The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter
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:1565386 2023-07-30T04:05:30+02:00 The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter Hoell, Andrew Funk, Chris Barlow, Mathew 2021-08-02 application/pdf http://www.osti.gov/servlets/purl/1565386 https://www.osti.gov/biblio/1565386 https://doi.org/10.1175/jcli-d-14-00344.1 unknown http://www.osti.gov/servlets/purl/1565386 https://www.osti.gov/biblio/1565386 https://doi.org/10.1175/jcli-d-14-00344.1 doi:10.1175/jcli-d-14-00344.1 54 ENVIRONMENTAL SCIENCES 2021 ftosti https://doi.org/10.1175/jcli-d-14-00344.1 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 NAOand winter precipitation in theHKKis 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 28 4 1511 1526 |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Hoell, Andrew Funk, Chris Barlow, Mathew The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter |
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 NAOand winter precipitation in theHKKis 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 |
Hoell, Andrew Funk, Chris Barlow, Mathew |
author_facet |
Hoell, Andrew Funk, Chris Barlow, Mathew |
author_sort |
Hoell, Andrew |
title |
The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter |
title_short |
The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter |
title_full |
The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter |
title_fullStr |
The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter |
title_full_unstemmed |
The Forcing of Southwestern Asia Teleconnections by Low-Frequency Sea Surface Temperature Variability during Boreal Winter |
title_sort |
forcing of southwestern asia teleconnections by low-frequency sea surface temperature variability during boreal winter |
publishDate |
2021 |
url |
http://www.osti.gov/servlets/purl/1565386 https://www.osti.gov/biblio/1565386 https://doi.org/10.1175/jcli-d-14-00344.1 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
http://www.osti.gov/servlets/purl/1565386 https://www.osti.gov/biblio/1565386 https://doi.org/10.1175/jcli-d-14-00344.1 doi:10.1175/jcli-d-14-00344.1 |
op_doi |
https://doi.org/10.1175/jcli-d-14-00344.1 |
container_title |
Journal of Climate |
container_volume |
28 |
container_issue |
4 |
container_start_page |
1511 |
op_container_end_page |
1526 |
_version_ |
1772817473184202752 |