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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]

To raise awareness of the potential of passive technologies, this paper addresses the major problem of maintaining the comfort of the built environment in the harsh climate of Saudi Arabia by estimating the potential reduction in residential building energy consumption resulting from the use of highly reflective "cool roof" details. To conduct this estimate, the impacts of cool roof installation on the cooling and heating loads of residential buildings in 13 major selected sites in Saudi Arabia are estimated. It is found that the use of a cool roof reduces the annual energy consumption required for building cooling by between 110.3 and 181.9 kWh/m2, while the maximum increase in annual energy consumption due to winter heating of cool roof equipped buildings in hot-dry climates is only 4.4 kWh/m2. The results show that installing a cool roof in place of a typical or dirty roof yields a reduction in peak roof conduction. This investigation concludes that the use of the passive cool roof technology is an effective method for improving the thermal performance of a roof and thus reducing building energy consumption in the harsh climate of Saudi Arabia and similar extreme climates. [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]

The paper proposes a low carbon domestic design framework for sustainable homes in Saudi Arabia, characterized by a rigorous climate and unique regional socio-cultural features. This is informed by (a) an in-depth investigation of the Saudi domestic building stock, including landscaping, massing, space layout, building fabric, on-site renewable potential, and occupants’ lifestyles; and (b) a consultation with 40 experts across Saudi Arabia. The consultation was carried out using the Delphi Technique in multiple rounds. The established framework factors in architectural design strategies, building envelope design, and on-site renewable energy strategies for Saudi Arabia, taking into account socio-cultural considerations. A consensus between the consulted experts was achieved. The proposed framework is applicable and suitable for Saudi Arabia and beyond, including the Middle Eastern 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]

The relationship between the Mediterranean 500-hPa storm tracks and wet season (November-April) rainfall over Saudi Arabia is investigated. The analysis is based on the application of an objective tracking scheme to the 6-hourly 500-hPa geopotential height ERA-Interim dataset (0.75° × 0.75°) for the period 1979-2012. The resulting tracks are then associated with the ERA-Interim rainfall events over Saudi Arabia. The association procedure showed that 34 % of the tracks are related to about 70 % of the rainfall. These associated tracks are used to construct climatology. A climatology of these storm tracks revealed that the eastern Mediterranean region is the preferred location for cyclogenesis with a maximum in the southwest parts of the Black Sea. The study also examined the mean radius, average intensity and average depth of the storms. The number of tracks in winter (December-February) is about 60 % of the total number which confirms the major contribution of the Mediterranean storms to rainfall over Saudi Arabia. A significant negative trend was found for storm cyclogenesis over the central Mediterranean, and the Black sea. A significant trend decrease in track density is observed over most of the northern parts of Saudi Arabia. The peaks of storm activities are observed in December and January in 1996, 1997 and 2009. Storm activity generally declines after 2000, especially in the second half of the wet season months (February-April). [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]

Energy simulation and modeling in buildings require annual hourly weather data. The accuracy and completeness of the data are vital to assess annual energy performance of building and to evaluate alternative building design strategies. Weather stations in Saudi Arabia conduct and archive weather data measurements for major cities and Airbases. However, these data are summaries or incomplete and in varying formats. In the first part of the present work, weather data were synthetically generated (Synthetic Metrological Year) by using METEONORM 7.0 (MN7), for the cities such as Riyadh, Jeddah, Dhahran, Tabuk, and Khamis, which represent Central, Upland, Northern, Western, and Eastern regions of Saudi Arabia. The weather parameters measured were dry bulb temperature (Ta), global solar radiation (Gh), relative humidity, and wind speed. The MN7 data were compared with the corresponding national Presidency of Meteorology and Environment (PME) data, and observed that in many cases the MN7 data needed proper scrutiny and rectification in order to maintain conformity with the actual data. Therefore, a Microsoft Excel-based normalization procedure was applied to make the MN7 data consistent with the corresponding PME data. It was found that the proposed normalization technique could rectify all the discrepancies of MN7 data and bring them excellently close to the PME data. [ABSTRACT FROM AUTHOR]

ABSTRACT Long-term changes in seasonal temperature extremes based on daily data across Saudi Arabia for the period 1981-2010 are analysed by assessing the trends for the four conventional seasons. Surface observations of daily maximum and minimum temperatures from high-quality datasets at 27 stations are used as the input. The trend throughout each season is then derived by employing Sen's slope estimator to four extreme value indices, four relative indices and three mean value indices. Warming trends for extreme value indices are observed for the majority of stations, particularly significant (at 95% level) in spring and summer seasons, however, mixed increase/decrease trends are found for the cold temperature extremes in autumn and winter seasons. Relative indices show significant warming trends for the majority of stations in all seasons; however, strong warming (above 5 days decade−1) is witnessed in the spring, summer and autumn seasons. The rapid rise (fall) of the number of warm (cool) days compared to warm (cool) nights is observed in the winter, summer and autumn (winter and spring) seasons. Warming of cool/warm nights is insignificant for the majority of stations in winter. The national average of mean value index diurnal temperature range shows an increasing trend for all seasons; however, its mixed increase/decrease trends are observed for the majority of stations in summer and autumn seasons. Time series analysis reveals that irrespective of seasons, warming is clearly visible in Saudi Arabia after 1997. Variations of warming for different regions across the country are also noticed. [ABSTRACT FROM AUTHOR]

One consequence of climate change is change in the phenology and distribution of plants, including the date palm (Phoenix dactylifera L.). Date palm, as a crop specifically adapted to arid conditions in desert oases and to very high temperatures, may be dramatically affected by climate changes. Some areas that are climatically suitable for date palm growth at the present time will become climatically unsuitable in the future, while other areas that are unsuitable under current climate will become suitable in the future. This study used CLIMEX to estimate potential date palm distribution under current and future climate scenarios using one emission scenario (A2) with two different global climate models (GCMs), CSIRO-Mk3.0 (CS) and MIROC-H (MR). The results of this study indicated that Saudi Arabia, Iraq and Iran are most affected countries as a result of climate change. In Saudi Arabia, 129 million ha (68%) of currently suitable area is projected to become unsuitable by 2100. However, this is based on climate modelling alone. The actual decrease in area may be much smaller when abiotic and other factors are taken into account. On the other hand, 13 million ha (33%) of currently unsuitable area is projected to become suitable by 2100 in Iran. Additionally, by 2050, Israel, Jordan and western Syria will become climatically more suitable. Cold and heat stresses will play a significant role in date palm distribution in the future. These results can inform strategic planning by government and agricultural organizations to identify areas for cultivation of this profitable crop in the future, and to address those areas that will need greater attention because they are becoming marginal regions for date palm cultivation. [ABSTRACT FROM PUBLISHER]

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]