Surface air temperature variability over the Arabian Peninsula and its links to circulation patterns

Abstract

This study investigates the long-term variability of surface air temperature (SAT) over the Arabian Peninsula (AP), using data from the Climate Research Unit (TS 3.22) for the 1960-2010 period. The long-term climatology suggests that the warmest AP mean temperatures occur during summer, with the highest temperatures over the northern AP (NAP), due to the monsoon-desert mechanism. During winter, the NAP exhibits low SATs under the influence of western disturbances originating from the Mediterranean. The southwestern AP exhibits the lowest temperatures because of its proximity to the Arabian Sea cold waters, and also because of the orographic effects. The inter-annual variability of the SAT is stronger during winters. A linear trend analysis reveals a significant increase in the SAT anomaly (0.10 C/decade) across the AP, consistently with the global temperature anomalies. Besides the local convective heating, summer SAT variability is associated with the weakening of the Asian jet stream and a Rossby wave train from the Indian Ocean. This variability is also influenced by the anomalous low pressure over the North Atlantic and the Sahara, a high-pressure system over Siberia and the northwest Pacific. Both in spring and autumn, sea surface temperature (SST) variations over the Indo-western Pacific are highly influenced the AP SATs, whereas winter SATs are modulated by the subtropical jet stream and the Middle East jet stream. In all seasons, the AP SAT is strongly influenced by the SST variations over the tropical oceans. The temperature variability is closely associated with the El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO) and Arctic Oscillation (AO). The warm phase of ENSO (i.e., El Niño) is one possible reason behind the inter-annual increase in SAT over the southern AP. The negative phases of NAO and AO also play a role in increasing AP SAT.

Prominent mode of summer surface air temperature variability and associated circulation anomalies over the Arabian Peninsula

“…The rate of decrease in temperature from the surface to the 750 hPa level is relatively lower than that of the above layers, suggesting the presence of an inversion layer at around 750 hPa level. In general, the summer SAT is high, owing to strong summer time solar insolation (being a cloud‐free region), strong adiabatic heating (large‐scale subsidence), and low thermal inertia of the dry desert soil (Yadav, ; ; Attada et al ., ). The vertical profile of the mean vertical velocity displayed an ascent from the surface to the lower troposphere (i.e., 700 hPa) due to surface heating, and a descent throughout the middle and upper troposphere.…”

“…Athar (2012) also noted a significant rise in the summer extreme temperatures in recent decades, and Hasanean and Almazroui (2016) reported an abrupt increase in surface air temperature (SAT) over the AP in the 1980s. Recently, Attada et al (2018b) suggested that the AP SATs gradually increased, particularly during the last decades. Very few efforts have been, however, investigated the dynamical factors behind the variations of the AP temperatures, despite several studies suggesting that the AP SATs are controlled by various large-scale circulation patterns (Hasanean and Almazroui, 2016;Attada et al, 2018b).…”

“…Recently, Attada et al (2018b) suggested that the AP SATs gradually increased, particularly during the last decades. Very few efforts have been, however, investigated the dynamical factors behind the variations of the AP temperatures, despite several studies suggesting that the AP SATs are controlled by various large-scale circulation patterns (Hasanean and Almazroui, 2016;Attada et al, 2018b).…”

Spatio‐temporal analysis for extreme temperature indices over the Levant region

“…For this study, the thresholds 30 and 25 C were applied for very summer days (SU30) and very tropical nights (TR25) indices, respectively, based on the long-term summer averages for T max and T min and in a detailed review of the literature for the surrounding regions such as the Arabian Peninsula and Saudi Arabia (Athar, 2014;Attada et al, 2019), Iran (Rahimzadeh et al, 2009;Rahimi and Hejabi, 2018) or Turkey (Erlat and Türkeş, 2013). A brief description and definition of each index are given in Table 2, and further details are available in Zhang et al (2011) and http:// etccdi.pacificclimate.org/list_27_indices.shtml.…”

Atlantic Ocean influence on Middle East summer surface air temperature

“…27 Several studies have examined the dominant modes of surface air temperature variability over different regions of Eurasia during different seasons, 28,29 including some studies specifically focusing on the Middle East-North Africa region. [30][31][32][33][34] The summertime climate variations of the ME were linked in these studies to various large-scale and regional processes, such as El Nino−Southern Oscillation, Indo−Pacific warm pool, tropical North and South Atlantic, Western Hemisphere warm pool, the North Atlantic and Arctic Oscillations, as well as the South Asian summer monsoon through the well-known monsoon-desert mechanism. 35 However, the spatial and temporal structures of the dominant mode of boreal summer ME-SAT, and particularly the main factors responsible for summer SAT anomalies related to the leading variability mode are less understood.…”