ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

Hari Prasad Dasari, Sabique Langodan, Yesubabu Viswanadhapalli, Brahmananda R. Vadlamudi, Vassilis P. Papadopoulos, Ibrahim Hoteit*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Scopus citations

Abstract

The Red Sea convergence zone (RSCZ) is formed by opposite surface winds blowing from northwest to southeast directions at around 18°–19°N between October and January. A reverse-oriented, low-level monsoon trough at 850 hPa, known as the Red Sea trough (RST), transfers moisture from the southern Red Sea to RSCZ. The positions of the RSCZ and RST and the intensity of the RST have been identified as important factors in modulating weather and climatic conditions across the Middle East. Here, we investigate the influence of the El Niño southern oscillation (ENSO) on the interannual variability of RSCZ, RST, and regional rainfall during winter months. Our results indicate that El Niño (warm ENSO phase) favours a shift of the RSCZ to the north and a strengthening of the RST in the same direction. Conversely, during November and December of La Niña periods (cold ENSO phase), the RSCZ shift to the south and the RST strengthens in the same direction. During El Niño periods, southeasterly wind speeds increase (20–30%) over the southern Red Sea and northwesterly wind speeds decrease (10–15%) over the northern Red Sea. Noticeable increases in the number of rainy days and the intensity of rain events are observed during El Niño phases. These increases are associated with colder than normal air intrusion at lower levels from the north combined with warm air intrusion from the south over the RSCZ. Our analysis suggests that during El Niño winters, warmer sea surface temperatures and higher convective instability over the Red Sea favour local storms conditions and increase rainfall over the Red Sea and adjoining regions.

Original languageEnglish (US)
Pages (from-to)761-775
Number of pages15
JournalInternational Journal of Climatology
Volume38
Issue number2
DOIs
StatePublished - Feb 2018

Bibliographical note

Publisher Copyright:
© 2017 Royal Meteorological Society

Keywords

  • ENSO
  • Red Sea convergence zone
  • Red Sea trough
  • moisture convergence
  • rainfall

ASJC Scopus subject areas

  • Atmospheric Science

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