Pub Date : 2025-02-06DOI: 10.1016/j.dynatmoce.2025.101539
Amirmahdi Gohari , Adem Akpınar
This study investigates future wind speed and wind energy changes in the Persian Gulf using a multi-model ensemble mean (MMM) derived from 20 CMIP6 models under the SSP5–8.5 scenario. ERA5 reanalysis wind speed data for the historical period (1995–2015) is compared to projections for the mid-future (2040–2059) and far-future (2080–2099). Quantile mapping based on Weibull distribution as a bias correction technique applied to the raw future data to obtain more reliable projections. Results show suitable wind conditions for power generation are expected to increase slightly, by 1.16 % in the mid-future and 0.75 % in the far-future. However, average annual wind speed and wind power density are projected to decrease by up to 2 % and 7 % respectively. The winter season is consistently shown to have the highest average wind speed, projected to increase over 5–7 % in the future. Spatial analysis identifies current and future wind energy hot spots, with a northward shift by the far-future. Assessments of variability over time highlight potential future alterations. The future change analysis reveals irregular regional shifts, indicating decreases in wind strength nearshore in the northern Gulf, while the southern part may experience increases, suggesting a promising trend for wind energy potential there.
{"title":"Projected changes in wind speed and wind energy resources over the Persian Gulf based on bias corrected CMIP6 models","authors":"Amirmahdi Gohari , Adem Akpınar","doi":"10.1016/j.dynatmoce.2025.101539","DOIUrl":"10.1016/j.dynatmoce.2025.101539","url":null,"abstract":"<div><div>This study investigates future wind speed and wind energy changes in the Persian Gulf using a multi-model ensemble mean (MMM) derived from 20 CMIP6 models under the SSP5–8.5 scenario. ERA5 reanalysis wind speed data for the historical period (1995–2015) is compared to projections for the mid-future (2040–2059) and far-future (2080–2099). Quantile mapping based on Weibull distribution as a bias correction technique applied to the raw future data to obtain more reliable projections. Results show suitable wind conditions for power generation are expected to increase slightly, by 1.16 % in the mid-future and 0.75 % in the far-future. However, average annual wind speed and wind power density are projected to decrease by up to 2 % and 7 % respectively. The winter season is consistently shown to have the highest average wind speed, projected to increase over 5–7 % in the future. Spatial analysis identifies current and future wind energy hot spots, with a northward shift by the far-future. Assessments of variability over time highlight potential future alterations. The future change analysis reveals irregular regional shifts, indicating decreases in wind strength nearshore in the northern Gulf, while the southern part may experience increases, suggesting a promising trend for wind energy potential there.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101539"},"PeriodicalIF":1.9,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-05DOI: 10.1016/j.dynatmoce.2025.101538
Amanuel Tsegaye Tadase , Andinet Kebede Tekile
Climate change has profound effects on precipitation, temperature, and meteorological drought patterns. This study addressed the knowledge gap regarding the future impacts of climate change on these variables in the Arsi Zone, Southeast Ethiopia. By utilizing data simulation from the Coupled Model Intercomparison Phase six (CMIP6) under two shared socioeconomic pathways (SSP2–4.5 and SSP5–8.5), future climatic conditions were projected. The quantile mapping (QM) bias correction technique was implemented in R to improve reliability. The nonparametric Mann–Kendall method and the standardized precipitation index (SPI-3) were employed for the climate variables trend analysis and to estimate drought characteristics, respectively. The findings of this study indicated an increasing trend in future precipitation and maximum temperature across both socioeconomic pathway scenarios from 2020 to 2100, with a more pronounced increase under the SSP5–8.5 scenario. The drought duration, severity, and intensity were also projected to increase from 1985–2014–2020–2049 under both scenarios. The intensity increased by 0.26 and 0.15 under SSP2–4.5 and SSP5–8.5, respectively; however, these values exhibited different trends in the two scenarios from 2020 to 2049–2080–2100. The SSP2–4.5 scenario suggested more frequent drought events, requiring specific strategies for water resource management. However, the SSP5–8.5 scenario exhibited variability in drought projections. As conclusion, there is a need for specific strategies to address the more frequent drought events projected under the SSP2–4.5 scenario, whereas the SSP5–8.5 scenario requires adaptable strategies due to the variable frequencies and it underlines the urgent need for comprehensive adaptation and mitigation strategies.
{"title":"Future projections of climate variables and meteorological drought: Insight from CMIP6 models in Southeast Ethiopia","authors":"Amanuel Tsegaye Tadase , Andinet Kebede Tekile","doi":"10.1016/j.dynatmoce.2025.101538","DOIUrl":"10.1016/j.dynatmoce.2025.101538","url":null,"abstract":"<div><div>Climate change has profound effects on precipitation, temperature, and meteorological drought patterns. This study addressed the knowledge gap regarding the future impacts of climate change on these variables in the Arsi Zone, Southeast Ethiopia. By utilizing data simulation from the Coupled Model Intercomparison Phase six (CMIP6) under two shared socioeconomic pathways (SSP2–4.5 and SSP5–8.5), future climatic conditions were projected. The quantile mapping (QM) bias correction technique was implemented in R to improve reliability. The nonparametric Mann–Kendall method and the standardized precipitation index (SPI-3) were employed for the climate variables trend analysis and to estimate drought characteristics, respectively. The findings of this study indicated an increasing trend in future precipitation and maximum temperature across both socioeconomic pathway scenarios from 2020 to 2100, with a more pronounced increase under the SSP5–8.5 scenario. The drought duration, severity, and intensity were also projected to increase from 1985–2014–2020–2049 under both scenarios. The intensity increased by 0.26 and 0.15 under SSP2–4.5 and SSP5–8.5, respectively; however, these values exhibited different trends in the two scenarios from 2020 to 2049–2080–2100. The SSP2–4.5 scenario suggested more frequent drought events, requiring specific strategies for water resource management. However, the SSP5–8.5 scenario exhibited variability in drought projections. As conclusion, there is a need for specific strategies to address the more frequent drought events projected under the SSP2–4.5 scenario, whereas the SSP5–8.5 scenario requires adaptable strategies due to the variable frequencies and it underlines the urgent need for comprehensive adaptation and mitigation strategies.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101538"},"PeriodicalIF":1.9,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-30DOI: 10.1016/j.dynatmoce.2025.101537
C.S. Neethu, B. Abish
Heat waves have emerged as one of the most severe and destructive meteorological phenomena, significantly threatening human health, agricultural productivity, and ecosystems due to their increasing frequency, duration, and intensity. In India, these extreme events predominantly occur during the pre-monsoon months (March to mid-June), with recent years (2016, 2019, 2022, and 2023) showing a clear intensification in their occurrence. This study aims to explore the dynamics of heat waves, synoptic conditions, surface land-atmosphere interactions, and regional variations in recent years across India, utilizing maximum temperature data from the India Meteorological Department (IMD) and heat wave indices to evaluate their intensity and impact. Analysis of maximum temperature data and heatwave indices highlights a notable rise in heatwave frequency and duration, particularly in northern and central India. The 2-meter (2 m) temperature anomaly in north, central, and southern India exceeded 2.5°C, while the 925hPa temperature showed significant warming trends in north and northwest India. The analysis of the spatial distribution of the planetary boundary layer (PBL) and total cloud cover (TCC) indicates reduced cloud cover and an increased PBL, intensifying heat wave conditions across north and central regions. The warm air advection and sinking air in the descending limb of the Walker circulation ensured a stable and drier atmosphere, favoring heatwave conditions. Moreover, a persistent anticyclonic circulation and its associated high-pressure system enabled heat-trapping within the atmosphere, leading to prolonged and intensified heat wave conditions. The study indicates a shift in the position and strength of the subtropical jet stream (STJ) during these years, highlighting its significant role in developing and intensifying heat waves.
{"title":"Climate variability and heat wave dynamics in India: Insights from land- atmospheric interactions","authors":"C.S. Neethu, B. Abish","doi":"10.1016/j.dynatmoce.2025.101537","DOIUrl":"10.1016/j.dynatmoce.2025.101537","url":null,"abstract":"<div><div>Heat waves have emerged as one of the most severe and destructive meteorological phenomena, significantly threatening human health, agricultural productivity, and ecosystems due to their increasing frequency, duration, and intensity. In India, these extreme events predominantly occur during the pre-monsoon months (March to mid-June), with recent years (2016, 2019, 2022, and 2023) showing a clear intensification in their occurrence. This study aims to explore the dynamics of heat waves, synoptic conditions, surface land-atmosphere interactions, and regional variations in recent years across India, utilizing maximum temperature data from the India Meteorological Department (IMD) and heat wave indices to evaluate their intensity and impact. Analysis of maximum temperature data and heatwave indices highlights a notable rise in heatwave frequency and duration, particularly in northern and central India. The 2-meter (2 m) temperature anomaly in north, central, and southern India exceeded 2.5°C, while the 925hPa temperature showed significant warming trends in north and northwest India. The analysis of the spatial distribution of the planetary boundary layer (PBL) and total cloud cover (TCC) indicates reduced cloud cover and an increased PBL, intensifying heat wave conditions across north and central regions. The warm air advection and sinking air in the descending limb of the Walker circulation ensured a stable and drier atmosphere, favoring heatwave conditions. Moreover, a persistent anticyclonic circulation and its associated high-pressure system enabled heat-trapping within the atmosphere, leading to prolonged and intensified heat wave conditions. The study indicates a shift in the position and strength of the subtropical jet stream (STJ) during these years, highlighting its significant role in developing and intensifying heat waves.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101537"},"PeriodicalIF":1.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-22DOI: 10.1016/j.dynatmoce.2025.101534
Ibrahim Shaik , M.P. Fida Fathima , P.V. Nagamani , Sandesh Yadav , Sibu Behera , Yash Manmode , G. Srinivasa Rao
The partial pressure of carbon dioxide (pCO2) in the North Indian Ocean (NIO) undergoes significant variations due to factors such as biological activity, ocean circulation patterns, and atmospheric influences. Understanding these variations is crucial for assessing the ocean role in the global carbon cycle and their impact on climate change. Estimating pCO2 through in-situ platforms is challenging due to the time-consuming, expensive, and complex nature of water sample collection, particularly under rough oceanic conditions. Conversely, remote sensing technology offers high spatiotemporal resolution data over extensive synoptic scales, making it a valuable tool for pCO2 estimation. Current models for estimating pCO2 in the NIO region are limited due to the improper selection of model parameters and the scarcity of in-situ measurements, highlighting the need for a more accurate approach. This study develops a Multiparametric Linear Regression (MLR) method, integrating satellite and in-situ observations of sea surface temperature (SST), sea surface salinity (SSS), and chlorophyll-a (Chla) concentration. To develop and validate this model, in-situ data were sourced from the Global Ocean Data Analysis Project (GLODAP). Validation results showed that the proposed MLR approach outperformed existing global models, achieving low mean relative error (MRE = 0.08), mean normalized bias (MNB = 0.013), and root mean square error (RMSE = 7.26 μatm), with a high correlation coefficient (R2 = 0.96). This study has the potential to improve understanding of carbon dynamics in the NIO region and its contribution to the global carbon cycle. The pCO2 maps generated in this study improve climate modeling and monitoring, supporting predictions and mitigation efforts. This accurate model also aids policy-making, environmental management, and ecological assessments.
{"title":"Satellite-derived ocean color data for monitoring pCO2 dynamics in the North Indian Ocean","authors":"Ibrahim Shaik , M.P. Fida Fathima , P.V. Nagamani , Sandesh Yadav , Sibu Behera , Yash Manmode , G. Srinivasa Rao","doi":"10.1016/j.dynatmoce.2025.101534","DOIUrl":"10.1016/j.dynatmoce.2025.101534","url":null,"abstract":"<div><div>The partial pressure of carbon dioxide (<em>p</em>CO<sub>2</sub>) in the North Indian Ocean (NIO) undergoes significant variations due to factors such as biological activity, ocean circulation patterns, and atmospheric influences. Understanding these variations is crucial for assessing the ocean role in the global carbon cycle and their impact on climate change. Estimating <em>p</em>CO<sub>2</sub> through in-situ platforms is challenging due to the time-consuming, expensive, and complex nature of water sample collection, particularly under rough oceanic conditions. Conversely, remote sensing technology offers high spatiotemporal resolution data over extensive synoptic scales, making it a valuable tool for <em>p</em>CO<sub>2</sub> estimation. Current models for estimating <em>p</em>CO<sub>2</sub> in the NIO region are limited due to the improper selection of model parameters and the scarcity of in-situ measurements, highlighting the need for a more accurate approach. This study develops a Multiparametric Linear Regression (MLR) method, integrating satellite and in-situ observations of sea surface temperature (SST), sea surface salinity (SSS), and chlorophyll-a (Chla) concentration. To develop and validate this model, in-situ data were sourced from the Global Ocean Data Analysis Project (GLODAP). Validation results showed that the proposed MLR approach outperformed existing global models, achieving low mean relative error (MRE = 0.08), mean normalized bias (MNB = 0.013), and root mean square error (RMSE = 7.26 μatm), with a high correlation coefficient (R<sup>2</sup> = 0.96). This study has the potential to improve understanding of carbon dynamics in the NIO region and its contribution to the global carbon cycle. The <em>p</em>CO<sub>2</sub> maps generated in this study improve climate modeling and monitoring, supporting predictions and mitigation efforts. This accurate model also aids policy-making, environmental management, and ecological assessments.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101534"},"PeriodicalIF":1.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143177318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-22DOI: 10.1016/j.dynatmoce.2025.101536
Xiangqin Xie , Run Liu , Ruyuan Xiao , Sijia Hu , Caixian Huang , Yongze Bi , Yifan Xu
This study investigates decadal variations in the frequency and intensity of extreme high temperature events (EHEs) during the summer months of July and August across the Northern Hemisphere from 1979 to 2023. Research results indicate that the frequency and intensity of EHEs on the Eurasian continent have increased more rapidly than in other Northern Hemisphere landmasses over time. By applying Empirical Orthogonal Function analysis, two dominant modes of EHEs were identified: a spatial consistency pattern and a quadrupole anomaly pattern. The spatial consistency pattern shows significant anomalies centered around the Caspian Sea and East Asia, with a notable upward trend in intensity. This pattern is strongly associated with atmospheric warming and increased sea surface temperatures in the tropical North Atlantic, which amplifies the North Atlantic-Eurasian wave train. The eastward propagation of wave activity flux, driven by the shifting positive geopotential height anomaly, further enhances the frequency and intensity of EHEs. The quadrupole anomaly pattern is characterized by four centers located in the mid-latitude region (30°N-50°N, 25°E-150°E), West Asia-South Asia-Southeast Asia, Central Europe-Northern Europe, and East Asia-Eastern West Asia. The EHEs in these regions exhibit anti-phase characteristics, meaning that while one region experiences higher-than-average frequency of EHEs, others simultaneously show lower-than-average frequency of EHEs. The formation of this quadrupole anomaly pattern is closely associated with the negative phase of the North Atlantic Oscillation (NAO). NAO influences regional temperatures by modulating the jet stream and geopotential height, forming anticyclones or cyclones that, in turn, increase or decrease EHEs. Under NAO influence, a double jet state is formed, and a blocking anticyclone emerges in the weak wind zone between the two zonal wind maxima, thus increasing the EHEs in local areas. This study underscores the importance of understanding these distinct patterns and their underlying mechanisms to better predict and manage the regional impacts of extreme heat in a changing climate.
{"title":"Characteristics and potential drivers of extreme high-temperature event frequency in Eurasia","authors":"Xiangqin Xie , Run Liu , Ruyuan Xiao , Sijia Hu , Caixian Huang , Yongze Bi , Yifan Xu","doi":"10.1016/j.dynatmoce.2025.101536","DOIUrl":"10.1016/j.dynatmoce.2025.101536","url":null,"abstract":"<div><div>This study investigates decadal variations in the frequency and intensity of extreme high temperature events (EHEs) during the summer months of July and August across the Northern Hemisphere from 1979 to 2023. Research results indicate that the frequency and intensity of EHEs on the Eurasian continent have increased more rapidly than in other Northern Hemisphere landmasses over time. By applying Empirical Orthogonal Function analysis, two dominant modes of EHEs were identified: a spatial consistency pattern and a quadrupole anomaly pattern. The spatial consistency pattern shows significant anomalies centered around the Caspian Sea and East Asia, with a notable upward trend in intensity. This pattern is strongly associated with atmospheric warming and increased sea surface temperatures in the tropical North Atlantic, which amplifies the North Atlantic-Eurasian wave train. The eastward propagation of wave activity flux, driven by the shifting positive geopotential height anomaly, further enhances the frequency and intensity of EHEs. The quadrupole anomaly pattern is characterized by four centers located in the mid-latitude region (30°N-50°N, 25°E-150°E), West Asia-South Asia-Southeast Asia, Central Europe-Northern Europe, and East Asia-Eastern West Asia. The EHEs in these regions exhibit anti-phase characteristics, meaning that while one region experiences higher-than-average frequency of EHEs, others simultaneously show lower-than-average frequency of EHEs. The formation of this quadrupole anomaly pattern is closely associated with the negative phase of the North Atlantic Oscillation (NAO). NAO influences regional temperatures by modulating the jet stream and geopotential height, forming anticyclones or cyclones that, in turn, increase or decrease EHEs. Under NAO influence, a double jet state is formed, and a blocking anticyclone emerges in the weak wind zone between the two zonal wind maxima, thus increasing the EHEs in local areas. This study underscores the importance of understanding these distinct patterns and their underlying mechanisms to better predict and manage the regional impacts of extreme heat in a changing climate.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101536"},"PeriodicalIF":1.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143177317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-20DOI: 10.1016/j.dynatmoce.2025.101535
Boris V. Divinsky, Yana V. Saprykina
The main aim of the study is to identify in the Black Sea quasi-homogeneous spatial areas and corresponding relevant features, the climatic statistical characteristics of which will determine these areas. Numerical modeling and discriminant analysis were applied. As a result of modeling an array of wind wave parameters for the period of 45 years (1979–2023) was obtained. The values of the main parameters (significant wave heights, spectrum peak periods, propagation directions) for this period at 92 points uniformly distributed over the Black Sea were analyzed. The main features, by which the zoning of the Black Sea was carried out, were climatic repeatabilities of the following parameters: significant wave heights in the ranges of hs< 1 m, 1 <hs< 3 m, 3 <hs< 5 m, hs> 5 m; and spectrum peak periods in the ranges tp< 3 s, 3 <tp< 6 s, 6 <tp< 9 s, tp> 9 s. According discriminant analysis six quasi-homogeneous areas (clusters) in the Black Sea were identified. The main zoning parameters are wave heights in the ranges 3 <hs< 5 m and hs> 5 m and periods 6 <tp< 9 s. The identified clusters are quite homogeneous in the repeatability of wave action of the north-eastern and north-western directions. The obtained quasi-homogeneous areas of the Black Sea significantly refine the zoning obtained earlier and can be used to study and forecast sea climate change.
{"title":"Quasi-homogeneous regions of climatic distributions of wind wave parameters in the Black Sea","authors":"Boris V. Divinsky, Yana V. Saprykina","doi":"10.1016/j.dynatmoce.2025.101535","DOIUrl":"10.1016/j.dynatmoce.2025.101535","url":null,"abstract":"<div><div>The main aim of the study is to identify in the Black Sea quasi-homogeneous spatial areas and corresponding relevant features, the climatic statistical characteristics of which will determine these areas. Numerical modeling and discriminant analysis were applied. As a result of modeling an array of wind wave parameters for the period of 45 years (1979–2023) was obtained. The values of the main parameters (significant wave heights, spectrum peak periods, propagation directions) for this period at 92 points uniformly distributed over the Black Sea were analyzed. The main features, by which the zoning of the Black Sea was carried out, were climatic repeatabilities of the following parameters: significant wave heights in the ranges of <em>h</em><sub>s</sub>< 1 m, 1 <<em>h</em><sub>s</sub>< 3 m, 3 <<em>h</em><sub>s</sub>< 5 m, <em>h</em><sub>s</sub>> 5 m; and spectrum peak periods in the ranges <em>t</em><sub>p</sub>< 3 s, 3 <<em>t</em><sub>p</sub>< 6 s, 6 <<em>t</em><sub>p</sub>< 9 s, <em>t</em><sub>p</sub>> 9 s. According discriminant analysis six quasi-homogeneous areas (clusters) in the Black Sea were identified. The main zoning parameters are wave heights in the ranges 3 <<em>h</em><sub>s</sub>< 5 m and <em>h</em><sub>s</sub>> 5 m and periods 6 <<em>t</em><sub>p</sub>< 9 s. The identified clusters are quite homogeneous in the repeatability of wave action of the north-eastern and north-western directions. The obtained quasi-homogeneous areas of the Black Sea significantly refine the zoning obtained earlier and can be used to study and forecast sea climate change.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101535"},"PeriodicalIF":1.9,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143177319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-30DOI: 10.1016/j.dynatmoce.2024.101524
Sudhakar Matle
The paper presents a comprehensive analysis of generating a Kuroshio current-like phenomenon using a novel mathematical model and advanced numerical methods. It helps to understand the streamline behavior on the western boundary over the time scales due to the presence of free slip conditions at the north and at the south coastal boundaries.
The ocean is modeled as a square domain occupied by homogeneous, incompressible fluid of constant density and a variable surface height. Dynamics of the flow are examined in a shallow water system. The salient parameters investigated here are the wind stress coefficient, the stochastic wind force coefficient, and time scales.
It is proved that streamlines are crowded on the western boundary through numerical study, and also these are bifurcated when the wind stress coefficient is 3.12. The bifurcation of the flow indicates the stability. It is also reported that the Milstein method and a standard numerical method are in good agreement while the Fokker–Planck equation-based method and the Milstein method are partially agreed. The solution by the Milstein method diverged while the solution by the Fokker–Planck method converged when .
{"title":"A 2D numerical study on Kuroshio currents with free slip coastal boundary","authors":"Sudhakar Matle","doi":"10.1016/j.dynatmoce.2024.101524","DOIUrl":"10.1016/j.dynatmoce.2024.101524","url":null,"abstract":"<div><div>The paper presents a comprehensive analysis of generating a Kuroshio current-like phenomenon using a novel mathematical model and advanced numerical methods. It helps to understand the streamline behavior on the western boundary over the time scales due to the presence of free slip conditions at the north and at the south coastal boundaries.</div><div>The ocean is modeled as a square domain occupied by homogeneous, incompressible fluid of constant density and a variable surface height. Dynamics of the flow are examined in a shallow water system. The salient parameters investigated here are the wind stress coefficient, the stochastic wind force coefficient, and time scales.</div><div>It is proved that streamlines are crowded on the western boundary through numerical study, and also these are bifurcated when the wind stress coefficient is 3.12. The bifurcation of the flow indicates the stability. It is also reported that the Milstein method and a standard numerical method are in good agreement while the Fokker–Planck equation-based method and the Milstein method are partially agreed. The solution by the Milstein method diverged while the solution by the Fokker–Planck method converged when <span><math><mrow><mi>ω</mi><mo>≥</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math></span>.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"109 ","pages":"Article 101524"},"PeriodicalIF":1.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-27DOI: 10.1016/j.dynatmoce.2024.101525
Javad Babagolimatikolaei
Advancements in atmospheric data have the potential to improve the accuracy of ocean modeling, as these models rely heavily on atmospheric parameters as key forcing inputs. One such dataset is the ECMWF reanalysis, with ERA5 being the latest version, succeeding ERA-Interim (ERA-I or ERAI). However, limited research has explored whether ERA5 improves ocean model accuracy compared to ERA-I. We use the ROMS model on the Adriatic Sea under two atmospheric forcing scenarios: ERA-I and ERA5. Results show that ERA5 calculates higher temperature and salinity values than ERA-I. ERA5 shows better alignment with satellite and Mediterranean reanalysis data than ERA-I. For temperature, ERA5 has a higher bias range (–2.29℃ to 0.83℃) compared to ERA-I (–2.34℃ to 0.80℃) and achieves a lower minimum bias, particularly in summer (0.02℃). Against Mediterranean reanalysis data, ERA5’s temperature bias range (–2.06℃ to 1.54℃) is lower range than ERA-I’s (–3.14℃ to 1.51℃). For salinity, ERA5 also has a smaller bias range (–0.02 PSU to 0.27 PSU) and achieves zero bias in spring, indicating a more accurate seasonal alignment than ERA-I. The warmer water temperatures in ERA5 are attributed to higher values of atmospheric parameters such as shortwave radiation flux, sensible heat flux, and air temperature, while, increased salinity is linked to more negative latent heat flux up to 10 W/m2, longwave radiation up to 5 W/m2, and higher wind speeds. These factors collectively lead to improved ocean modeling performance in ERA5.
{"title":"A comparative study of the sensitivity of an ocean model outputs to atmospheric forcing: ERA-Interim vs. ERA5 for Adriatic Sea Ocean modelling","authors":"Javad Babagolimatikolaei","doi":"10.1016/j.dynatmoce.2024.101525","DOIUrl":"10.1016/j.dynatmoce.2024.101525","url":null,"abstract":"<div><div>Advancements in atmospheric data have the potential to improve the accuracy of ocean modeling, as these models rely heavily on atmospheric parameters as key forcing inputs. One such dataset is the ECMWF reanalysis, with ERA5 being the latest version, succeeding ERA-Interim (ERA-I or ERAI). However, limited research has explored whether ERA5 improves ocean model accuracy compared to ERA-I. We use the ROMS model on the Adriatic Sea under two atmospheric forcing scenarios: ERA-I and ERA5. Results show that ERA5 calculates higher temperature and salinity values than ERA-I. ERA5 shows better alignment with satellite and Mediterranean reanalysis data than ERA-I. For temperature, ERA5 has a higher bias range (–2.29℃ to 0.83℃) compared to ERA-I (–2.34℃ to 0.80℃) and achieves a lower minimum bias, particularly in summer (0.02℃). Against Mediterranean reanalysis data, ERA5’s temperature bias range (–2.06℃ to 1.54℃) is lower range than ERA-I’s (–3.14℃ to 1.51℃). For salinity, ERA5 also has a smaller bias range (–0.02 PSU to 0.27 PSU) and achieves zero bias in spring, indicating a more accurate seasonal alignment than ERA-I. The warmer water temperatures in ERA5 are attributed to higher values of atmospheric parameters such as shortwave radiation flux, sensible heat flux, and air temperature, while, increased salinity is linked to more negative latent heat flux up to 10 W/m<sup>2</sup>, longwave radiation up to 5 W/m<sup>2</sup>, and higher wind speeds. These factors collectively lead to improved ocean modeling performance in ERA5.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"109 ","pages":"Article 101525"},"PeriodicalIF":1.9,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160134","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}
Pub Date : 2024-12-23DOI: 10.1016/j.dynatmoce.2024.101523
Suraj Singh , Christian E. Buckingham , Amit Tandon
Baroclinic instability has traditionally been examined using a model of a straight front in approximate geostrophic and hydrostatic balance. However, mesoscale curved fronts and eddies are ubiquitous in the oceans and their curvature may have an impact on baroclinic instability. In this study, we present modifications of the classical Eady and Charney problems, introducing a small amount of curvature in the small-Rossby, large-Richardson number limit. Employing quasi-geostrophic scalings for a predominantly zonal flow in cylindrical polar coordinates, we derive the governing equation of perturbation pressure in the presence of small curvature, treating this quantity as a deviation from a straight front. We find the importance of curvature principally arises through the potential vorticity (PV) gradient. Consequently, although curvature enters the Eady model via an introduction of so-called Green modes, the introduction of curvature does not modify the most unstable mode. In Charney’s model, however, the curvature of the flow introduces a depth scale that governs the vertical extent of the unstable modes and whose importance often presides over planetary beta. We find that introducing cyclonic curvature in Charney’s model increases the horizontal wavelength of the most unstable mode. We also report that curvature modifies the vertical buoyancy flux by extending the vertical scale of the most unstable mode. The possible consequences of these results are discussed. Since our present-day understanding of baroclinic instability assumes centrifugal forces in the mean state to be zero and since this undergirds existing eddy parameterizations, this study (1) offers a new interpretation of at least some of the observed vortices in the ocean and (2) suggests a weakly-curved Charney model might inform future sub-grid-scale parameterizations of baroclinic instability of curved fronts in the oceans.
{"title":"On baroclinic instability of curved fronts","authors":"Suraj Singh , Christian E. Buckingham , Amit Tandon","doi":"10.1016/j.dynatmoce.2024.101523","DOIUrl":"10.1016/j.dynatmoce.2024.101523","url":null,"abstract":"<div><div>Baroclinic instability has traditionally been examined using a model of a straight front in approximate geostrophic and hydrostatic balance. However, mesoscale curved fronts and eddies are ubiquitous in the oceans and their curvature may have an impact on baroclinic instability. In this study, we present modifications of the classical Eady and Charney problems, introducing a small amount of curvature in the small-Rossby, large-Richardson number limit. Employing quasi-geostrophic scalings for a predominantly zonal flow in cylindrical polar coordinates, we derive the governing equation of perturbation pressure in the presence of small curvature, treating this quantity as a deviation from a straight front. We find the importance of curvature principally arises through the potential vorticity (PV) gradient. Consequently, although curvature enters the Eady model via an introduction of so-called Green modes, the introduction of curvature does not modify the most unstable mode. In Charney’s model, however, the curvature of the flow introduces a depth scale that governs the vertical extent of the unstable modes and whose importance often presides over planetary beta. We find that introducing cyclonic curvature in Charney’s model increases the horizontal wavelength of the most unstable mode. We also report that curvature modifies the vertical buoyancy flux by extending the vertical scale of the most unstable mode. The possible consequences of these results are discussed. Since our present-day understanding of baroclinic instability assumes centrifugal forces in the mean state to be zero and since this undergirds existing eddy parameterizations, this study (1) offers a new interpretation of at least some of the observed vortices in the ocean and (2) suggests a weakly-curved Charney model might inform future sub-grid-scale parameterizations of baroclinic instability of curved fronts in the oceans.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"109 ","pages":"Article 101523"},"PeriodicalIF":1.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-11DOI: 10.1016/j.dynatmoce.2024.101522
Shaolei Guo , Yuehan Zhang , Xianqi Zhang , Yang Yang , Wanhui Cheng
This study aims to simulate the reservoir area by constructing a coupled model to analyze the variations in the water flow field and the migration patterns of pollutants in the Baisha Reservoir under different flow increments. One of the key challenges in this process is selecting an appropriate model and calibrating its parameters. The MIKE21 hydrodynamic-water quality coupled model was employed to simulate the reservoir area, with extensive experimental calibration of the HD and Ecolab models' parameters based on the actual conditions of Baisha Reservoir. The performance of the models was evaluated, and the results indicated a high level of reliability. In the Ecolab model, three commonly used water quality indicators—BOD, NH₃-N, and NO₃—were considered for simulation and analysis. To examine the changes in the water flow field under different flow increments, three distinct flow increment scenarios were tested. The results showed that the best simulation performance occurred when the flow increment was 30 %, with BOD improvement of 51.02 %, NH₃-N improvement of 26.31 %, and NO₃ improvement of 37.13 %. Furthermore, an ESN model was developed to predict future water quality changes in Baisha Reservoir. The accuracy of the ESN model was validated using the water quality simulation results from Scenario 3, yielding an average relative error of 3.26 %. The water quality concentrations predicted under this scenario were significantly lower than the initial concentrations, providing practical insights into addressing issues related to water quantity and quality in the reservoir.
{"title":"Simulation study of reservoir water environment based on Mike21-taking Baisha reservoir as an example","authors":"Shaolei Guo , Yuehan Zhang , Xianqi Zhang , Yang Yang , Wanhui Cheng","doi":"10.1016/j.dynatmoce.2024.101522","DOIUrl":"10.1016/j.dynatmoce.2024.101522","url":null,"abstract":"<div><div>This study aims to simulate the reservoir area by constructing a coupled model to analyze the variations in the water flow field and the migration patterns of pollutants in the Baisha Reservoir under different flow increments. One of the key challenges in this process is selecting an appropriate model and calibrating its parameters. The MIKE21 hydrodynamic-water quality coupled model was employed to simulate the reservoir area, with extensive experimental calibration of the HD and Ecolab models' parameters based on the actual conditions of Baisha Reservoir. The performance of the models was evaluated, and the results indicated a high level of reliability. In the Ecolab model, three commonly used water quality indicators—BOD, NH₃-N, and NO₃—were considered for simulation and analysis. To examine the changes in the water flow field under different flow increments, three distinct flow increment scenarios were tested. The results showed that the best simulation performance occurred when the flow increment was 30 %, with BOD improvement of 51.02 %, NH₃-N improvement of 26.31 %, and NO₃ improvement of 37.13 %. Furthermore, an ESN model was developed to predict future water quality changes in Baisha Reservoir. The accuracy of the ESN model was validated using the water quality simulation results from Scenario 3, yielding an average relative error of 3.26 %. The water quality concentrations predicted under this scenario were significantly lower than the initial concentrations, providing practical insights into addressing issues related to water quantity and quality in the reservoir.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"109 ","pages":"Article 101522"},"PeriodicalIF":1.9,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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