PULSING OF THE BENGUELA UPWELLING REGION - LARGE-SCALE ATMOSPHERIC CONTROLS
Submitted by Mark R Jury on
PDF version| Title | PULSING OF THE BENGUELA UPWELLING REGION - LARGE-SCALE ATMOSPHERIC CONTROLS |
| Publication Type | Journal Article |
| Year of Publication | 1990 |
| Authors | Jury, MR, MACARTHUR, CI, BRUNDRIT, GB |
| Journal | SOUTH AFRICAN JOURNAL OF MARINE SCIENCE-SUID-AFRIKAANSE TYDSKRIF VIR SEEWETENSKAP |
| Volume | 9 |
| Pagination | 27-41 |
| Type of Article | Article |
| ISSN | 0257-7615 |
| Abstract | Large-scale atmospheric mechanisms which control coastal sea temperatures, sea levels and alongshore currents in the southern Benguela region are investigated. The influence of upper atmospheric Rossby waves in the mid-latitude westerlies is transmitted to the shelf circulation via coastal trapped waves in the atmosphere/ocean, and the physical environment becomes pulsed. Autocorrelation statistics identify an irregular upwelling-downwelling cycle with periods of > 20 days in winter; summers exhibit a faster 10-day pulsing. The average time between successive upwelling pulses is 23 days. Relationships between large-scale atmospheric Rossby wave structure and the local shelf response are analysed on the basis of selected hemispheric weather charts at the 500 hPa level. Cohesive hemispheric waves of length 8 000 km (Wave 4) contribute significant energy to the pulsing. The shorter westerly waves (5 and 6) induce rapid and less distinct oscillations. |
