Bioenergetik: Offener Zugang  

Abstrakt

Analysis of extreme summer temperatures in Saudi Arabia and the association with largescale atmospheric circulation

Irfan Ur Rashid

Extreme temperature events (ETEs) over Saudi Arabia, have
been receiving special attention in recent decades due to their
impacts on water resources, the energy sector, human health
and crop yields. In this study, maximum temperature (Tmax)
data for the summer season (June-Aug) obtained from 27 meteorological
stations in Saudi Arabia have been analysed for
the period 1981-2017. Frequency analysis revealed that stations
located in the Central, Northern and Coastal regions have a
relatively higher number of summer ETEs. A composite analysis
has been performed to assess the association between global
circulations and ETEs in Saudi Arabia using global reanalysis
data. It is found that the summer ETEs in Saudi Arabia are
associated with a mid-latitude circumglobal wave-like (CGT)
pattern. The upper level circulations associated with the ETEs
in various regions of Saudi Arabia display a weak (e.g., Coastal
region) to well-developed (e.g., Central region) CGT wave pattern
in the mid-latitudes. The upper level anomalous high (low)
pressure over Eurasia (Central Asia) coupled with the surface
anomalous low (high) pressure anomalies assists the hot dry air
from desert regions that favor the occurrence of ETEs in different
regions of Saudi Arabia. A lead-lag relationship between
200 hPa geopotential height and ETEs in the Central region
of Saudi Arabia reveals a strong association between mid-latitude
circulation and ETEs. Moreover, an inverse relationship
between Tmax over Saudi Arabia and the El Nino Southern
Oscillation (ENSO) is found. The ENSO modulates the regional
Tmax anomalies over Saudi Arabia through the upper
level mid-latitude circulation.