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A dust storm is the main attenuation factor that can disturb receiving radio signals in arid climate condition as in Saudi Arabia. This paper presents a study on the effect of dust storms on the received radio frequency power in a homogenous environment in the city of Riyadh. A number of micrometer and millimeter wave links have been considered along with several measured dust storm data to investigate the dust storm effects. The results showed that dust storm can critically influence the communication link and this effect grows up as the physical distance between the transmitter and the receiver increases. The negative effect of the dust storm apparently appears at highfrequency bands allocated for the next communication generation (5G) which imposes finding solutions to mitigate the effects of this phenomenon. [ABSTRACT FROM AUTHOR]

This paper investigates the temperature and precipitation extremes over the Arabian Peninsula using data from the regional climate model RegCM4 forced by three Coupled Model Intercomparison Project Phase 5 (CMIP5) models and ERA–Interim reanalysis data. Indices of extremes are calculated using daily temperature and precipitation data at 27 meteorological stations located across Saudi Arabia in line with the suggested procedure from the Expert Team on Climate Change Detection and Indices (ETCCDI) for the present climate (1986–2005) using 1981–2000 as the reference period. The results show that RegCM4 accurately captures the main features of temperature extremes found in surface observations. The results also show that RegCM4 with the CLM land–surface scheme performs better in the simulation of precipitation and minimum temperature, while the BATS scheme is better than CLM in simulating maximum temperature. Among the three CMIP5 models, the two best performing models are found to accurately reproduce the observations in calculating the extreme indices, while the other is not so successful. The reason for the good performance by these two models is that they successfully capture the circulation patterns and the humidity fields, which in turn influence the temperature and precipitation patterns that determine the extremes over the study region. [ABSTRACT FROM AUTHOR]

Objective: This study aims to explore the resident's perspectives of the training climate and the different learning domains within the Saudi Residency Training Program of Emergency Medicine using the Dutch Residency Educational Climate Test (D-RECT). Methods: A cross sectional survey was conducted using email to all residents of the Saudi Residency Training Program of Emergency Medicine in Riyadh. The survey consisted of the validated Dutch Residency Educational Climate Test (D-RECT). The responses received from the participants were analyzed using JMP. ANOVA and the reliability test were applied after determining Cronbach's alpha. Results: Ninety residents out of 215 responded to the survey. Males represented 57% of the sample with equal distribution of residents across the years of training. The overall D-RECT score was 3.51 ± 0.46. The training climate scored very well (>4) for the following subscales: Teamwork, peer collaboration, and formal education. The training climate did poorly on the scale for the item of Feedback (<3). All the other items were within an average score of 3-4. Cronbach's alpha was calculated to be above 0.6 in all scales. Conclusion: The study shows that the emergency training program has a relatively good training climate with the need to improve on feedback for residents. Possible options to improve feedback are discussed in the article. In addition, the D-RECT score offers a good method of monitoring the training climate. [ABSTRACT FROM AUTHOR]

Annual rainfall records of 20 stations for 30 years are used in order to detect rainfall regimes and climatic features of Saudi Arabia using harmonic analysis techniques. In this study, the percentages of variance, amplitudes, and phase angles are calculated in order to depict the spatial and temporal characteristics of the country's rainfall. The first harmonic explains 42 % of rainfall variation in the western (W) region. This percentage increases toward east (E) and north (N) with 69 and 67 %, respectively. In the southwest (SW) region, the percentages explain 43 % of rainfall variation. The percentages of variance in W and SW are lower than in the E, NW, and central (C) regions. This implies significant contributions of the second harmonic in W and SW regions with 26 and 16 %, respectively. The high percentages of the second and third harmonics in W and SW regions suggest that these two regions are affected by different weather systems at different times. The SW region has the highest amplitudes of the first, second, and third harmonics. The amplitude of the first harmonic reaches to 21 mm in SW and 9 mm in both C and E regions. The time of maximum rainfall is calculated using phase angle; the result reflects that maximum rainfall is shifted forward on the time axis toward the spring season in SW and C regions, January in E and NW regions, and October and November in the W region. This reveals that the SW region is a completely different climatic region, though some of what affects this region also affects the central region. Conditions in the E and NW regions are mainly affected by Mediterranean weather systems, while the W region is affected by unstable conditions caused by the active Red Sea Trough (RST) in October and November. [ABSTRACT FROM AUTHOR]

Solar radiation is the most important parameter in defining the energy budget at the surface thereby influencing the hydroclimate. Several empirical models based on air temperature are developed and used in several decision-making needs such as agriculture and energy sector. However, a calibration against direct observations is a priori for implementing such models. A calibrated model is developed for Saudi Arabia (Madinah) based on observations during 2007-2011. The model $$ \left( {\mathrm{Rs}=A+B\cdot \mathrm{R}{{\mathrm{s}}_0}{{{\left( {{T_{\max }}-{T_{\min }}} \right)}}^C}} \right) $$ is used to estimate daily solar radiation and results show a correlation coefficient of 0.94. The calibrated model outperforms the uncalibrated model available for this location. To increase the confidence, the calibrated model is also compared with a simple artificial neural network. [ABSTRACT FROM AUTHOR]

a step towards the adoption and use of the regional climate model (RegCM3) for the simulation of intense rainfall events over the Arabian Peninsula, this study examines its sensitivity to domain size, boundary location, forcing fields, and resolution. In the climatological results, RegCM3 performs well in reproducing the annual and the seasonal mean precipitation as well as the contrast between wet and dry years in terms of the amounts and locations of the rainbands. In addition, simulations are performed for two cases of intense rainfall events in the Jeddah area and surroundings using a combination of three domains and two boundary forcings at 50 km. The results show that different combinations of these parameters provide different skills for the regional model. However, RegCM3 performs relatively better when ERA40 (NNRP2) is used at the boundaries in the smaller domain (larger domain), indicating the importance of the stronger (relatively weaker) influence of boundary forcing needed to capture these intense rainfall events around Jeddah. This may be explained by the fact that around that region, RegCM3 produces, in the smaller domain, higher relative humidity and stronger wind vectors closer to the reanalyses when nested within the ERA40, while it shows its best performance with the larger domain when driven by NNRP2. It is also shown that the use of high resolution does not systematically improve the simulation of such events, although some encouraging results were produced. [ABSTRACT FROM AUTHOR]

A diagnostic study of atmospheric moisture data over Saudi Arabia derived from a 43-yr National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis revealed that moisture convergence in the lower troposphere and divergence in and above the middle troposphere occurs throughout the year. Although the amount of precipitable water content in the middle troposphere is high, precipitation is less than expected over this semiarid region during a boreal summer monsoon season because of strong moisture divergence. The net tropospheric moisture flux over the arid and semiarid regions of Saudi Arabia shows seasonal and interannual variability. The seasonal variability has a strong semiannual signal with its primary peak February–April and its secondary peak June–August. This pattern is consistent with a similar semiannual signal observed in rainfall climatology. The restricted moisture supply to southwestern Saudi Arabia during summer presumably explains the lack of precipitation in other areas of the country. Winter precipitation, however, is widespread. The increased transport of net atmospheric moisture flux is higher during El Niño and positive Indian Ocean dipole (IOD) phenomena. During these events, influx across the Red Sea (west) side of Saudi Arabia increases. The net flux to the region is reduced by a slight increase of outflux across the Persian Gulf (east) side. Reanalysis data and model-sensitivity experiments show that El Niño or a concurrent positive IOD and El Niño event more strongly amplify net transport than does an independent positive IOD event. The partial-lag correlation analysis with net moisture flux from the Red Sea side shows that the positive IOD mode has a peak correlation coefficient of ∼0.5 with close to a 5-month lead and that El Niño has a peak correlation coefficient of ∼0.6 with close to a 2-month lead. [ABSTRACT FROM AUTHOR]

As global temperatures warm and populations and incomes rise, the demand for cooling will soar, creating a positive feedback loop between global warming and electricity-related carbon dioxide (CO2) emissions. This study explores the relationship between temperature, electricity, air conditioning (AC) and CO2 emissions, and the sustainability of cooling in the Kingdom of Saudi Arabia. With the highest share of AC in household electricity consumption in the world and its already very hot summers warming by 3 °C in many areas over the last 40 years, Saudi Arabia provides an important case study of how the cooling challenge can be managed. Data from the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5) is used to illustrate local warming trends (1979–2018) and show the relationship between temperature and power generation within a typical year using hourly data (2011–2015). Using annual data (2010–2018), we then show that since 2016 the rapid growth in the Kingdom's electricity demand for AC and its associated CO2 emissions have plateaued. This suggests energy efficiency measures, higher electricity prices and a shift from the use of oil towards gas in the power sector are having a positive effect on energy sustainability. We identify key policies and technologies that will be important for the sustainable use of cooling in Saudi Arabia and beyond. [ABSTRACT FROM AUTHOR]