Table 1 Key large scale forcing factors of the regional climate system and their impact on oceanic and atmospheric patterns.
Climate index | Abbrev | Parameter | Location of high | Location of low | References | Effect |
|---|---|---|---|---|---|---|
Atlantic multidecadal oscillation | AMO | North atlantic SST anomaly | Warmer waters in the North Atlantic | Cooler waters in the north atlantic | Enfield et al.28 | Influences Atlantic SSTs and climate variability over multidecadal timescales |
Indian ocean dipole mode index | DMI | Western—eastern tropical Indian ocean SST gradient | Positive phase: Warmer waters in the west, cooler waters in the east | Negative phase: Reversed temperature gradient | Affects monsoon patterns, rainfall in the Indian Ocean region (East Africa, Australia, and Southeast Asia.) | |
Niño3 index | Niño3 (150°W–90°W, 5°S–5°N) | Eastern tropical pacific SST anomaly | Eastern pacific | Eastern pacific | Trenberth and Stepaniak31 | Key indicator of El Niño-Southern Oscillation (ENSO) events, affecting global atmospheric circulation and regional climates |
Tropical atlantic SST index | TASI | Gradient of meridional SST anomalies in the tropical Atlantic | Tropical atlantic | Tropical atlantic | Chang et al.32 | Influences Atlantic hurricane activity and West African monsoon. It is associated with a potential decadal 'dipole' mode of coupled variability in the tropical Atlantic |
Tropical northern atlantic index | TNA (55°W–15°W, 5°N–25°N) | SST anomalies in the northern tropical atlantic ocean | Northern tropical atlantic | Northern tropical atlantic | Enfield et al.28 | Affects Atlantic hurricane activity and rainfall over the Americas |
Tropical southern atlantic index | TSA (30°W–10°E, 20°S–Eq) | SST anomalies in the southern tropical atlantic ocean | Southern tropical atlantic | Southern tropical atlantic | Enfield et al.28 | Indicator of the surface temperatures in the GoG, the eastern tropical South Atlantic Ocean. Influences rainfall patterns in South America and Africa |
Atlantic niño | ATL3 or EAUS (3°N–3°S, 0–20°W) | Eastern tropical atlantic SST anomaly | Eastern tropical atlantic | Eastern tropical atlantic | Influences West African summer monsoon, leading to reduced rainfall in the Sahel region and increased flooding in northeastern South America and the West African sub-Sahel countries bordering the GoG |
