Maqola

Trends in Total and Extreme South American Rainfall in 1960–2000 and Links with Sea Surface Temperature

M. R. HaylockClimatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, United KingdomT. C. PetersonNational Climatic Data Center, Asheville, North CarolinaLincoln Muniz AlvesCentro de Previsão de Tempo e Estudos Climáticos, Instituto Nacional de Pesquisas Espaciais, Cachoeira Paulista, BrazilTércio AmbrizziUniversidade de São Paulo, São Paulo, BrazilYumiko Marina Tanaka da AnunciaçãoJulián BaézVicente BarrosDepartamento de Ciencias de la Atmósfera y los Océanos, FCEN, Universidad de Buenos Aires, Buenos Aires, ArgentinaMoacir Antônio BerlatoUniversidade Federal do Rio Grande do Sul, Port Alegre, BrazilMario Pérez BidegainFaculty of Science, Universidad de la Republica, Montevideo, UruguayGenaro CoronelUniversidad Nacional de Asunción, San Lorenzo, ParaguayV. CorradiVíctor J. GarcíaUniversidad Nacional Agraria La Molina, La Molina, PeruAlice M. GrimmFederal University of Parana, Curitiba, BrazilDavid J. KarolyUniversity of Oklahoma, Norman, OklahomaJosé A. MarengoCentro de Previsão de Tempo e Estudos Climáticos, Instituto Nacional de Pesquisas Espaciais, Cachoeira Paulista, BrazilMónica MarinoBanco Nacional De Datos, Servicio Meteorológico Nacional, Buenos Aires, ArgentinaDavid Ferran MoncunillFundação Cearense de Meteorologia e Recursos Hídricos (FUNCEME), Fortaleza, BrazilDimitrie NechetUniversidade Federal do Para, Belem, BrazilJuan QuintanaDirección Meteorológica de Chile, Santiago, ChileExpedito Ronald Gomes RebelloMatilde RusticucciDepartamento de Ciencias de la Atmósfera y los Océanos, FCEN, Universidad de Buenos Aires, Buenos Aires, ArgentinaJosé SantosFaculty of Marine Sciences, Escuela Superior Politécnica del Litoral, Guayaquil, EcuadorI. TrebejoServicio Nacional de Meteorología e Hidrología, Lima, PeruLucie A. Vincent

2006en

ABI

Annotatsiya

Abstract A weeklong workshop in Brazil in August 2004 provided the opportunity for 28 scientists from southern South America to examine daily rainfall observations to determine changes in both total and extreme rainfall. Twelve annual indices of daily rainfall were calculated over the period 1960 to 2000, examining changes to both the entire distribution as well as the extremes. Maps of trends in the 12 rainfall indices showed large regions of coherent change, with many stations showing statistically significant changes in some of the indices. The pattern of trends for the extremes was generally the same as that for total annual rainfall, with a change to wetter conditions in Ecuador and northern Peru and the region of southern Brazil, Paraguay, Uruguay, and northern and central Argentina. A decrease was observed in southern Peru and southern Chile, with the latter showing significant decreases in many indices. A canonical correlation analysis between each of the indices and sea surface temperatures (SSTs) revealed two large-scale patterns that have contributed to the observed trends in the rainfall indices. A coupled pattern with ENSO-like SST loadings and rainfall loadings showing similarities with the pattern of the observed trend reveals that the change to a generally more negative Southern Oscillation index (SOI) has had an important effect on regional rainfall trends. A significant decrease in many of the rainfall indices at several stations in southern Chile and Argentina can be explained by a canonical pattern reflecting a weakening of the continental trough leading to a southward shift in storm tracks. This latter signal is a change that has been seen at similar latitudes in other parts of the Southern Hemisphere. A similar analysis was carried out for eastern Brazil using gridded indices calculated from 354 stations from the Global Historical Climatology Network (GHCN) database. The observed trend toward wetter conditions in the southwest and drier conditions in the northeast could again be explained by changes in ENSO.

Hali tarjima qilinmagan

Identifikatorlar

DOI: 10.1175/jcli3695.1

Iqtiboslar va manbalar

2 ta iqtibos0 ta foydalanilgan manba

Koʻrsatkichlar — AkademScholar