Abstract
Climate change has significantly influenced the characteristics of seasons and
negatively affected ecosystems and socio-economic life. This study presents a
new, objective definition for seasons in the Arabian Peninsula. Specifically, the
study determines disruptions in the onset, cessation, and duration of winter,
spring, summer, and autumn based on mean intra-annual changes of 12 climatological parameters from 1950 to 2019. Data for climatological parameters
were obtained from the National Centers for Environmental Prediction
(NCEP)/National Center for Atmospheric Research (NCAR) reanalysis. These
data were analyzed using two multivariate statistical methods: principal component analysis and cluster analysis. The results show that the characteristics
of the four seasons differ from conventionally defined seasons. The differing
characteristics of the four seasons are (a) that winter extends for 91 days,
between 2 November (the previous year) and 31 January; (b) spring extends
for 111 days, until 22 May; (c) summer extends for 106 days, until 5 September
and, finally; (d) autumn completes the cycle, extending for 57 days. To investigate the decadal disruption of seasons' characteristics, the analysis was
performed on the data collected during five overlapping 30-year periods: 1950–
1979, 1960–1989, 1970–1999, 1980–2009, and 1990–2019. The most remarkable
changes were noticed during the last 30 years. Compared to the 70-year analysis, the 1990–2019 analysis showed extra prolongation in the duration of summer and a shortage in winter, which aligns with the recent warming and
drying of the Arabian Peninsula. Summer (winter) lasts for 126 (76) days. All
analyses propose that all seasons start earlier, compared with the astronomical
definition. The findings of this study are key to understanding the consequences of seasons changes in the Arabian Peninsula. These consequences
include impacts on agriculture, water deficits, ecosystems, and land cover.
Keywords
Arabian Peninsula
Climate change
Cluster analysis
Principal component analysis
Seasons
classification