The role of eastern Siberian snow . . .
Variations in the Arctic Oscillation (AO), and its regional manifestation the North Atlantic Oscillation (NAO), generate much of the nonseasonal variability in winter climate over the Northern Hemisphere (NH) mid-latitudes. Despite being an internal mode of the atmosphere, the AO/NAO exhibits a slig...
| Main Authors: | , |
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| Format: | Text |
| Language: | English |
| Published: |
2010
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.185.4154 http://dust.ess.uci.edu/ppr/ppr_AlZ112.pdf |
| Summary: | Variations in the Arctic Oscillation (AO), and its regional manifestation the North Atlantic Oscillation (NAO), generate much of the nonseasonal variability in winter climate over the Northern Hemisphere (NH) mid-latitudes. Despite being an internal mode of the atmosphere, the AO/NAO exhibits a slightly red spectrum, varying on quasi-biennial and quasi-decadal times scales. Such low-frequency variability is likely due to coupling of the atmosphere to boundary conditions and/or external forcings. Here we show that Eurasian snow cover−particularly over eastern Siberia (ESB)−exhibits multi-annual persistence similar to the AO/NAO. Furthermore, the snow-AO mechanism operates on multi-annual time scales, with fall ESB snow cover significantly related to vertically propagating Rossby wave activity, and the AO/NAO, for the next three to four winters. Based on land surface model (LSM) simulations from the Global Land Data Assimilation System (GLDAS), the interseasonal carryover of ESB snow is related to soil moisture anomalies. These findings suggest multi-annual persistence of the AO/NAO is partly due to land surface forcing in the form of both ESB snow and soil moisture |
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