Dynamics of Atmospheres and Oceans最新文献

{"title":"Corrigendum to “Effects of equatorially-confined shear flow on MRG and Rossby waves” [Dyn. Atmos. Oceans 100 (2022) 101331]","authors":"Mukesh Singh Raghav , Sharath Jose , Amit Apte , Rama Govindarajan","doi":"10.1016/j.dynatmoce.2024.101499","DOIUrl":"10.1016/j.dynatmoce.2024.101499","url":null,"abstract":"","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101499"},"PeriodicalIF":1.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757542","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":"Multi-timescale variability of tropical convection in the Indo-western Pacific Ocean","authors":"Yanjun Qi,&nbsp;Ting Zhong","doi":"10.1016/j.dynatmoce.2024.101508","DOIUrl":"10.1016/j.dynatmoce.2024.101508","url":null,"abstract":"<div><div>The convective activity is one of the most important features of the tropics, which is closely related to climate variability on multiple time scales. Observational evidence of the coexistence of different time scales in the variation of tropical convective activity was presented in previous studies. This paper mainly reviews the recent progress of variability of convective system over the Indo-western Pacific sector on diurnal, synoptic, intraseasonal, interannual, and decadal-interdecadal time scales, as well as the associated physical processes. The interannual variability of tropical convective activity is strongly modulated by the anomalous large-scale Walker circulation, which is tied to ENSO event. Periodical intraseasonal oscillations in convection are the prominent feature in the tropical Indo-western Pacific Ocean. The tropical cyclones and monsoonal precipitation occurred at the equator and off-equator are closely linked to the synoptic-scale variation of convective activity, northward- and northwestward-propagating intraseasonal oscillation of convection in the Asian monsoon region during boreal summer. The impact of anomalous tropical convective system and associated large-scale circulation on climate variability is of great importance to surrounding countries in the Asian summer monsoon region.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"109 ","pages":"Article 101508"},"PeriodicalIF":1.9,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743191","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":"Impact of boundary layer parameterizations on simulated seasonal meteorology over North-East India","authors":"Neeldip Barman ,&nbsp;Sharad Gokhale ,&nbsp;Dewashish Tiwari","doi":"10.1016/j.dynatmoce.2024.101505","DOIUrl":"10.1016/j.dynatmoce.2024.101505","url":null,"abstract":"<div><div>This study evaluated the accuracy of six planetary boundary layer (PBL) parameterization schemes in simulating two different seasons of pre-monsoon and monsoon in India's North-East region through the Weather Research and Forecasting (WRF) model. Twelve one-month simulations were conducted with the PBL schemes, six each for April (pre-monsoon) and July (monsoon), and the model outputs were compared against observations. Three non-local schemes, Asymmetric Convective Model (ACM2), Yonsei University (YSU), Shin-Hong (HONG), and three local schemes, Quasi Normal Scale Elimination (QNSE), Mellor Yamada Janjic (MYJ) and Mellor Yamada Nakanishi Nino (MYNN3), were tested. The meteorological variables of temperature, relative humidity (RH), wind speed, wind direction, and rainfall were evaluated, and the performance of each scheme for each meteorological variable is reported. The 2 m temperature (T2) variable was well simulated by ACM2, MYJ in April, and YSU in July, while MYNN3 best simulated the 2 m RH (RH2) during both seasons. 10 m wind speed (WS10) and directions (WD10) were better simulated by MYNN3, HONG and YSU. HONG also best-simulated rainfall in April and MYJ in July. April and July being rainfall periods, an analysis of the schemes’ simulated rainfall frequency was also carried out. Moreover, the PBL schemes were also ranked, considering their combined performance with all the above meteorological parameters. While considering both the seasons and all meteorological variables, the scale-aware scheme, HONG, was the best scheme and can be used to simulate both seasons. Additionally, an in-depth analysis of surface and atmospheric parameters was also carried out to reason the simulated meteorology. QNSE expends the highest amount of its surface energy through surface evaporation, leading to the lowest surface skin temperature and T2 predictions. In contrast, MYNN3 produced the lowest mixing, which caused the moistest boundary layer, highest RH, cloud cover, and highly overestimated rainfall. Besides evaluation, which will help to choose a suitable PBL scheme for weather predictions in this region, this study also identifies the characteristics and deficiencies of PBL and surface layer schemes for improvement.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101505"},"PeriodicalIF":1.9,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652131","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":"Mapping the dynamics of global sea surface nitrate using ocean color data","authors":"Ibrahim Shaik ,&nbsp;P.V. Nagamani ,&nbsp;Yash Manmode ,&nbsp;Sandesh Yadav ,&nbsp;Venkatesh Degala ,&nbsp;G. Srinivasa Rao","doi":"10.1016/j.dynatmoce.2024.101507","DOIUrl":"10.1016/j.dynatmoce.2024.101507","url":null,"abstract":"<div><div>Sea Surface Nitrate (SSN) is crucial for assessing phytoplankton growth and the initiation of new production within the marine environment. Precise estimation of SSN concentrations plays a significant role in understanding marine ecosystem dynamics. In this study, the deep learning model TabularNet (TabNet) was assessed using quality-controlled in-situ measurements from the Global Ocean Data Analysis Project (GLODAP). These measurements included Sea Surface Temperature (SST), Sea Surface Salinity (SSS), Chlorophyll-a concentration (Chla), and nitrate, collected from various regions of the global ocean to achieve accurate SSN estimation. The TabNet model demonstrated superior performance and robustness, achieving accurate global SSN estimations using satellite data. The model yielded a root mean square error (RMSE) of 2.02 μmol/kg, a mean bias (MB) of −0.32 μmol/kg, a mean ratio (MR) of 0.78, and a coefficient of determination (R²) of 0.96. Furthermore, a comparative analysis of TabNet against Random Forest (RF) and Feed Forward Neural Network (FFNN) models was conducted. The results highlighted the robust performance of TabNet in accurately estimating SSN dynamics. TabNet effectively utilized in-situ and satellite data, providing accurate SSN dynamics. This technique offers valuable insights for monitoring global surface ocean nitrate dynamics, enhancing our ability to understand and manage marine ecosystems.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101507"},"PeriodicalIF":1.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652132","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 vortex splitting process from interaction between a mesoscale vortex and two islands","authors":"Mingze Ji ,&nbsp;Xiongbo Zheng ,&nbsp;Fangli Qiao ,&nbsp;Jingyi Lu ,&nbsp;He Liu ,&nbsp;Xiaole Li","doi":"10.1016/j.dynatmoce.2024.101506","DOIUrl":"10.1016/j.dynatmoce.2024.101506","url":null,"abstract":"<div><div>Mesoscale vortices are major carriers of oceanic material and energy transfer, transporting large amounts of high-energy, temperature-anomalous water bodies during their movement. This significantly impacts both the ocean and the atmosphere. Based on the distribution of the North Brazil Curren rings and the Lesser Antilles in the eastern Caribbean Sea, we use the Regional Ocean Model System ocean circulation model to construct an idealized vortex. Simulations are conducted by varying the distances between the two islands and the scales of the islands to analyze how different parameters affect the vortex path and structural evolution. Using theoretical derivation and numerical simulation results, we construct a dimensionless parameter involving vortex diameter, island diameter, and the distance between the islands to determine the conditions under which vortex splitting occurs. The reliability of this dimensionless parameter is verified using experimental data and satellite data from St. Vincent and Barbados from April 6 to May 6, 2000.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101506"},"PeriodicalIF":1.9,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652130","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 curious case of a strong relationship between ENSO and Indian summer monsoon in CFSv2 model","authors":"Priyanshi Singhai ,&nbsp;Arindam Chakraborty ,&nbsp;Kaushik Jana ,&nbsp;Kavirajan Rajendran ,&nbsp;Sajani Surendran ,&nbsp;Kathy Pegion","doi":"10.1016/j.dynatmoce.2024.101504","DOIUrl":"10.1016/j.dynatmoce.2024.101504","url":null,"abstract":"<div><div>An ensemble of forecasts is necessary to identify the uncertainty in predicting a non-linear system like climate. While ensemble averages are often used to represent the mean state and diagnose physical mechanisms, they can lead to information loss and inaccurate assessment of the model’s characteristics. Here, we highlight an intriguing case in the seasonal hindcasts of the Climate Forecast System version 2 (CFSv2). While all ensemble members often agree on the sign of predicted El Niño Southern Oscillation (ENSO) for a particular season, non-ENSO climate forcings, although present in some of the individual members, are disparate. As a result, an ensemble mean retains ENSO anomalies while diminishing non-ENSO signals. This difference between ENSO and non-ENSO signals significantly influences moisture convergence and Indian summer monsoon rainfall (ISMR). This stronger influence of ENSO on seasonal predictions increases ENSO–ISMR correlation in ensemble mean seasonal hindcasts. Thus, this discrepancy in the ENSO–ISMR relationship is not present in the individual ensemble members, considered individually or together (without averaging) as independent realizations. Therefore, adequate care should be taken while evaluating physical mechanisms of teleconnection in ensemble mean predictions that can often be skewed due to constructive or destructive superposition of different impacts.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101504"},"PeriodicalIF":1.9,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593276","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":"Study on the genesis and development trend of tropical depressions under different large-scale backgrounds","authors":"Xiaowen Wei ,&nbsp;Xiuping Yao ,&nbsp;Xun Li ,&nbsp;Zhiyan Wu ,&nbsp;Qingchuan Wu","doi":"10.1016/j.dynatmoce.2024.101501","DOIUrl":"10.1016/j.dynatmoce.2024.101501","url":null,"abstract":"<div><div>Based on self-organizing maps (SOM), large-scale backgrounds associated with tropical depression (TD) genesis over the western North Pacific (WNP) in 1949–2021 are classified into four circulation patterns, monsoon gyre (MG) pattern, monsoon confluence (MC) pattern, monsoon trough (MT) pattern and easterly wave (EW) pattern. TDs generated in the MC pattern has the southernmost average genesis location and the highest development probability, while TDs occurred in the EW pattern are averagely located northernmost and their probability of development is the lowest. TDs formed in the MG, MT and EW patterns are most active in August, whereas in the MC pattern, TD genesis number peaks in October. Advantageous conditions for TD genesis vary in different circulation patterns. The vigorous vorticity \"embryo\" provides stronger initial disturbances for MG pattern; The strong upper-level divergence and the weak deep-layer VWS provide sufficient dynamic conditions for the MC pattern; The MT pattern possess the highest SST, which supplies an ample supply of heat and moisture; The EW pattern has less beneficial conditions compared with other three patterns. The Extreme Gradient Boosting (XGBoost) method is applied to quantify the relative importance of individual factors to TD development trend. 500-hPa vorticity, 200-hPa divergence and SST are major dynamic and thermal affecting factors for TD development, the importance of which all ranked at top four in the four patterns; VWS plays an indispensable role in TD development for the MC and EW patterns; Comparely,850-hPa vorticity and vertically integrated water vapor flux are not as important as above environmental factors in deciding whether a TD develops.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101501"},"PeriodicalIF":1.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571933","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":"Role of met-oceanic response to the intensification of tropical cyclones: A comparative analysis on cyclone Tauktae and Yaas","authors":"Amit Kumar Jena ,&nbsp;Manasa Ranjan Behera ,&nbsp;Sachiko Mohanty ,&nbsp;Srineash VK","doi":"10.1016/j.dynatmoce.2024.101502","DOIUrl":"10.1016/j.dynatmoce.2024.101502","url":null,"abstract":"<div><div>The present study investigates the physical response of surface met-ocean variables during the tropical cyclones (TCs) Tauktae (14–19 May) and Yaas (23–28 May) along the eastern Arabian Sea and western Bay of Bengal respectively using multi-platform datasets. This study synthesizes scientific understanding of the complex interplay between TCs, Marine heat waves (MHWs), and vertical wind shear; and focuses on their combined effects on ocean dynamics. The TC Tauktae developed and rapidly intensified without encountering any MHW event and required longer lifespan (∼3 days) to reach its peak as an Extremely Severe Cyclonic Storm (ESCS). Conversely, prolonged MHW event, persisting for five-fold duration (26 days), significantly influenced the intensification of TC Yaas into a Very Severe Cyclonic Storm (VSCS) within a shorter duration (∼1.5 days). TC Yaas intensified due to vertical wind shear, which transported heat and moisture from the Arabian Sea, creating favorable environment for its growth and development. Furthermore, the low vertical wind shear preceding Yaas provides favorable conditions for the persistence of MHW events. The presence of an anticyclonic eddy along the track played a crucial role in the intensification of TC Tauktae and Yaas. Before TC Yaas, elevated shortwave radiation and reduced longwave radiation played a significant role in sustaining the MHW event, unlike TC Tauktae. After the landfall of TC Yaas, the barrier layer thickness and mixed layer heat content were still high, whereas these were low in case of Tauktae. This signifies that higher translational speed of TC Yaas, relative to Tauktae, leads to reduced churning effects within the ocean, allowing for the retention of a substantial amount of heat within the mixed layer.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101502"},"PeriodicalIF":1.9,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531110","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 robust stepwise jump in the Arctic wintertime warming in 2005 coherent with the increased clear-sky downward longwave radiation flux","authors":"Mikhail M. Latonin ,&nbsp;Anna Yu. Demchenko","doi":"10.1016/j.dynatmoce.2024.101503","DOIUrl":"10.1016/j.dynatmoce.2024.101503","url":null,"abstract":"<div><div>In some areas of the Arctic, the Earth's surface temperature and near-surface air temperature are rising faster than in others. The purpose of this study is to identify, based on the ERA5 climate reanalysis data, the spatiotemporal structure of climatic changes in the Arctic during 1959–2022. The main emphasis is put on the following three parameters: mean surface clear-sky downward longwave radiation flux, near-surface air temperature, and skin temperature. A statistical model of stepwise changes was applied to the time series of the studied characteristics at each grid point of the entire Arctic (67°N–90°N). The results obtained indicate a close relationship between all parameters in the winter season. The dominant year of stepwise changes in the Arctic is 2005. Moreover, it is precisely this transition from one state of the climate system to another that is statistically significant over a large territory, which is located mainly in the Eastern Hemisphere. The time series averaged over the identified areas are highly correlated with each other, and the year 2005 characterizes the change from a sharp increase in values to their variability without a pronounced trend. The available satellite observations fully confirm the temporal structure of the stepwise changes for the studied parameters and largely confirm its spatial structure. Thus, the clear-sky downward longwave radiation flux is one of the leading factors in the formation of the thermal regime of the Arctic.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101503"},"PeriodicalIF":1.9,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531056","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":"Adjustment of the marine atmospheric boundary-layer to the North Brazil Current during the EUREC4A-OA experiment","authors":"Hervé Giordani ,&nbsp;Carlos Conejero ,&nbsp;Lionel Renault","doi":"10.1016/j.dynatmoce.2024.101500","DOIUrl":"10.1016/j.dynatmoce.2024.101500","url":null,"abstract":"<div><div>The region of Barbados is characterized by the presence of the North Brazil Current (NBC), which transports warm water along the Brazilian coasts and creates a large-scale northeast–southwest SST-gradient of 3 °C 1300 km<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. This study examines how the marine atmospheric boundary-layer (MABL) adjusts to the NBC SST-front represented by the SST analyses produced by the operational forecasting systems ECMWF and Mercator Ocean International (MOI). The NBC SST-front imprints large-scale dipole-anomalies in the surface buoyancy flux, sea level pressure, sea surface wind intensity, vertical shear of zonal wind (main component of trade winds), liquid water content and precipitable water in the MABL ranging from <span><math><mrow><mn>50</mn><mtext>%</mtext></mrow></math></span> to <span><math><mrow><mn>100</mn><mtext>%</mtext></mrow></math></span>, compared to no NBC. The mesoscale SST structures associated with the difference between MOI and ECMWF induce MABL anomalies that are an order of magnitude weaker than those associated with the NBC SST-front. This adjustment is only statistically significant in areas where SST differences are greater than 0.3 °C. The dynamics of the MABL adjustment is investigated through the precipitable water and temperature budgets. The NBC increases the water loss by advection (<span><math><mrow><mo>≃</mo><mn>1</mn><mspace></mspace><msup><mrow><mi>mm day</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>) and entrainment (<span><math><mrow><mo>≃</mo><mn>2</mn><mspace></mspace><msup><mrow><mi>mm day</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>) and increases the gain of water by surface evaporation (<span><math><mrow><mo>≃</mo><mn>2</mn><mspace></mspace><msup><mrow><mi>mm day</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>), while the SST difference between MOI and ECMWF increases the magnitudes of advection, entrainment and surface evaporation around <span><math><mrow><mn>10</mn><mtext>%</mtext></mrow></math></span>. Regarding the energy budget, the NBC forces warming by surface sensible heat flux, water vapor and cloud-induced infrared radiation flux (<span><math><mrow><mo>≃</mo><mn>1</mn><mspace></mspace><msup><mrow><mi>K day</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>), which are partially balanced by negative horizontal advection. The SST difference between MOI and ECMWF alters the heat budget components by <span><math><mrow><mn>10</mn><mtext>%</mtext></mrow></math></span>.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"108 ","pages":"Article 101500"},"PeriodicalIF":1.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586334","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}