{"title":"Estimating Probabilities of Extreme ENSO Events from Copernicus Seasonal Hindcasts","authors":"William J. Merryfield, Woo-Sung Lee","doi":"10.1007/s13143-023-00328-2","DOIUrl":"10.1007/s13143-023-00328-2","url":null,"abstract":"<div><p>Multi-system seasonal hindcasts supporting operational seasonal forecasts of the Copernicus Climate Change Service (C3S) are examined to estimate probabilities that El Niño and La Niña episodes more extreme than any in the reliable observational record could occur in the current climate. With 184 total ensemble members initialized each month from 1993 to 2016, this dataset greatly multiplies the realizations of ENSO variability during this period beyond the single observed realization, potentially enabling a detailed assessment of the chances of extreme ENSO events. The validity of such an assessment is predicated on model fidelity, which is examined through two-sample Cramér–von Mises tests. These do not detect differences between observed and modeled distributions of the Niño 3.4 index once multiplicative adjustments are applied to the latter to match the observed variance, although differences too small to be detected cannot be excluded. Statistics of variance-adjusted hindcast Niño 3.4 values imply that El Niño and La Niña extremes exceeding any that have been instrumentally observed would be expected to occur with a > 3% chance per year on average across multiple realizations of the hindcast period. This estimation could also apply over the next several decades, provided ENSO variability remains statistically similar to the hindcast period.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 4","pages":"479 - 493"},"PeriodicalIF":2.3,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13143-023-00328-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48326245","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":"Climatic Factors Suppressing Tropical Cyclone Activity around Taiwan during October","authors":"Wei-Teh Li, Jau-Ming Chen, Ruo-Shan Tseng","doi":"10.1007/s13143-023-00327-3","DOIUrl":"10.1007/s13143-023-00327-3","url":null,"abstract":"<div><p>During Octobers of 1970–2019, no tropical cyclones (TCs) affected Taiwan in 32 out of 50 years (64%). Suppressed TC activity in these years results from different modulating processes imposed by various climatic features. During Octobers of El Niño years, TC genesis in the western North Pacific (WNP) shifts eastward and decreases in the western WNP to the southeast of Taiwan. An anomalous anticyclone across the South China Sea (SCS) and Taiwan hinders TC movement toward Taiwan. In La Niña years, TC genesis increases in the region southeast of Taiwan. These TCs are guided by an anomalous cyclone centering in the SCS to have major TC tracks to the southwest of Taiwan toward the SCS. A year with a September–November value on the Oceanic Niño Index (ONI) of between 0°-0.5 °C (-0.5°-0 °C) is categorized as a positive (negative) Normal year. During the positive Normal years, an anomalous cyclone over the WNP enhances TC genesis in its southern section and guides these TCs northward along the regions east of Taiwan. An anomalous anticyclone across the SCS and Taiwan hinders TC movement toward Taiwan. During the negative Normal years, a westward elongation of warm sea surface temperature anomalies from the WNP into the eastern Indian Ocean forces an anomalous anticyclone to extend westward from the WNP toward the SCS. TC genesis to the south of this anomalous anticyclone decreases and is accompanied by reduced TC movement toward Taiwan.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 4","pages":"459 - 477"},"PeriodicalIF":2.3,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48219499","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":"Field-based Heatwave Risk Assessment of Outdoor Workers Measured by Wearable Sensors","authors":"Ara Kim, Gayoung Yoo","doi":"10.1007/s13143-023-00326-4","DOIUrl":"10.1007/s13143-023-00326-4","url":null,"abstract":"<div><p>Increasing heatwave frequency due to climate change threatens outdoor workers’ health. We aimed to assess the on-site heat strain level of outdoor workers using wearable sensors and identify the factors for consideration in developing individual-based heat adaptation strategies. Seven road construction workers were recruited and asked to wear necklace-form temperature loggers and smartwatches monitoring heart rate (HR). The questionnaire was delivered daily to ask about their psychological comfort level during work. Workers were exposed to up to 5.4 °C higher temperature than the official air temperature, indicating that the national heatwave alarm does not reflect on-site heat conditions. Based on the measured HR data, heat strain levels were defined. When HR exceeded the level of “180-age,” we assumed extreme heat strain occurred, which requires immediate cessation of work. When HR exceeded 40% of the individual heart rate reserve (the difference between the maximum and resting HR), we assumed high heat strain occurred, indicating a stressed condition. High heat strain occurred in all workers on 9 of the 13 monitored days, whereas the official heatwave alarms were issued only on four dates. Additionally, three workers experienced extreme heat strain on two dates. The main factor for workers experiencing extreme heat strain was age. Comparing the heat strain levels from HR with the survey results, we found that the older workers considered their condition comfortable even under extreme and high heat strain. Thus, an individual sensor-based early-warning system is needed to prevent heat strain not perceived by outdoor workers. The findings emphasize the need for a personalized adaptation strategy for heatwaves and will be a baseline for developing a new work manual that mainstreams climate change impacts.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 4","pages":"447 - 458"},"PeriodicalIF":2.3,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46048591","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":"Two Typical Synoptic-Scale Weather Patterns of Dust Events over the Tibetan Plateau","authors":"Xingya Feng, Rui Mao, Dao-Yi Gong, Guangjian Wu, Cuicui Shi, Guohao Liang, Yufei Wang","doi":"10.1007/s13143-023-00325-5","DOIUrl":"10.1007/s13143-023-00325-5","url":null,"abstract":"<div><p>Synoptic-scale weather systems play dominant roles in inducing high tropospheric dust over the Tibetan Plateau (TP). However, few studies have summarized the typical synoptic-scale weather patterns when high tropospheric dust occurs over the TP, as well as the difference between the distribution and transport methods of dust under weather patterns. Based on dust optical depth (DOD) from remote sensing data and reanalysis data during 2000 to 2019, two typical synoptic-scale weather patterns (T1 and T2) in the middle troposphere in association with high DOD in spring over the TP were obtained by using the self-organizing map (SOM) clustering method. The results show that the T1 features a deep trough over the Altai Mountains and the westerly wind increases over the TP. As a result, dust is transported from the Taklimakan Desert and Qaidam Basin to the upper troposphere and extends to the TP and northern China. T2 shows a low-pressure system over the western TP and decreased westerly winds over the TP, resulting in dust from the Taklimakan Desert, Qaidam Basin, and western TP to downstream areas. T1 (T2) contributes more to DOD over the eastern (western) TP. Therefore, we believe that a small increase (decrease) in DOD in the western (eastern) part of the TP from 2000 to 2019 may be related to an increase (decrease) in the occurrence of the T2 (T1). This work may provide a new possibility for projecting dust transport and its influence on tropospheric dust over the TP.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 4","pages":"403 - 416"},"PeriodicalIF":2.3,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44046402","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}
Seon-Ok Hong, Jinwon Kim, Young-Hwa Byun, Jinkyu Hong, Je-Woo Hong, Keunmin Lee, Young-San Park, Sang-Sam Lee, Yeon-Hee Kim
{"title":"Intra-urban Variations of the CO2 Fluxes at the Surface-Atmosphere Interface in the Seoul Metropolitan Area","authors":"Seon-Ok Hong, Jinwon Kim, Young-Hwa Byun, Jinkyu Hong, Je-Woo Hong, Keunmin Lee, Young-San Park, Sang-Sam Lee, Yeon-Hee Kim","doi":"10.1007/s13143-023-00324-6","DOIUrl":"10.1007/s13143-023-00324-6","url":null,"abstract":"<div><p>Severe spatiotemporal heterogeneity of emissions sources and limited measurement networks have been hampering the monitoring and understanding of CO<sub>2</sub> fluxes in large cities, a great concern in climate research as big cities are among the major sources of anthropogenic CO<sub>2</sub> in the climate system. To understand the CO<sub>2</sub> fluxes in Seoul, Korea, CO<sub>2</sub> fluxes at eight surface energy balance sites, six urban (vegetation-area fraction < 15%) and two suburban (vegetation-area fraction > 60%), for 2017–2018 are analyzed and attributed to the local land-use and business types. The analyses show that the CO<sub>2</sub> flux variations at the suburban sites are mainly driven by vegetation and that the CO<sub>2</sub> flux differences between the urban and suburban sites originate from the differences in the vegetation-area fraction and anthropogenic CO<sub>2</sub> emissions. For the CO<sub>2</sub> fluxes at the urban sites; (1) vehicle traffic (traffic) and heating-fuel consumption (heating) contribute > 80% to the total, (2) vegetation effects are minimal, (3) the seasonal cycle is driven mainly by heating, (4) the contribution of heating is positively related to the building-area fraction, (5) the annual total is positively (negatively) correlated with the commercial-area (residential-area) fraction, and (6) the traffic at the commercial sites depend further on the main business types to induce distinct CO<sub>2</sub> flux weekly cycles. This study shows that understanding and estimation of CO2 fluxes in large urban areas require careful site selections and analyses based on detailed consideration of the land-use and business types refined beyond the single representative land-use type widely-used in contemporary studies.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 4","pages":"417 - 431"},"PeriodicalIF":2.3,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13143-023-00324-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47716914","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}
Yafeng Yin, Yangyang Yong, Shandong Qi, Kai Yang, Yizhao Lan
{"title":"Cluster Analyses of Tropical Cyclones with Genesis in the South China Sea Based on K-Means Method","authors":"Yafeng Yin, Yangyang Yong, Shandong Qi, Kai Yang, Yizhao Lan","doi":"10.1007/s13143-023-00322-8","DOIUrl":"10.1007/s13143-023-00322-8","url":null,"abstract":"<div><p>Tropical cyclone (TC) with genesis in the South China Sea (SCS) has been a major concern because of their high landfall frequency and associated serious hazards to the surrounding coastal areas. The classification of TCs from records of historical tracks is an important way to obtain their characteristics and to help predict their future behavior. According to the generation location, intensity, direction, and track length of TC, TCs with genesis in the SCS from 1950 to 2020 are classified into four clusters by the K-means clustering method, including northwestward track cluster A, westward track cluster C and two long northeastward track clusters B and D. The landfall probability, peak season, climate trend, lifespan, maximum wind speed, and power dissipation index show a significant distinction for each cluster. All clusters had a landfall probability exceeding 50%, with the highest probability in cluster A (90.44%), followed by cluster C, cluster B, and cluster D with the lowest probability (54.55%). The clustering results indicate that tracks of TCs are strongly affected by the distribution pattern of the Western Pacific Subtropical High. When the WPSH moves southward, the southwesterly anomalies provide a significantly favorable steering flow for TC northeastward. Conversely, the WPSH located northward in July-September, the strong southeasterly anomaly favoring the northwestward movement of TC. From October to November, the WPSH shrinking in size gives way to the prevailing anomalous easterlies that steer the TCs westward. Further concerning the influence of TCs in the different clusters by the WPSH movement will be helpful for prediction in terms of the occurrence, track and landfall probability of TCs in the SCS.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 4","pages":"433 - 446"},"PeriodicalIF":2.3,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13143-023-00322-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42237936","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}
Hye-Ryeom Kim, Mincheol Moon, Junghee Yun, Kyung-Ja Ha
{"title":"Trends and Spatio-Temporal Variability of Summer Mean and Extreme Precipitation across South Korea for 1973–2022","authors":"Hye-Ryeom Kim, Mincheol Moon, Junghee Yun, Kyung-Ja Ha","doi":"10.1007/s13143-023-00323-7","DOIUrl":"10.1007/s13143-023-00323-7","url":null,"abstract":"<div><h2>Abstract\u0000</h2><div><p>Climate change has altered the frequency, intensity, and timing of mean and extreme precipitation. Extreme precipitation has caused tremendous socio-economic losses, and severe impacts on human life, livelihood, and ecosystems. In recent years, heavy rainfall events occurred during the boreal summer (June-to-August) frequently and sporadically over South Korea. Given that its severity, a call for an urgent investigation of summer extreme rainfall is needed. Although many previous studies have addressed daily extreme precipitation, hourly extreme rainfall still needs to be thoroughly investigated. Therefore, in this study, we investigated the trends, spatio-temporal variability, and long-term variations in mean and extreme precipitation over South Korea during the boreal summertime using daily and hourly observational data through various analysis methods. During the past 50 years (1973–2022), there has been a notable escalation in maximum hourly precipitation, although the boreal summer mean precipitation has increased only marginally. Regionally, an increase in mean and extreme rainfall occurred in the northern part of the central region and the southern coast of the Korean peninsula. Moreover, the increase in intensity and frequency of extreme precipitation as well as in dry day have contributed more to the total summer precipitation in recent years. Our findings provide scientific insights into the progression of extreme summer precipitation events in South Korea.</p></div></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 3","pages":"385 - 398"},"PeriodicalIF":2.3,"publicationDate":"2023-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13143-023-00323-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9705649","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}
Seok-Geun Oh, Bong-Gwan Kim, Yang-Ki Cho, Seok-Woo Son
{"title":"Quantification of The Performance of CMIP6 Models for Dynamic Downscaling in The North Pacific and Northwest Pacific Oceans","authors":"Seok-Geun Oh, Bong-Gwan Kim, Yang-Ki Cho, Seok-Woo Son","doi":"10.1007/s13143-023-00320-w","DOIUrl":"10.1007/s13143-023-00320-w","url":null,"abstract":"<div><p>Selecting a reliable global climate model as the driving forcing in simulations with dynamic downscaling is critical for obtaining a reliable regional ocean climate. With respect to their accuracy in providing physical quantities and long-term trends, we quantify the performances of 17 models from the Coupled Model Inter-comparison Project Phase 6 (CMIP6) over the North Pacific (NP) and Northwest Pacific (NWP) oceans for 1979–2014. Based on normalized evaluation measures, each model’s performance for a physical quantity is mainly quantified by the performance score (PS), which ranges from 0 to 100. Overall, the CMIP6 models reasonably reproduce the physical quantities of the driving variables and the warming ocean heat content and temperature trends. However, their performances significantly depend on the variables and region analyzed. The EC-Earth-Veg and CNRM-CM6-1 models show the best performances for the NP and NWP oceans, respectively, with the highest PS values of 85.89 and 76.97, respectively. The EC-Earth3 model series are less sensitive to the driving variables in the NP ocean, as reflected in their PS. The model performance is significantly dependent on the driving variables in the NWP ocean. Nevertheless, providing a better physical quantity does not correlate with a better performance for trend. However, MRI-ESM2-0 model shows a high performance for the physical quantity in the NWP ocean with warming trends similar to references, and it could thus be used as an appropriate driving forcing in dynamic downscaling of this ocean. This study provides objective information for studies involving dynamic downscaling of the NP and NWP oceans.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 3","pages":"367 - 383"},"PeriodicalIF":2.3,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13143-023-00320-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42810838","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":"Comments on “Numerical Errors in Ice Microphysics Parameterizations and Their Effects on Simulated Regional Climate”","authors":"Song-You Hong, Jimy Dudhia","doi":"10.1007/s13143-023-00321-9","DOIUrl":"10.1007/s13143-023-00321-9","url":null,"abstract":"<div><h2>Abstract\u0000</h2><div><p>The purpose of this comment is to provide a physical reasoning for the ice crystals-habit parameters in WSM and WDM MPs (Hong et al. 2004), in which intrinsic numerical “errors” in the original scheme are corrected in the subject paper (Kim et al. 2022). Here, we confirm that the parameters in Hong et al. are revisions made to the originally derived values (new method in Kim et al.) by considering uncertainties in the derived formula from limited observations and characteristics of ice-microphysical processes that were devised in Hong et al. Thus, “<i>Numerical errors in ice microphysics parameterizations</i>” in the title of the subject paper is incorrect and related discussions could be <i>misleading</i>.\u0000</p></div></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 3","pages":"399 - 400"},"PeriodicalIF":2.3,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45065272","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}
Yannic Lops, Yunsoo Choi, Seyedali Mousavinezhad, Ahmed Khan Salman, Delaney L. Nelson, Deveshwar Singh
{"title":"Development of Deep Convolutional Neural Network Ensemble Models for 36-Month ENSO Forecasts","authors":"Yannic Lops, Yunsoo Choi, Seyedali Mousavinezhad, Ahmed Khan Salman, Delaney L. Nelson, Deveshwar Singh","doi":"10.1007/s13143-023-00319-3","DOIUrl":"10.1007/s13143-023-00319-3","url":null,"abstract":"<div><p>The state of the El Niño-Southern Oscillation (ENSO) has chaotic yet deterministic seasonal patterns and inter-annual fluctuations over the equatorial Pacific Ocean. ENSO has impacts and global teleconnections on regional temperature, precipitation, and mid-tropospheric atmospheric circulation and has been used as a predictor of regional weather. Despite being developed over several decades, dynamical and statistical models are still unable to reliably predict seasonal ENSO. This paper presents the unique utilization of several deep convolutional neural networks, identified preferable model parameters, and an optimized ensemble output to extend the ENSO forecast by up to 36 months in advance. While individual models performed differently depending on the forecasting lead month, the ensemble output is the only model that produces a correlation of 0.52 with an index of agreement of 0.60 for the 36th month forecast, a 4% and 7% improvement in the cumulative index of agreement and <i>r</i> score, respectively, over the best single model. The results demonstrate the moderate ENSO forecasting capability of the system and the next step in extending the prediction lead time to previous generations of ENSO forecasting models.</p></div>","PeriodicalId":8556,"journal":{"name":"Asia-Pacific Journal of Atmospheric Sciences","volume":"59 5","pages":"597 - 605"},"PeriodicalIF":2.2,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45863112","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}