Preprints
Filtering by Subject: Climate
A Changing North Atlantic Background Amplifies Western European Heatwaves
Published: 2026-09-06
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Western European summer heatwaves have increased markedly since the 1990s, culminating in the record warmth of May–July 2026 since 1950. We show that this rise is closely associated with the slowly evolving North Atlantic background. We combine two leading April sea surface temperature modes, representing basin-wide warming and a tripole-like pattern, into an Atlantic Two-Mode Index (ATMI). The [...]
Evaluating forecast baselines and network representativeness for daily PM2.5 in the Kathmandu Valley, Nepal
Published: 2026-09-03
Subjects: Atmospheric Sciences, Climate, Environmental Indicators and Impact Assessment, Environmental Monitoring, Meteorology
An order-fair attribution of daily PM2.5 predictability in the Kathmandu Valley assigns 72% of achievable error reduction to persistence, 19% to meteorology and 9% to day-of-year climatology, with the latter two largely redundant; no fitted model, including random forests and gradient boosting tuned by nested chronological cross-validation, outperforms an unfitted lag-1 forecast (11.22 µg m-3). [...]
A Project-based Learning Activity Involving Hybrid Intelligence in the Undergraduate Engineering Class
Published: 2026-09-02
Subjects: Climate, Higher Education, Scholarship of Teaching and Learning
Artificial intelligence (AI) is increasingly embedded in academic practice, creating opportunities to support learning and improve educational outcomes. We implemented a project-based learning activity in an undergraduate engineering course in which students used meteorological data to construct a temperature time series and assess local climate change at a selected location from the national [...]
Super El Niño Winters and the Arctic Polar Vortex: Response Heterogeneity, QBO Modulation, and a Prospectively Defined Test for Winter 2026/27
Published: 2026-08-30
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Other Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
In the three strongest El Niño winters of the instrumental record (1982/83, 1997/98, 2015/16) the Arctic polar vortex did not collapse in a major midwinter sudden stratospheric warming (SSW). This study starts from the premise that the observation is not a paradox: 58% of El Niño winters contain at least one major SSW, so the chance probability of three consecutive SSW-free winters is 0.42³≈0.07, [...]
Climate change has intensified exceptional El Niño events like the 2026/27 forecast
Published: 2026-08-29
Subjects: Applied Statistics, Climate, Physical Sciences and Mathematics, Statistics and Probability
Extreme El Niño events disrupt weather across much of the globe, with adverse effects on agriculture, fisheries and economic output that persist for several years. Event attribution routinely quantifies the human influence on individual heatwaves, droughts and floods, but its application to the El Niño events that drive many of them has been much more limited. Here we investigate the 2026/27 El [...]
Contrasting oil and gas methane emission intensities across Algeria's major production basins derived using MethaneSAT data
Published: 2026-08-28
Subjects: Atmospheric Sciences, Climate, Natural Resources Management and Policy, Oil, Gas, and Energy
Algeria, Africa's largest natural gas producer and a major European Union gas supplier, has limited basin-scale assessment of oil and gas methane emissions. Here, we use MethaneSAT observations from September 2024 to May 2025 to quantify methane emissions across three Algerian production regions representing 73% of national onshore production. Total methane emissions are 18 t h⁻¹ [11–25] in Hassi [...]
Coupling between Walker and Hadley circulations mediated by low cloud feedback
Published: 2026-08-28
Subjects: Atmospheric Sciences, Climate
The tropical Pacific hosts the primary region of deep convection and forms the shared ascending branch of the Walker and Hadley circulations, which regulate the distribution of energy, angular momentum, and moisture across the climate system. Despite their importance and spatial entanglement, the dynamical coupling between these two circulations remains poorly understood. Here we show that the [...]
Quantifying onset period rather than single date reveals projected intensification of dry-to-wet season transition.
Published: 2026-08-28
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology
Recent years have seen increasingly frequent delayed rainfall onset, especially in South America (SAm) and Southern Africa (SAfr). This arrival of the wet season is critical to water resources, ecosystems, and rain-fed agriculture. Existing rainfall-based approaches define the rainfall onset by a single date, limiting their ability to characterise the progression into the wet season. We introduce [...]
Biological Dynamics for Sustainable Carbon Sequestration
Published: 2026-08-27
Subjects: Atmospheric Sciences, Biology, Climate, Environmental Microbiology and Microbial Ecology Life Sciences, Forest Management, Planetary Biogeochemistry
Earth’s atmosphere is shaped by the interplay of biological systems operating across interlinked biogeochemical cycles and, more recently, by anthropogenic emissions. Here, we thoroughly examine the potential for engineering biological systems across ecosystems for sustainable carbon storage. This centralization and comparative analysis of the potential of all key global ecosystems aims to [...]
Probabilistic assessment of tropical cyclone recovery burden across US Atlantic and Gulf Coast counties
Published: 2026-08-27
Subjects: Climate, Other Earth Sciences
Tropical cyclones cause widespread damage to housing and infrastructure, and recovery is often slow and uneven. Climate risk assessments quantify the likelihood and direct impacts of extreme events, but post-disaster recovery remains largely absent from these models, limiting our ability to assess long-term resilience. We therefore integrate simplified recovery modeling into probabilistic [...]
Observed warming is shrinking favourable daylight windows for outdoor recreation: evidence from sports facilities across France
Published: 2026-08-25
Subjects: Climate, Nature and Society Relations
Observed warming is changing not only the severity of heat exposure during outdoor recreation, but also the time of day when thermally favourable conditions remain available. We quantify this emerging temporal constraint across metropolitan France from 1991 to 2025 by combining hourly ERA5-Land meteorology, Wet-Bulb Globe Temperature (WBGT), solar geometry and the national Data ES inventory of [...]
Independent lidar observations support declining low cloud cover trends seen in satellite and reanalysis records
Published: 2026-08-21
Subjects: Atmospheric Sciences, Climate
Low clouds strongly influence Earth's radiation budget, yet their response to climate change remains uncertain. Recent satellite and reanalysis studies indicate declining low cloud cover that may have contributed to increasing absorbed solar radiation, but independent ground-based evidence over land is limited. Here we show that ground-based lidar observations support a decrease in low cloud [...]
Source-composition sensitivity in historical marine wind observations: a CLIWOC case study, 1750--1855
Published: 2026-08-15
Subjects: Climate, Earth Sciences, Environmental Monitoring, Environmental Sciences, Environmental Studies, Library and Information Science, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Other Applied Mathematics, Other Computer Sciences
Recovering Climate’s History with Artificial Intelligence used the CLIWOC ship-logbook database to argue that sailors’ wind observations reveal a previously undetected shift in global atmospheric circulation between the late eighteenth and early nineteenth centuries. We reproduce the article's principal annual aggregate from CLIWOC release 2.1 and find that this unstandardized, record-weighted [...]
Large-Scale Modulation of Mesoscale Convective System Propagation and Diurnal Rainfall over the Western Maritime Continent
Published: 2026-08-14
Subjects: Atmospheric Sciences, Climate, Meteorology
The western Maritime Continent exhibits a pronounced regional diurnal cycle of rainfall, to which the propagating Mesoscale Convective Systems (MCSs) make a significant contribution. Using an automated tracking algorithm based on brightness temperature, we quantify the contribution of MCSs to the regional diurnal cycle over Singapore and the South China Sea. MCSs affecting the Singapore sector [...]
Hydroclimatic Regime Shifts and Compound Heat–Dry Events in Rajshahi Division, Bangladesh: Integrating Thermal Gradients, Change-Point Detection, and Heat-Driven Dryness Dynamics (1992–2022)
Published: 2026-08-07
Subjects: Climate, Environmental Indicators and Impact Assessment, Environmental Monitoring, Hydrology, Meteorology, Other Earth Sciences, Other Oceanography and Atmospheric Sciences and Meteorology, Statistical Models
Hydroclimatic variability and compound climate extremes are increasingly affecting monsoon-dominated regions of South Asia, particularly drought-prone northwestern Bangladesh. However, integrated assessments of thermal dynamics, atmospheric moisture, land–atmosphere coupling, and compound heat–dry events remain limited in the regional context. Therefore, this study investigated long-term [...]