Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence
Targeted numerical modelling experimaents are conducted to complement the previous empirical diagnostics of circulation mechanisms leading from sea surface temperature (SST) departures in the equatorial Pacific in January to anomalies in the March-April rainy season of Brazil's Nordeste. A weak...
Published in: | Revista Brasileira de Meteorologia |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2008
|
Subjects: | |
Online Access: | https://www.openaccessrepository.it/record/53412 https://doi.org/10.1590/s0102-77862008000200001 |
id |
ftopenaccessrep:oai:zenodo.org:53412 |
---|---|
record_format |
openpolar |
spelling |
ftopenaccessrep:oai:zenodo.org:53412 2024-09-15T18:21:29+00:00 Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence Fred Kucharski Dierk Polzin Stefan Hastenrath 2008-06-01 https://www.openaccessrepository.it/record/53412 https://doi.org/10.1590/s0102-77862008000200001 eng eng url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/53412 doi:10.1590/s0102-77862008000200001 info:eu-repo/semantics/openAccess Atmospheric Science info:eu-repo/semantics/article publication-article 2008 ftopenaccessrep https://doi.org/10.1590/s0102-77862008000200001 2024-07-29T03:27:39Z Targeted numerical modelling experimaents are conducted to complement the previous empirical diagnostics of circulation mechanisms leading from sea surface temperature (SST) departures in the equatorial Pacific in January to anomalies in the March-April rainy season of Brazil's Nordeste. A weak interhemispheric northward directed SST gradient in the Atlantic favors a more southerly position of the hydrostatically controlled low pressure trough, embedded in which is the Intertropical Convergence Zone (ITCZ), which is the main rainbearing system for the Nordeste. In addition, anomalously warm waters in the equatorial Pacific in January tend to be followed by Nordeste drought. The underlying chain of causalities has been explored by empirical diagnostics and numerical modelling. During El Nino years, an upper-tropospheric wave train extends from the equatorial eastern Pacific to the tropical North Atlantic, affecting the patterns of upper-tropospheric topography and divergence, and hence of vertical motion over the Atlantic. This leads to a weaker meridional pressure gradient on the equatorward flank of the North Atlantic subtropical high, weaker North Atlantic tradewinds, an anomalously far northerly ITCZ position and thus Nordeste drought. The previous empirical diagnostics are overall supported by the modelling experiments. Article in Journal/Newspaper North Atlantic Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository Revista Brasileira de Meteorologia 23 2 115 125 |
institution |
Open Polar |
collection |
Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository |
op_collection_id |
ftopenaccessrep |
language |
English |
topic |
Atmospheric Science |
spellingShingle |
Atmospheric Science Fred Kucharski Dierk Polzin Stefan Hastenrath Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence |
topic_facet |
Atmospheric Science |
description |
Targeted numerical modelling experimaents are conducted to complement the previous empirical diagnostics of circulation mechanisms leading from sea surface temperature (SST) departures in the equatorial Pacific in January to anomalies in the March-April rainy season of Brazil's Nordeste. A weak interhemispheric northward directed SST gradient in the Atlantic favors a more southerly position of the hydrostatically controlled low pressure trough, embedded in which is the Intertropical Convergence Zone (ITCZ), which is the main rainbearing system for the Nordeste. In addition, anomalously warm waters in the equatorial Pacific in January tend to be followed by Nordeste drought. The underlying chain of causalities has been explored by empirical diagnostics and numerical modelling. During El Nino years, an upper-tropospheric wave train extends from the equatorial eastern Pacific to the tropical North Atlantic, affecting the patterns of upper-tropospheric topography and divergence, and hence of vertical motion over the Atlantic. This leads to a weaker meridional pressure gradient on the equatorward flank of the North Atlantic subtropical high, weaker North Atlantic tradewinds, an anomalously far northerly ITCZ position and thus Nordeste drought. The previous empirical diagnostics are overall supported by the modelling experiments. |
format |
Article in Journal/Newspaper |
author |
Fred Kucharski Dierk Polzin Stefan Hastenrath |
author_facet |
Fred Kucharski Dierk Polzin Stefan Hastenrath |
author_sort |
Fred Kucharski |
title |
Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence |
title_short |
Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence |
title_full |
Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence |
title_fullStr |
Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence |
title_full_unstemmed |
Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence |
title_sort |
teleconnection mechanisms of northeast brazil droughts: modeling and empirical evidence |
publishDate |
2008 |
url |
https://www.openaccessrepository.it/record/53412 https://doi.org/10.1590/s0102-77862008000200001 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/53412 doi:10.1590/s0102-77862008000200001 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1590/s0102-77862008000200001 |
container_title |
Revista Brasileira de Meteorologia |
container_volume |
23 |
container_issue |
2 |
container_start_page |
115 |
op_container_end_page |
125 |
_version_ |
1810460072931753984 |