Atmospheric Research最新文献

{"title":"An Evolution-Unet-ConvNeXt approach based on feature fusion for enhancing the accuracy of short-term precipitation forecasting","authors":"Yihong Su ,&nbsp;Qiming Cheng ,&nbsp;Yang He ,&nbsp;Fei Liu ,&nbsp;Jun Liu ,&nbsp;Jiayue Zhu ,&nbsp;Ye Rao ,&nbsp;Yunsong Chao ,&nbsp;Zhen Liu ,&nbsp;Yao Chen","doi":"10.1016/j.atmosres.2025.107984","DOIUrl":"10.1016/j.atmosres.2025.107984","url":null,"abstract":"<div><div>Accurate short-term convective weather prediction is crucial for mitigating the impact of natural disasters. Although radar echo extrapolation is a commonly employed forecasting method, traditional optical flow-based approaches face computational accuracy challenges when dealing with rapidly changing weather systems. Additionally, some deep learning models experience degradation in prediction accuracy due to blurring effects over extended forecast periods. In this study, we proposed Evolution-Unet-ConvNeXt, a novel deep learning model that effectively addresses these limitations by incorporating feature fusion of latent physical information. The experiments conducted on MeteoNet dataset have demonstrated a significant enhancement in prediction accuracy and reduction of blurring effects when dealing with complex convective phenomena using this model. The Evolution module successfully extracted both motion and intensity fields from radar images, while the recently developed Unet-ConvNeXt network enhanced the efficiency of feature extraction and processing workflow. Quantitative evaluations indicated that our model achieved substantial improvements in meteorological metrics, such as Critical Success Index (CSI) and Probability of Detection (POD), as well as in image clarity and spatial structure metrics like Tenengrad (TEN) and Structure Similarity Index Measure (SSIM), compared to existing baseline model architectures. Furthermore, qualitative analysis of specific rainfall events demonstrated that the robust predictive capability of this model for the intricated nonlinear dynamics of intense echo weather systems.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107984"},"PeriodicalIF":4.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating diurnal cloud cycle and its radiative effects from CMIP6","authors":"Xinyi Han,&nbsp;Jing Su,&nbsp;Xingzhu Deng,&nbsp;Nan Peng,&nbsp;Weiqi Lan","doi":"10.1016/j.atmosres.2025.107985","DOIUrl":"10.1016/j.atmosres.2025.107985","url":null,"abstract":"<div><div>Diurnal cloud cycle (DCC) is closely related not only to the physical processes of cloud formation and development, but also to the different times of the day when clouds cause different radiative effects, which can significantly affect the Earth-atmosphere energy system and its hydrological cycle. Compared with the large number of model assessment studies on seasonal and interannual characteristics of clouds, fewer studies assessed DCC and its radiative effects. In this study, we select three characteristic parameters of DCC, namely mean cloud cover, amplitude and factor of centroid (F), and carry out a quantitative assessment of CMIP6 simulation results based on a systematic analysis of global DCC characteristics and Diurnal cloud cycle radiative effect (DCCRE) using the 2001–2014 ISCCP, CERES satellite observations and MERRA2 reanalysis. The main factors affecting DCCRE are also investigated. The results show that the models perform well in terms of daily mean cloud cover, but diurnal amplitude is smaller in some regions (e.g., the Southern Ocean); and there are large inter-model differences. However, limited comparative results between CMIP5 and CMIP6 indicate that the CMIP6 model makes a significant improvement in simulating the daily amplitude of cloud cover. We also find significant differences in daily phase of cloud amount between CMIP5&amp;6 models and satellite results, namely the models are unable to accurately simulate the timing of daily cloud appearance, suggesting that the models do not represent cloud formation and maintenance mechanisms accurately. The satellite results show that the net radiative effects caused by DCC is mainly dominated by shortwave and that there are significant regional differences. The cloud daily amplitude shows a strong correlation with DCCRE globally, which is the main factor affecting DCCRE. In regions with significant daily variations in cloud cover, cloud daily fluctuations can induce radiative forcing of approximately ±15 W/m² at TOA. However, the global distribution of simulated DCCRE of the CMIP6 models is significantly different from that of the satellite data, and the correlation between simulated DCCRE and amplitude is not exhibited in most regions, which is mainly due to the inaccuracy of the models in simulating cloud amplitude and phase, resulting in simulated radiative flux error.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"318 ","pages":"Article 107985"},"PeriodicalIF":4.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploration of daytime atmospheric boundary layer thermodynamics across fronts over land using in-situ airborne measurements","authors":"Zachary Medley,&nbsp;Sandip Pal","doi":"10.1016/j.atmosres.2025.107980","DOIUrl":"10.1016/j.atmosres.2025.107980","url":null,"abstract":"<div><div>An accurate numerical weather prediction (NWP) model for the atmospheric boundary layer (ABL) has remained a demand of society, agriculture, energy sectors, policy makers, and urban planners. Even miniscule inaccuracies in initial and boundary conditions and associated parameterizations can cause errors in NWP forecasts. The combination of factors such as synoptic scale airmass exchange, convergence, lifting, subsidence, convection initiation, and cloud formation cause frontal systems to be particularly complex with respect to ABL kinematics and thermodynamics. Though previous studies provided extensive information on surface fronts, empirical evidence of the horizontal and vertical variability in front-relative daytime ABL thermodynamic features remained underexplored. We investigated the impacts of frontal passages on daytime ABL thermodynamics during summer and winter across three regions of the continental US using in-situ aircraft measurements of state variables. Results revealed that ABL moisture heterogeneity during frontal passages may occur due to terrain heterogeneity, front-induced precipitation and subsequent soil moisture impacts, and synoptic scale mixing near frontal boundaries. The vertical contrasts in moisture between the ABL and overlying free troposphere were larger in the warm sectors than the cold sectors for most cases due to cold air advection and enhanced turbulent mixing near the front. The vertical contrasts in moisture did not yield a clear pattern based on sector, meaning that the vertical moisture structures in our cases depended on the properties of the individual airmasses. Our findings on front-relative ABL thermodynamic features provide unprecedented information which could help improve parameterizations for more accurate NWP for frontal ABL regimes.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107980"},"PeriodicalIF":4.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 sea ice on sulfate aerosol budgets in Antarctic Regions with distinct climate conditions","authors":"Bo Zhang ,&nbsp;Guitao Shi ,&nbsp;Chuanjin Li ,&nbsp;Su Jiang ,&nbsp;Yilan Li ,&nbsp;Guangmei Wu ,&nbsp;Hongmei Ma ,&nbsp;Imali Kaushalya Herath ,&nbsp;Danhe Wang","doi":"10.1016/j.atmosres.2025.107974","DOIUrl":"10.1016/j.atmosres.2025.107974","url":null,"abstract":"<div><div>Sulfate (SO₄²⁻) is an essential constituent of aerosols that play an important role in regulating global climate. Over the past decades, polar sea-ice cover changed significantly, potentially influencing the atmospheric budget of SO₄²⁻. However, limited research has been conducted to quantify the effects of sea ice on atmospheric SO₄²⁻ over different times and regions. Here, we report the SO₄²⁻/Na⁺ mass ratios of aerosols and precipitation samples collected in coastal East Antarctica and the Antarctic Peninsula during 2016–2022. The SO₄²⁻/Na⁺ mass ratios at both sites show similar seasonal trends; aerosols display higher ratios than precipitation in summer, with no significant difference in winter, possibly due to precipitation preferentially removing coarse-mode aerosols. The percentage of air mass travelling time over sea ice (P-Time) is positively correlated with SO₄²⁻/Na⁺ mass ratio (or nss-SO₄²⁻ concentrations) in summer, suggesting the enhanced atmospheric SO₄²⁻ production over sea ice due to higher dimethyl sulfide (DMS) emissions and/or enhanced oxidation chemistry of DMS. But this relationship becomes negative during winter, suggesting the predominant influence of sea salt aerosols (SSA) from the sea ice surface on atmospheric SO₄²⁻ levels. In winter, the SO₄²⁻/Na⁺ mass ratio appears to be relatively invariable when the P-Time exceeds ∼40–60 %, ranging from ∼0.08 to 0.18. The lower limit of the mass ratio, ∼0.08, likely representing the influence of sea ice SSA on the mass ratio. Based on this value, it is estimated that approximately half of the atmospheric SO₄²⁻ in winter originates from sea ice SSA. These findings highlight the importance of sea ice on aerosol budgets and atmospheric chemistry in polar regions.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107974"},"PeriodicalIF":4.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical loss and source apportionment of atmospheric volatile organic compounds in a typical basin city of the Chengdu-Chongqing Economic Circle","authors":"Xingnuo Ren ,&nbsp;Fengwen Wang ,&nbsp;Xiaochen Wang ,&nbsp;Mulan Chen ,&nbsp;Weikai Fang ,&nbsp;Xu Deng ,&nbsp;Peili Lu ,&nbsp;Zhenliang Li ,&nbsp;Hai Guo ,&nbsp;Neil L. Rose","doi":"10.1016/j.atmosres.2025.107979","DOIUrl":"10.1016/j.atmosres.2025.107979","url":null,"abstract":"<div><div>Volatile organic compounds (VOCs) are key precursors in ozone formation, and their photochemical losses during atmospheric transport critically influence pollution characterization and source apportionment. The Chengdu-Chongqing region experiences heightened ozone pollution during the summer months. In light of this, we conducted an in-depth analysis of the atmospheric concentrations and photochemical losses of 56 VOC species in Rongchang of Chongqing, a representative city within the Chengdu-Chongqing Economic Circle from June to September 2023. We employed a combination of Positive matrix factorization and backward trajectory analysis to comprehensively resolve emission sources. The results indicate that not considering photochemical losses could lead to substantial underestimations in VOC concentrations (TVOC, 20.87 %), ozone formation potential (OFP, 27.40 %) and hydroxyl radical loss (L_OH, 56.20 %). Positive matrix factorization (PMF) analysis, based on the initial and observed concentrations, revealed that the motor vehicle emissions are overestimated by 7.95 % if neglecting the photochemical losses. Conversely, the industrial emissions, natural emissions, fossil fuel combustion, and solvent use sources are underestimated by 70.49 %, 44.24 %, 13.02 %, and 25.07 %, respectively. Backward trajectory analysis identified that industrial emissions predominantly originated from southeastern Sichuan and southwestern Chongqing, while solvent use emissions were concentrated in the main urban area of Chongqing. This study quantifies the impact of photochemical reactions on the characterization of atmospheric VOCs and source apportionment in Chongqing. The results provide critical insights to inform more effective control strategies for VOC pollution in the Chengdu-Chongqing metropolitan area.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107979"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the performance of GSMaP and IMERG in representing the diurnal cycle of precipitation in the Philippines during the southwest monsoon season","authors":"Enrico Alejandro S. Taña ,&nbsp;Lyndon Mark P. Olaguera ,&nbsp;Shane Marie A. Visaga ,&nbsp;Angela Monina T. Magnaye ,&nbsp;Alyssa Gewell A. Llorin ,&nbsp;Faye Abigail T. Cruz ,&nbsp;Jose Ramon T. Villarin ,&nbsp;Jun Matsumoto","doi":"10.1016/j.atmosres.2025.107983","DOIUrl":"10.1016/j.atmosres.2025.107983","url":null,"abstract":"<div><div>The Philippines faces the challenge of having a limited number of rain-gauge stations, which are a vital source of observation data. Satellite-based precipitation data is a viable alternative; however, it is necessary to assess the strengths and weaknesses of these products over various regions in the Philippines. This study analyzes the performance of two leading products from the Global Precipitation Measurement (GPM) mission, namely: GSMaP_G v08 and IMERG_F v07. In particular, the diurnal cycle of precipitation in the Philippines during the southwest monsoon season (May to September) from 2013 to 2018 is assessed, in terms of precipitation amount (PA), frequency (PF) and intensity (PI), which has not been done in previous works. Results show that GSMaP_G outperforms IMERG_F in capturing the diurnal cycle for PA and PF, whereas IMERG_F better captures PI as GSMaP_G tends to underestimate PI consistently. In terms of timing, peak values for PA (PPA) and PF (PPF) have similar patterns for both station data and satellite products where these events develop during the afternoon to evening hours (15 to 18 Local Standard Time). Further examination of the possible drivers of these observed patterns suggests that for both station data and IMERG_F, short-duration events have the highest frequency contribution (≥ 60 %), while GSMaP_G has higher contribution (≥ 40 %) from long-duration precipitation events. However, in analyzing the contributions where intensity is considered, both station data and satellite products were observed to be dominated by short-duration light precipitation events (≥ 60 %). These results indicate that during the southwest monsoon season in the Philippines, the main drivers for PA and PF are short-duration light precipitation events, whereas PI may be driven more by localized rain showers. This may indicate that GSMaP_G is more suitable for examining hourly precipitation events that are more frequent but have a lower intensity, whereas IMERG_F may prove to be more useful when analyzing hourly precipitation events with higher intensities such as localized rain showers.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107983"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Behavior of Cloud Base Height over Sumatra Mountains Region from Ceilometer Observations","authors":"Helmi Yusnaini ,&nbsp;Marzuki Marzuki ,&nbsp;Hiroyuki Hashiguchi ,&nbsp;Ravidho Ramadhan ,&nbsp;Elfira Saufina","doi":"10.1016/j.atmosres.2025.107978","DOIUrl":"10.1016/j.atmosres.2025.107978","url":null,"abstract":"<div><div>Accurate knowledge of cloud properties is essential for reducing uncertainties in weather forecasts and improving climate prediction models. This study investigates the characteristics of cloud base height (CBH) using high-resolution ceilometer data collected at Kototabang, West Sumatra, Indonesia (0.202°S, 100.317°E), situated at 864.5 m above sea level. Analyzing data recorded over 18 years (April 2002 – December 2021), we found that clouds in Kototabang are predominantly characterized by low CBH (below 2 km), which accounts for 71.3 % of total cloud occurrences, followed by medium CBH (2–6 km) at 25.4 %. Most clouds in Kototabang consist of single-layer clouds (57.78 %), while two-layer and three-layer clouds are observed at 8.41 % and 0.56 %, respectively. Furthermore, CBH tends to decrease as the number of cloud layers increases, with the distance between cloud layers being relatively small, typically less than 0.5 km. The dominance of low CBH in Kototabang is consistent with the frequent occurrence of intense convective clouds in this region, as reported in previous studies. This pattern is also evident from cloud cover data derived from the fifth-generation ECMWF reanalysis (ERA5), which shows high cloud cover (HCC) during the wet season and low HCC during the dry season. Additionally, the mean CBH of the lowest cloud layer varies with weather conditions, reaching 1.80 km during non-rainy condition and decreasing to 1.3 km during rainfall events. CBH in Kototabang exhibits distinct seasonal and diurnal variations. The monthly cloud occurrence follows a bimodal pattern, closely aligning with the monthly average rainfall recorded by an optical rain gauge, which peaks in November and April. During the wet season (April and November), low-CBH clouds (&lt;2 km) are more dominant, whereas clouds with medium and high CBH (2–6 km) are more frequently observed during the dry season (May–July). The prevalence of low CBH in the wet season indicates the presence of thick convective clouds that develop rapidly, as corroborated by ERA5 cloud cover data. A clear diurnal pattern of CBH is also observed. In the morning (06:00–12:00 LST), when rainfall occurrence is minimal, CBH is generally higher. However, a noticeable decline in CBH is observed after 13:00 LST, coinciding with the increasing dominance of convective clouds over the Sumatran landmass. ERA5 data also support this diurnal variation. The observed CBH variations in Kototabang are a genuine atmospheric phenomenon rather than an artefact of ceilometer measurement limitations. Separating CBH data between rainy and non-rainy periods confirms the persistence of these seasonal and diurnal variations.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"317 ","pages":"Article 107978"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving soil surface evaporation estimates with transformer-based model","authors":"Mijun Zou ,&nbsp;Lei Zhong ,&nbsp;Weijia Jia ,&nbsp;Yangfei Ge ,&nbsp;Ali Mamtimin","doi":"10.1016/j.atmosres.2025.107972","DOIUrl":"10.1016/j.atmosres.2025.107972","url":null,"abstract":"<div><div>Soil surface evaporation (E) is an important component of evapotranspiration from barren or sparsely vegetated (BSV) areas, and accurately estimating E in areas with limited water resources remains challenging due to the complexity of influencing factors. In this study, a large number of global ground-based measurements from bare soil conditions were collected, and a transformer-based model based on transformer architecture was developed to estimate E. The estimated instantaneous E achieved an R value of 0.73–0.96 and an RMSE of 0.03–0.05 mm/h, outperforming the process-based model, in which the surface evaporation resistance is considered as a function of soil moisture in exponential form or power form. The RMSE value of estimated E was low when the soil was relatively dry, indicating that the model is suited for water-limited regions. Furthermore, the transformer-based model was applied to BSV regions in Northwestern China, producing spatial patterns that were not only reasonable but also more detailed and consistent with river distributions. Compared to the other two products (GLEAM and BESS), the spatial annual mean E from our model and BESS were similar, while GLEAM's result was significantly lower, particularly in summer. Our findings suggest that applying deep learning to E simulation can greatly improve the accuracy and help overcome current challenges related to unclear mechanisms and the lack of universal modeling approaches.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"316 ","pages":"Article 107972"},"PeriodicalIF":4.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topographic effects on nitrogen deposition and critical load exceedance in the Sichuan Basin, China","authors":"Mingrui Ma ,&nbsp;Yuan Ji ,&nbsp;Weiyang Hu ,&nbsp;Wenxin Zhao ,&nbsp;Yu Zhao","doi":"10.1016/j.atmosres.2025.107977","DOIUrl":"10.1016/j.atmosres.2025.107977","url":null,"abstract":"<div><div>Atmospheric reactive nitrogen (Nr) deposition plays a crucial role in linking air pollution to ecosystem risks. As the primary source region of air pollutants in southwestern China, the Sichuan Basin (SCB) consistently experiences high Nr deposition, while the impact of its complex terrain on Nr deposition remains unclear. This study applied a basin-filling experiment in WRF-CMAQ modeling to investigate the effect of special topography on Nr deposition and exceedance of critical loads in SCB. We find that the basin terrain enhanced Nr deposition in SCB, particularly for oxidized nitrogen (OXN), with its annual dry and wet deposition elevated by 28 % and 25 %, respectively. These topography-induced changes in Nr deposition further deteriorated the ecosystem. The basin topography increased the Nr exceedance of critical load from 0.14 to 0.65 keq ha⁻¹ yr⁻¹. The southwest-to-northeast gradient of Nr deposition in SCB was primarily influenced by topography-induced changes in planetary boundary layer height (PBLH) and accumulated precipitation (PREP). The vertical circulation structure in the lower troposphere and weak winds inhibited the outflow of Nr pollutants, while the leeward eddy from the surface to around 3 km due to the Tibetan Plateau blocking effect promoted the accumulation of near-surface pollutants on the western side. Additionally, the western updrafts transported sufficient moisture to higher, cooler layers, enhancing convective activities and precipitation, and thereby wet deposition. These findings improve the scientific understanding on how topography modulates regional Nr deposition and provide insights for Nr pollution control strategies for areas with complex terrain and abundant air pollutant emissions.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"316 ","pages":"Article 107977"},"PeriodicalIF":4.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the causes of cloud diurnal variation biases in global climate models using the TaiESM1","authors":"I-Chun Tsai ,&nbsp;Chein-Jung Shiu ,&nbsp;Cheng-An Chen ,&nbsp;Huang-Hsiung Hsu ,&nbsp;You-Yu Mao ,&nbsp;Wei-Chyung Wang","doi":"10.1016/j.atmosres.2025.107976","DOIUrl":"10.1016/j.atmosres.2025.107976","url":null,"abstract":"<div><div>Global climate models (GCMs) have significantly advanced in simulating mean cloud properties, yet challenges persist in accurately capturing cloud diurnal variations (CDVs), especially over land. This study explores the underlying causes of CDV biases by leveraging the Taiwan Earth System Model version 1 (TaiESM1), satellite observations, and reanalysis data. An assessment of CMIP6 models, including TaiESM1, indicates that these models perform well in simulating high and middle clouds over land and ocean. However, low clouds exhibit the weakest correlation, highlighting ongoing difficulties in their representation. Our analysis shows that TaiESM1 underestimates the diurnal amplitude of cloud fraction over land and predicts peak cloud coverage earlier than observed. While the simulated convective cloud fractions from shallow and deep convection schemes align well with observations, the stratiform cloud fractions produced by macrophysical schemes show a phase misalignment with observed CDVs. Moreover, the diurnal variations of stratiform clouds and their associated moisture tendencies deviate notably from observations, revealing limitations in the current parameterizations for stratiform clouds.</div><div>We recommend enhancing the macrophysical and microphysical parameterization schemes to address these biases. Specifically, integrating stratiform cloud macrophysics, microphysics, and turbulent boundary layer processes within GCMs, such as incorporating the Cloud Layers Unified By Binormals framework, might improve the simulation of diurnal variations in cloud fraction over land. Moreover, shifting from bulk moisture budget approaches to models emphasizing variations in convective detrainment and subgrid vertical velocities associated with turbulent mixing will enhance the realism of stratiform cloud simulations. Implementing these adjustments is anticipated to improve the accuracy of CDV simulations in TaiESM1 and other GCMs, leading to better climate simulations.</div></div>","PeriodicalId":8600,"journal":{"name":"Atmospheric Research","volume":"316 ","pages":"Article 107976"},"PeriodicalIF":4.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}