Abstract
AbstractThis study analyses the connection between extreme rainfall events in Jeddah, Saudi Arabia, and synoptic‐scale weather patterns over the Arabian Peninsula. Mean rainfall follows a decreasing trend; however, the number of rainy days has increased. Interestingly, extreme rainfall is becoming less frequent but shows an increased intensity. Here we utilize self‐organizing maps (SOMs) to identify the weather patterns of the most intense rainy days and the synoptic systems causing extreme rainfall in the Jeddah region. Three main weather patterns that cause heavy rainfall events over Jeddah during the cooler months (November–April) are identified, all reflect tropical‐extratropical interactions. Extreme events in the early period (1979–1998) are characterized by a stronger tropical influence and local precipitation patterns, while a stronger extratropical forcing and higher extreme rainfall amounts are spotted in the late period (1999–2018). Our results suggest that in recent decades, the mechanism causing extreme rainfall over the city of Jeddah has shifted toward a weather regime with stronger extratropical influence.
Highlights
To investigate changes in weather patterns associated with extreme precipitation over Jeddah, we further explore the changes of identified self-organizing maps (SOMs) patterns between two 20-year periods, as in Hewitson and Crane (2002), Lee et al (2017), who established the connections between the hemispheric teleconnection and temperature extremes over the Northern Hemisphere
We assessed the reliability of SOM clusters using a bootstrapping technique by empirically estimating the distribution of 1,000 SOM errors
The test suggests that the null hypothesis is rejected at alpha .05, and the SOM maps of the 73 extreme events are statistically significant at the .05 level
Summary
We apply the self-organizing maps (SOMs) technique (Kohonen, 1995; Hewitson and Crane, 2002) on atmospheric variables to classify the large-scale circulation patterns of extreme precipitation events over Jeddah. We aim to relate the observed extreme rainfall days recorded over Jeddah in the past 40 years to large-scale atmospheric circulations patterns in the ERA-Interim atmospheric reanalysis.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have