Search Results (401)

Explosive volcanic eruptions are key drivers of climate variability, yet their hemispheric-dependent impacts remain uncertain. Using multi-model ensembles from Coupled Model Intercomparison Project Phase 6 (CMIP6) historical data and Decadal Climate Prediction Project (DCPP) simulations, this study examines how the spatial distribution of volcanic aerosols modulates climate responses to Northern Hemisphere (NH), Tropical (TR), and Southern Hemisphere (SH) eruptions. The CMIP6 ensemble captures observed temperature and precipitation patterns, providing a robust basis for assessing volcanic effects. The results show that the hemispheric distribution of aerosols strongly controls radiative forcing, surface air temperature, and hydrological responses. TR eruptions cause nearly symmetric cooling and widespread tropical rainfall reduction, while NH and SH eruptions produce asymmetric temperature anomalies and clear Intertropical Convergence Zone (ITCZ) displacements away from the perturbed hemisphere. The vertical temperature structure, characterized by stratospheric warming and tropospheric cooling, further amplifies hemispheric contrasts through enhanced cross-equatorial energy transport and shifts in the Hadley circulation. ENSO-like responses depend on eruption latitude, TR and NH eruptions favor El Niño–like warming through westerly wind anomalies and Bjerknes feedback, and SH eruptions induce La Niña–like cooling. The DCPP experiments confirm that these signals primarily arise from volcanic forcing rather than internal variability. These findings highlight the critical role of aerosol asymmetry and vertical temperature structure in shaping post-eruption climate patterns and advancing the understanding of volcanic–climate interactions. Full article

The East Asian winter monsoon (EAWM) is a critical component of the boreal winter global climate system, exerting profound influences on weather and climate anomalies across East Asia. This study systematically evaluates the capability of 15 Coupled Model Intercomparison Project Phase 6 (CMIP6) models in simulating the typical associated circulation, temporal characteristics, and the relationship with the El Niño–Southern Oscillation (ENSO) during the historical period of 1951–2013. Results indicate that the multi-model ensemble demonstrates considerable fidelity in reproducing the climatological spatial patterns of key EAWM systems, including the Siberian High, Aleutian Low, and low-level meridional winds. However, a systematic eastward shift is identified in the simulated sea level pressure anomaly centers over the North Pacific. In terms of temporal variability, most models realistically capture the dominant interdecadal periodicity of 15–20 years found in observations after 11-year low-passed filter. Four models reproduce a similar bimodal periodicity. Regarding the ENSO–EAWM relationship, approximately 80% of the evaluated models successfully capture the observed negative correlation, although its strength is consistently underestimated across the model ensemble. More notably, only three CMIP6 models faithfully capture the observed intrinsic asymmetry in the ENSO–EAWM relationship (i.e., the stronger impact of El Niño compared to La Niña). Full article

The influence of tropical oscillations on the thermodynamics of the middle and upper atmosphere at high latitudes was studied using a nonlinear model of the general circulation of the middle and upper atmosphere (MUAM). The observed oscillations include the quasi-biennial oscillation of the zonal wind in the equatorial stratosphere (QBO) and the El Niño–Southern Oscillation (ENSO). The main focus of this work is to study the influence of these oscillations on the strength and persistence of the stratospheric polar vortex. Four ensemble calculations were carried out (10 runs for each QBO and ENSO phase combination) for January–February. It was shown that the polar vortex and Eliassen–Palm (EP) flux divergence were especially strong under La Niña and the westerly QBO phase (wQBO). This was accompanied by a strengthening of the residual mean circulation (RMC) from the summer to the winter hemisphere, causing positive temperature anomalies in the polar mesosphere and negative anomalies in the stratosphere. The greatest RMC weakening and the weakest and warmest polar vortex occurred during El Niño and eQBO conditions in January and during El Niño and wQBO conditions in February. Such diverse manifestations of tropical oscillations via teleconnections can provide valuable information for predicting the frequency and intensity of sudden stratospheric warmings (SSWs) and subsequent extreme cold wave events in the troposphere. Specifically, SSWs are the least probable during La Niña and wQBO conditions in both January and February. The QBO phase most significantly influences the polar vortex during El Niño events in both months. We conclude that SSW development is more favorable during eQBO in January and wQBO in February under El Niño conditions. Full article

The Pearl River Basin (PRB) is a humid subtropical system where frequent floods and recurrent droughts challenge water management. GRACE and GRACE Follow-On provide basin-scale constraints on terrestrial water storage anomalies (TWSA), yet their coarse native resolution limits applications at regional scales. We employ a downscaled TWSA product derived via a joint inversion that integrates GRACE/GFO observations with the high-resolution spatial patterns of WaterGap Global Hydrological Model (WGHM). Validation against GRACE/GFO shows that the downscaled product outperforms WGHM at basin and pixel scales, with consistently lower errors and higher skill, and with improved terrestrial water flux (TWF) estimates that agree more closely with water balance calculations in both magnitude and phase. The TWSA in the PRB exhibits strong seasonality, with precipitation (P) exceeding evapotranspiration (E) and runoff (R) from April to July and storage peaking in July. From 2002 to 2022, the basin alternates between multi-year declines and recoveries. On the annual scale, TWSA covaries with precipitation and runoff, and large-scale climate modes modulate these relationships, with El Niño and a warm Pacific Decadal Oscillation (PDO) favoring wetter conditions and La Niña and a cold PDO favoring drier conditions. extreme gradient boosting (XGBoost) with shapley additive explanations (SHAP) attribution identifies P as the primary driver of storage variability, followed by R and E, while vegetation and radiation variables play secondary roles. Drought and flood diagnostics based on drought severity index (DSI) and a standardized flood potential index (FPI) capture the severe 2021 drought and major wet-season floods. The results demonstrate that joint inversion downscaling enhances the spatiotemporal fidelity of satellite-informed storage estimates and provides actionable information for risk assessment and water resources management. Full article

Climate change intensifies ecosystem vulnerability in mountainous regions, particularly in Northwestern Sichuan’s Terrestrial Ecosystems (TENS), where complex terrain amplifies impacts on biodiversity and carbon dynamics. This study assesses spatiotemporal ecological vulnerability using the IPCC exposure-sensitivity-resilience framework. We applied autoregressive modeling and a 5-year moving window to monthly NDVI, temperature, and precipitation data from 1983 to 2022. Results show vulnerability index (VI) increases latitudinally from south to north, driven by inverse temperature correlations. Longitudinally, VI forms a V-shaped pattern due to topographic and monsoon influences. Wetlands are most vulnerable (VI ≈ 0.48) from precipitation sensitivity, while forests show lowest vulnerability (VI ≈ 0.43) due to high resilience. Temporally, VI fluctuates nonlinearly with decline (1985–1994) under cool-humid conditions, increase (1994–2008) amid warmer-drier El Niño effects, and sharp decline (2008–2011) from La Niña and sand control initiatives. Spatially, 34.6% of areas exhibit decline-increase-decline-increase trends. Centroids of decreasing VI shift southwest-to-north, indicating recovery diffusion. Increasing VI centroids move northwest-central-north. These findings underscore ecosystem-specific adaptive management and conservation policies, especially in northern TENS, to mitigate accelerating climate pressures. Full article

Meiofaunal assemblages are crucial components of benthic ecosystems, significantly contributing to organic matter cycling and energy transfer. However, baseline quantitative data from some upwelling systems remain limited. This study characterizes the abundance, vertical distribution, and secondary production of meiofauna at a coastal upwelling station off southern Peru (14°16′ S) for July 2006 (Neutral conditions) and May 2007 (moderate La Niña, LN), using four-replicated sediment cores sectioned into 0–1, 1–2, 2–5, and 5–10 cm layers. While Nematoda (families Desmodoridae, Chromadoridae, Monhysteridae, Oxystominidae, Comesomatidae) dominated the community (>79% in all layers, both years), the total taxonomic richness did not differ substantially between study periods nor across the sediment column for 2006 or for 2007. Total density (0–10 cm) fluctuated between 3916 ± 2202 Ind 10 cm⁻² in 2006 and 4203 ± 2274 Ind 10 cm⁻² in 2007, with non-significant changes. Biomass (µgC 10 cm⁻²) in 2006 ranged from 80 ± 24 in the 5–10 cm section to 455 ± 134 in the 2–5 cm section. The uppermost 0–1 cm layer showed 238 ± 155, while the 1–2 cm section reached 302 ± 69. In 2007, biomass was consistently higher in the surface layers, with maximum values in the 1–2 cm section (500 ± 534), followed by the 0–1 cm section (376 ± 34). Hierarchical clustering produced depth-ordered groups with high within-depth similarity (>80–90%). SIMPER results identified Desmodora, Comesomatidae, and Chromadoridae among the top contributors to within-depth similarity and to the dissimilarity observed between surface and subsurface assemblages. A depth-related gradient of community composition was detected, suggesting vertical habitat heterogeneity modulated by several environmental factors; however, PERMANOVA analysis residuals (96.73%) indicate a high variation not explained by ENSO phase, sediment section, or their interaction, suggesting other unmeasured factors explaining meiofaunal community structure. Meiofauna’s production ranged from 2.836 ± 0.049 gC m⁻² y⁻¹ in 2006 to 3.106 ± 1.566 gC m⁻² y⁻¹ in 2007. These findings expand the limited knowledge on meiofaunal abundance and metabolic demands in this ocean region, fostering future efforts for comparative analyses across latitudes, depth gradients, and oceanographic regimes. Full article

This study examines how ENSO episodes affect maize price volatility transmission between the United States and South Africa. Using daily price data, from 1997 to 2024, for U.S. corn and South African white and yellow maize futures, the study employs GARCH models augmented with ENSO phase indicators and the Southern Oscillation Index (SOI) to determine volatility spillovers. The results show that South African maize prices respond to lagged US corn prices and exchange rate fluctuations, with price volatility of both white and yellow maize prices being more persistent during El Niño and La Niña events. This study integrates climate variability indicators, specifically different ENSO phases and the SOI, to investigate climate-driven volatility transmission between developed and emerging markets. Significant results were obtained when the Southern Oscillation Index was added in the volatility equations. Not only does the inclusion of ENSO indicators and SOI enhance the explanatory power of GARCH models beyond existing studies, it also provides evidence of climate-driven volatility spillovers between a developed and developing market. These findings highlight the role of climate variability in agricultural market dynamics and stress the need for proactive risk management strategies such as buffer stocks and climate responsive financial instruments to ensure food security and market resilience in Southern Africa. Full article

The northwest of Mexico has important zones for biodiversity conservation, denominated Priority Marine Regions (PMRs), and to study key oceanographic features related to ecological structure, it is necessary to understand environmental variability and observe climatic trends. Sea Surface Temperature (SST) is tightly associated with photosynthesis and serves as a control and driver for biological processes linked to the phytoplankton. Global climatic systems, like El Niño Southern Oscillation (ENSO), are responsible for the interannual and interdecadal variation in SST, since global circulation is modified by them. An important metric to assess phytoplanktonic biomass/photosynthesis is Chlorophyll a (Chl a), constituting the primary basis of the marine trophic web. The present study aims to examine the interannual oceanographic variability across 24 PMRs by employing monthly SST (°C) and Chl a (mg/m³) data derived from remote sensing instruments with spatial resolution of 4 km and 1 km from September 1997 to October 2018. We grouped the Priority Marine Regions into 18 main areas, based on a cluster analysis of Sea Surface Temperature. Significant differences were observed, showing higher SST levels during El Niño phase and higher Chl a concentration during La Niña phase, primarily in winter and spring, which will impact marine ecosystems. Full article

The El Niño–Southern Oscillation (ENSO) is one of the most important climate phenomena on Earth due to its impacts on the global atmospheric circulation. This paper conducts a comprehensive analysis of the spatiotemporal variations and characteristics of ENSO from 1950 to 2023. A number of indices, including the Oceanic Niño index, Modoki index, and the modified El Niño Modoki Index, were used to differentiate between various ENSO types and assess their respective impacts on the global climate. The analysis reveals notable changes in the frequency and intensity of ENSO events over the past seven decades. Notably, since 1990, the sea surface temperature anomalies (SSTAs) in the tropical Western Pacific regions have shifted westward by approximately 18 degrees longitude, potentially a result of global warming. During the same time period, the frequency and intensity of ENSO events have also changed, with an increase in the frequency of Central Pacific El Niño events and a decline in the frequency of Eastern Pacific El Niño events. The occurrence frequency of both Central and Eastern Pacific La Niña events has remained relatively stable but shows some variability. Based on the analysis results, this article also suggests potential improvement in data collection, which is critical to further understanding and verification of the spatiotemporal variations of ENSO events. Full article

Climate projections suggest ecosystems could face drastic changes due to global climate change, including more severe and frequent droughts than those recorded in the last century. Paleoclimatic series provide more extensive information than that available with instrumental records, allowing for the analysis of trends and recurrence of extreme events over a longer time periods. The objective of this research was to reconstruct the precipitation variability for southwestern Chihuahua, based on the tree-ring records of Pinus arizonica Engelm. and to assess the influence of ocean atmospheric circulations like El Niño Southern Oscillation (ENSO) and the North American Monsoon (NAM) on both low- and high-frequency climate variability. We developed three dendrochronological series covering 214 years (1802–2015), 265 years (1750–2014) and 369 years (1647–2015), for the Talayotes (TAL), Predio Particular Las Chinas (PPC) and El Cuervo (CUE) sites, respectively. The 369-year regional chronology was significantly related to cumulative precipitation variability between January and September. Recurring droughts were observed at approximately 50-year intervals. This regional climate variability was significantly related (p < 0.05) to Niño 3 SST and PDSI (JJA) indices. Maximum and minimum extreme events reconstructed in the last 369 years were synchronized with ENSO events, both in the El Niño warm phase and the La Niña cold phase. These results suggest that P. arizonica tree rings record shared a common response to the regional climate that was significantly modulated by ENSO and the NAM. This is the first dendroclimatic study to reconstruct summer precipitation patterns in northern Mexico, which is valuable given the importance of this seasonal precipitation on the regional economy. Full article

Longitudinal shifts in the zonal dipole associated with the El Niño–Southern Oscillation (ENSO) in the tropical Pacific have implications for the summer climate of Southern Africa. These features are studied via Empirical Orthogonal Function analysis applied to monthly standardized sea temperatures from 1 to 100 m in depth and spanning 1980–2024. The dipole exhibits two modes: central and east Pacific. The central mode has 4–7 yr oscillations, while the east mode has a periodicity of 3 yr and 8–14 yr, with a trend toward La Niña. Correlations are mapped with environmental fields around Southern Africa. During east-mode La Niña, there are low-level westerlies over the Kalahari Plateau that coincide with a warm-west Indian Ocean and neutral summer (Dec–Mar) weather conditions over Southern Africa. The weak climatic response across the Atlantic–Indian basins during east Pacific La Niña is linked to an isolated Walker cell that feeds tropical moisture into a trough over the dateline (180° W). It is the central mode that has greater influence over Southern Africa, by triggering global Walker cells that link with the Indian Ocean Dipole. Full article

The macro-economic growth rate of Peru is analyzed for sensitivity to climatic conditions. Year-on-year fluctuations in the inflation-adjusted gross domestic product (GDP) per capita over the period 1970–2024 are subjected to correlation and composite statistical methods. Upturns relate to cool east Pacific La Niña, downturns with warm El Niño. Composites are analyzed by subtracting upper and lower terciles, representing a difference of ~USD 40 B at current value. These reveal how the regional climate exerts a partial influence among external factors. During the austral summer with southeasterly winds over the east Pacific, sea temperatures undergo a 2.5 °C cooling. Consequently, atmospheric subsidence draws humid air from the Amazon toward the Peruvian highlands, improving crop production. Dry weather along the coast sustains transportation networks and urban infrastructure, ensuring good economic performance over the year. The opposing influence of El Niño is built into the statistics. A multi-variate algorithm is developed to predict changes in the Peru growth rate. Austral summer winds and subsurface temperatures over the tropical east Pacific account for a modest 23% of year-on-year variance. Although external factors and the varied landscape weaken macro-economic links with climate, our predictors significantly improve on traditional indices: SOI and Nino3. Adaptive measures are suggested to take advantage of Southern Oscillation’s influence on Peru’s economy. Full article

The objective of this study is to determine how easterly jets and associated convections interact over tropical North Africa during the Jul–Sep season, using reanalysis and satellite datasets for 1990–2024. Four indices are formed to describe mid- and upper-level zonal winds, and moist convection over the Sahel and India. Time-space regression identifies the large-scale features modulating the easterly jets. Cumulative departures are analyzed and ranked to form composites in east wind/convective phases and weak wind/subsident phases. The upper-level tropical easterly jet accelerates over the Arabian Sea during and after Pacific La Nina and the cool-west Indian Ocean dipole, and shows four year cycling aligned with thermocline oscillations. The mid-level Africa easterly jet strengthens during Atlantic Nino conditions that enhance the Sahel’s convection in the Jul–Sep season. Both jets accelerate when convection spreads west of India, whereas brief spells of decoupling suppress North African crop yields. The case of 15–20 August 2018 is analyzed, when a surge of Indian monsoon convection and tropical easterly jet penetrated the Sahel, leading to widespread uplift and rainfall. Full article

Analysis of global mean sea-level (GMSL) variations provides insights into their spatial and temporal characteristics. To analyze the sea-level cycle and its correlation with the El Niño–Southern Oscillation (ENSO, represented by the Oceanic Niño Index), this study proposes an enhanced analytical framework integrating Local Mean Decomposition with an improved wavelet thresholding technique and wavelet transform. The GMSL time series (January 1993 to July 2020) underwent multi-scale decomposition and noise reduction using Local Mean Decomposition combined with improved wavelet thresholding. Subsequently, the Morlet continuous wavelet transform was applied to analyze the signal characteristics of both GMSL and the Oceanic Niño Index. Finally, cross-wavelet transform and wavelet coherence analyses were employed to investigate their correlation and phase relationships. Key findings include the following: (1) Persistent intra-annual variability (8–16-month cycles) dominates the GMSL signal, superimposed by interannual fluctuations (4–8-month cycles) related to climatic and seasonal forcing. (2) Phase analysis reveals that GMSL generally leads the Oceanic Niño Index during El Niño events but lags during La Niña events. (3) Strong El Niño episodes (May 1997 to May 1998 and October 2014 to April 2016) resulted in substantial net GMSL increases (+7 mm and +6 mm) and significant peak anomalies (+8 mm and +10 mm). (4) Pronounced negative peak anomalies occur during La Niña events, though prolonged events are often masked by the long-term sea-level rise trend, whereas shorter events exhibit clearly discernible and rapid GMSL decline. The results demonstrate that the proposed framework effectively elucidates the multi-scale coupling between ENSO and sea-level variations, underscoring its value for refining the understanding and prediction of climate-driven sea-level changes. Full article

The effects of climate change are facing extreme drought during the summer period in the cities of Central Europe due to insufficient and limited green infrastructure surfaces, especially in the centers of some built-up capitals (Berlin, Warsaw). As young people shape the future of our planet, young students from Poland and Germany were asked to fill out a survey on how unused spaces of cemeteries as reservoirs of green (a forgotten and often overlooked element of green infrastructure) can serve as a recreation benefit in the age of climate change. The results indicated that the German (the tradition of the cemetery as a park garden) and Polish examples provide many valuable clues, such as biodiversity, passive recreation, and care for elderly people who need more peace and quiet rather than having it in the bustling spaces of cities. Reassessment guidelines for greenery managers balance the challenging city conditions during climate change, especially heat waves, due to cemeteries’ underutilized natural and recreational functions. The future directions may be valuable for other regions of Europe and the World, especially since various scientific spheres now consider the El Niño and La Niña phenomena as globally interdisciplinary research collaborations. Full article