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 (NAG). Larger precipitation is typically recorded during the positive NAO phase. In this work, the relationship...
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ftpoltorinoiris:oai:iris.polito.it:11583/2814994 2024-04-14T08:15:58+00:00 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 Filippi, Luca Palazzi, Elisa von Hardenberg, Jost Provenzale, Antonello 2014 http://hdl.handle.net/11583/2814994 https://doi.org/10.1175/JCLI-D-14-00286.1 eng eng AMER METEOROLOGICAL SOC info:eu-repo/semantics/altIdentifier/wos/WOS:000342883400021 volume:27 issue:20 firstpage:7890 lastpage:7902 numberofpages:13 journal:JOURNAL OF CLIMATE http://hdl.handle.net/11583/2814994 doi:10.1175/JCLI-D-14-00286.1 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-84907841747 info:eu-repo/semantics/openAccess info:eu-repo/semantics/article 2014 ftpoltorinoiris https://doi.org/10.1175/JCLI-D-14-00286.1 2024-03-21T16:40:28Z 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 (NAG). 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. Article in Journal/Newspaper North Atlantic North Atlantic oscillation PORTO@iris (Publications Open Repository TOrino - Politecnico di Torino) Journal of Climate 27 20 7890 7902 |
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PORTO@iris (Publications Open Repository TOrino - Politecnico di Torino) |
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ftpoltorinoiris |
language |
English |
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 (NAG). 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. |
author2 |
Filippi, Luca Palazzi, Elisa von Hardenberg, Jost Provenzale, Antonello |
format |
Article in Journal/Newspaper |
author |
Filippi, Luca Palazzi, Elisa von Hardenberg, Jost Provenzale, Antonello |
spellingShingle |
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 |
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 |
publisher |
AMER METEOROLOGICAL SOC |
publishDate |
2014 |
url |
http://hdl.handle.net/11583/2814994 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 |
info:eu-repo/semantics/altIdentifier/wos/WOS:000342883400021 volume:27 issue:20 firstpage:7890 lastpage:7902 numberofpages:13 journal:JOURNAL OF CLIMATE http://hdl.handle.net/11583/2814994 doi:10.1175/JCLI-D-14-00286.1 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-84907841747 |
op_rights |
info:eu-repo/semantics/openAccess |
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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