Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram
Winter precipitation over the Hindu Kush–Karakoram (HKK) range in the western Himalayas is generated by westerly perturbations whose dynamics is affected by the North Atlantic Oscillation (NAO). Larger precipitation is typically recorded during the positive NAO phase. In this work, the relationship...
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ftosti:oai:osti.gov:1565385 2023-07-30T04:05:30+02:00 Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram Filippi, Luca Palazzi, Elisa von Hardenberg, Jost Provenzale, Antonello 2023-06-23 application/pdf http://www.osti.gov/servlets/purl/1565385 https://www.osti.gov/biblio/1565385 https://doi.org/10.1175/jcli-d-14-00286.1 unknown http://www.osti.gov/servlets/purl/1565385 https://www.osti.gov/biblio/1565385 https://doi.org/10.1175/jcli-d-14-00286.1 doi:10.1175/jcli-d-14-00286.1 54 ENVIRONMENTAL SCIENCES 2023 ftosti https://doi.org/10.1175/jcli-d-14-00286.1 2023-07-11T09:37:06Z Winter precipitation over the Hindu Kush–Karakoram (HKK) range in the western Himalayas is generated by westerly perturbations whose dynamics is affected by the North Atlantic Oscillation (NAO). Larger precipitation is typically recorded during the positive NAO phase. In this work, the relationship between the NAO and winter precipitation in the HKK is explored further, using an ensemble of precipitation datasets and the 40-yr ECMWF Re-Analysis (ERA-40) and Twentieth Century Reanalysis (20CR) data. The mechanisms underlying this relationship are discussed, with a focus on the secular variations that occurred in the last century. The NAO exerts its control on HKK precipitation by altering the intensity of westerly winds in the region of the Middle East jet stream (MEJS). Results indicate that evaporation from the Persian Gulf, the northern Arabian Sea, and the Red Sea plays an important role. During positive NAO phases, westerlies are strengthened and enhanced evaporation occurs from these basins owing to higher surface wind speed. The extra moisture combines with stronger westerlies and results in enhanced moisture transport toward the HKK. Precipitation datasets covering the twentieth century show an alternation of periods of strong and weaker influence of the NAO on precipitation in the HKK. It is found that these variations are associated with changes in the spatial pattern of the NAO: the relative position of the two centers of action of the NAO determines to what extent it can modulate the MEJS, affecting precipitation in the HKK. Other/Unknown Material North Atlantic North Atlantic oscillation SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Journal of Climate 27 20 7890 7902 |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Filippi, Luca Palazzi, Elisa von Hardenberg, Jost Provenzale, Antonello Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Winter precipitation over the Hindu Kush–Karakoram (HKK) range in the western Himalayas is generated by westerly perturbations whose dynamics is affected by the North Atlantic Oscillation (NAO). Larger precipitation is typically recorded during the positive NAO phase. In this work, the relationship between the NAO and winter precipitation in the HKK is explored further, using an ensemble of precipitation datasets and the 40-yr ECMWF Re-Analysis (ERA-40) and Twentieth Century Reanalysis (20CR) data. The mechanisms underlying this relationship are discussed, with a focus on the secular variations that occurred in the last century. The NAO exerts its control on HKK precipitation by altering the intensity of westerly winds in the region of the Middle East jet stream (MEJS). Results indicate that evaporation from the Persian Gulf, the northern Arabian Sea, and the Red Sea plays an important role. During positive NAO phases, westerlies are strengthened and enhanced evaporation occurs from these basins owing to higher surface wind speed. The extra moisture combines with stronger westerlies and results in enhanced moisture transport toward the HKK. Precipitation datasets covering the twentieth century show an alternation of periods of strong and weaker influence of the NAO on precipitation in the HKK. It is found that these variations are associated with changes in the spatial pattern of the NAO: the relative position of the two centers of action of the NAO determines to what extent it can modulate the MEJS, affecting precipitation in the HKK. |
author |
Filippi, Luca Palazzi, Elisa von Hardenberg, Jost Provenzale, Antonello |
author_facet |
Filippi, Luca Palazzi, Elisa von Hardenberg, Jost Provenzale, Antonello |
author_sort |
Filippi, Luca |
title |
Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram |
title_short |
Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram |
title_full |
Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram |
title_fullStr |
Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram |
title_full_unstemmed |
Multidecadal Variations in the Relationship between the NAO and Winter Precipitation in the Hindu Kush–Karakoram |
title_sort |
multidecadal variations in the relationship between the nao and winter precipitation in the hindu kush–karakoram |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1565385 https://www.osti.gov/biblio/1565385 https://doi.org/10.1175/jcli-d-14-00286.1 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
http://www.osti.gov/servlets/purl/1565385 https://www.osti.gov/biblio/1565385 https://doi.org/10.1175/jcli-d-14-00286.1 doi:10.1175/jcli-d-14-00286.1 |
op_doi |
https://doi.org/10.1175/jcli-d-14-00286.1 |
container_title |
Journal of Climate |
container_volume |
27 |
container_issue |
20 |
container_start_page |
7890 |
op_container_end_page |
7902 |
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1772817473024819200 |