 226 articolo 96monsoon96.pdf Articolo in rivista Elsevier 0048 9697 Science of the total environment Science of the total environment Sci. total environ. stefano.polesello POLESELLO STEFANO gianni.tartari TARTARI GIANNI saramaria.valsecchi VALSECCHI SARA MARIA |