Causal Factors for Nighttime Increases in Temperature Observed at a Coastal Meteorological Station

Abstract

The study describes the frequency of significant nighttime temperature increases and analyses the event occurrence with respect to various meteorological parameters, including wind speed and direction at the coastal station and pressure at various nearby stations. Four years of meteorological records from a weather station in northern Oman were analysed. The results indicate that nighttime temperature increases occurred approximately 20 times per year between the months of April and August from 2002 to 2005. Over the study period, the mean significant temperature increase overnight, within 1 h, was 4.5°C, while the maximum observed was 8.1°C. These temperature events are associated with above average nighttime mean wind speeds, categorized as “moderate” or “fresh breezes” on the Beaufort scale, coming from a southwesterly direction. The wind direction and speed suggest that the temperature events at the station are due to a combination of a funnelling effect through a nearby valley and föhn winds from a mountain range located to the south of the case study site.