Atmospheric Science Letters最新文献

{"title":"Meridional shift of climatological tropical cyclone genesis location in the western North Pacific","authors":"Haoyu Tong,&nbsp;Tim Li,&nbsp;Xiao Pan","doi":"10.1002/asl.1263","DOIUrl":"10.1002/asl.1263","url":null,"abstract":"<p>Climatological monthly mean tropical cyclone (TC) genesis location in the western North Pacific exhibits a marked meridional shift from June to November and the physical cause of such a shift was investigated through the diagnosis of observational and reanalysis datasets. Two genesis potential indices were used to examine key environmental parameters affecting the meridional shift. The diagnosis results indicate that dynamic parameters such as vertical and meridional wind shears play a dominant role in promoting both the northward advance and southward retreat of the mean genesis latitude, while the effect of vertical velocity is negligible. The thermodynamic parameters such as relative humidity and potential intensity in general play a minor role, except that the latter helps promote northward advance during the early TC season. The change of the environmental parameters is closely linked to the sub-seasonal evolution of the monsoon trough and subtropical high in the western North Pacific. Maximum synoptic-scale variability also experiences a similar meridional shift, contributing to the TC genesis location shift.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 11","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1263","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142191277","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":"A hypothesis on ergodicity and the signal-to-noise paradox","authors":"Daniel J. Brener","doi":"10.1002/asl.1265","DOIUrl":"10.1002/asl.1265","url":null,"abstract":"<p>This letter raises the possibility that ergodicity concerns might have some bearing on the signal-to-noise paradox. This is explored by applying the ergodic theorem to the theory behind ensemble weather forecasting and the ensemble mean. Using the ensemble mean as our best forecast of observations amounts to interpreting it as the most likely phase-space trajectory, which relies on the ergodic theorem. This can fail for ensemble forecasting systems if members are not perfectly exchangeable with each other, the averaging window is too short and/or there are too few members. We argue these failures can occur in cases such as the winter North Atlantic Oscillation (NAO) forecasts due to intransitivity or regime behaviour for regions such as the North Atlantic and Arctic. This behaviour, where different ensemble members may become stuck in different relatively persistent flow states (intransitivity) or multi-modality (regime behaviour), can in certain situations break the ergodic theorem. The problem of non-ergodic systems and models in the case of weather forecasting is discussed, as are potential mitigation methods and metrics for ergodicity in ensemble systems.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 11","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1265","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968907","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":"Increased threat of strong typhoons along the Pacific coast of Japan: Combined effect of track change and seasonal advance","authors":"Zheng-Qin Shen,&nbsp;Jian-Feng Gu,&nbsp;Qi-Wei Wang,&nbsp;Xin Qiu","doi":"10.1002/asl.1261","DOIUrl":"10.1002/asl.1261","url":null,"abstract":"<p>This study analyses the landfall intensity of tropical cyclones (TCs) affecting the Pacific coast of Japan and found that the proportion of strong typhoons increased significantly in the second 22 years from 1977 to 2020. With an objective cluster analysis of TC tracks, one could isolate a cluster of TCs originating from the southeastern part of the western North Pacific (WNP), which plays a dominant role in increasing landfalls of strong typhoons. These TCs are characterized by a long-recurving track and could achieve significantly higher intensity and larger size. Further analysis of TC trajectories and the environmental steering flow show a greater tendency for TCs originating from the southeastern WNP to approach the Pacific coast of Japan, even though there was a dramatic decrease in TC genesis number during autumn. Meanwhile, a notable earlier onset of strong typhoons occurred within this cluster of TCs due to more favorable atmospheric and oceanic conditions in summer. The results of this study emphasize the impacts of TC track change and seasonal advance of strong typhoons on the variation of intensity and potential destructiveness of landfalling TCs.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 11","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1261","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141869826","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":"The detailed moisture transport structure in extreme precipitation on the Tibetan Plateau caused by storm over the Bay of Bengal","authors":"Pengchao An,&nbsp;Ying Li,&nbsp;Xiaoting Fan,&nbsp;Wei Ye","doi":"10.1002/asl.1257","DOIUrl":"10.1002/asl.1257","url":null,"abstract":"<p>The storms over the Bay of Bengal (BoB) often combine with the weather systems such as the South Branch Trough (SBT) and the West Pacific Subtropical High (WPSH) to transport plenty of moisture inducing extreme precipitation on the Tibetan Plateau (TP). Determining the fine moisture structures of storms helps understand mechanism of this kind of extreme precipitation. An extreme precipitation occurred on the TP influenced by storm Rashmi (2008). A Lagrangian approach is scrutinized the forward and backward moisture transport trajectories of Rashmi and the TP, respectively. The moisture source of this extreme precipitation is relatively clear, which comes from the collaborative influence of Rashmi with the southwest jet generated by the SBT and the WPSH. Utilizing a three-dimensional <i>K</i>-means clustering method devised in this study, the Rashmi's forward trajectories are classified into three categories, the particles ascending with the northward movement of Rashmi (45%), consistently below 1 km (37.5%), and rapidly ascending into the southwest jet stream (17.5%). Notably, 97.5%, 1.2%, and 91% of these categories impact the TP, respectively. The moisture transport structure of storm is verified by backward tracking of moisture over the TP. In addition, the three-dimensional moisture trajectories classification method is recommended when trajectories suffer rapid altitude changes.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 10","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1257","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141614433","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":"Profound interdecadal variability of the summer precipitation over the upper reaches of the Yangtze River Basin","authors":"Mengyu Deng,&nbsp;Chaofan Li,&nbsp;Riyu Lu,&nbsp;Nick J. Dunstone,&nbsp;Philip E. Bett,&nbsp;Miaoyuan Xiao","doi":"10.1002/asl.1258","DOIUrl":"10.1002/asl.1258","url":null,"abstract":"<p>The upper reaches of the Yangtze River Basin (UYRB) are famous for their hydropower generation and water resources in China, relying greatly on precipitation. The UYRB summer precipitation has decreased since the early 2000s and has been exposed to a particularly dry period in the most recent two decades. By analyzing the long-term variability from the beginning of the 20th Century, we found that the precipitation exhibits a profound periodic interdecadal variation, with a significant cycle of 30–50 years. The interdecadal variability of precipitation is shown to be significantly modulated by both the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), exerting their impact through related circulation anomalies. Moreover, the periodical nature of the UYRB precipitation variation and its correlation with AMO/PDO suggest that the UYRB might enter a wet period in the forthcoming decade, i.e. rich in hydroelectric resources but a high risk of flood.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 10","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1258","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141614432","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":"Will 2024 be the first year that global temperature exceeds 1.5°C?","authors":"Nick J. Dunstone,&nbsp;Doug M. Smith,&nbsp;Chris Atkinson,&nbsp;Andrew Colman,&nbsp;Chris Folland,&nbsp;Leon Hermanson,&nbsp;Sarah Ineson,&nbsp;Rachel Killick,&nbsp;Colin Morice,&nbsp;Nick Rayner,&nbsp;Melissa Seabrook,&nbsp;Adam A. Scaife","doi":"10.1002/asl.1254","DOIUrl":"10.1002/asl.1254","url":null,"abstract":"<p>Global mean near surface temperature change is the key metric by which our warming climate is monitored and for which international climate policy is set. At the end of each year the Met Office issues a global mean temperature forecast for the coming year. Following on from the new record in 2023, we predict that 2024 will likely (76% chance) be a new record year with a 1-in-3 chance of exceeding 1.5°C above pre-industrial. Whilst a one-year temporary exceedance of 1.5°C would not constitute a breach of the Paris Agreement target, our forecast highlights how close we are now to this. Our 2024 forecast is primarily driven by the strong warming trend of +0.2°C/decade (1981–2023) and secondly by the lagged warming effect of a strong tropical Pacific El Niño event. We highlight that 2023 itself was significantly warmer than the Met Office DePreSys3 forecast, with much of this additional observed warming coming from the southern hemisphere, the cause of which requires further understanding.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 9","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141345747","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":"Predictability of European winter 2021/2022: Influence of La Niña and stratospheric polar vortex","authors":"Peter McLean,&nbsp;Chris Bulmer,&nbsp;Paul Davies,&nbsp;Nick Dunstone,&nbsp;Margaret Gordon,&nbsp;Sarah Ineson,&nbsp;Jason Kelly,&nbsp;Jamie Kettleborough,&nbsp;Jeff Knight,&nbsp;Julia Florence Lockwood,&nbsp;Adam A. Scaife,&nbsp;Doug Smith,&nbsp;Nicky Stringer,&nbsp;Brent Walker","doi":"10.1002/asl.1255","DOIUrl":"10.1002/asl.1255","url":null,"abstract":"<p>The Northern Hemisphere winter of 2021/2022 exhibited a positive North Atlantic Oscillation (NAO) which led to largely mild and wet conditions for Northern Europe. A moderate La Niña in the tropical Pacific and a stronger than average stratospheric polar vortex together explained the observed anomalies over the winter. Winter 2021/2022 was well predicted in general by seasonal forecast systems. The ensemble mean indicated a positive winter NAO and the forecast spread of forecasts from the Met Office GloSea6 seasonal prediction system spanned the observed mean sea level pressure anomaly for the whole winter and the individual months. However, December showed the largest departure from the mean of the forecast which is consistent with evidence from previous work that early winter ENSO teleconnections are too weak in model predictions. Nevertheless, around one in four members captured the negative NAO pattern in December. The strong pressure gradient and positive NAO predicted for the latter part of the winter allowed successful warning of the possibility of above average storminess and strong winds which occurred in February 2022. This is potentially useful information for the energy sector who increasingly rely on wind power and the insurance industry for warning of storm damage.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 9","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1255","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141368077","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":"Assessing the extended-range forecast skills of the extreme heat events over South China based on three S2S models","authors":"Xiaoqi Li,&nbsp;Ruidan Chen,&nbsp;Yunting Qiao","doi":"10.1002/asl.1253","DOIUrl":"10.1002/asl.1253","url":null,"abstract":"<p>This paper assesses the extended-range forecast skills of the extreme heat events (EHEs) over South China based on three subseasonal-to-seasonal models (European Centre for Medium-Range Weather Forecasts [ECMWF], National Centers for Environmental Prediction [NCEP], and China Meteorological Administration [CMA]). Overall, ECMWF has the best skill, NCEP the second and CMA the poorest. The predicting skills of EHEs depend on the predicting skills of relevant circulation. Cases studies (June 4–6, 1999, August 19–29, 2009, and August 3–5, 2010) show that the three models generally predict circulation anomalies weaker than observation, leading to the misses of some extreme heat days (EHDs). In these cases, ECMWF is able to well predict the influence of tropical circulation, capture the major characteristics of mid-latitude circulation but with a slower propagating speed. NCEP could capture the main signals of tropical (mid-latitude) circulation, but with slower propagating speed (slower propagating speed, deviated direction or more northward location). CMA might produce some EHDs but is derived from the circulation anomaly with the wrong origin or location. Therefore, ECMWF could predict the EHEs most accurately, NCEP could reasonably predict the formation of EHEs and tend to have more delayed predictions, while CMA has the poorest skill due to the false origins of anomalies. These results suggest potential ways to improve the current models' extended-range forecast skills.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 9","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1253","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141387895","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":"Can seasonal prediction models capture the Arctic mid-latitude teleconnection on monthly time scales?","authors":"Gaeun Kim,&nbsp;Woo-Seop Lee,&nbsp;Baek-Min Kim","doi":"10.1002/asl.1235","DOIUrl":"10.1002/asl.1235","url":null,"abstract":"<p>This study explores Arctic warming's effect on Eurasia's temperature variability, notably the warm Arctic–cold Eurasia (WACE) pattern, and assesses seasonal prediction models' accuracy in capturing this phenomenon and its monthly variation. Arctic warming events are categorized into deep Arctic warming (DAW), shallow Arctic warming (SAW), warming aloft (WA), and no Arctic warming (NOAW), based on the temperatures at 2 m and 500 hPa in the Barents–Kara Sea. It is revealed that DAW events are significantly correlated with monthly cold temperature anomalies in East Asia, predominantly occurring in January–February, excluding December. This study evaluates two primary capabilities of seasonal prediction models: their proficiency in forecasting these Arctic warming events, particularly DAW, and their ability to replicate the spatial patterns associated with DAW. Some models demonstrated notable predictive skill for DAW events, with enhanced performance in January and February. Regarding spatial pattern reproduction, models showed limited alignment with the reference dataset over the Northern Hemisphere (above 25° N) in December, whereas a higher degree of concordance was observed in January–February. This indicates their capability in capturing the atmospheric circulation patterns associated with DAW, pointing to areas where model performance can be enhanced.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 8","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1235","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141121867","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":"The observed evolution of sub-daily to multi-day heavy precipitation in Switzerland","authors":"Victoria M. Bauer,&nbsp;Simon C. Scherrer","doi":"10.1002/asl.1240","DOIUrl":"10.1002/asl.1240","url":null,"abstract":"<p>Heavy precipitation is a major natural hazard in the Alps. Understanding the possible changes due to climate change is a prerequisite for effective climate adaptation and protection. In this study, we revisit the long-term (1901–2023) evolution of daily and multi-day heavy precipitation intensity and frequency, discuss trends for sub-daily to multi-day events in the recent period 1981–2023 and investigate elevation dependencies in the complex topography of Switzerland. We analyze station measurements from MeteoSwiss' dense operational network covering the whole country and a wide range of elevation levels. We find that daily maximum precipitation and the frequency of precipitation events exceeding the 99th all-day percentile have increased since 1901 with a peak in the 1980s and decreases thereafter. For the recent period 1981–2023, positive trends in summer heavy precipitation intensity are detected for short (10-min to 3-h) events, but no changes are found for the frequency of these moderate extreme events. For longer (1- to 5-day) events on the other hand, decreases in intensity and frequency are found, especially for the winter half-year. We hypothesize that the opposing trends on the centennial (1901–2023) vs. decadal (1981–2023) time scales are caused by the interaction between thermodynamics, reflecting the primary influence of human-induced climate change, and the internal variability of atmospheric dynamics. Moreover, we observe a small negative elevation dependency of the daily long-term trends up to 2300 m above sea level. For the 1981–2023 trends, no strong elevation dependencies are found for sub-daily events. For daily events, we find small opposing negative summer and positive winter elevation dependencies for both intensities and frequencies. The reason for these tendencies remains unclear. Our results underscore the need to further investigate the interplay between climate change, internal variability of large-scale dynamics and elevation to better understand heavy precipitation variability in the complex Alpine terrain.</p>","PeriodicalId":50734,"journal":{"name":"Atmospheric Science Letters","volume":"25 9","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asl.1240","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141121791","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}