Elements of the dynamical response to climate change over the Mediterranean
© 2021 American Meteorological Society. Future climate simulations indicate that the Mediterranean Basin will experience large low-level circulation changes during winter, characterized by a strong anomalous ridge that drives a regional precipitation decline. Previous research highlighted how shifts...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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American Meteorological Society
2021
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| Online Access: | https://hdl.handle.net/1721.1/133828 |
| _version_ | 1811085171180437504 |
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| author | Tuel, Alexandre O’Gorman, Paul A Eltahir, Elfatih AB |
| author_facet | Tuel, Alexandre O’Gorman, Paul A Eltahir, Elfatih AB |
| author_sort | Tuel, Alexandre |
| collection | MIT |
| description | © 2021 American Meteorological Society. Future climate simulations indicate that the Mediterranean Basin will experience large low-level circulation changes during winter, characterized by a strong anomalous ridge that drives a regional precipitation decline. Previous research highlighted how shifts in stationary wave structure and the atmospheric response to reduced warming of the Mediterranean Sea relative to land could explain the development of this anomalous pressure high. Here, we expand on these results and provide new arguments for why and how the Mediterranean is projected to experience large circulation changes during winter. First, we find that zonal asymmetries in the vertical structure of stationary waves are important to explain the enhanced circulation response in the region and that these asymmetries are related through the external mode to the vertical structure of the mean zonal wind. Second, in winter, the Mediterranean is located just to the north of the Hadley cell edge and consequently is relatively free of large-scale descent; together with low near-surface static stability above the sea, this condition allows the weaker warming trend above the sea to propagate to the low troposphere and trigger a major circulation response. During summer, however, remotely forced descent and strong static stability prevent the cooling anomaly from expanding upward. Most of the intermodel scatter in the projected low-level circulation response in winter is related to the spread in upper-tropospheric dynamical trends. Importantly, because climate models exhibit too much vertical coherence over the Mediterranean, they likely overestimate the sensitivity of Mediterranean near-surface circulation to large-scale dynamical changes. |
| first_indexed | 2024-09-23T13:04:16Z |
| format | Article |
| id | mit-1721.1/133828 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T13:04:16Z |
| publishDate | 2021 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/1338282021-10-28T03:57:08Z Elements of the dynamical response to climate change over the Mediterranean Tuel, Alexandre O’Gorman, Paul A Eltahir, Elfatih AB © 2021 American Meteorological Society. Future climate simulations indicate that the Mediterranean Basin will experience large low-level circulation changes during winter, characterized by a strong anomalous ridge that drives a regional precipitation decline. Previous research highlighted how shifts in stationary wave structure and the atmospheric response to reduced warming of the Mediterranean Sea relative to land could explain the development of this anomalous pressure high. Here, we expand on these results and provide new arguments for why and how the Mediterranean is projected to experience large circulation changes during winter. First, we find that zonal asymmetries in the vertical structure of stationary waves are important to explain the enhanced circulation response in the region and that these asymmetries are related through the external mode to the vertical structure of the mean zonal wind. Second, in winter, the Mediterranean is located just to the north of the Hadley cell edge and consequently is relatively free of large-scale descent; together with low near-surface static stability above the sea, this condition allows the weaker warming trend above the sea to propagate to the low troposphere and trigger a major circulation response. During summer, however, remotely forced descent and strong static stability prevent the cooling anomaly from expanding upward. Most of the intermodel scatter in the projected low-level circulation response in winter is related to the spread in upper-tropospheric dynamical trends. Importantly, because climate models exhibit too much vertical coherence over the Mediterranean, they likely overestimate the sensitivity of Mediterranean near-surface circulation to large-scale dynamical changes. 2021-10-27T19:56:51Z 2021-10-27T19:56:51Z 2021 2021-09-17T16:45:59Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/133828 en 10.1175/JCLI-D-20-0429.1 Journal of Climate Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society (AMS) |
| spellingShingle | Tuel, Alexandre O’Gorman, Paul A Eltahir, Elfatih AB Elements of the dynamical response to climate change over the Mediterranean |
| title | Elements of the dynamical response to climate change over the Mediterranean |
| title_full | Elements of the dynamical response to climate change over the Mediterranean |
| title_fullStr | Elements of the dynamical response to climate change over the Mediterranean |
| title_full_unstemmed | Elements of the dynamical response to climate change over the Mediterranean |
| title_short | Elements of the dynamical response to climate change over the Mediterranean |
| title_sort | elements of the dynamical response to climate change over the mediterranean |
| url | https://hdl.handle.net/1721.1/133828 |
| work_keys_str_mv | AT tuelalexandre elementsofthedynamicalresponsetoclimatechangeoverthemediterranean AT ogormanpaula elementsofthedynamicalresponsetoclimatechangeoverthemediterranean AT eltahirelfatihab elementsofthedynamicalresponsetoclimatechangeoverthemediterranean |