Altitudinal variation of the stable isotopes of snow in regions of high relief
| Autor: | H. Roy Krouse, Gerald Holdsworth |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
010506 paleontology
geography Oxygen-18 geography.geographical_feature_category 010504 meteorology & atmospheric sciences Mixed layer Stable isotope ratio Glacier Snow 01 natural sciences Isotopes of oxygen Synoptic scale meteorology Paleoclimatology Physical geography Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Journal of Glaciology. 48:31-41 |
| ISSN: | 1727-5652 0022-1430 |
| DOI: | 10.3189/172756502781831638 |
| Popis: | A major discontinuity in the variation of δ18O (δD) with altitude in high mountains was first seen in data from Mount Logan, YukonTerritory, Canada (Holdsworth and others, 1991). The profile of δ vs altitude revealed three well-defined regions: (1) a lower, monotonic, fractionation sequence below ∼3 km; (2) a middle layer, typically 1–2 km thick, within which δ values are nearly constant or stepped with altitude, and (3) part of another fractionation sequence in the “quasi-geostrophic flow region” above ∼5.3 km. The middle region was inferred to be a “mixed layer”, combining moisture from regions (1) and (3). This type of structure is now seen to occur on other high-altitude mountains, including Cerro Aconcagua, Argentina, where observations reach almost 7 km. The new observations confirm the general occurrence of a multi-layered atmosphere during precipitation at high-altitude glacier sites. This structure is linked to synoptic-scale polar cyclones, where the middle layer is identified as being the signature of the warm-front zone. These results have implications for the common practice of using a specific, spatially derived, isotopic thermometer in the time domain for the paleoclimatic interpretation of high-altitude ice-core δ records. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|