2025

1. [Chen et al. 2025] Greater accessibility to China’s vast archive of satellite Earth observations could enhance scientific progress, disaster preparedness, and international cooperation.
   Satellite observations

2. [Spengler et al. 2025] Mensaje de las conferencias y consejos episcopales católicos de África, América Latina y el Caribe, y Asia con ocasión de la cop30
   Cambio climático, Iglesia

3. [Fernández-Castillo et al. 2025] Snow cover can significantly alter the energy fluxes that take part on the surface energy balance (SEB), which subsequently affects surface air temperature. However, studies of the influence of snow cover on the SEB are scarce due to limited observational data and usually constrained to high altitudes or mountainous areas. In this study, the SEB is analysed under two differentiated land surface conditions: with and without snow cover, for a non-mountainous region in the midlatitudes. This is done in order to analyse the physical processes leading to one of the most extreme and disruptive cold waves of the present century in Spain. The cold wave took place in January 2021 after historical snowstorm Filomena left widespread snowfall amounts of 30–50 cm in the interior of Spain. By means of analysis of in-situ observational data from a micrometeorological tower and synoptic fields, we determine the contribution of synoptic and microscale processes to the extremely cold surface air temperatures recorded. The SEB analysis reveals the decisive role of snow cover in the cold wave. Surface albedo increased from 20 % to 80 %, leading to a 60 % decrease in the surface net radiative flux. Together with weak turbulence conditions due to weak synoptic forcing, this allowed extraordinarily low surface air temperatures. Thus, this event stands out from the typical pattern leading to cold waves in this region, characterised by cold air advection. This study highlights the importance of having observational data of micrometeorological variables, which have proven very insightful into the physical mechanisms contributing to the cold wave.
   Microvariability, Filomena

4. [García-Pereira et al. 2025] Abstract: The limited representation of soil processes in Land Surface Models (LSMs) contributes to the uncertainty in current state and future projections of permafrost change. In particular, insufficient LSM depths, coarse vertical dis- cretizations, and the omission of hydro-thermodynamic cou- pling can strongly affect subsurface temperatures, active layer thickness (ALT), and permafrost extent. This work aims to gain knowledge on permafrost sensitivity to changes in the soil hydrology and thermodynamics in permafrost-affected regions. We explore the response of the Max Planck Institute Earth System Model (MPI-ESM) to historical and climate change scenario forcing using an ensemble of fully-coupled simulations under three configurations of permafrost hydrol- ogy: the standard model that will be taken as a reference, and two variants that generate rather dry or wet conditions across permafrost areas. Enhanced soil depth and vertical resolution within the LSM, JSBACH, were also incorporated globally to capture fine-scale thermodynamics and allow for deeper heat propagation. Deepening the LSM reduces near-surface soil warming by about 0.1 °C per decade in high radiative forcing scenarios, reducing permafrost retreat by up to 1.9–3.1 × 106 km2 by the end of the 21st century. However, the greatest influences are produced by the dry and wet configurations, which lead to distinct initial states, historical, and future evolution for permafrost temperatures (offset of 3 °C), active layer thick- ness (1–2 m) and permafrost extent (5 × 106 km2). These re- sults indicate that inter-model spread in permafrost responses to climate change can be partly explained by differences in the representation of soil physics. Our findings underscore the importance of refining LSM hydrological and thermody- namic processes in ESMs, with implications for the assess- ment of risks related to carbon feedbacks and infrastructure vulnerabilities in Arctic regions.
   Permafrost

5. [Langille et al. 2025] Abstract The High-altitude Aerosols, Water vapour and Clouds (HAWC) mission is an observing system, with a planned launch around 2031, that is being developed by the Canadian Space Agency to provide co-located global measurements of aerosols, water vapour, and thin ice clouds in the upper troposphere and lower stratosphere with vertical coverage that extends into the troposphere in the polar regions. The mission is the Canadian contribution to NASA’s Atmospheric Observing System (AOS, aos.gsfc.nasa.gov); a satellite constellation that will include multiple instruments to monitor aerosols, clouds, and precipitation as part of the Earth System Observatory (ESO,https://science.nasa.gov/earth-science/missions/earth-system-observatory). The HAWC mission includes three innovative Canadian instruments: the Aerosol Limb Imager (ALI), the Thin Ice Clouds and Far InfraRed Emissions (TICFIRE) instrument, and the Spatial Heterodyne Observations of Water (SHOW) instrument. ALI and SHOW will provide limb profiles of aerosol and water vapour with high spatial resolution (vertical and along-track) and high sensitivity to fine aerosols and dry conditions. TICFIRE will provide nadir measurements of infrared radiation, thin ice cloud content, and cloud microphysical properties. These coordinated measurements will help build a more comprehensive picture of high-altitude aerosols, clouds, and water vapour in the atmosphere. In this paper, we present the HAWC concept and discuss the primary science objectives and requirements of the mission. The instrument payloads and data products are introduced and synergies between HAWC and other AOS instruments are identified.
   Iphone Hugo

6. [Losada et al. 2025] Abstract La Evaluación de Riesgos e Impactos derivados del Cambio Climático en España (ERICC-2025) constituye el primer ejercicio integral a escala nacional orientado a identificar, caracterizar y priorizar los riesgos climáticos que afectan a los sistemas naturales, productivos y sociales del país. Su finalidad es proporcionar una base científica y metodológica sólida que oriente la planificación de políticas públicas de adaptación, la gestión del riesgo climático y la inte- gración de la variable climática en la toma de decisiones estratégicas.
   Informe de riesgos ministerio

7. [Molina et al. 2025] Abstract: The anthropogenic nature of global environmental change demands that it is viewed not only as a scientific, technological, and economic issue, but as a philosophical, religious, and ethical one. In this article, we intend to explore Biology-Based Mimetic Ethics (BBME) as a subdiscipline of ethics that seeks to learn, adapt, implement, and evaluate models of response observed in living organisms to help social agents make pro-environmental decisions. Based on this the- oretical foundation, we aim to explore the relationship between moral and environmental education by presenting this teaching proposal as an innovative tool for bridging both disciplines, while reframing the global socio-environmental crisis as an ethical and educational one. The proposal rests on two premises. First, it recog- nizes that nature operates amorally, rendering ethological value judgments inappropriate. Second, it emphasizes, nevertheless, that any insight derived from a scientific analysis requires rational and ethical scrutiny. Finally, by providing both a theoretical framework and practical examples, this article aims to guide university educators —particularly those working in faith-based institutions—aspiring to develop character-based environmental education programs.
   Environmental ethics

8. [Nakamura et al. 2025] Reanalysis goes back to the dawn of modern operational numerical weather prediction (NWP). Relying on using a consistent data assimilation system for an extended period back in time at reduced resolution to manage cost, reanalysis integrates historical observations into physically consistent gapless fields and, in the case of an atmospheric reanalysis, provides a comprehensive picture of the historical global atmospheric circulation. There have been con- tinued efforts to improve data quality and to include not only the atmosphere but also other Earth system components (e.g., land, ocean, and cryosphere). Demands for higher resolution and quality have become a driving force of regional reanalysis. The increasing usage across successive Intergovernmental Panel on Climate Change (IPCC) assessment cycles attests to the improvement in the quality and comprehensiveness of reanalysis. Reanalysis data have enabled significant contributions not only to research on the climate system concerning its variability and predictability but also to operational services such as the Copernicus Climate Change Service (C3S) and the Copernicus Marine Service (CMEMS), offering great potential for applications in socioeconomic activity. Reanalyses’ recent usage as training datasets for machine learning (ML) activities may revolutionize the provision of weather forecasts and how weather/ocean forecasts benefit from reanalysis.

   The Sixth World Climate Research Program (WCRP) International Conference on Reanalysis (ICR6) took place in Tokyo from 28 October to 1 November 2024 and brought together reanalysis producers, observation data providers, numerical modelers, and members of the user community to discuss progress, applications, challenges, and future priorities in the field. The ultimate aim was to guide the development and use of reanalysis data in science, public services, policymaking, and socioeconomic activity.
   Global and regional reanalyses, recommendations of a WCRP conference on reanalysis.

9. [Sakamoto et al. 2025] Abstract = Abstract The strong East Asian winter monsoon (EAWM) frequently brings severe cold weather and heavy snowfall to East Asia, emphasizing the needs for a comprehensive understanding of its underlying mechanisms. This study investigates how midlatitude atmosphere–ocean interactions, as a feedback process, influence EAWM variability. Strong EAWM brings lower-tropospheric cold air in early winter, enhancing upward surface heat fluxes over the midlatitude western North Pacific (WNP) around 30°N. These anomalous fluxes progressively cool sea surface temperature (SST) south of Japan until late winter. Atmospheric general circulation model experiments revealed that the resulting cold SST anomalies modulate storm-track activity and transient eddy-mean flow interaction, facilitating an EAWM-related cyclonic anomaly east of Japan in late winter. This circulation response acts to reinforces the EAWM, leading to further lower-tropospheric cooling around Japan. These findings highlight the active role of the midlatitude WNP and importance of the atmosphere–ocean interactions in driving the EAWM variability.
   EAWM

10. [Soukissian et al. 2025] Abstract. The Copernicus European Regional Reanalysis (CERRA) was released in August 2022, providing a continental atmospheric reanalysis, and, in addition, the New European Wind Atlas (NEWA) is a recently released hindcast product that can be used to create a high temporal and spatial resolution wind resource atlas of Europe. In order to demonstrate the suitability of the NEWA and CERRA wind datasets for offshore wind energy applications, the accuracy of these datasets was assessed for the Mediterranean Sea, a basin with a high potential for the development of offshore wind projects. Long-term in situ measurements from 13 offshore locations along the basin were used in order to assess the performance of the CERRA and NEWA wind speed datasets in the hourly and seasonal time scales by using a variety of different evaluation tools. The results revealed that the CERRA dataset outperforms NEWA and is a reliable source for offshore wind energy assessment studies in the examined areas, although special attention should be paid to extreme value analysis of the wind speed.
    Newa and Cerra evaluation over the Mediterranean

11. [Sobolowski et al. 2025] Abstract. High-resolution climate information is critical for the Vulnerability, Impacts, Adaptation, and Climate Services (VIACS) communities. Coordinated ensembles generated by initiatives like the Coordinated Regional Climate Downscaling Experiment (CORDEX) provide consistent and comparable information for the present and future over all land areas of the globe. This manuscript focuses on the European CORDEX initiative (EURO-CORDEX) and its coordinated effort to build regional climate ensembles for the years to come. In its first phase, EURO-CORDEX produced a rich ensemble of regional climate simulations under different representative concentration pathway scenarios. The EURO-CORDEX dataset is openly available and was fed into the Regional Atlas of the IPCC Sixth Assessment Report. However, this ensemble suffered from several shortcomings, which the com- munity seeks to address in the next phase of production. Chief among these is the oft-cited criticism that the selection of GCMs that provide input to the regional climate models was not rigorous and that the resulting ensemble represents an “ensemble of opportunity.” The present paper provides a description of how the community has addressed these shortcomings. We present a comprehensive, flexible, and traceable evaluation framework and toolkit for assessing the suitability of GCMs for downscaling, using EURO-CORDEX as an example. Its value lies in its explicit recognition of sub- jectivity and mechanisms implemented to transparently track decision-making. Further, the utility of the framework extends well beyond predownscaling decisions to also include postdownscaling investigations performed by the VIACS communities and beyond, to include researchers investigating such topics as model biases, future constraints, and exploring future storylines.
    GCM selection, best practices

12. [Wang et al. 2025] Abstract. To unravel the equilibrium climate sensitivity (ECS) changes of the models of the Coupled Model Intercomparison Project (CMIP) during the upgrade, 10 pairs of CMIP phase 5 (CMIP5) and phase 6 (CMIP6) models from different centers were categorized into high and low ECS groups according to their ECS and surface air temperature response to CO2. Results showed that the higher ECS of the CMIP6 multimodel mean is derived primarily from five models of the high group, and is contributed by both stronger positive cloud feedback (CF) and stronger albedo feedback relative to the corresponding values in the CMIP5 models, and the spread of CF is associated with that of the ECS. Positive albedo feedback in the Arctic may be related to the relationship between weakening of the Atlantic Meridional Overturning Circulation (AMOC) and diminishing sea ice area (SIA). For example, the stronger albedo feedback in the CMIP6 high group is linked to the strongly weakening AMOC and sharply reducing SIA, further associated with their mean states compared with those of the CMIP5 models. The higher CF in the CMIP6 high group results from the greater reduction in both cloud area fraction (CAF) and ice water path (IWP) and the weaker increase in the liquid water path (LWP), leading to enhanced shortwave CF and reduced longwave CF. Furthermore, when the total precipitation response is dominated by only the convective or stratiform component, it is prone to substantial increase by the model upgrade, thereby notably affecting the changes in CAF, IWP, and LWP and the variation in CF and ECS in the high group
    Climate sensitivity cmip6

13. [Zuo et al. 2025] Abstract. Accurate surface wind speed data are vital for atmospheric science, climatology, and energy applications. European Centre for Medium-Range Weather Forecasts Reanalysis v.5 (ERA5), as one of the most widely used global reanalysis datasets, has insufficient assessment of its applicability across diverse landform types. Using the gridded observational dataset over China (CN05.1) and the Global Basic Landform Units dataset, this study evaluated the surface wind speed data from ERA5 over various altitudinal zones and undulating terrains in China via root-mean-square differences (RMSD) and mean absolute percentage error (MAPE) against CN05.1 observations. Results reveal significant regional variations, with ERA5 effectively capturing the spatial distribution of mean wind speeds but systematically underestimating magnitudes, particularly in plateau and mountainous regions. ERA5 reanalysis fails to reproduce the observed altitudinal increase in surface wind speed. Elevation-dependent biases are prominent, with RMSD and MAPE increasing from low-altitude to high-altitude areas. Terrain complexity exacerbates errors, showing maximum deviations in high-relief mountains and minimum deviations in hilly regions. These biases evolve seasonally, peaking in spring and reaching minima in winter. In summary, discrepancies between observations and ERA5 vary with altitude, topographic relief, and season. The most significant deviations occur for spring surface winds in high-altitude, high-relief mountains, with mean RMSD reaching 3.3 m/s and MAPE 553%. The findings highlight the limitations of ERA5 reanalysis data in scientific and operational contexts over complex terrains.
    Wind, reanalyses, China