Dynamics of Atmospheres and Oceans最新文献

{"title":"Current and density observations on a flow through a contraction and over a bottom elevation at the southern edge of the Cycladic Plateau in the Aegean Sea – East Mediterranean","authors":"Harilaos Kontoyiannis ,&nbsp;Larry J. Pratt ,&nbsp;Vassilis Zervakis ,&nbsp;Mathew H. Alford ,&nbsp;Sarantis Sofianos ,&nbsp;Alexander Theocharis","doi":"10.1016/j.dynatmoce.2024.101460","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2024.101460","url":null,"abstract":"<div><p>A CTD/ADCP/surface-drifter survey in fall 2004 reveals the behaviour of a mesoscale unidirectional flow coming from the Cretan sea in the south with depths ∼1000 m and entering a channel-like area of the Cycladic shelf in the north, that forms a contraction which leads to a bottom elevation (sill depth ∼100 m), and finally returning into the Cretan Sea in the lee-side of the sill. The flow decelerates/accelerates upstream/downstream of the sill. The along-stream density contours near the sill bottom are raised prior to reaching the sill, while they deepen in the lee side of it indicating supercriticality. The long-wavelength internal wave speeds with realistic stratification and no-rotation are higher than the section averaged flow speeds and indicate subcriticality. A key element in this apparent paradox is the large height of the sill that potentially increases the body (drag) force exerted on the flow by the sill while flow blocking is also observed upstream of the sill.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101460"},"PeriodicalIF":1.7,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140825384","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}

{"title":"A fractal approach to ocean Ekman transport","authors":"Rami Ahmad El-Nabulsi ,&nbsp;Waranont Anukool","doi":"10.1016/j.dynatmoce.2024.101459","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2024.101459","url":null,"abstract":"<div><p>This work examines ocean Ekman current dynamics in fractal dimensions based on the concept of product-like fractal measure introduced recently by Li and Ostoja-Starzewski in their formulation of anisotropic continuum media. We show that fractal dimensions of the fluid affects the amplitude and the shape of the velocity profile. It was observed that fast-moving current occurs for fractal dimensions much less than unity whereas slow-moving current arises for fractal dimensions close to unity. A large flow velocity leads to a decrease in the shear rate and an increase in the viscosity, a fact that has been observed in physical oceanography.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101459"},"PeriodicalIF":1.7,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140651038","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}

{"title":"The analytical solutions of long waves over geometries with linear and nonlinear variations in the form of power-law nonlinearities with solid inclined wall","authors":"Ali Rıza Alan ,&nbsp;Cihan Bayındır","doi":"10.1016/j.dynatmoce.2024.101458","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2024.101458","url":null,"abstract":"<div><p>In this paper, we derive the exact analytical solutions for the long-wave equation in both linear and nonlinear power-law form depth and breadth geometries containing a solid inclined wall. Firstly, we give general information about the concept of partial reflection and its components, and formulate the solid inclined wall boundary condition. For these specific power-law forms of depth and breadth geometries, we show that in the presence of the solid inclined wall, the long-wave equation admits solutions in terms of Bessel-Z functions and the Cauchy–Euler series. Since the presence of solid vertical wall removes the singular point from the domain, the solution admits both the first and the second kind of the Bessel functions and Cauchy–Euler series terms. We derive results for the general case and also discuss their significance using six different geometries with solid inclined wall.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101458"},"PeriodicalIF":1.7,"publicationDate":"2024-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140558097","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}

{"title":"Developmental mechanism of the SWCV nonlinear inertial waves","authors":"Chun Liu ,&nbsp;Yueqing Li ,&nbsp;Jun Sun ,&nbsp;Yunlong Zhao ,&nbsp;Jiaqi Yu","doi":"10.1016/j.dynatmoce.2024.101457","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2024.101457","url":null,"abstract":"<div><p>Based on the Boussinosq Approximation formulas in the symmetric, cylindric coordinates, the nonlinear effects of the internal inertial gravity waves on the meso-micro scale convective activities of Southwest China Vortex system are analyzed by the multi-scale and perturbation approximation methods. The results obtain two main conclusions: (1) When the atmospheric stratification is stable, the inertial gravity waves for Southwest China Vortex may also develop into finite-amplitude wave packet with a solitonic characteristics of large amplitude and short duration, forming a long-narrow wave band which activates and organizes severe convective activities like high wind and thunderstorm of Southwest China Vortex. When the atmospheric stratification is unstable, the inertial gravity waves exhibits attenuating oscillation characteristics and develops into finite-amplitude wave packet with large amplitude and fast speed, forming queue-type wave band that activates and organizes extreme weather like persistent heavy rainfall of Southwest China Vortex. (2) Under different atmospheric stratifications, the effects of thermal forcing on the inertial gravity waves for Southwest China Vortex are different. In the stable atmospheric stratification, the thermal forcing mainly intensifies the inertial gravity waves and has no significant effect on its duration. And in the unstable atmospheric stratification, the thermal forcing not only strengthens its growth but also obviously extends its duration. The research has revealed the some nonlinear characteristics of the internal inertial gravity waves for Southwest China Vortex, and improved the theoretical understanding about the critical role of the internal inertial gravity waves dynamic processes and its influence mechanism on the meso-micro scale severe convection weather for Southwest China Vortex.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101457"},"PeriodicalIF":1.7,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0377026524000253/pdfft?md5=9e3d1b34a0176002165f9b88a13fed25&pid=1-s2.0-S0377026524000253-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140551772","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":"Intercomparison of tropical Indian Ocean circulation in ocean reanalysis and evaluation in CMIP6 climate models","authors":"P. Bhanu Deepika ,&nbsp;Soumya Mohan ,&nbsp;G. Srinivas","doi":"10.1016/j.dynatmoce.2024.101456","DOIUrl":"10.1016/j.dynatmoce.2024.101456","url":null,"abstract":"<div><p>In the present study, we assess the Tropical Indian Ocean (TIO) circulation features from the available ocean reanalysis products and the latest version of Coupled Model Intercomparison Project (CMIP6) climate model simulations. We considered the following reanalysis products; Ocean Reanalysis System 5 (ORAS5), Estimating the Circulation and Climate of the Ocean (ECCO), Global Ocean Data Assimilation System (GODAS), Ensemble Coupled Data Assimilation (ECDA), the Bluelink Reanalysis (BRAN) and Simple Ocean Data Assimilation (SODA) and compared them against in-situ observations and the satellite-derived Ocean Surface Current Analyses Real-time (OSCAR). The reanalysis products underestimate the strength and location of the Wyrtki Jets. The BRAN reanalysis performed well compared to the other products in representing the TIO surface zonal currents, followed by ORAS5. The vertical extension of subsurface zonal currents in the equatorial Indian Ocean and their seasonal maxima are well captured in ORAS5. Thus, our analysis suggests that the ORAS5 is a qualitative product to estimate the TIO circulation. We further evaluated the TIO current patterns simulated by CMIP6 models with in-situ data/ ORAS5. The majority of the models show discrepancies in simulating equatorial and south equatorial current systems with a mean bias of 0.1cms⁻¹ and 0.2cms^−1, respectively. NorESM2-MM, NorESM2-LM, CanESM5, CESM2-WACCM-FV2, and E3SM-1-ECA models showed a superior skill in reproducing the TIO circulation compared to the rest of the models. Our analysis highlights the importance of assessing various reanalysis products and coupled climate models in representing the circulation of the TIO and, consequently, their role in depicting regional weather and climate.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101456"},"PeriodicalIF":1.7,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140272558","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}

{"title":"Investigating the possibilities of temperature concentration distribution in Zayanderood based on climate change","authors":"Mohammad Nazeri Tahroudi ,&nbsp;Rasoul Mirabbasi ,&nbsp;Aliheidar Nasrolahi","doi":"10.1016/j.dynatmoce.2024.101454","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2024.101454","url":null,"abstract":"<div><p>In this study, temperature changes and its concentration distribution in the period of 1984–2015 and 2015–2100 were investigated under CanESM5 climate model and SSP126, SSP245 and SSP585 scenarios. By confirming the correlation (more than 0.96) and the efficiency coefficient of the model (more than 0.82), the trend of temperature values using modified Mann-Kendall test and temperature concentration index (TCI) values in the sub-basins of Zayanderood Dam, Iran was estimated. The results indicated a non-significant upward trend in the base period (1984–2015) and a significant increasing trend at the level of 5% in the future period (2015–2100) produced by the mentioned scenarios. According to the slope of the trend line, an increase of 1.45, 4 and 9.8 degrees Celsius is predicted during the period of 2015–2100 according to the SSP126, SSP245 and SSP585 scenarios, respectively. The evaluation of changes in TCI values in the studied area showed that in the future period, the distribution of rainfall patterns will be regular and the uniformity of temperature distribution in the SSP585 scenario is more than in the other two scenarios. The results of the temperature pattern distribution in the study area showed that according to the upcoming climate changes and under the studied scenarios, it is expected that while the study area is warming in the future, the uniformity of the temperature distribution will also appear in the months of the year. This shows the reduction of temperature fluctuations and the uniformity of the average temperature in the months of the year. The reduction of TCI values shows the equalization of average temperature changes in the seasons. The results of the investigations showed that the combination of climate change scenarios with the TCI can well show the concentration and distribution of the temperature in different periods.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101454"},"PeriodicalIF":1.7,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140191738","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}

{"title":"Evaluating the climatic state of Indian Summer Monsoon during the mid-Pliocene period using CMIP6 model simulations","authors":"Karishma Dahiya ,&nbsp;Nagaraju Chilukoti ,&nbsp;Raju Attada","doi":"10.1016/j.dynatmoce.2024.101455","DOIUrl":"10.1016/j.dynatmoce.2024.101455","url":null,"abstract":"<div><p>The Indian Summer Monsoon Rainfall (ISMR) plays a critical role in agriculture, thereby significantly affecting the economy of India. Yet, there is a large spread in the ISMR variability for future projections (by the end of 21st century) as simulated by coupled general circulation models. Gaining insight into the variations of the ISMR during warm periods could enhance our ability to understand ISMR variability in the future. In this study, we have selected the mid-Pliocene warm period from 3.0 to 3.3 million years ago (Ma), which has similar external forcing (orbital parameters) comparable to the end of the 21st century. To evaluate the ISMR mean state during the mid-Pliocene, we have used six available Coupled Model Intercomparison Project phase 6 (CMIP6) model simulations and their multi-model ensemble mean. Our analysis suggests that the ensemble of CMIP6 models is better than individual models in capturing the ISM rainfall patterns and its characteristics for the historical period of 1914–2013. During the mid-Pliocene, we find an increase in the JJAS rainfall over most parts of India in comparison to the pre-industrial period with an increase of 34% in seasonal precipitation. This higher precipitation conditions during the mid-Pliocene is accompanied by thermo dynamical (higher CO₂ forcing led to higher tropospheric temperature and higher precipitable water) and dynamical (larger tropospheric temperature gradient between Indian landmass and southern Indian Ocean corresponds to enhanced moisture transport, enhanced low-level cross-equatorial flow and intensified Monsoon Hadley Circulation) aspects.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101455"},"PeriodicalIF":1.7,"publicationDate":"2024-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140201424","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}

{"title":"Decoding low-frequency climate variations: A case study on ENSO and ocean surface warming","authors":"Rameshan Kallummal","doi":"10.1016/j.dynatmoce.2024.101453","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2024.101453","url":null,"abstract":"<div><p>Current perspectives on lower frequency variations and secular warming have predominantly been shaped by traditional anomalies that assume an annual cycle (AC) with a time-invariant amplitude. However, this anomaly framework falls short in capturing the complexity of multiple periodic modes with intricate waveforms and time dependent amplitude—the traits, in general, shared by externally forced responses of complex dynamical systems. By allowing interannual amplitude modulation of ACs, we show that the monotonic amplitude increases of the first AC of Sea Surface Temperature (SST) are manifested as the basin-wide secular warming of the ocean surface. Notably, the first SST-AC exhibits significant interannual variances and the largest linear warming rates in the Pacific Warm Pool. While the linear warming pattern mirrors that of a long-term mean SST, it depicts an entirely different warming pattern on the surface of the tropical Pacific Ocean compared to those reported so far. Moreover, all interannual warm (El Niño) and cold (La Niña) events in tropical Pacific regions are abnormal interannual modulations in the third and fourth ACs of SST, respectively. Specifically, a strong El Niño event occurs when a positive amplitude modulation leads to the overlap of two consecutive positive phases of the third AC of SST. Conversely, the absence of such overlaps during negative amplitude modulations significantly contributes to the positive skewness of SST anomalies. No systematic decadal changes in the zonal propagation characteristics of SST in the eastern Pacific (EP) and central Pacific (CP) regions were detected. These findings underscore that the secular warming and low-frequency events in EP and CP are intrinsic to three distinct ACs.</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101453"},"PeriodicalIF":1.7,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140052609","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}

{"title":"Corrigendum to “On the phenology of coastal upwelling off central-southern Chile” [Dyn. Atmos. Oceans 104 (2023) 1–17]","authors":"Richard Muñoz ,&nbsp;Odette A. Vergara ,&nbsp;Pedro A. Figueroa ,&nbsp;Piero Mardones ,&nbsp;Marcus Sobarzo ,&nbsp;Gonzalo S. Saldías","doi":"10.1016/j.dynatmoce.2024.101447","DOIUrl":"https://doi.org/10.1016/j.dynatmoce.2024.101447","url":null,"abstract":"","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101447"},"PeriodicalIF":1.7,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0377026524000150/pdfft?md5=b54b1621a0b373392695ed08e6e186c8&pid=1-s2.0-S0377026524000150-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139992434","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":"Assessment of mean precipitation and precipitation extremes in Iran as simulated by dynamically downscaled RegCM4","authors":"Azar Zarrin,&nbsp;Abbasali Dadashi-Roudbari","doi":"10.1016/j.dynatmoce.2024.101452","DOIUrl":"10.1016/j.dynatmoce.2024.101452","url":null,"abstract":"<div><p>This paper aims to assess the mean precipitation and precipitation extremes over Iran as simulated by the Regional Climate Model (RegCM4). A simulation spanning 20 years (1991–2010) at a horizontal resolution of 20 Km is driven by the NCEP / NCAR reanalysis. We evaluated the model by comparing simulated precipitation with observations using Bias, Root-Mean-Square Error, and Index of Agreement metrics. We examined the extreme precipitations based on a set of extreme indices recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI) in three categories of intensity (Rx1day and SDII), duration (CDD and CWD), and frequency (R10mm and R20mm). The linear trends are calculated using the Theil–Sen estimator method, and the statistical significance (95% confidence level) is determined by using a modified Mann-Kendall (MMK) trend test. The RegCM4 model satisfactory captured the spatial distribution of precipitation and precipitation extremes, although high bias remained in small parts of Iran, including the northwest and southeast. The northwest bias is due to spring convectional precipitation and the southeast bias could be caused by precipitation from the Asian summer monsoon system, which both of them may not be well simulated by the applied Grell convective scheme. Results indicate that the model reasonably captures Rx1day, SDII, CWD, R10mm, and R20mm Indices over Iran. In good agreement with precipitation observations, the southern coast of the Caspian Sea represents the second-highest extreme precipitation, except for SDII, which is probably due to the high frequency of rainy days in this region. The highest CDD of more than 200 days is found in the arid and semi-arid regions of the southeast. In general, precipitation decreased in most regions of Iran, especially the western, southern, and interior regions. In addition, the results reveal that heavy (R10mm) and very heavy (R20mm) precipitation events have also decreased in the same regions. Results also emphasize an increase in consecutive dry days (CDD) in most parts, especially in the southeast, which deserves more attention in future research. The decreasing trend of precipitation and the increasing trend of CDD show that Iran has become drier in the 2000 s compared to the 1990 s</p></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"106 ","pages":"Article 101452"},"PeriodicalIF":1.7,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139956536","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}