Atmósfera (Journal)
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Influence of ENSO and SAM on the occurrence of absolute extremes and behavior of Ta, SST, and SIC anomalies in the western Antarctic Peninsula
Full text linkThis study aims to improve the understanding of the interaction between El Niño-Southern Oscillation (ENSO) events and the phases of the Southern Annular Mode (SAM), as well as their influence on the western Antarctic Peninsula (WAP). Monthly series of air temperature (Ta), sea surface temperature (SST), and sea ice coverage (SIC) from 1981 to 2020 were analyzed at six representative points within the study area. Ta, SIC, and SST data were obtained from the ERA5 database. The Southern Oscillation Index (SOI) and Antarctic Oscillation Index (AAOI) were sourced from NOAA’s Climate Prediction Center. The spectral density of the anomaly series for each variable was calculated, and the characteristic cycles of SAM and ENSO were extracted. The most influential components driving the oscillations of the studied series were identified. A cross-correlation analysis was conducted between the anomaly components of Ta, SIC, and SST and those of SOI and AAOI. The results indicate that Ta series exhibit moderate positive correlations with SAM, particularly between the 5.2-year quasi-period of AAOI and the 4.4-year quasi period of Ta in the Drake Passage and Bransfield Strait. The SST series in Bransfield correlate with AAOI5.2, while the quasi-periods of 4.6 and 5.2 years in the Drake Passage correlate with SOI3.5. The SIC series show positive correlations with the 3.5-year quasi-period of SOI for lag times greater than one year, except in the Bransfield Strait. Extreme absolute Ta and SST events in the WAP region are strongly influenced by SAM and ENSO. It is concluded that the coupling of ENSO and SAM phases amplifies their effects on meteo-marine variables
A quantitative study of extreme rainfall intensity and occurrence in northern Algeria
Full text linkThis paper examines the characteristics associated with the spatiotemporal evolution of extreme precipitation, assesses its recurrence frequency, and predicts future return levels over northern Algeria. The study employs extreme precipitation indices in conjunction with the application of extreme value theory to a rainfall dataset spanning from 1982 to 2022. The study focused on modeling the index that demonstrated the highest percentage of significant positive trends at the α = 0.05 significance level. This was accomplished through the utilization of the Mann-Kendall test and the generalized extreme value distribution. Subsequently, the model was validated using the Kolmogorov-Smirnov fit test. The results revealed that the northeastern region of the study area experienced a more pronounced increase in rainfall intensity compared to the southern and western regions. Significant trends in precipitation intensity were observed over time. Notably, the index of days with rainfall exceeding 20 mm demonstrated the highest percentage of positive trends, with 88% of meteorological stations exhibiting an upward trend. Furthermore, a strong correlation was identified between the index of days with rainfall exceeding 20 mm and the very wet days index, particularly in the high plateaus and western region. This finding supports the hypothesis that extreme rainfall patterns are becoming more frequent in the region
Precipitation climatology and ENSO influence in the Grijalva sub-basins
Full text linkThe Grijalva basin is of great relevance in southern Mexico because it receives the highest precipitation and has the most extensive hydroelectric system in the country. In addition, the lower basin has been impacted by extreme flooding in recent years. It is the source of water for several million people and the regional industry. For this study, the basin was divided into four sub-basins: Angostura, Chicoasén, Malpaso, and Peñitas. Each of these sub-basins has a dam that helps regulate the water flow and generate hydroelectric energy. To better understand the region’s climatology, this study uses long-term rainfall observations from sub-basins to describe precipitation patterns and their variability. Various statistics are computed to describe the annual precipitation cycle for each sub-basin. The results show that Angostura, Chicoasén, and Malpaso share a common climatology, with precipitation peaks in June and September and a mid-summer drought (MSD) in July. Peñitas receives considerably more precipitation throughout the year, with the highest values in October-November. In all sub-basins, La Niña (El Niño) years are characterized by increased (decreased) precipitation in the rainy season. The study demonstrates that the extreme precipitation observed during La Niña years in late summer and autumn is mainly due to an increased number of tropical cyclones over the western Caribbean Sea and the Gulf of Mexico. The interquartile range and other percentile values of monthly precipitation provide additional information that may be useful for dam management
Assessment of aerosol remote sensing uncertainty in urban centers of Latin America
Full text linkSatellite-derived aerosol optical depth (AOD) is a key indicator for expanding spatial coverage in air quality studies, particularly for estimating PM2.5 concentrations. However, validation of high-resolution AOD products remains limited in Latin American urban environments, which are characterized by complex aerosol dynamics and sparse ground-based monitoring. In this study, we evaluated the performance of MAIAC C6.1 AOD in six densely populated Latin American cities (São Paulo, Santiago, Buenos Aires, Medellín, La Paz, and Mexico City) from 2015 to 2022, using the AERONET network as a reference. MAIAC C6.1 performance was also compared with the previous version (C6.0) and MODIS DT to analyze differences in spatial resolution and assess performance improvements. A lack of ground-level AOD was observed, especially in Medellín and São Paulo, along with low average levels (AOD < 0.2) in La Paz and Buenos Aires. MAIAC C6.1 performance showed notable variability depending on the spatial window size, although no considerable impact was seen in the temporal window. Two site groups were identified: (i) La Paz and Buenos Aires, with lower AOD levels, lower performance, and positive bias; and (ii) São Paulo, Santiago, and Mexico City, with higher AOD levels, better performance, and negative bias. MAIAC C6.1 showed improvement in bias reduction, but no significant changes in R2 or RMSE compared to C6.0. Compared to MODIS DT, MAIAC C6.1 exhibited greater accuracy and lower bias, with MODIS overestimating AOD across all sites. Despite advances with high-resolution products, limitations in data coverage and uncertainty persist, especially in urban Latin American areas
Spatial patterns of statistical relationship between the North Atlantic Oscillation and the Western Mediterranean Oscillation, and precipitation in Peninsular Spain
Full text linkThe Iberian Peninsula, located in a transitional zone between the temperate oceanic climate of the mid-latitudes and the Mediterranean climate, exhibits significant temporal precipitation variability. The contrasting topography further enhances considerable spatial variability. Using the MOPREDAS monthly precipitation database for Peninsular Spain, with a fine resolution (10 × 10 km), the spatial patterns of correlation between the NAOi and the WeMOi and precipitation for the period 1915-2015, as well as three subperiods, are analyzed. The results reveal almost opposite spatial patterns between the two low-frequency variability indexes, especially in December, the month with the highest correlation. The NAOi shows a clearly negative correlation with precipitation in the southwestern quadrant of peninsular Spain, sometimes extending diagonally towards the northeast. In contrast, the most typical pattern of the WeMOi is a dipole, with negative correlations in the eastern-southeastern peninsula and positive correlations along the eastern Cantabrian coast. Additionally, we examine the similarities between the aforementioned correlation maps and other rainfall-related variables, such as the interannual coefficient of variation, drought duration, the consecutive disparity index, the concentration index, and precipitation seasonality. The location of the maximum concentration index value corresponds to the maximum negative correlation between the WeMOi and precipitation, as well as to an autumn rainfall maximum
Variability of the Atlantic Niño: Impacts on precipitation in the state of Maranhão, Brazil
Full text linkThe study analyzed the influence of the Atlantic Niño on precipitation anomalies in Maranhão from 1980 to 2020. Using the Atlantic Niño index, 20 events were identified, predominantly with 2- to 8-year scales. A significant reduction was noted from the 2000s, likely due to the weakening of the Bjerknes feedback and the Atlantic Multidecadal Oscillation. However, events in 2019 and 2021 suggested that the negative phase of the Atlantic Multidecadal Oscillation may have contributed to the reactivation of the Atlantic Niño after 19 inactive years. The negative early termination event was “non-canonical”, with positive sea surface temperature anomalies in the North Tropical Atlantic and positive east winds. A relationship was found between the Atlantic Niño and the Atlantic Meridional Mode, influencing elements like sea surface temperature and interhemispheric winds, which in turn affected precipitation patterns in Maranhão. These findings highlight the complex climate interactions in the region, emphasizing the need to consider multiple factors, including local and remote climate modes, for understanding precipitation variability. The study underscores the importance of continuous monitoring and research on the Atlantic Niño and the Atlantic Meridional Mode to anticipate impacts on rainfall volume and distribution in Maranhão, aiding regional strategic planning
Connecting Iraq’s summer and autumn temperature variability with global sea surface temperature
Full text linkThe present study examined the monthly summer and autumn temperature (ºC) variability in Iraq and its relation to the global sea surface temperatures (SST). The dataset, collated from eight meteorological stations and spanning the period from 1971 to 2010, was provided by the Iraq Meteorological Organization and the Seismology Department. The SST modes were obtained from the Hadley Centre (HadiSST2). The statistical analysis used Empirical Orthogonal Functions (EOFs) and Principal Components (PCs) to identify the characteristics of Iraq’s spatial and temporal variability. EOFs’ results for summer and autumn identify that EOF1 is monopolar, with variances of 77.26 and 69.23%, respectively, which refer to the links between the climatological parameters and the large-scale. Meanwhile, the second EOF is bipolar, with variances of 8.04 and 10.10%, respectively, due to the local connection. The derived results from the correlation maps demonstrate a relationship between Iraq’s summer and autumn temperatures and large-scale SST patterns. The occurrence of La Niña in the Pacific Ocean, accompanied by a positive Atlantic Multidecadal Oscillation (AMO), is expected to lead to a rise in temperatures in the region. The Pearson correlation coefficients between ENSO and summer and autumn PC1 and PC2 are 0.11, 0.59, and 0.14, –0.27, respectively. The correlation coefficients of the AMO index with summer and autumn (PC1, PC2) are 0.31, –0.2, and 0.03, 0.19, respectively. The results confirm the slight impact of the two modes on Iraq’s climate variability
Climatic suitability variations for climbing bean cultivation under climate change scenarios in Cundinamarca, Colombia
Full text linkClimate change is expected to modify the current suitable areas for bean cultivation, driven by regional shifts in temperature and precipitation. Despite the economic and food security importance of beans in Colombia, there is a lack of knowledge about how ongoing and future climate change may reshape their agroclimatic suitability across the country. This study aimed to assess the potential future shifts in suitable areas for climbing bean (Phaseolus vulgaris L.) cultivation in the department of Cundinamarca under projected climate change scenarios. Suitable areas were categorized into A1 (best conditions), A2 (moderate constraints), A3 (strong restrictions), and N1 (not suitable), based on a decision tree with defined altitude, temperature, and precipitation intervals. The period 1981-2010 was utilized as the present climate, and the future periods 2011-2040, 2041-2070, and 2071-2100 were considered under the climate change scenarios RCP 4.5 and RCP 8.5. Information from the Global Climate Model CCSM4 from the National Center for Atmospheric Research was used to identify new potential areas and changes in optimal zones under future scenarios. The forecast for Cundinamarca indicates that under the RCP 4.5 scenario, the total suitable area decreases slightly by 3.8%, while the A1 zone expands, especially in cooler highland regions. In a high-emission future (the RCP 8.5 scenario), the total suitable area declines more sharply (by 14.8% between 2071 and 2100), while the unsuitable area increases by 6.5%. The expansion of A3 zones by up to 13.3% in the early and mid-21st century reflects the downgrading of currently optimal or moderate areas to low suitability due to rising temperatures, particularly in the Llanos foothills and the Magdalena slopes subregions
Temporal variability of PM10 and PM2.5 in Puerto Plata, Dominican Republic
Full text linkParticulate matter (PM) concentrations in the Caribbean result from complex interactions between transboundary natural sources and local anthropogenic and natural emissions. This study presents a five-year analysis of PM10 and PM2.5 levels in Puerto Plata, a coastal tourist city that hosts significant port and cruise ship activity. Annual average PM10 and PM2.5 concentrations were 35.0 ± 16.4 and 8.8 ± 5.1 µg m–3, respectively, exceeding annual guidelines established by the World Health Organization (WHO) by factors of 2.3 and 1.8, respectively. PM2.5/PM10 ratios below 0.4 occurred on 88.6% of days during the study period, with a global average of 0.27, indicating a dominance of coarse particles driven by Saharan dust intrusions and sea spray emissions. The weak correlation between PM10 and PM2.5 (ρ = 0.61) suggests different emission sources and atmospheric behavior. Fine-particle episodes (PM2.5/PM10 ratio ≥ 0.6) were sporadic (2.3%) and primarily associated with localized combustion sources, such as fireworks displays during tourism-related events. Seasonal dynamics revealed marked PM10 peaks during summer associated with dust transport (June-August). Conversely, PM2.5 concentrations showed a limited seasonal variability, reflecting steady local emissions of fine PM. WHO’s 24-h thresholds were exceeded on 19% of days for PM10 and 7% for PM2.5, underscoring chronic exposure risks
Analysis of extreme precipitation in eastern China from 1960 to 2020 and future projections
Full text linkThis study analyzes extreme precipitation in eastern China over the past 60 years through climatology and trend detection, with future projections using 10 indices. Data from 1310 meteorological stations and 20 CMIP6 models were employed to examine the spatiotemporal evolution of these indices from 1961 to 2020 during summer, both regionally and across eight major river basins. Key findings include: (1) the spatial distribution of extreme precipitation generally decreases from south to north and east to west. High-value centers for extreme precipitation are found south of the Yangtze River, while the maximum consecutive wet days decline from the southeast coast inland. (2) Extreme summer precipitation in eastern China increased over six decades, with intensity, 1-day max, heavy, extreme heavy precipitation, and very heavy rain days rising at 0.03, 0.11, 0.22, 0.13 mm yr–1, and 0.02 d yr–1, respectively. Trends show growth in the Yangtze River Basin and the northeast, but declines in the Hai and Yellow River basins, with decreases up to 0.50 mm yr–1. (3) Multi-model ensemble simulations reliably capture summer extreme precipitation trends, indicating that by 2060, heavy and extreme precipitation amounts will increase by up to 10% under SSP-1.26. Higher carbon emissions will further accelerate this increase, particularly in the southeast rivers, the Pearl River, and the Yangtze River basins. These results provide important references for predicting extreme precipitation in eastern China