Role of indian and atlantic oceans on southern african climatic variability
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Role of Indian and Atlantic Oceans on Southern African Climatic Variability. A Makarau Department of Physics University of Zimbabwe. Intercorrelations (99% sig level). Atlantic Ocean Influence. Direct influence - Sub-tropical high pressure belt and associated wave- trains

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Role of indian and atlantic oceans on southern african climatic variability

Role of Indian and Atlantic Oceans on Southern African Climatic Variability

A Makarau

Department of Physics

University of Zimbabwe


Intercorrelations 99 sig level
Intercorrelations (99% sig level) Climatic Variability


Atlantic ocean influence
Atlantic Ocean Influence Climatic Variability

  • Direct influence

    - Sub-tropical high pressure belt and associated wave- trains

    - cold upwelling (west coasts of S Africa, Namibia, Angola, DRC)

    - westerly waves (S Africa, Namibia, Botswana, Zimbabwe)


OUTGOING LONG WAVE RADIATION (OLR) Climatic Variability

SEP

NOV

JAN


Atlantic ocean influence1
Atlantic Ocean Influence Climatic Variability

Indirect influence

- Botswana Anticyclone (Namibia, Botswana, South

Africa, Zimbabwe, Zambia)

- Tropical-sub-tropical troughs (Namibia, South Africa, Lesotho, Angola, Botswana, Zimbabwe)

- Reinforcement of the Indian Ocean Anticyclone


Indian ocean influence
Indian Ocean Influence Climatic Variability

  • Direct influence

    - Tropical cyclones (islands, Tanzania, Malawi,

    Mozambique, Zimbabwe, Swaziland, South Africa)

    - Monsoons and easterly waves (Tanzania, DRC, Zambia,

    Malawi, Mozambique, islands)

    - Inter-Tropical Convergence Zone (ITCZ)


Correlations : Zimbabwe rainfall with SSTs Climatic Variability

MAM

JJA


SON Climatic Variability

DJF


Summary the atlantic ocean
Summary: The Atlantic Ocean Climatic Variability

  • Correlations between Atlantic Ocean SSTs and area-averaged rainfall in Southern Africa have been relatively weak for operational usage (e.g., Walker, Pathack, Landman, Rocha, Mason, Makarau, Zhakata)

  • Central Atlantic SST are however positively correlated with early summer rainfall over western South Africa, Namibia, Angola and DRC


Summary the indian ocean
Summary: The Indian Ocean Climatic Variability

  • Negative correlations (up to –0.6) exist between area-averaged rainfall in southern Africa and central equatorial Indian Ocean SSTs (Makarau, Rocha, Jury, Pathack, Mason, Zhakata, Landman). The window comprising the equator-10°S and 60-70 ° E offers useful forecast guidance at 3-6 months prior to austral summer.

  • At –9 months, rainfall is positively correlated with SSTs in the South Indian Ocean (r=+0.42 near 35 ° S, 65 ° E)


Summary the indian ocean1
Summary: The Indian Ocean Climatic Variability

  • Central Equatorial Indian Ocean is the source of moisture and energy variability over northeastern southern Africa (Islands, Tanzania, DRC, Zambia, Malawi, Mozambique, Zimbabwe, northeastern South Africa and Swaziland) modulating the ITCZ, monsoons, low-level jet and related easterly waves and tropical cyclones


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