Atmosphere-Ocean最新文献

{"title":"Future Climate Scenarios for Northern Baffin Bay and the Pikialasorsuaq (North Water Polynya) Region","authors":"Liam Buchart, Laura Castro de la Guardia, Yiran Xu, N. Ridenour, J. M. Marson, Inge Deschepper, A. Hamilton, Nathan Grivault, P. Myers","doi":"10.1080/07055900.2022.2067028","DOIUrl":"https://doi.org/10.1080/07055900.2022.2067028","url":null,"abstract":"ABSTRACT Northern Baffin Bay is distinct due to the presence of the North Water Polynya, a region referred to as “Pikialasorsuaq” by Inuit in Greenland and “Sarvarjuaq” by Inuit in Canada. Surrounding communities rely on the polynya as hunting and shipping grounds for much of the year due to its lower sea ice concentration and high primary productivity; however, Arctic warming threatens the dynamics of the region by altering the sea ice cycle, oceanic heat content and freshwater input. The aim of this study is to examine the future of northern Baffin Bay and Pikialasorsuaq under various climate warming scenarios using the Nucleus for Modelling of the Ocean (NEMO) engine, coupled to the Louvain-la-Neuve (LIM2) sea ice model. Five experiments were run on a resolution Arctic and Northern Hemispheric Atlantic (ANHA4) configuration over the period 1981–2070 forced by a range of global climate models. By 2070 there is a significant decrease in sea ice thickness and concentration, with an overall warming and salinity increase in the upper 500 m of the water column. Increased freshwater input from melting Greenland glaciers results in a more muted salinity increase in the top 50 m, while deeper waters are impacted by increased penetration of warm, saline Atlantic Water into Baffin Bay through Davis Strait. These physical changes impact the formation of the polynya in the future. The polynya is expected to continue to form on the eastern side near Greenland through mixing of warm Atlantic Waters to the surface, while the western side near Ellesmere Island has an increased ice area flux through Nares Strait and increased stratification. Additionally, there is a shallowing of mixed layer depth and increase in density stratification under the greatest warming scenarios. Implications to biogeochemical properties include a 0.5% decrease in total alkalinity, a 3.4% decreased in dissolved oxygen concentration but no net change in annual phytoplankton primary production. However, there are large changes in the phytoplankton bloom dynamics, including a 50% decrease in the autumn bloom and a 20-day advance in the spring bloom. Overall, our study suggests significant oceanographic changes which could lead to a loss of the recurrent polynya in its historical state, and shifts in primary production which could have, as yet uncertain, consequences for the food web and higher trophic levels.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"102 - 123"},"PeriodicalIF":1.2,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45670057","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":"Towards a Computational Workflow for Studying the Effects of Climate Change on Wind Loads on High-Rise Buildings in Urban Areas","authors":"Alfonso S. Teran, S. Agrawal, H. Naderian, J. Wong, Jie Song, O. Mercan, P. Kushner, Jamil Mardukhi, Xuebin Zhang","doi":"10.1080/07055900.2022.2061412","DOIUrl":"https://doi.org/10.1080/07055900.2022.2061412","url":null,"abstract":"ABSTRACT Structures in the built environment that are serviceable under current climate conditions may experience problems in the coming decades as wind loads respond to anthropogenic climate change. Given the great uncertainty in the ability of current climate models to represent winds in the atmospheric boundary layer and the consequent uncertainty in the projection of future wind conditions, there is a need to formulate flexible adaptation strategies that mitigate the effects of climate change in urban regions. The present work thus proposes a multi-disciplinary workflow to investigate climate change-associated wind load effects on the built environment. As an application, projected, statistically downscaled surface wind information from global climate models is used to estimate future design wind speed for Toronto and Vancouver. CFD simulations are then performed on a building in downtown Toronto, under different projected wind scenarios. Wind loads on the building under different projected wind conditions are quantified and compared with the load associated with the National Building Code of Canada (NBCC) design wind speed. Using the proposed workflow, it was found that some climate models suggest reduced wind loads in the future (2071–2100) for buildings in Toronto, while others suggest the opposite. This cross-disciplinary workflow seeks to translate the range of projected effects of climate change into actionable knowledge useful for building design. This will deliver sustainability and resiliency-focused design, as well as retrofit recommendations for decision-makers.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"124 - 140"},"PeriodicalIF":1.2,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43804835","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":"An Extreme Tropical Cyclone Silence in the Western North Pacific in July 2020","authors":"Rui Jin, Hui Yu, Ming Ying, Zhiwei Wu","doi":"10.1080/07055900.2022.2060179","DOIUrl":"https://doi.org/10.1080/07055900.2022.2060179","url":null,"abstract":"ABSTRACT The western North Pacific (WNP) tropical cyclone (TC) number in July 2020 hit a record low since 1949, with no TC formation throughout July. It is shown that this record-breaking TC event can be largely attributed to the extremely strong lower-level anticyclone and subsidence over the TC-genesis-prone region (GPR), concurrent with an intensified western Pacific subtropical high (WPSH) there. This configuration is closely linked to both the air–sea interaction in the tropical Indo-western Pacific and the vigorous wave activities over the mid-high latitude Eurasia. The warming western Indian Ocean and the resultant active convection excited an anomalous lower-level anticyclone and descending atmospheric Kelvin wave over the GPR, together with a strengthened WPSH. Accompanied with this monthly background field, long-lasting Madden-Julian Oscillation was confined west of 90°E, which intensified the proposed anticyclonic vorticity and decreased the moisture condition in the South China Sea and tropical WNP. Meanwhile, two active wave fluxes prevailed across the jet streams over the mid-high latitude Eurasia with a quasi-barotropic cyclonic abnormity dominating from Northeast China to Japan. The resultant positive potential vorticity on its south excited the anomalous local ascending around 35°N, which favoured the upper-level convergence in the tropical WNP and reinforced the local subsidence through modulating the meridional circulation. This extratropical impact further aggravated the suppressed circulation condition for TC formation and increased the chance that the extreme tropical cyclone silence would happen.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"23 - 34"},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43018726","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":"Recherche en Prévision Numérique Contributions to Numerical Weather Prediction","authors":"Hal Ritchie, Stéphane Bélair, Natacha B. Bernier, Mark Buehner, M. Charron, Vincent Fortin, L. Garand, Pieter Houtekamer, Syed Husain, Stéphane Laroche, Jean-François. Lemieux, H. Lin, Ron McTaggart-Cowan, Jason Milbrandt, H. Mitchell, P. Pellerin, Janusz Pudykiewicz, Leo Separovic, Gregory C. Smith, M. Tanguay, Paul A. Vaillancourt","doi":"10.1080/07055900.2022.2038071","DOIUrl":"https://doi.org/10.1080/07055900.2022.2038071","url":null,"abstract":"ABSTRACT This is a review article invited by Atmosphere-Ocean to document the contributions of Recherche en Prévision Numérique (RPN) to Numerical Weather Prediction (NWP). It is structured as a historical review and documents RPN’s contributions to numerical methods, numerical modelling, data assimilation, and ensemble systems, with a look ahead to potential future systems. Through this review, we highlight the evolution of RPN’s contributions. We begin with early NWP efforts and continue through to environmental predictions with a broad range of applications. This synthesis is intended to be a helpful reference, consolidating developments and generating broader interest for future work on NWP in Canada.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"35 - 64"},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49410333","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":"Mechanisms of Short-Duration Heavy Rainfall in the Western Pacific Subtropical High Area: An Analysis of Two Rainstorms of 2018 in Hunan Province, China","authors":"Mingcai Lan, Fei Huo, Li Zhou, Shuai Jiang, Ronghui Cai, Jingjing Chen","doi":"10.1080/07055900.2022.2060177","DOIUrl":"https://doi.org/10.1080/07055900.2022.2060177","url":null,"abstract":"ABSTRACT This study examines two short-duration heavy rainfall cases of 2018 in Hunan province, China, using observations and the NCEP FNL analyses. Short-duration heavy rainfall occurring in the western Pacific subtropical high (WPSH) area is one of the major natural hazards during spring and summer over the middle reaches of the Yangtze River basin. Rainstorms in the two cases selected showed high echo-top height but low storm centroid elevation, resembling the “low-echo centroid” structure. Weak vertical shear was observed in the mid-lower troposphere, thereby leading to a short life cycle of storms. Before the heavy rainfall events, in addition to substantial changes in convective available potential energy (CAPE) and convective inhibition (CIN), both cases were characterized by a lack of troughs and jet streams in the middle and upper troposphere over the middle reaches of the Yangtze River basin. A proper configuration of the WPSH extending to the middle reaches of the Yangtze River basin along with low-level synoptic systems (e.g. a surface convergence line or the cold air invading) favoured moisture supply and lifting mechanisms for convection and the rainstorms. During the hot afternoon hours, the thermals forming at the surface further enhanced convection and the rainstorms.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"1 - 12"},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44285592","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":"Upper Vertical Thermal Contrast Over Western North Pacific and its Impact on the East Side of Tibetan Plateau During ENSO Years","authors":"B. H. Vaid, R. Kripalani","doi":"10.1080/07055900.2022.2060180","DOIUrl":"https://doi.org/10.1080/07055900.2022.2060180","url":null,"abstract":"ABSTRACT The present study reveals significantly out-of-phase changes at 100 and 250 hPa over the western North Pacific (WNP) during ENSO years. We found that the tropospheric temperature exhibits an increase and decrease in the 100 and 250 hPa respectively over the WNP during the La Niña episodes. The tropospheric temperature pattern over the 100 and 250 hPa during La Niña episodes are found to be described by an anti-cyclonic and cyclonic circulation in the wind shear respectively. Concomitant with the tropospheric temperature change an increase/decrease of convection over the WNP is observed during the La Niña/El Niño years. The further finding shows the robust dynamical changes in the subtropical jet over the WNP during ENSO episodes act as pathways leading to moisture transport towards the east side of the Tibetan Plateau and thereby affect the convection pattern over there. To affirm the findings, a novel causal inference technique is used to identify a dominant causality between the WNP vertical thermal contrast (VTC) and the longwave fluxes over the east side of the Tibetan plateau.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"13 - 22"},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45477427","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":"Cloud Microphysics in Global Cloud Resolving Models","authors":"T. Seiki, W. Roh, Masaki Satoh","doi":"10.1080/07055900.2022.2075310","DOIUrl":"https://doi.org/10.1080/07055900.2022.2075310","url":null,"abstract":"ABSTRACT Global cloud resolving models (GCRMs) are a new type of general circulation model that explicitly calculates the growth of cloud systems with fine spatial resolutions and more than 10 GCRMs have been developed at present. This work reviews cloud microphysics schemes used in GCRMs with introductions to the recent progress and researches with GCRMs. Especially, research progress using a pioneer of GCRMs, Nonhydrostatic ICosahedral Atmospheric Model (NICAM), is focused. Since GCRMs deal with climatology and meteorology, it is a challenging issue to establish cloud microphysics schemes for GCRMs. A brief history of the development of cloud microphysics schemes and cloud-radiation coupling in NICAM is described. In addition, current progress in analytical techniques using satellite simulators is described. The combined use of multi-optical sensors enables us to constrain uncertain processes in cloud microphysics without artificial tuning. As a result, cloud microphysics schemes used in the NICAM naturally represent cloud systems, and hence, the radiative budget is well balanced with little optimization. Finally, a new satellite and a ground validation campaign are introduced for future work.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"477 - 505"},"PeriodicalIF":1.2,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45429044","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 Deep Learning Approach for the Identification of Long-Duration Mixed Precipitation in Montréal (Canada)","authors":"M. Mittermeier, É. Bresson, D. Paquin, R. Ludwig","doi":"10.1080/07055900.2021.1992341","DOIUrl":"https://doi.org/10.1080/07055900.2021.1992341","url":null,"abstract":"ABSTRACT Long-duration mixed-precipitation events (freezing rain and/or ice pellets) are important cold-season hazards and understanding how climate change alters their occurrence is of high societal interest, particularly in urban areas. This study introduces a two-staged approach that employs deep learning to identify long-duration mixed precipitation over the Montréal area (Quebec, Canada) in archived climate model data using large-scale pressure patterns. The dominant dynamic mechanism leading to mixed precipitation in Montréal is pressure-driven channelling of winds along the St. Lawrence River Valley. A convolutional neural network (CNN) identifies the corresponding synoptic pattern by using a large training database derived from an ensemble of the Canadian Regional Climate Model, version 5 (CRCM5). The CRCM5 uses the diagnostic method of Bourgouin (2000) to simulate mixed precipitation and delivers training examples and corresponding class affiliations (labels) for this supervised classification task. The CNN correctly identifies more than 80% of the Bourgouin mixed-precipitation cases. In the next stage, the CNN is combined with temperature and precipitation conditions, which consider important preconditions for mixed precipitation and improve the performance of the approach. The evaluation of a CRCM5 run driven by ERA-Interim reanalysis data gives a Matthews correlation coefficient of 0.50. The deep learning approach can be applied to ensembles of regional climate models on the North American grid of the Coordinated Regional Downscaling Experiment (CORDEX-NA).","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"60 1","pages":"554 - 565"},"PeriodicalIF":1.2,"publicationDate":"2021-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42070185","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":"Interaction between the Tropical Atlantic and Pacific Oceans on an Interannual Time Scale","authors":"Weibang He, Jing Ma","doi":"10.1080/07055900.2021.2014300","DOIUrl":"https://doi.org/10.1080/07055900.2021.2014300","url":null,"abstract":"ABSTRACT Based on the fifth-generation reanalysis of the European Centre for Medium-range Weather Forecasts (ECMWF), the Hadley Centre sea surface temperature (SST) data, and the Global Precipitation Climatology Project (GPCP) precipitation data, the interaction between the tropical Atlantic and Pacific Oceans on an interannual time scale is investigated using correlation, regression, and composite analyses, and the quantitative estimates of the relative and collective contribution of the tropical North Atlantic (NTA) and equatorial Atlantic (ETA) SST anomalies to the El Niño–Southern Oscillation (ENSO) are presented. An El Niño or La Niña event can cause a same-sign SST anomaly in the NTA in the following boreal spring, accounting for 33% of the interannual variability of the NTA SST. The NTA SST anomaly may excite a same-sign SST anomaly of the ETA in boreal summer with an ETA SST anomaly of 0.44°C per 1°C NTA SST anomaly. Moreover, an SST anomaly in the NTA and ETA can cause an opposite-sign SST anomaly in the equatorial Pacific during the following winter. The NTA SST anomaly influences the central equatorial Pacific with a Niño 3.4 SST anomaly of −0.85°C per 1°C NTA SST anomaly, while the ETA SST anomaly exerts an impact on the central-eastern equatorial Pacific with a Niño 3.4 SST anomaly of −1.85°C per 1°C ETA SST anomaly based on a multiple regression analysis. The composite analyses based on Ensemble-Based Predictions of Climate Changes and Their Impacts (ENSEMBLES) hindcasts show that the ETA SST anomaly in summer acts as a primary contributor to the interaction between the tropical Atlantic and Pacific Oceans. The ETA impact can relay and amplify the NTA SST anomaly such that it affects the equatorial Pacific. The collective impact of spring NTA and summer ETA SST anomalies can explain 33% of the total variance of the winter Niño 3.4 index. This study deepens our understanding of the interannual interaction between the tropical Atlantic and Pacific Oceans and highlights the role of the tropical Atlantic Ocean, especially the ETA region, in the pan-tropical air–sea interaction.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"59 1","pages":"285 - 298"},"PeriodicalIF":1.2,"publicationDate":"2021-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41836243","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":"Nocturnal Rainfall East of the Antilles Islands","authors":"M. Jury, Didier Bernard","doi":"10.1080/07055900.2021.1995317","DOIUrl":"https://doi.org/10.1080/07055900.2021.1995317","url":null,"abstract":"ABSTRACT We analyze nocturnal rainfall caused by the interaction of trade winds and land breezes on the windward flank of the islands of Guadeloupe, Dominica, and Martinique of the eastern Caribbean Antilles. Climatology for the 2000–2019 period and a nocturnal rainfall case study 8–9 February 2018 are supplemented by modern 5–25 km hourly resolution satellite and reanalysis products and station measurements that describe the diurnal cycle around the islands. Mean trade winds of 7 m s−1 decelerate upstream, ∂U/∂x less than −10−5 s−1, causing an increase in warm-cloud rainfall from 2 to 4 mm d−1 between 03:30 and 06:30 local time (local time is UTC-4). The incoming airflow has a characteristic Froude number less than 1 and stagnates on the windward slopes of these volcanic islands. Nocturnal land breezes spread toward the east coast about one-third of the time. Additional work considers whether air–sea interactions play a role. Low salinity and wave-induced turbulence to the east of the Antilles add buoyancy and moisture to the atmospheric boundary layer. Yet areas of low turbidity encircling the east Antilles suggest that nocturnal airflow creates a divergent “cushion” around Guadeloupe, Dominica, and Martinique. Thermal and orographic influences merge and rain falls over the eastern flank of the islands, contributing to the water resources.","PeriodicalId":55434,"journal":{"name":"Atmosphere-Ocean","volume":"59 1","pages":"201 - 213"},"PeriodicalIF":1.2,"publicationDate":"2021-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43470114","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}