Summary
Previous observational work and experiments with global atmospheric circulation models have provided evidence that a dipole-like sea surface temperature (SST) pattern in the subtropical South Indian Ocean may influence austral summer rainfall over a southern African region stretching southeast from Zambia towards the south coast of South Africa. Increased rainfall tends to occur during positive events when the SW Indian Ocean anomaly is warm and the SE Indian Ocean anomaly is cool, and decreased rainfall during negative events when the SST anomalies are reversed.
In this study, the regional climate model MM5 is used to investigate the atmospheric response to two strong events of opposite sign (1981 and 1998). In general, the MM5 response is broadly consistent with NCEP re-analyses for these years but tends to advect more low level moisture over than NCEP. The model results indicate that more moisture is advected over the subcontinent from the South West Indian Ocean during the positive event than during the negative event. This is consistent with observed rainfall over the region during these events.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
SK Behera T Yamagata (2001) ArticleTitleSubtropical SST dipole events in the southern Indian Ocean Geophys Res Lett 28 327–330 Occurrence Handle10.1029/2000GL011451
C Cook CJC Reason BC Hewitson (2004) ArticleTitleWet and dry spells within particular wet and dry summers in the South African summer rainfall region Climate Res 26 17–31 Occurrence Handle10.3354/cr026017
PC d’Abreton PD Tyson (1995) ArticleTitleDivergent and non-divergent water vapour transport over southern Africa during wet and dry conditions Meteorol Atmos Phys 55 47–59 Occurrence Handle10.1007/BF01029601
PC D’Abreton PD Tyson (1996) ArticleTitleThree dimensional kinematic trajectory modelling of water vapour transport over southern Africa Wates SA 22 297–306
MSJ Harrison (1984) ArticleTitleA generalized classification of South African summer rain-bearing synoptic systems Int J Climatol 4 547–560 Occurrence Handle10.1002/joc.3370040510
A Hirst S Hastenrath (1983) ArticleTitleAtmosphere-Ocean mechanisms of climate anomalies in Angola-tropical Atlantic sector J Phys Oceanogr 13 1146–1157 Occurrence Handle10.1175/1520-0485(1983)013<1146:AOMOCA>2.0.CO;2
GJ Huffman FA Adler P Arkin F Chang R Ferraro A Gruber J Janowiak A McNab B Rudolf U Schneider (1997) ArticleTitleThe Global Precipitation Climatology Project (GPCP) combined data set Bull Amer Meteorol Soc 78 5–20 Occurrence Handle10.1175/1520-0477(1997)078<0005:TGPCPG>2.0.CO;2
MR Jury B Pathack B Parker (1999) ArticleTitleClimatic determinants and statistical prediction of tropical cyclone days in the southwest Indian Ocean J Climate 12 IssueID6 1738–1746 Occurrence Handle10.1175/1520-0442(1999)012<1738:CDASPO>2.0.CO;2
E Kalnay M Kanamitsu R Kistler W Collins D Deaven L Gandin M Iredell S Saha G White J Woollen Y Zhu M Chelliah W Ebisuzaki W Higgins J Janowiak KC Mo C Ropelewski J Wang A Leetmaa R Reynolds R Jenne D Joseph (1996) ArticleTitleThe NCEP/NCAR 40-year reanalysis project Bull Amer Meteor Soc 77 437–471 Occurrence Handle10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2
WA Landman SJ Mason (1999) ArticleTitleChange in the association between Indian Ocean sea-surface temperature and summer rainfall over South Africa and Namibia Int J Climatol 19 1477–1492 Occurrence Handle10.1002/(SICI)1097-0088(19991115)19:13<1477::AID-JOC432>3.0.CO;2-W
HM Mulenga M Rouault CJC Reason (2003) ArticleTitleDry summers over northeastern South Africa and associated circulation anomalies Climate Res 25 29–41 Occurrence Handle10.3354/cr025029
CJC Reason (2001) ArticleTitleSubtropical Indian Ocean SST dipole events and southern African rainfall Geophys Res Lett 28 IssueID11 2225–2227 Occurrence Handle10.1029/2000GL012735
CJC Reason (2002) ArticleTitleSensitivity of the southern African circulation to dipole sea-surface temperature patterns in the south Indian Ocean Int J Climatol 22 377–393 Occurrence Handle10.1002/joc.744
CJC Reason H Mulenga (1999) ArticleTitleRelationships between South African rainfall and SST anomalies in the south west Indian Ocean Int J Climatol 19 1651–1673 Occurrence Handle10.1002/(SICI)1097-0088(199912)19:15<1651::AID-JOC439>3.0.CO;2-U
CJC Reason W Landman W Tennant (2006) ArticleTitleSeasonal to decadal prediction of southern African climate and its links with variability of the Atlantic Ocean Bull Amer Met Soc 87 941–955 Occurrence Handle10.1175/BAMS-87-7-941
A Rocha IH Simmonds (1997) ArticleTitleInterannual variability of southern African summer rainfall. Part I: Relationships with air–sea interactions processes Int J Climatol 17 235–265 Occurrence Handle10.1002/(SICI)1097-0088(19970315)17:3<235::AID-JOC123>3.0.CO;2-N
Rouault M, Florenchie P, Fauchereau N, Reason CJC (2003) South East Tropical Atlantic Warm Events and Southern African Rainfall. Geophys Res Lett 30(5); DOI: 10.1029/2002/GL014840
PD Tyson RA Preston-Whyte (2000) The Atmosphere and Weather of Southern Africa Oxford University Press Cape Town
ND Walker (1990) ArticleTitleLinks between South African summer rainfall and temperature variability of the Agulhas and Benguela current systems J Geophys Res 95 3297–3319 Occurrence Handle10.1029/JC095iC03p03297
Author information
Authors and Affiliations
Corresponding author
Additional information
Correspondence: Chris J. C. Reason, Department of Oceanography, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa
Rights and permissions
About this article
Cite this article
Hansingo, K., Reason, C. Modelling the atmospheric response to SST dipole patterns in the South Indian Ocean with a regional climate model. Meteorol Atmos Phys 100, 37–52 (2008). https://doi.org/10.1007/s00703-008-0294-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00703-008-0294-7