Atmospheric Science Letters最新文献

{"title":"Improving vertical detail in simulated temperature and humidity data using machine learning","authors":"Joana D. da Silva Rodrigues,&nbsp;Cyril J. Morcrette","doi":"10.1002/asl.1288","DOIUrl":"https://doi.org/10.1002/asl.1288","url":null,"abstract":"<p>Atmospheric models used for weather forecasting and climate predictions discretise the atmosphere onto a vertical grid. There are however atmospheric phenomena that occur on scales smaller than the thickness of those model layers. The formation of low-level clouds due to temperature inversions is an example. This leads to atmospheric models underestimating, or even missing, these clouds and their radiative effects. Using radiosonde observations as training data, a machine learning model is used to improve the vertical detail of modelled profiles of temperature and specific humidity. In addition, a physics-informed machine learning model is developed and compared to the traditional approach; showing improvements in the cloud fraction profiles calculated from its predictions. The vertically enhanced profiles also improve the representation of layers of convective inhibition and anomalous refractivity gradients. This work facilitates targeted improvements to the representation of certain atmospheric processes without the burden of increased memory and computational cost from increasing vertical resolution throughout the whole model.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1288","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143248777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A generalized extreme value approach for the analysis of stationary climatic covariate in a Mediterranean city","authors":"Cherif Semia","doi":"10.1002/asl.1291","DOIUrl":"https://doi.org/10.1002/asl.1291","url":null,"abstract":"<p>Extreme value theory (EVT) is used as univariate extreme value analysis (EVA) in order to analyze and model the covariates temperature, relative humidity (RH) and the thermal comfort index (humidex) issued from a dataset of 38 years in Tunis. It is a South Mediterranean area known as a hotspot for climate change. The best approach is to reduce the data considerably by taking annual block maxima from mean monthly data. It will converge to a generalized extreme value distribution in order to estimate the return levels of the studied parameters. The stationarity of the series are checked by augmented Dickey-Fuller test. The modeling of the three parameters shows a Weibull distribution pattern. The extreme/maximum monthly means temperature of 30.2°C and humidex of 39.4 have a common return level between 300 and 350 years. The highest mean monthly RH of 86.0% is expected to be exceeded every 50 years. For the next 38 years, the maxima monthly mean temperatures are expected to be stable, and the maxima monthly mean RH values, as well as the humidex monthly mean maxima are expected to decrease. The percentile air temperature hot day (TX90p) and night (TN90p) indices show globally linear upward trends and the ones of cold days (TX10p) and cold nights (TN10p) have a downward trend. The diurnal yearly temperature range shows an almost flat trend for its evolution through the years of study.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1291","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial and temporal dependence in distribution-based evaluation of CMIP6 daily maximum temperatures","authors":"Mala Virdee,&nbsp;Ieva Kazlauskaite,&nbsp;Emma J. D. Boland,&nbsp;Emily Shuckburgh,&nbsp;Alison Ming","doi":"10.1002/asl.1290","DOIUrl":"https://doi.org/10.1002/asl.1290","url":null,"abstract":"<p>Climate models are increasingly used to derive localised, specific information to guide adaptation to climate change. Model projections of future scenarios are conferred credibility by evaluating model skill in reproducing large-scale properties of the observed climate system. Model evaluation at fine spatial and temporal scales and for rare extreme events is critical for provision of reliable adaptation-relevant information, but may be challenging given significant internal variability and limited observed data in this setting. Comparing distributions of physical variables from historical simulations of Coupled Model Intercomparison Project models against observed distributions provides a comprehensive, concise and physically-justified skill measure. Calculating divergence between distributions requires aggregation of data spatially or temporally. The spatial and temporal scales at which a divergence measure converges to a consistent value can indicate the scales at which a well-defined climate signal emerges from internal variability. Below this threshold, there may be insufficient data for robust evaluation, particularly for rare extremes. Here, the behaviour of several divergence measures in response to spatial and temporal aggregation is analysed empirically to give a novel evaluation of CMIP6 daily maximum temperature simulations against reanalysis. Some key insights presented here can inform methodological choices made when deriving adaptation-relevant information. Convergence varies according to model, geographic region and divergence measure; selection of the level of precision at which models can provide reliable information therefore requires a context-specific understanding. For this purpose, an interactive tool provided alongside this study demonstrates scale-dependent evaluation across several geographic regions. Commonly applied measures are found to be only weakly sensitive to discrepancies in the tails of distributions.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1290","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near-surface permafrost extent and active layer thickness characterized by reanalysis/assimilation data","authors":"Zequn Liu,&nbsp;Donglin Guo,&nbsp;Wei Hua,&nbsp;Yihui Chen","doi":"10.1002/asl.1289","DOIUrl":"https://doi.org/10.1002/asl.1289","url":null,"abstract":"<p>Whilst permafrost change is widely concerned in the context of global warming, lack of observations becomes one of major limitations for conducting large-scale and long-term permafrost change research. Reanalysis/assimilation data in theory can make up for the lack of observations, but how they characterize permafrost extent and active layer thickness remains unclear. Here, we investigate the near-surface permafrost extent and active layer thickness characterized by seven reanalysis/assimilation datasets (CFSR, MERRA-2, ERA5, ERA5-Land, GLDAS-CLSMv20, GLDAS-CLSMv21, and GLDAS-Noah). Results indicate that most of reanalysis/assimilation data have limited abilities in characterizing near-surface permafrost extent and active layer thickness. GLDAS-CLSMv20 is overall optimal in terms of comprehensive performance in characterizing both present-day near-surface permafrost extent and active layer thickness change. The GLDAS-CLSMv20 indicates that near-surface permafrost extent decreases by −0.69 × 10⁶ km² decade⁻¹ and active layer deepens by 0.06 m decade⁻¹ from 1979 to 2014. Change in active layer is significantly correlated to air temperature, precipitation, and downward longwave radiation in summer, but the correlations show regional differences. Our study implies an imperative to advance reanalysis/assimilation data's abilities to reproduce permafrost, especially for reanalysis data.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1289","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel sea surface evaporation scheme assessed by the thermal rotating shallow water model","authors":"Masoud Rostami,&nbsp;Stefan Petri,&nbsp;Bijan Fallah,&nbsp;Farahnaz Fazel-Rastgar","doi":"10.1002/asl.1287","DOIUrl":"https://doi.org/10.1002/asl.1287","url":null,"abstract":"<p>In this study, a novel sea surface evaporation scheme, along with its corresponding bulk aerodynamic formulation, is proposed to estimate sea surface evaporation, columnar humidity, and precipitation distribution within the atmosphere. The scheme is based on three distinct functions, each dependent on a single variable: zonal wind velocity, tropospheric (potential) temperature, and free convection. It is shown that the normalized Clausius–Clapeyron formula requires an adjustable scaling factor for real-world applications, calibrated using empirical fitness curves. To validate the proposed approach, we employ a model based on the pseudo-spectral moist-convective thermal rotating shallow water model, with minimal parameterization over the entire sphere. ECMWF Reanalysis 5th Generation (ERA5) reanalysis data are used to compare the model's results with observations. The model is tested across different seasons to assess its reliability under various weather conditions. The Dedalus algorithm, which handles spin-weighted spherical harmonics, is employed to address the pseudo-spectral problem-solving tasks of the model.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1287","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Raindrop size distribution variability associated with size-dependent advection in convective precipitation systems","authors":"Megumi Okazaki,&nbsp;Kosei Yamaguchi,&nbsp;Tomoro Yanase,&nbsp;Eiichi Nakakita","doi":"10.1002/asl.1286","DOIUrl":"https://doi.org/10.1002/asl.1286","url":null,"abstract":"<p>Raindrop size distribution (DSD) is fundamental for understanding precipitation processes. This study utilized a two-dimensional simulation with bin cloud microphysics parameterizations to investigate the spatiotemporal variability of DSDs owing to the influence of mesoscale circulation associated with the precipitation system. The simulated multicellular convection went through developing, mature, and dissipating stages, with updraft weakening and rainfall area expanding through these stages. The width of the DSD narrowed as rainfall weakened. In addition, a significant bimodal DSD was observed during the dissipating stage. Furthermore, we investigated the spatial distribution of the number density of raindrops corresponding to the maximum, local minimum, and local maximum of the significant bimodal DSD in the dissipating stage. According to the results, the raindrops constituting the maximum, local minimum, and local maximum followed different advection processes. This size-dependent advection effect may have contributed to the bimodal DSD formation.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1286","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143113669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate change attribution of Typhoon Haiyan with the Imperial College Storm Model","authors":"Nathan Sparks,&nbsp;Ralf Toumi","doi":"10.1002/asl.1285","DOIUrl":"https://doi.org/10.1002/asl.1285","url":null,"abstract":"<p>It is difficult to model changes in the likelihood of tropical cyclones under climate change to date. We do this, for the first time, by a applying a stochastic tropical cyclone event set generated by the Imperial College Storm Model to attribute the contribution of climate change to the case of Typhoon Haiyan in 2013. Compared to a pre-industrial baseline, we estimate that a typhoon with a landfall maximum wind speed like Haiyan was larger by +3.5 m/s. This is in good agreement with previous full physics numerical model estimates. A Haiyan type of event has a current return period of 850 years, and the fractional attributable risk due to climate change is 98%. Without climate change, this event was very unlikely. The type of information available from the IRIS model could inform subsidizing of catastrophe bond yield in the context of the loss and damage fund.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1285","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143113670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Historical rainstorm in Hong Kong on 7–8 September 2023: Diagnosis, forecasting and nowcasting","authors":"Hiu Ching Tam,&nbsp;Yu-Heng He,&nbsp;Pak Wai Chan,&nbsp;Shiwei Yu,&nbsp;Huisi Mo,&nbsp;Hui Su,&nbsp;Ling-Feng Hsiao,&nbsp;Yangzhao Gong","doi":"10.1002/asl.1284","DOIUrl":"https://doi.org/10.1002/asl.1284","url":null,"abstract":"<p>On 7–8 September 2023, Hong Kong was hit by a historical and record-breaking rainstorm associated with the remnant of Tropical Cyclone Haikui (2311). The hourly rainfall recorded at the Hong Kong Observatory Headquarters once reached 158.1 mm, the highest since record began in 1884. The 24-h rainfall even exceeded 600 mm in some parts of the territory. The historical rainstorm resulted in heavy flooding and landslides, bringing significant societal impact to Hong Kong. This paper aims to review this unprecedented heavy rain event from the aspects of diagnosis, forecasting and nowcasting. Early indicators of such events over Hong Kong with substantial lead time are limited from the dynamics and thermodynamics consideration, the numerical weather prediction models, given the present technology. The only indication may come from the climatologically extreme total precipitable water. While recent research of developing a regional risk-based alerting system on the higher impact event of flooding associated with heavy rain might have potential to enhance the weather service, and emerging AI model showed some promising post-simulations, predicting historical and record-breaking rainstorms remains a challenge for operational weather forecasting and warning services.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143114003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Classification of urban underlying surfaces in Beijing and its impact on summer high temperature and heat wave event","authors":"Zuofang Zheng,&nbsp;Guirong Xu,&nbsp;Nana Li,&nbsp;Hua Gao","doi":"10.1002/asl.1283","DOIUrl":"https://doi.org/10.1002/asl.1283","url":null,"abstract":"<p>With analysis of local climate zone (LCZ) classification, approximately 52.0% of underlying surfaces in Beijing are covered by buildings with LCZ 5 (open midrise) accounting for the highest proportion, and LCZ D (low plants) is the most distributed among natural surface types. Compared to natural underlying surfaces, building underlying surfaces have higher values in the high temperature (HT) and heat wave (HW) days, HW intensity, and maximum HW duration. In recent decades, HT days on building underlying surfaces in Beijing start earlier and end later than those on natural underlying surfaces. Building underlying surfaces make greater contribution to urban heat island intensity of apparent temperature than to that of temperature, yet it is opposite for natural underlying surfaces.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1283","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143114004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the boreal summer intraseasonal oscillation on temperature and precipitation in South Korea","authors":"Yoo-Rim Jung,&nbsp;Woo-Seop Lee","doi":"10.1002/asl.1282","DOIUrl":"https://doi.org/10.1002/asl.1282","url":null,"abstract":"<p>The boreal summer intraseasonal oscillation (BSISO) is a major mode of sub-seasonal variability that regulates the summer climate in East Asia. This study investigates the four possible effects of two different time-scale BSISOs on temperature and precipitation variations in South Korea. When active BSISO convection is positioned over the subtropical western Pacific, it induces anomalous anticyclonic circulation accompanied by subsidence, leading to significant positive temperature anomalies. Conversely, the anomalous cyclonic circulation near the Korean Peninsula, resulting from suppressed convection in the subtropical western Pacific, along with low-level cold advection anomalies, contributes to a decrease in temperature. The spatial distribution of BSISO convection, which drives precipitation variation, shows a distinctive pattern of three meridionally narrow cells extending from the Philippines to the Korean Peninsula. Suppressed (enhanced) convection to the north of 20°N in the western North Pacific (WNP) promotes the northwestward expansion (eastward contraction) of the WNP Subtropical High in conjunction with a southwesterly (northeasterly) moisture flux anomaly. Furthermore, enhanced (reduced) moisture flux convergence and intensified ascending (descending) motion create favorable conditions for positive (negative) precipitation anomalies in South Korea. The combined effect of BSISOs not only amplifies the mean temperature and precipitation anomalies compared to individual modes but also increases the frequency of warmer, wetter, and drier events. Therefore, monitoring both BSISO modes together is crucial for comprehending and predicting the anomalous summer climate in South Korea.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1282","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143113457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}