AbstractDrought‐related risks pose a threat to the agricultural sector of Guyana despite the country's wealth of freshwater resources. As a result, the advancement of the understanding of soil moisture deficits as a means of forecasting agricultural drought is needed to aid farmers, extension officers, and other agricultural decision‐makers. Hence, this study has been motivated by the following research question: Can the Tropical Applications of Meteorology using SATellite data—AgriculturaL Early waRning sysTem (TAMSAT‐ALERT) be used to assess the meteorological risk to cultivation at key points in the growing season? Due to the absence of in situ soil moisture data for the area of study, the Joint UK Land and Environment Simulator (JULES) model was used to model the historical soil moisture, based on gauge precipitation data and NCEP reanalysis data. A case study approach during the 1997 growing seasons of the rice crop was taken to determine whether the TAMSAT‐ALERT can be used to detect drought‐related risks during the growing season of the crop. Additionally, the skill of the TAMSAT‐ALERT drought forecasting system was highly dependent on the land surface state at the initialization of the forecast period. Therefore, the meteorological conditions over the area of interest mainly precipitation in the months or weeks leading up to the initialization of the forecast will have a strong influence on the soil moisture at that period.

AbstractClimate classification provides a framework for a better understanding of the dominant weather patterns in different regions of the Earth. This study aims at identifying climate zones in Iran based on the analysis of monthly temperature and precipitation over 139 synoptic stations across Iran during the period 1991–2020. Based on the application of the principal component analysis, we identified six distinct climate zones in Iran: mild and humid, cool and sub‐humid, cold and temperate semi‐arid, warm and semi‐arid, cool and arid, and warm and hyperarid. The highest precipitation occurs in the southern coastal plains of the Caspian Sea, characterized by a mild and humid climate. The climate of western Iran is identified as cool and sub‐humid, while northwestern Iran is characterized by a cold and temperate semi‐arid climate. Southwestern Iran is identified as a region with a warm and semi‐arid climate, while northeastern Iran has a cool and arid climate. Southeastern and central Iran are both characterized by a warm and hyperarid climate. The highest monthly and seasonal precipitation values over Iran occur in March (48.6 mm) and winter (134.2 mm), respectively, while the highest monthly and seasonal mean temperature values occur in July (29.1°C) and summer (28.0°C), respectively. In terms of seasonal variation, the maximum precipitation occurs in the southern coastal plains of the Caspian Sea in autumn, while the minimum occurs in southwestern Iran in summer. Our results have important implications for better understanding and analysing the climatic characteristics across Iran.

AbstractThe EU Copernicus Climate Change Service (C3S) has produced an operational climate service, called C3S Energy, designed to enable the energy industry and policymakers to assess the impacts of climate variability and climate change on the energy sector in Europe. The C3S Energy service covers different time horizons, for the past 40 years and the future. It provides time series of electricity demand and supply from wind, solar photovoltaic and hydropower, and can be used for recent trends analysis, seasonal outlooks or the assessment of climate change impacts on energy mixes in the long term. This article introduces this service and the resulting dataset, with a focus on the design and validation of the energy conversion models, based on ENTSO‐E energy data and the ERA5 climate reanalysis. Flexibility and coherence across all countries have been preferred upon models' accuracy. However, the comparison with ENTSO‐E data shows that the models provide plausible energy indicators and, in particular, allow comparing climate variability effects on power demand and generation in a harmonized manner all over Europe.

AbstractFloods as a result of severe storms cause significant impacts on lives and properties. Therefore, timely and accurate forecasts of the storms will reduce the associated risks. In this study, we look at the characteristics of a storm on 28 June, 2018 in Kumasi from a rain gauge network and satellite data, and reanalysis data. The storm claimed at least 8 lives and displaced 293 people in Kumasi, Ghana. The ability of satellite and reanalysis data to capture the temporal variations of the storm was assessed using a high temporal resolution (accumulation per minute) rain gauge data. We employed the observation data from the Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa (DACCIWA) rain gauges to assess the storm's onset, duration, and cessation. Subsequently, the performance of the ERA5 reanalysis and Global Precipitation Measurement (GPM) satellite precipitation estimates in capturing the rainfall is assessed. Both GPM and the ERA5 had difficulty reproducing the hourly pattern of the rain. However, the GPM produced variability that is similar to the observed. Generally, the region of maximum rainfall was located in the southern parts of the study domain in ERA5, while GPM placed it in the northern parts. The study contributes a verification measure to improve weather forecasting in Ghana as part of the objectives of the GCRF African Science for Weather Information and Forecasting Techniques (SWIFT) project.

AbstractThis paper analyzes rainfall data to characterize the rainy season and define rice and maize crop calendars for current and future conditions in Madagascar. The daily rainfall data are taken from observational climate records and climate model simulations from the CMIP6 under the SSP245 and SSP585 scenarios. Rainy season characteristics are calibrated to fit rice and maize crop growth stages. The comparison between the past (1950–2018) and the future (2030–2100) highlights changes in the onset and cessation dates, which happen later and earlier, respectively. This causes the reduction of the rainy season duration, which affects the rice and maize crop calendars, especially its sowing or seeding periods. The worst (best) case is mainly observed in the southeast (southwest). On the one hand, the southwestern region may need to adapt to grow rice and maize crops with short or medium crop cycles in the future. In the Highland or Central land, the length of the sowing or seeding period increases. On the other hand, the North and East face a significant reduction in the length of the sowing or seeding period. Rice endures more than maize. Growing rice crops twice a year may not be possible in the future. But rather, we observe minor changes in the West. Our analysis suggests the imperative necessity to advise smallholder farmers to rely on short crop cycle varieties of rice and maize crops. Predominantly, the harvesting period is postponed. It is recommended to carefully consider our results for the definition of food policies.

AbstractProjecting precipitation changes is essential for researchers to understand climate change impacts on hydrological cycle. This study projected future precipitation over the Hanjiang River Basin (HRB) based on the multimodel ensemble (ME) of six global climate models from Phase 6 of the Coupled Model Intercomparison Project (CMIP6). An ME method using the fusion of four machine learning (ML) algorithms (random forest [RF], K‐nearest neighbors [KNN], extra tree [ET], and gradient boosting decision tree [GBDT]) was proposed in this study. The future precipitation changes were investigated during 2023–2042 (Near‐term), 2043–2062 (Mid‐term), and 2081–2100 (Long‐term) periods, with reference to the base period 1995–2014, under three integrated scenarios (SSP1‐2.6, SSP2‐4.5, and SSP5‐8.5) of the Shared Socioeconomic Pathways (SSPs) and the representative concentration pathways (RCPs). The results show that: (1) the proposed ME method performs better than the ME mean and individual ML algorithms, with a correlation coefficient value reaching 0.88 and Taylor skill score reaching 0.764. (2) The precipitation under SSP5‐8.5 has the largest upward trend with the annual precipitation variation range of −9.27% to 112.84% from 2023 to 2100, followed by SSP2‐4.5 with −30.48% to 44.67%, and the smallest under SSP1‐2.6 with −37.19% to 37.78%, which show a significant trend of humidification over the HRB in the future. (3) The precipitation changes over the HRB are projected to increase over time, with the largest in the Long‐term, followed by Mid‐term, and the smallest in the Near‐term. (4) The northeastern parts of the HRB are projected to experience a large precipitation in the future, and the southeastern parts are smaller. (5) Uncertainties in the projected precipitation over the HRB still exist, which can be reduced by ME. The findings obtained in this study have important implications for hydrological policymakers to make adaptive strategies to reduce the risks of climate change.

AbstractIn 2019, Hurricane Dorian affected Atlantic Canada with widespread impacts across the region. In the days preceding landfall, there was a great deal of discussion about the storm and its potential impacts. This discussion also extended onto Twitter, which provided a platform for users to engage with storm‐related information. In this research, we disseminated a questionnaire to residents of Atlantic Canada from late September to late October through Qualtrics, an online survey provider. The questionnaire explored how Twitter influenced respondents' (n = 1218) self‐reported informational behaviors (i.e., searching, sharing, and processing) and behavioral responses before, during, and after the storm. The results demonstrate that users' informational needs and preferences were closely related to their online behaviors. For example, conduits (i.e., those who both searched for and shared information) were highly proactive users who disseminated information about evacuations, recommended protective actions, and other official guidance more so than others. Conduits were also the most likely to heed official guidance in terms of their own preparedness and response. Amplifiers (i.e., those who only share information) and consumers (i.e., those who only search for information) were also motivated to take action by information they saw online, albeit at lower rates than conduits. Lastly, the results demonstrate that users can be positively influenced by information they see online even if they do not actively engage with it. Taken together, the results of this study suggest that Twitter users may interact with storm‐related information in more nuanced and complex ways than previously understood.

AbstractThe study uses numerical weather prediction models to predict the occurrence of heavy convective rainfall associated with the passage of the African Easterly Wave (AEW) during the period 23–26 August 2017 over Nigeria. Fraction skill score (FSS) and method for object‐based diagnostic evaluation (MODE) verification techniques were applied to verify how well the models predict the high‐impact event and to demonstrate how these tools can support operational forecasting. Ensemble model forecasts at a convective scale from UK Met Office Unified Model (MetUM) and a one‐way nested weather research and forecasting (WRF) model were compared with the integrated multisatellite retrievals for global precipitation measurement (IMERG GPM). The purpose is to examine skills of improved model resolution and ensemble in reproducing rainfall forecasts on useful scales and how the skill varies with spatial scale. WRF 2 and 6 km model forecasts show comparable skill at smaller grid scales. The skill of MetUM improves dramatically when the verification statistics are applied to the ensemble mean of the binary fields of the individual member forecast. The object‐based analysis reveals a similar structure as observed, although displaced eastwards. Most improvement occurred for heavier rainfall events associated with the passage of the AEW. WRF 6 km compares reasonably well with WRF 2 km in terms of shape and structure of rainfall underscoring the ability of the model to reasonably represent convection at 6 km horizontal resolution. The ensemble members in MetUM explicitly reproduce convection at 4 km resolution but are displaced at about 166 km behind observed rainfall.

AbstractThe increasing impact of severe weather over Europe on lives and weather‐sensitive economies can be mitigated by accurate 0–6 h forecasts (nowcasts), supporting a vital ‘last line of defence’ for civil protection and many other applications. Recognizing lack of skill in some complex situations, often at convective and local sub‐kilometre scales and associated with rare events, we identify seven recommendations with the aim to improve nowcasting in Europe by the national meteorological and hydrological services (NMHSs) by 2030. These recommendations are based on a review of user needs, the state of the observing system, techniques based on observations and high‐resolution numerical weather models, as well as tools, data and infrastructure supporting the nowcasting community in Europe. Denser and more accurate observations are necessary particularly in the boundary layer to better characterize the ingredients of severe storms. A key driver for improvement is next‐generation European satellite data becoming available as of 2023. Seamless ensemble prediction methods to produce enhanced weather forecasts with 0–24 h lead times and probabilistic products require further development. Such products need to be understood and interpreted by skilled forecasters operating in an evolving forecasting context. We argue that stronger co‐development and collaboration between providers and users of nowcasting‐relevant data and information are key ingredients for progress. We recommend establishing pan‐European nowcasting consortia, better exchange of data, common development platforms and common verification approaches as key elements for progressing nowcasting in Europe in this decade.

AbstractIt is important for territorial spatial planning to master meteorological disaster risk under the conditions of climate change and then carry out risk adaptation planning according to local conditions. Taking Beijing, a large city in China, as an example, a meteorological disaster risk assessment model was established based on the framework of hazard factors, disaster‐bearing body exposure, and vulnerability of underlying surface. Combined with 11 years of observation data from 293 high‐density weather stations, the rainstorm and high‐temperature risks of urban, agriculture, and ecological spaces were studied. The results show that (1) rainstorms and high‐temperature are mainly distributed in the built‐up areas of plain towns, which are the climate risk factors that need to be considered. (2) The central city of Beijing is at a high risk of rainstorms and high temperature, indicating that the underlying surface and disaster‐bearing body are highly vulnerable to meteorological disasters. (3) In suburbs with agricultural land, there is a certain rainstorm risk in Fangshan and Daxing districts, and a risk of high temperatures in the southern part of Tongzhou and Daxing. (4) The risk of high temperatures in the ecological space (eco‐zone) is relatively low, but the rainstorm risk is relatively high in Pinggu and Miyun. (5) The strategies of coping with rainstorm and high‐temperature disaster risk in Beijing's territorial space planning were discussed.