Coastal Arid Research Articles

The complete chloroplast genome of a centennial olive tree (Olea europaea, Oleaceae) from the southern Peruvian coast

Olive (Olea europaea Linaeus 1753) is one of the valuable fruit trees and very important edible oil plant in the world. The chloroplast (cp) genome of an olive tree (Olea europaea) from the southern Peruvian arid coast was obtained for the first time. Genomic DNA of high quality was used to generate librarieswith Illumina Hiseq paired-end methods. The cp genome is 155,886 pb in length and contains a large single-copy region (LSC) of 86,610 pb and a small single copy region (SSC) of 17,790 pb separated by two inverted repeat (IR) regions (25,741bp). The cp genome of olive contains 124 genes that consists of 80 protein-coding genes, 36 tRNA, eight rRNA. Phylogenetic analysis showed this olive tree is sister to O. europaea subsp. maroccana (Oleeae tribe). This study presents the first overview of the chloroplast genome organization and phylogenetics of O. europaea, offering valuable insights for genetic and evolutionary research in the genus Olea.

Performance Evaluation of Global Precipitation Datasets in Northern Mexico Drylands

Abstract Precipitation is a fundamental process in the hydrological cycle; hence, reliable and accurate information on the spatiotemporal rainfall distribution is critical for climate change modeling, local decision-making, and the development of climate adaptation policies. In Mexico’s drylands, the rainfall gauge network is highly heterogeneously distributed and frequently with incomplete datasets. Here, we examine how this deficient rainfall information can be best compensated by information derived from global precipitation datasets. We applied a performance evaluation of Climate Hazards Group Infrared Precipitation with Station data (CHIRPS), CFS-2, AgERA5, PERSIANN-CDR, and TerraClimate and compared these data with observed monthly precipitation records (1983–2018) for dryland regions associated with a network of Participatory Social–Ecological Observatories including Mediterranean climate in northwest (NW) Mexico, coastal arid climate in the Sonora Desert, and semiarid climate in the Chihuahua Desert. We compared monthly and annual rainfall of the global datasets with observed data with Pearson’s correlation coefficient, means, standard deviations, root-mean-square errors, and Taylor diagrams. The results indicate that CHIRPS and AgERA5 can reproduce the precipitation cycle at monthly and annual scales; also, the interannual variability is well captured. Our results suggest that for Mexican drylands, global precipitation datasets can be used to understand drought patterns, for hydrological modeling, for local decision-making, and for the development of urgently needed climate adaptation policies.

Molecular analysis reveals the evolutionary distinctiveness of the Silver-backed Chevrotain within the genus Tragulus

Abstract The Silver-backed Chevrotain (Tragulus versicolor), a mammal endemic to the unique coastal arid ecosystem in south-central Vietnam, is an enigmatic mouse deer with little information available about its ecology and evolutionary history. The recent rediscovery of the species provides a rare opportunity to clarify its taxonomy and phylogenetic relationship within the genus Tragulus. In this study, we sequenced the complete mitochondrial cytochrome b gene for samples of T. versicolor and T. kanchil from Vietnam. Our molecular results show that the species forms a distinct evolutionary lineage sister to all other species in the genus, confirming the earlier hypothesis based on morphological evidence. However, further research is needed to assess the genetic diversity of the species and design appropriate conservation measures. As the species has not been secured over much of its range, it is recommended that the population in Nui Chua National Park, the only one covered by a protected area, be prioritized for conservation actions. Conserving the species in this unique and imperiled ecosystem will also benefits a suite of locally endemic and threatened species of fauna and flora.

Assessment of Desertification Dynamics in Arid Coastal Areas by Integrating Remote Sensing Data and Statistical Techniques

Arid coastal regions are threatened by land desertification, which poses a serious threat to desert ecosystems, urban areas, and sustainability on a local as well as global scale. The present study aims to map desertification and the degree of its severity over the Jazan province on the western coast of Saudi Arabia. This investigation was conducted through the integration of remote sensing data (2001 and 2020) and statistical techniques. A scatter diagram, Karl Pearson correlation coefficient, and significance p-value test were performed on various spectral indices and tasseled cap transformation (TCT) derivative matrices to determine the strong significant relation of the spectral indices combination. Based on these analyses, the desertification degree index (DDI) was developed using a NDVI–TCG combination. The desertification grades were mapped and categorized into five classes, namely, non-desertification, low, moderate, severe, and extreme desertification. The results indicated that the spatial distribution of desertification grades declined from west to east during the period from 2001 to 2020. The degree of desertification improved during the study period since there was a significant reduction in extremely serious desertification land by 15.5% and an increase in weak desertification land by 7.8%. The dynamic changes in the DDI classes in the Jazan province mainly involve transformation from extremely serious to serious, serious to moderate, and moderate to weak, with areas of 2268.1 km2, 1518.5 km2, and 1062.5 km2, respectively. Generally, over the 19-year period, the restoration of vegetated areas accounted for 41.99% of the total study area, while desertification degradation land represented 15.57% of the total area of the Jazan province.

The camouflaged tsunami record of arid coasts: Looking for sand in the Atacama Desert

The camouflaged tsunami record of arid coasts: Looking for sand in the Atacama Desert

Groundwater Contamination in Arid Coastal Areas: Qatar as a Case Study.

The Arab region is located in an arid environment and suffers from water scarcity and poor water quality which are expected to become more severe in coming years due to global warming. In this study, the groundwater quality of 205 wells in Qatar was investigated. The physical parameters of pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, inorganic carbon (IC), and organic carbon (OC) were determined. The study characterized the concentrations of major anions of Cl, F, Br, NO3, PO4, and SO4, and major cations of Ca, K, Mg, and Na. Importantly, metals and metalloids including V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Pb, and U were determined. The results revealed that the groundwater of all wells is not drinkable due to high salinity (average TDS 4598 mg/L and salinity 0.4%, respectively). Additionally, average concentrations of major anions Cl, SO4, and F were 1472, 1064, and 1.9 mg/L, respectively, and all exceed the World Health Organization (WHO) guidelines for drinking water. However, NO3 concentration in 11 out of 205 wells was above the WHO guidelines of 50 mg/L due to intensive agriculture and fertilizer applications. Major cations of Ca, K, Mg, and Na were higher than WHO guidelines with average concentrations of 345, 63, 127, and 923 mg/L, respectively. All trace metals were much lower than the WHO guidelines for drinking water; however, the vanadium (V) average concentration in groundwater of all wells was 31 μg/L, which is five times higher than the Dutch guidelines (whereas the WHO has no guidelines for V). The groundwater of Qatar is dominated by Ca and Mg sulfates in Sabkha environments and dominated by NaCl in the coastal zones from evaporate environments consisting of coastal salt flats, salt pans, estuaries, and lagoons supersaturated by salts and the influence of sea water intrusion.

Transitions between different estuarine states in a low-inflow estuary of arid coasts (Mond Estuary, Persian Gulf) with a focus on freshwater lenses

This study shows that the Mond Estuary, Persian Gulf experiences notable time-dependent longitudinal salinity variations. Monthly-seasonal variability in salinity changes from a positive estuarine system in wintertime to inverse and salt-plug estuaries during summertime. A highly unsteady state (time scale of hours-days) occurs in the wintertime named the freshwater lens estuary (FLE), in which a low-salinity water mass (lens) is confined by both marine and riverine saltwater sources. Here, FLE dynamics is investigated using realistic and idealized numerical models and two 25-hour data sets collected immediately before a hypersaline runoff (weak FLE condition) and during another one (strong FLE condition). The Péclet Number (Pe) reveals a much stronger advective transports than diffusive one (Pe>5.7) throughout the estuary. An exception from this behavior (stronger mixing with Pe=0.8) is observed at the estuary downstream, where a significant amount of freshwater mixes with seawater during the weak FLE conditions. Also, the minimum hypersaline runoff of ∼400 m3/s estimated by the numerical model can dampen tidal waves at the head of the estuary. In an idealized basin, the model shows that FLE longitudinal flows form two cells of positive estuarine circulation separated by a maximum mixing zone (the potential energy anomaly <0.75 J/m3). In the Mond Estuary, a sea-level rise of 20 cm increases salinity in the FLE state and the positive estuary during winter. Conversely, it decreases salinity in the inverse and salt-plug estuaries in summer.

Geometry for low-inertia aerosol capture: Lessons from fog-basking beetles.

Water in the form of windborne fog droplets supports life in many coastal arid regions, where natural selection has driven nontrivial physical adaptation toward its separation and collection. For two species of Namib desert beetle whose body geometry makes for a poor filter, subtle modifications in shape and texture have been previously associated with improved performance by facilitating water drainage from its collecting surface. However, little is known about the relevance of these modifications to the flow physics that underlies droplets' impaction in the first place. We find, through coupled experiments and simulations, that such alterations can produce large relative gains in water collection by encouraging droplets to "slip" toward targets at the millimetric scale, and by disrupting boundary and lubrication layer effects at the microscopic scale. Our results offer a lesson in biological fog collection and design principles for controlling particle separation beyond the specific case of fog-basking beetles.

An enhanced drought forecasting in coastal arid regions using deep learning approach with evaporation index

Coastal arid regions are similar to deserts, where it receives significantly less rainfall, less than 10 cm. Perhaps the world's worst natural disaster, coastal area droughts, can only be detected using reliable monitoring systems. Creating a reliable drought forecast model and figuring out how well various models can analyze drought factors in coastal arid regions are two of the biggest obstacles in this field. Different time-series methods and machine-learning models have traditionally been utilized in forecasting strategies. Deep learning is promising when describing the complex interplay between coastal drought and its contributing variables. Considering the possibility of enhancing our understanding of drought features, applying deep learning approaches has yet to be tried widely. The current investigation employs a deep learning strategy. Coastal Drought indices are commonly used to comprehend the situation better; hence the Standard Precipitation Evaporation Index (SPEI) was used since it incorporates temperatures and precipitation into its computation. An integrated coastal drought monitoring model was presented and validated using convolutional long short-term memory with self-attention (SA-CLSTM). The Climatic Research Unit (CRU) dataset, which spans 1901–2018, was mined for the drought index and predictor data. To learn how LSTM forecasting could enhance drought forecasting, we analyzed the findings regarding numerous drought parameters (drought severity, drought category, or geographic variation). The model's ability to predict drought intensity was assessed using the Coefficient of Determination (R2), the Root Mean Square Error (RMSE), and the Mean Absolute Error (MAE). Both the SPEI 1 and SPEI 3 examples had R2 values more than 0.99 for the model. The range of predicted outcomes for each drought group was analyzed using a multi-class Receiver Operating Characteristic based Area under Curves (ROC-AUC) method. The research showed that the AUC for SPEI 1 was 0.99 and for SPEI 3, 0.99. The study's results indicate progress over machine learning models for one month in advance, accounting for various drought conditions. This work's findings may be used to mitigate drought, and additional improvement can be achieved by testing other models.

Foraminiferal assemblages and organic matter relationships in a coastal lagoon of the arid coast of the Southeast Pacific

Foraminiferal assemblages and organic matter relationships in a coastal lagoon of the arid coast of the Southeast Pacific

Population Trends of Waterfowl on the Arid Coast of the Western Caspian During the Epoch of Climate Warming

Population Trends of Waterfowl on the Arid Coast of the Western Caspian During the Epoch of Climate Warming

Techno-economic feasibility of marine eco-parks driven by wave energy: A case study at the coastal arid region of Mexico

Coastal arid regions face significant challenges in ensuring energy, water, and food security. Given the urgency of meeting these demands, it is necessary to consider innovative solutions that enhance adaptive capacity and sustainable development of coastal zones. Harnessing wave energy has become a potential ocean renewable resource that can provide significant benefits to mitigating coastal vulnerability and climate change. However, most wave energy projects still face different challenges that limit their financing and commercial deployment. This paper aims to evaluate the techno-economic feasibility of 0.5 MW Marine Ecoparks as maritime clusters coupled with wave energy converter, seawater desalination, and marine aquaculture modules to produce the water-energy-food nexus and boost, symbiotically, the viability of the wave energy sector and the blue economy in the arid coastal communities of Baja California, a Mexican Pacific region with a mid-wave energy resource. Based on technical and economic data available in the literature, the cost estimates and the contribution of each coupled module to the Marine Ecopark profitability were carried out and compared against other forms of energy generation using different current and projected 2030 market scenarios. All the cases analyzed show that the Pelamis device generates higher techno-economic performance than the WaveDragon. While individual wave energy devised siting is not profitable, economic scaling in increases maritime clusters' profitability. Optimally selected Pelamis facilities attain capacity factors over 40 % and a Levelized Cost of Energy of 480 $/MWh. The coupled seaweed aquaculture module generates the highest water-energy-food nexus profitability, whereas seawater desalination is not economically viable. All wave energy farms show a decrease in estimated electricity cost by 2030, reaching 198 USD/MWh for the most competitive Pelamis farms.

Design of Noble-Metal-Free Membrane Electrode Assemblies Based on Metal Chalcogenides for Electrochemical Hydrogen Production Via Alkaline Seawater Electrolysis

The production of large amounts of green hydrogen (H2) by electrochemical water splitting represents one of the key pillars to reach net-zero by 2050. As one of the major drawbacks, both low-temperature proton-exchange membrane (PEM) as well as anion-exchange membrane (AEM) electrolysis still rely on the utilization of noble metals in the catalyst layers driving the evolution of H2 and oxygen (O2) on the cathode (HER) and on the anode (OER), respectively. Beyond that, the requirement for highly pure water feeds to prevent degradation of the cell performance over time was previously addressed as one of the main concerns. In particular, this holds true for arid regions located close to the ocean. Advantageously, these coastal arid zones provide essentially unlimited access to seawater, coupled with ample solar irradiation and wind throughout the entire year.[1]One of the major challenges for direct seawater electrolysis lies in the development of selective catalysts, especially for the anode due to the inherently faster reaction kinetics of the competing two-electron chlorine evolution reaction (ClER). Nickel-iron layered double hydroxides (NiFe-LDH) were identified as active and selective OER electrocatalysts in a previous study[2] by our group. Dionigi et al.[3] recently reported a general design principle for selective seawater electrolysis, in which alkaline pH values > 7.5 are claimed to favor OER over ClER for overpotentials < 480 mV.At the cathode, state-of-the-art electrolyzers utilize Pt-based catalysts for an efficient HER.[2] For direct seawater electrolysis, however, not only the high cost but also the weak stability due to chloride-induced corrosion restrict the applicability of Pt-based electrodes. In our contribution, we thus present noble-metal free catalyst materials based on metal chalcogenides with high HER activity and improved stability in alkaline seawater electrolyte in a single-cell electrolyzer setup. Membrane-electrode assemblies (MEAs) with superior corrosion-resistance by a modification of the porous transport layers (PTLs) for both cathode and anode will be presented, which outperform reference MEAs containing Pt-based cathodes in alkaline seawater electrolysis. The optimized noble-metal-free electrode design (fig. 1) combined with well-controlled electrolyte feeding enables alkaline seawater electrolysis operating at industrially relevant current densities.

Feeding behaviour and food preferences of native and introduced snail species from the Lomas formations, threatened seasonal fog oases

The Lomas formations are ephemeral seasonal oases found along the Pacific arid coast of South America. Whereas fast-growing plants are characteristic in the Lomas, other organisms such as land snails are also conspicuous. In the Lomas, several snails can occur sympatrically and therefore they might have adapted their food requirements to the limited available items while avoiding competing for food (resource partitioning). Since the dietary items and food preferences of Lomas’ snails are almost completely unknown, our study aimed to document these in three snails occurring sympatrically, two native (Succinea peruviana and Bostryx conspersus) and one introduced (Cornu aspersum) species in Lomas de Lucumo, a threatened Lomas from Central Peru. We recorded the snails’ activity, host, and food items. We also carried out dual-choice bioassays to evaluate the feeding preferences of B. conspersus and C. aspersum when offered leaf disks of the two dominant plant Lomas species, Senecio abadianus and Sicyos baderoa. Whereas we were unable to record any food item used by C. aspersum, we recorded the two native Lomas species (B. conspersus and S. peruviana) having contrasting patterns of feeding as they were on different hosts (plants vs soil) and food items (vascular plants vs. lichens/organic material/mosses/algae). Although the feeding preferences were similar between B. conspersus and C. aspersum (i.e., both species preferred the leaves of Si. baderoa over Se. abadianus), C. aspersum, after feeding stimulation, consumed significantly less leaf area of Se. abadianus than B. conspersus. Sicyos individuals are fast-growing plants and might be less herbivore-resistant, while Senecio species are characterized to produce defensive alkaloids which make plants less palatable. Our results indicate that Lomas’ snail species have evolved distinct trophic niches by partitioning the limited food resources and native herbivorous species are better adapted to feed on Lomas’ native plants given their common evolutionary history.

Geochemistry and assessment of groundwater resource in coastal arid region aquifer (Dahab delta, South Sinai, Egypt)

Dahab is a tourist city located in the Sinai Peninsula, downstream of the Dahab watershed, as a part of the arid coastal region. Groundwater samples have been collected from the Dahab delta and were tested for salinity, major ions, minor elements, and heavy metals to investigate the geochemical processes deteriorating the groundwater quality. The spatial distribution of major, minor, and trace elements integrated with the geochemical interrelationships using the cumulative salinity bases mixing curves have been utilized to investigate the main source(s) of groundwater recharge and salinization origin in Dahab delta aquifer. The groundwater salinity ranges from 339 upstream of Dahab watershed to 53,216 mg/L downstream in the delta area. The groundwater varies from fresh, brackish, and saline water. The spatial distributions of major ions, minor elements (Si, and Br), and heavy metals (B and Sr) confirm that the recharge comes from the upstream watershed. According to the mixing model curves, groundwater quality has declined due to interactions with the aquifer matrix, mixing with seawater, and rejected brine from the reverse osmosis desalination plants. The fresh/brackish groundwater classes have been recorded in the northwestern part of the study area close to the basement rocks, where the Quaternary aquifer receives considerable recharge through the underneath fractures, joints, and faults that enhance the subsurface recharge. The samples with a high saline groundwater class have been recorded in the eastern and southern parts of the delta, demonstrating the effects of seawater intrusion. Based on WHO guideline criteria, the assessment of groundwater for various uses has determined that most groundwater samples from the alluvial aquifer (91%) are unfit for human consumption. The Water Quality Index indicates that the groundwater in the southern part of the delta is not suitable for all uses due to mixing with the seawater, and injection of rejected brine water from the desalination plants. In the north, groundwater is unfit for drinking and aquatics, excellent for recreation, marginal for irrigation, and fair for livestock. The groundwater in coastal arid region aquifers has deteriorated due to seawater intrusion.

Assessment of groundwater hydrogeochemical characteristics and salinization intrusion in coastal arid area (South Gabes, South-East Tunisia)

In the southern region of Gabes, groundwater is experiencing a quality deterioration in relation to the increase in demand to meet the various sectors of economic and agricultural activities. Indeed, the degradation of quality generally results in high concentrations of total dissolved solids, ranging from 2.44 to 13.68 g/L, and waters contamination by nitrates. The determination of the groundwater salinity origin from Gabes, largely influenced by tectonics, was approached from the study of the evolution in the space of major chemical elements and by statistical treatment. Based on these methods, this work aims to demonstrate that the high waters’ salinity in this aquifer is explained by an interaction between its waters and the evaporitic levels of the aquifer formation, by the marine intrusion around the El Hajel Wadi, and by the return of irrigation water to the Mareth-Arram region. The hypothesis of marine intrusion is justified by the high chloride content due to the presence of reverse reactions of cation exchange. Geochemical interactions (reverse basic exchanges and precipitation/dissolution phenomena of minerals from the aquifer formation) show that these waters have poor to bad quality.

Geophysical studies to delineate groundwater aquifer in arid regions: A case study, Gara Oasis, Egypt

Groundwater is an important factor in establishing new urban communities, especially in coastal arid and semi-arid regions. Egypt is one of the world's driest countries, with hyper-arid territory accounting for 86% of the total area and arid and semi-arid terrain accounting for the rest. The present work aims to demonstrate the powerful integration of geophysical techniques to assess groundwater potentiality and suitability in Gara Oasis (GO), which describes a good example of Egypt's strategic southern extension of its arid north-western coast. Geophysical methods, including electrical resistivity and aeromagnetics, were used to evaluate groundwater resources. The study region reduced to pole total magnetic intensity map is subjected to digital filters that include derivatives, analytic signal, and tilt angle. The possible structures controlling the shallow and deep aquifers are delineated and integrated with geoelectric results. Moreover, two magnetic tomography sections are constructed to show the subsurface distribution of magnetic susceptibilities and formation boundaries. Ten vertical electric soundings (VESs) are measured and used in this study to construct four geoelectrical cross-sections. According to the results, Gara's commonly calculated subsurface resistivity model comprises six major resistivity layers. The 5th layer, in particular, is composed of Fractured dolomitic Limestone and represents a possible promising shallow aquifer. Moreover, as evidenced by various magnetic data filters, the shallow (Miocene carbonate) and deep (Nubian sandstone) aquifers are structurally controlled and regulated by a system of faults or contacts. These contacts trends NW–SE, E–W, and NE–SW as common trends emerged from the total derivative and tilt maps. Results suggest that the central part (N–S zone) together with the western side of Gara, have the most notable aquifer possibility demanded future improvement strategies.

Changes in the moisture contribution over global arid regions

Arid regions have deficient precipitation, understanding the sources and transportation of moisture for precipitation are crucial. This study examined the major moisture contributions for global six arid regions, which are classified as inland arid region (China-Mongolia) and coastal arid regions (North Africa, West Asia, West United States, South Africa, South Africa and Australia). Results indicated that, the moisture for precipitation in coastal arid regions originates mostly from the ocean, which is influenced by the general circulation, particularly by the sinking branch of the Hadley cell. For inland arid region (China–Mongolia), the surrounding mountains supply more than 150 mm of moisture in wet months due to the ablation of glacial and snow melting. In arid regions, the moisture for precipitation is mostly contributed by advection of large-scale circulation, while the contribution of local moisture recycling is secondary. The moisture available for precipitation in wet and dry months depends on the general circulation. Moisture transportation in wet months is 10 times more than that in dry months, and the moisture sources differ greatly in wet and dry months. In both wet and dry months, the external moisture transported into arid regions has significantly decreasing trend during the period 1990–2019. The decreasing trend of precipitation recycling ratio in arid regions are greater than that in the globe. The decreased precipitation and moisture in arid regions suggest a potential drying trend.

Techno-environmental Simulations for Solar Energy-Powered Seawater Reverse Osmosis Desalination for a Hyper Arid Coastal Region

This study investigates the efficiency of a solar-powered seawater desalination plant (DP) using reverse osmosis for an arid coastal region. The solar models are investigated using local meteorological data, including direct, diffused and global irradiance. The meteorological data are obtained using local typical meteorological data set collected from a ground weather station. The PVsyst simulation tool is used to model a grid-connected solar PV system utilizing three photovoltaic (PV) technologies: thin-film, monocrystalline, and polycrystalline. Three scenarios were considered: restricted area, daily water production and design capacity. The optimum configuration for the restricted area scenario at the seawater DP location considered is an on-grid thin-film module (170 W) with a tilt angle of 20° and an inverter unit of 2000 kW. The solution module area is 15,248 m2. The annual electricity production will be approximately 4251.1 MWh/y, which represents only 3.1% of the DP demand. Thin-films produce higher annual electricity than monocrystalline and polycrystalline silicon by 8.3% and 5.9%, respectively, but require 15.9% and 5.7% more space than monocrystalline and polycrystalline silicon, respectively. For Shuwaikh DP, a 30 MIGD DP will require a PV system with a capacity of 120 MWp at 30° tilt angles and 60 inverters. The design environmental impact was assessed using life cycle assessment (LCA). The carbon footprint will decrease from 7.3 x10-5 to 1.8 x10-5 (kg CO2 equivalent), for the 30 MIGD production. The fossil fuel depletion will decrease by approximately 80%. However, the large number of solar panels and the significant total ground area required for the 30 MIGD. The solar array of 1,531,054 m2 will adversely affect the urban land occupation impact category by 84% and will increase metal depletion by 37%.The response surface optimization indicates that the optimal performance in the coastal region for power desalination plants is achieved when using a thin-film at a tilt angle of 20 o.

Comparisons of climate change characteristics in typical arid regions of the Northern Hemisphere

In recent years, with the frequent occurrence of severe drought events, climate change in arid regions has become one of the research hotspots. However, previous studies mainly focused on a specific arid region, and the correlations and differences of drought among various arid regions have not been clearly understood. In this study, based on the latest monthly gridded dataset of the CRU, we compare the characteristics of climate change and its relationship with large-scale oceanic oscillation indexes in the three typical arid regions of Pan-Central-Asia (PCA), North America (NAm) and North Africa (NAf) in multiple perspectives. The results show that the precipitation in the PCA and NAm has increased obviously over the past 80 years, while the NAf precipitation has decreased. After the 1980s, the climate in the PCA and NAm show warm-wet types. This type of the former continues to the present, but the latter’s has changed to a warm-dry type since the 21st century. The NAf climate remains the warm-dry type since the 1990s. Nonetheless, the arid and semi-arid climate patterns in the three typical arid regions remain unchanged. The NAm precipitation has an anti-phase variability pattern compared with the NAf precipitation on both interdecadal and multi-decadal time scales. The Pacific Decadal Oscillation (PDO) has a great influence on the precipitation of the PCA and NAm. The temperature of three arid regions is significantly related to the variations in the Arctic oscillation (AO). In the inland arid region, the contribution of strong warming effect during cold season to the whole year is much greater than that during warm season, while the contribution of the coastal arid regions in warm season is greater. The precipitation in the mid-latitude arid regions is dominated by cold-season precipitation regardless of whether these regions are near the sea or not. The precipitation in the low-latitude arid regions has little difference between cold and warm seasons.