Pub Date : 2024-06-10DOI: 10.1088/1748-9326/ad560c
Zilin Wang, F. Chan, Meili Feng, Matthew Johnson
Hydropower reservoirs, as vital inland waters bodies of anthropogenic origin, exhibit distinct characteristics from natural waters, thereby garnering research interest in the quantification and mapping of greenhouse gas (GHG) emissions. In this review, we systematically examine studies focusing on GHG emissions from hydropower reservoirs. We identify two key primary physical mechanisms resulting from river damming, namely water impoundment and water regulation, which can significantly influence GHG emissions in hydropower reservoirs. Reservoirs vary in size, with smaller reservoirs tending to exhibit higher CH4 emissions per unit area. For instance, small reservoirs have an average flux rate of 327.54 mg C-CH4/m2/day, while medium-sized reservoirs emit 267.12 mg C-CH4/m2/day, and large ones emit 37.34 mg C-CH4/m2/day. This difference is potentially attributable to shorter water residence times in small reservoirs and increased susceptibility to littoral disturbance. In addition to reservoir scale, variations in GHG emissions between reservoirs are also influenced by the type of hydropower. Run-of-river and closed-loop pumped storage hydropower (PSH) systems are anticipated to exhibit lower GHG emissions (PSH: 4.2-46.5 mg C-CH4/m2/day) in comparison to conventional impoundment hydropower, owing to their operational characteristics, facilitating mixing and oxygenation within the reservoir water column and reducing sedimentation. Nonetheless, further field measurements are warranted. Through the integration of literature insights, we propose solutions aimed at managing emissions, considering both physical mechanisms and hydropower planning. Ultimately, these findings will advance our understanding of GHG emissions from hydropower reservoirs and facilitate sustainable carbon reduction management practices.
{"title":"Greenhouse gas emissions from hydropower reservoirs: Emission processes and management approaches","authors":"Zilin Wang, F. Chan, Meili Feng, Matthew Johnson","doi":"10.1088/1748-9326/ad560c","DOIUrl":"https://doi.org/10.1088/1748-9326/ad560c","url":null,"abstract":"\u0000 Hydropower reservoirs, as vital inland waters bodies of anthropogenic origin, exhibit distinct characteristics from natural waters, thereby garnering research interest in the quantification and mapping of greenhouse gas (GHG) emissions. In this review, we systematically examine studies focusing on GHG emissions from hydropower reservoirs. We identify two key primary physical mechanisms resulting from river damming, namely water impoundment and water regulation, which can significantly influence GHG emissions in hydropower reservoirs. Reservoirs vary in size, with smaller reservoirs tending to exhibit higher CH4 emissions per unit area. For instance, small reservoirs have an average flux rate of 327.54 mg C-CH4/m2/day, while medium-sized reservoirs emit 267.12 mg C-CH4/m2/day, and large ones emit 37.34 mg C-CH4/m2/day. This difference is potentially attributable to shorter water residence times in small reservoirs and increased susceptibility to littoral disturbance. In addition to reservoir scale, variations in GHG emissions between reservoirs are also influenced by the type of hydropower. Run-of-river and closed-loop pumped storage hydropower (PSH) systems are anticipated to exhibit lower GHG emissions (PSH: 4.2-46.5 mg C-CH4/m2/day) in comparison to conventional impoundment hydropower, owing to their operational characteristics, facilitating mixing and oxygenation within the reservoir water column and reducing sedimentation. Nonetheless, further field measurements are warranted. Through the integration of literature insights, we propose solutions aimed at managing emissions, considering both physical mechanisms and hydropower planning. Ultimately, these findings will advance our understanding of GHG emissions from hydropower reservoirs and facilitate sustainable carbon reduction management practices.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141362279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1088/1748-9326/ad560b
Luis Gimeno‐Sotelo, M. Stojanovic, Rogert Sorí, R. Nieto, S. Vicente‐Serrano, L. Gimeno
In this article, we focus on studying the nexus between moisture transport deficit and drought occurrence in nine key regions across the world where the magnitude of meteorological drought is projected to increase from 1850 to 2100 under a high anthropogenic emission scenario. These regions are central America, southwestern South America, northern Brazil, the Amazon, northeastern Brazil, the western Mediterranean, southern Africa, the eastern Mediterranean, and southwestern Australia. Using the Lagrangian particle dispersion model FLEXPART, we identify the specific moisture sources of the regions (the own region, the nearby continental source and the oceanic sources) and obtain their contributions to the precipitation in the regions for the period 1980-2018. For each region and specific moisture source, the conditional probability of meteorological drought occurrence given an equivalent contribution deficit from the source is estimated using copula models, a statistical methodology that allows us to capture complex relationships between variables. We identify the dominant moisture source in each region, which is the source for which the contribution deficit maximises drought probability. A variety of cases are found: in three regions, the dominant source is the region itself, in one region, it is the nearby terrestrial source, and in five regions, it is an oceanic source. In general, contribution deficits from specific moisture sources are associated with only slightly greater drought probabilities than those from major global moisture sources. We also reveal that the source that contributes the most to precipitation in a given region is not necessarily the dominant source of drought in the region. These results highlight the importance of understanding the role of dominant moisture sources and moisture transport deficits on meteorological drought occurrence at a regional scale.
{"title":"Nexus between the deficit in moisture transport and drought occurrence in regions with projected drought trends","authors":"Luis Gimeno‐Sotelo, M. Stojanovic, Rogert Sorí, R. Nieto, S. Vicente‐Serrano, L. Gimeno","doi":"10.1088/1748-9326/ad560b","DOIUrl":"https://doi.org/10.1088/1748-9326/ad560b","url":null,"abstract":"\u0000 In this article, we focus on studying the nexus between moisture transport deficit and drought occurrence in nine key regions across the world where the magnitude of meteorological drought is projected to increase from 1850 to 2100 under a high anthropogenic emission scenario. These regions are central America, southwestern South America, northern Brazil, the Amazon, northeastern Brazil, the western Mediterranean, southern Africa, the eastern Mediterranean, and southwestern Australia. Using the Lagrangian particle dispersion model FLEXPART, we identify the specific moisture sources of the regions (the own region, the nearby continental source and the oceanic sources) and obtain their contributions to the precipitation in the regions for the period 1980-2018. For each region and specific moisture source, the conditional probability of meteorological drought occurrence given an equivalent contribution deficit from the source is estimated using copula models, a statistical methodology that allows us to capture complex relationships between variables. We identify the dominant moisture source in each region, which is the source for which the contribution deficit maximises drought probability. A variety of cases are found: in three regions, the dominant source is the region itself, in one region, it is the nearby terrestrial source, and in five regions, it is an oceanic source. In general, contribution deficits from specific moisture sources are associated with only slightly greater drought probabilities than those from major global moisture sources. We also reveal that the source that contributes the most to precipitation in a given region is not necessarily the dominant source of drought in the region. These results highlight the importance of understanding the role of dominant moisture sources and moisture transport deficits on meteorological drought occurrence at a regional scale.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141361116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1088/1748-9326/ad50ed
Valeria Briones, Elchin E Jafarov, Hélène Genet, Brendan M Rogers, Ruth M Rutter, Tobey B Carman, Joy Clein, Eugénie S Euschkirchen, Edward AG Schuur, Jennifer D Watts and Susan M Natali
Accelerated warming of the Arctic can affect the global climate system by thawing permafrost and exposing organic carbon in soils to decompose and release greenhouse gases into the atmosphere. We used a process-based biosphere model (DVM-DOS-TEM) designed to simulate biophysical and biogeochemical interactions between the soil, vegetation, and atmosphere. We varied soil and environmental parameters to assess the impact on cryohydrological and biogeochemical outputs in the model. We analyzed the responses of ecosystem carbon balances to permafrost thaw by running site-level simulations at two long-term tundra ecological monitoring sites in Alaska: Eight Mile Lake (EML) and Imnavait Creek Watershed (IMN), which are characterized by similar tussock tundra vegetation but differing soil drainage conditions and climate. Model outputs showed agreement with field observations at both sites for soil physical properties and ecosystem CO2 fluxes. Model simulations of Net Ecosystem Exchange (NEE) showed an overestimation during the frozen season (higher CO2 emissions) at EML with a mean NEE of 26.98 ± 4.83 gC/m2/month compared to observational mean of 22.01 ± 5.67 gC/m2/month, and during the fall months at IMN, with a modeled mean of 19.21 ± 7.49 gC/m2/month compared to observation mean of 11.9 ± 4.45 gC/m2/month. Our results underscore the importance of representing the impact of soil drainage conditions on the thawing of permafrost soils, particularly poorly drained soils, which will drive the magnitude of carbon released at sites across the high-latitude tundra. These findings can help improve predictions of net carbon releases from thawing permafrost, ultimately contributing to a better understanding of the impact of Arctic warming on the global climate system.
{"title":"Exploring the interplay between soil thermal and hydrological changes and their impact on carbon fluxes in permafrost ecosystems","authors":"Valeria Briones, Elchin E Jafarov, Hélène Genet, Brendan M Rogers, Ruth M Rutter, Tobey B Carman, Joy Clein, Eugénie S Euschkirchen, Edward AG Schuur, Jennifer D Watts and Susan M Natali","doi":"10.1088/1748-9326/ad50ed","DOIUrl":"https://doi.org/10.1088/1748-9326/ad50ed","url":null,"abstract":"Accelerated warming of the Arctic can affect the global climate system by thawing permafrost and exposing organic carbon in soils to decompose and release greenhouse gases into the atmosphere. We used a process-based biosphere model (DVM-DOS-TEM) designed to simulate biophysical and biogeochemical interactions between the soil, vegetation, and atmosphere. We varied soil and environmental parameters to assess the impact on cryohydrological and biogeochemical outputs in the model. We analyzed the responses of ecosystem carbon balances to permafrost thaw by running site-level simulations at two long-term tundra ecological monitoring sites in Alaska: Eight Mile Lake (EML) and Imnavait Creek Watershed (IMN), which are characterized by similar tussock tundra vegetation but differing soil drainage conditions and climate. Model outputs showed agreement with field observations at both sites for soil physical properties and ecosystem CO2 fluxes. Model simulations of Net Ecosystem Exchange (NEE) showed an overestimation during the frozen season (higher CO2 emissions) at EML with a mean NEE of 26.98 ± 4.83 gC/m2/month compared to observational mean of 22.01 ± 5.67 gC/m2/month, and during the fall months at IMN, with a modeled mean of 19.21 ± 7.49 gC/m2/month compared to observation mean of 11.9 ± 4.45 gC/m2/month. Our results underscore the importance of representing the impact of soil drainage conditions on the thawing of permafrost soils, particularly poorly drained soils, which will drive the magnitude of carbon released at sites across the high-latitude tundra. These findings can help improve predictions of net carbon releases from thawing permafrost, ultimately contributing to a better understanding of the impact of Arctic warming on the global climate system.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141511056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1088/1748-9326/ad521e
Jiarui Zhao, Huilin Chen, Ximeng Qi, Xuguang Chi, Mengwei Jia, Fei Jiang, Sheng Zhong, Bo Zheng and Aijun Ding
The ΔCO/ΔCO2 ratio is a good indicator of the combustion efficiency of carbon-containing fuels, and can be useful to assess the combustion efficiency on a regional scale. In this study, we analyzed in-situ observations of CO2 and CO concentrations from 2011 to 2021 at the Station for Observing Regional Processes of the Earth System (SORPES), in the Yangtze River Delta (YRD) region of eastern China, and calculated the ΔCO/ΔCO2 ratio to investigate the combustion efficiency in the YRD region. Furthermore, we used a Lagrangian particle dispersion model WRF-FLEXPART to evaluate the contribution of each emission sources to the observed ΔCO/ΔCO2 ratio. We found that the observed ΔCO/ΔCO2 ratio showed a persistent decreasing trend of 1.0 ppb/ppm per year and decreased ∼47.9% during this period, illustrating an evident improvement in the combustion efficiency in the YRD region. The improvement of the combustion efficiency is a result of China’s Air Pollution Prevention and Control Action Plan announced in 2013. However, the decrease of ΔCO/ΔCO2 ratio slowed down from 1.3 ppb ppm−1 per year during 2011–2016 to 0.6 ppb ppm−1 per year during 2017–2021. The simulation results reveal that the slowdown of the decrease in the ΔCO/ΔCO2 ratios can be explained by the slowing improvement of combustion efficiency in steel source in the industry sector. Our results verify the effectiveness of emission reduction efforts in the YRD region and highlight the necessity of long-term observations of CO2 and CO.
{"title":"Observed decade-long improvement of combustion efficiency in the Yangtze River Delta region in China","authors":"Jiarui Zhao, Huilin Chen, Ximeng Qi, Xuguang Chi, Mengwei Jia, Fei Jiang, Sheng Zhong, Bo Zheng and Aijun Ding","doi":"10.1088/1748-9326/ad521e","DOIUrl":"https://doi.org/10.1088/1748-9326/ad521e","url":null,"abstract":"The ΔCO/ΔCO2 ratio is a good indicator of the combustion efficiency of carbon-containing fuels, and can be useful to assess the combustion efficiency on a regional scale. In this study, we analyzed in-situ observations of CO2 and CO concentrations from 2011 to 2021 at the Station for Observing Regional Processes of the Earth System (SORPES), in the Yangtze River Delta (YRD) region of eastern China, and calculated the ΔCO/ΔCO2 ratio to investigate the combustion efficiency in the YRD region. Furthermore, we used a Lagrangian particle dispersion model WRF-FLEXPART to evaluate the contribution of each emission sources to the observed ΔCO/ΔCO2 ratio. We found that the observed ΔCO/ΔCO2 ratio showed a persistent decreasing trend of 1.0 ppb/ppm per year and decreased ∼47.9% during this period, illustrating an evident improvement in the combustion efficiency in the YRD region. The improvement of the combustion efficiency is a result of China’s Air Pollution Prevention and Control Action Plan announced in 2013. However, the decrease of ΔCO/ΔCO2 ratio slowed down from 1.3 ppb ppm−1 per year during 2011–2016 to 0.6 ppb ppm−1 per year during 2017–2021. The simulation results reveal that the slowdown of the decrease in the ΔCO/ΔCO2 ratios can be explained by the slowing improvement of combustion efficiency in steel source in the industry sector. Our results verify the effectiveness of emission reduction efforts in the YRD region and highlight the necessity of long-term observations of CO2 and CO.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141511077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1088/1748-9326/ad5608
Francesco Semeria, Luca Ridolfi, Marta Tuninetti
Food loss and waste (FLW) is an issue of great public concern, due to its major impact on food security and on the social, economic and environmental resources involved in food production, trade and consumption. In this work, we put the lens on water resources, as those lost in the different stages of FLW represent about a quarter of the total freshwater resources used in food crop production. To this end, we propose the NETFLOW model (Network-based Evaluation Tool for Food LOss and Waste) as an innovative tool capable of reconstructing, for each commodity, the complex global multi-layered network linking FLW at each stage of the value chain with the corresponding wasted water resources. Food re-exports, nested supply chains, telecoupling of food markets, and different levels of food transformation are taken into account. Focusing on the emblematic case of wheat and its derived food commodities (e.g. flour, bread, pasta), we show the complexity and extent of the FLW-linked water network. For example, in 2016, more than 100 countries used their water resources (almost 3 km3) to produce wheat which was ultimately lost or wasted along the food consumption value chain in Italy, with almost half of this amount being directly attributable to the bread value chain. On the supply side, we show that about 18.3 km3 of water resources in the U.S. were lost through wheat-related FLW in 144 countries, about 40% for flour, 27% for raw wheat (mainly used for feed), and 24% for bread. The NETFLOW model proves useful in unravelling the complex links between (i) product-specific global trade networks, (ii) primary and derived products, (iii) country- and stage-dependent FLW, and (iv) country- and product-specific virtual water content.
{"title":"A multi-level network tool to trace wasted water from farm to fork and backwards","authors":"Francesco Semeria, Luca Ridolfi, Marta Tuninetti","doi":"10.1088/1748-9326/ad5608","DOIUrl":"https://doi.org/10.1088/1748-9326/ad5608","url":null,"abstract":"Food loss and waste (FLW) is an issue of great public concern, due to its major impact on food security and on the social, economic and environmental resources involved in food production, trade and consumption. In this work, we put the lens on water resources, as those lost in the different stages of FLW represent about a quarter of the total freshwater resources used in food crop production. To this end, we propose the NETFLOW model (Network-based Evaluation Tool for Food LOss and Waste) as an innovative tool capable of reconstructing, for each commodity, the complex global multi-layered network linking FLW at each stage of the value chain with the corresponding wasted water resources. Food re-exports, nested supply chains, telecoupling of food markets, and different levels of food transformation are taken into account. Focusing on the emblematic case of wheat and its derived food commodities (e.g. flour, bread, pasta), we show the complexity and extent of the FLW-linked water network. For example, in 2016, more than 100 countries used their water resources (almost 3 km3) to produce wheat which was ultimately lost or wasted along the food consumption value chain in Italy, with almost half of this amount being directly attributable to the bread value chain. On the supply side, we show that about 18.3 km3 of water resources in the U.S. were lost through wheat-related FLW in 144 countries, about 40% for flour, 27% for raw wheat (mainly used for feed), and 24% for bread. The NETFLOW model proves useful in unravelling the complex links between (i) product-specific global trade networks, (ii) primary and derived products, (iii) country- and stage-dependent FLW, and (iv) country- and product-specific virtual water content.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141362962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the characteristics of compound heat wave and drought events (CHDEs) across various subregions of China from 1961 to 2022 by utilizing a monthly probability-based index. The results uncover significant interregional and subseasonal variations. The trend analysis of CHDEs reveals statistically significant increases in most regions of China, however, there is no significant trend in the JiangHuai region throughout the entire summer season. The trends across regions exhibited subseasonal differences, especially in the eastern regions (Northeast China, North China, and South China (SC)). Furthermore, the occurrence of severe CHDEs (SCHDEs) in China has significantly increased in both frequency and extent since the 1990s. Southwest China and eastern Northwest China have witnessed the highest frequency of SCHDEs, while SC has remained relatively unaffected compared to other regions. The occurrences of SCHDE demonstrate a higher frequency occurred in June than in July and August, especially in the southern regions. The local driving factors are further explored. The incidence of CHDEs in eastern China is significantly influenced by anticyclonic circulation anomalies, which span from the upper to the lower troposphere. These anomalies are crucial in shaping the dynamic and moisture conditions necessary for CHDE formation. Their specific locations dictate the unique atmospheric conditions that lead to the regional characteristics of CHDEs across eastern China.
{"title":"Summertime compound heat wave and drought events in China: interregional and subseasonal characteristics, and the associated driving factors","authors":"Jiani Zeng, Huixin Li, Bo Sun, Huopo Chen, Huijun Wang, Botao Zhou, Mingkeng Duan","doi":"10.1088/1748-9326/ad5576","DOIUrl":"https://doi.org/10.1088/1748-9326/ad5576","url":null,"abstract":"\u0000 This study investigates the characteristics of compound heat wave and drought events (CHDEs) across various subregions of China from 1961 to 2022 by utilizing a monthly probability-based index. The results uncover significant interregional and subseasonal variations. The trend analysis of CHDEs reveals statistically significant increases in most regions of China, however, there is no significant trend in the JiangHuai region throughout the entire summer season. The trends across regions exhibited subseasonal differences, especially in the eastern regions (Northeast China, North China, and South China (SC)). Furthermore, the occurrence of severe CHDEs (SCHDEs) in China has significantly increased in both frequency and extent since the 1990s. Southwest China and eastern Northwest China have witnessed the highest frequency of SCHDEs, while SC has remained relatively unaffected compared to other regions. The occurrences of SCHDE demonstrate a higher frequency occurred in June than in July and August, especially in the southern regions. The local driving factors are further explored. The incidence of CHDEs in eastern China is significantly influenced by anticyclonic circulation anomalies, which span from the upper to the lower troposphere. These anomalies are crucial in shaping the dynamic and moisture conditions necessary for CHDE formation. Their specific locations dictate the unique atmospheric conditions that lead to the regional characteristics of CHDEs across eastern China.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141371168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-07DOI: 10.1088/1748-9326/ad5578
Sihua Huang, Zhiping Wen
The upper-tropospheric tropical easterly jet (TEJ) is one of the most important systems in modulating the Asian summer monsoon rainfall. In addition to the intensity variability that has been extensively studied, the TEJ’s core experiences remarkable changes in the zonal and meridional directions. The TEJ can be identified as three locational patterns using the cluster analysis: the east, northwest, and southwest modes. The frequencies of the three locational modes exhibit discernable changes on the monthly and the interannual-decadal time scales. While the anomalous zonal divergent circulation with the convergent/divergent center over the tropical Indian Ocean (IO) determines the zonal location of the TEJ’s core, the meridional temperature gradient between the Eurasian continent and the tropical IO distinguishes the meridional location of the TEJ’s core. It reflects the fundamental role of the large-scale east-west and north-south thermal contrasts in the movement of the TEJ’s core location. The variability of the TEJ’s core location has distinct impacts on the summer monsoon precipitation via redistributing the upper-level divergence and modulating the monsoon meridional circulation, especially in South, Southeast, and East Asia. In conjunction with the thermal effect of the Tibetan Plateau, the meridional shift of the TEJ’s core can affect the precipitation along the south slope of the Tibetan Plateau. These findings highlight the cause of the diversified TEJ’s core location and the significant impacts on the summer monsoon rainfall.
上对流层热带东风喷流（TEJ）是调节亚洲夏季季风降雨的最重要系统之一。除了已被广泛研究的强度变化外，TEJ 的核心还经历了显著的地带性和经向变化。通过聚类分析，可以将 TEJ 识别为三种定位模式：东部模式、西北模式和西南模式。这三种定位模式的频率在月度和年际-年代时间尺度上呈现出明显的变化。热带印度洋（IO）上空的辐合/发散中心的异常带状发散环流决定了 TEJ 核心的带状位置，而欧亚大陆和热带 IO 之间的经向温度梯度则区分了 TEJ 核心的经向位置。它反映了大尺度东西向和南北向热对比在 TEJ 核心位置移动中的基本作用。TEJ 核心位置的变化通过重新分配高层辐散和调节季风经向环流，对夏季季风降水有明显的影响，特别是在南亚、东南亚和东亚。结合青藏高原的热效应，TEJ 核心的经向移动会影响青藏高原南坡的降水。这些发现强调了TEJ核心位置多样化的原因及其对夏季季风降水的重大影响。
{"title":"Diversity of the tropical easterly jet’s core location","authors":"Sihua Huang, Zhiping Wen","doi":"10.1088/1748-9326/ad5578","DOIUrl":"https://doi.org/10.1088/1748-9326/ad5578","url":null,"abstract":"The upper-tropospheric tropical easterly jet (TEJ) is one of the most important systems in modulating the Asian summer monsoon rainfall. In addition to the intensity variability that has been extensively studied, the TEJ’s core experiences remarkable changes in the zonal and meridional directions. The TEJ can be identified as three locational patterns using the cluster analysis: the east, northwest, and southwest modes. The frequencies of the three locational modes exhibit discernable changes on the monthly and the interannual-decadal time scales. While the anomalous zonal divergent circulation with the convergent/divergent center over the tropical Indian Ocean (IO) determines the zonal location of the TEJ’s core, the meridional temperature gradient between the Eurasian continent and the tropical IO distinguishes the meridional location of the TEJ’s core. It reflects the fundamental role of the large-scale east-west and north-south thermal contrasts in the movement of the TEJ’s core location. The variability of the TEJ’s core location has distinct impacts on the summer monsoon precipitation via redistributing the upper-level divergence and modulating the monsoon meridional circulation, especially in South, Southeast, and East Asia. In conjunction with the thermal effect of the Tibetan Plateau, the meridional shift of the TEJ’s core can affect the precipitation along the south slope of the Tibetan Plateau. These findings highlight the cause of the diversified TEJ’s core location and the significant impacts on the summer monsoon rainfall.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141372675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-07DOI: 10.1088/1748-9326/ad5577
Yang Lyu, Shoupeng Zhu, Xiefei Zhi, Jingyu Wang, Yan Ji, Yi Fan, Fu Dong
Reliable Subseasonal-to-Seasonal (S2S) forecasts of precipitation are critical for disaster prevention and mitigation. In this study, an innovative hybrid method CSG-UNET combining the UNET with the censored and shifted gamma distribution based ensemble model output statistic (CSG-EMOS), is proposed to calibrate the ensemble precipitation forecasts from ECMWF over the China mainland during boreal summer. Additional atmospheric variable forecasts and the data augmentation are also included to deal with the potential issues of low signal-to-noise ratio and relatively small sample sizes in traditional S2S precipitation forecast correction. The hybrid CSG-UNET exhibits a notable advantage over both individual UNET and CSG-EMOS in improving ensemble precipitation forecasts, simultaneously improving the forecast skills for lead times of 1-2 weeks and further extending the effective forecast timeliness to ~4 weeks. Specifically, the climatology-based Brier Skill Scores are improved by ~0.4 for the extreme precipitation forecasts almost throughout the whole timescale compared with the ECMWF. Feature importance analyze towards CSG-EMOS model indicates that the atmospheric factors make great contributions to the prediction skill with the increasing lead times. The CSG-UNET method is promising in subseasonal precipitation forecasts and could be applied to the routine forecast of other atmospheric and ocean phenomena in the future.
{"title":"Significant advancement in Subseasonal-to-Seasonal summer precipitation ensemble forecast skills in China mainland through an innovative hybrid CSG-UNET method","authors":"Yang Lyu, Shoupeng Zhu, Xiefei Zhi, Jingyu Wang, Yan Ji, Yi Fan, Fu Dong","doi":"10.1088/1748-9326/ad5577","DOIUrl":"https://doi.org/10.1088/1748-9326/ad5577","url":null,"abstract":"\u0000 Reliable Subseasonal-to-Seasonal (S2S) forecasts of precipitation are critical for disaster prevention and mitigation. In this study, an innovative hybrid method CSG-UNET combining the UNET with the censored and shifted gamma distribution based ensemble model output statistic (CSG-EMOS), is proposed to calibrate the ensemble precipitation forecasts from ECMWF over the China mainland during boreal summer. Additional atmospheric variable forecasts and the data augmentation are also included to deal with the potential issues of low signal-to-noise ratio and relatively small sample sizes in traditional S2S precipitation forecast correction. The hybrid CSG-UNET exhibits a notable advantage over both individual UNET and CSG-EMOS in improving ensemble precipitation forecasts, simultaneously improving the forecast skills for lead times of 1-2 weeks and further extending the effective forecast timeliness to ~4 weeks. Specifically, the climatology-based Brier Skill Scores are improved by ~0.4 for the extreme precipitation forecasts almost throughout the whole timescale compared with the ECMWF. Feature importance analyze towards CSG-EMOS model indicates that the atmospheric factors make great contributions to the prediction skill with the increasing lead times. The CSG-UNET method is promising in subseasonal precipitation forecasts and could be applied to the routine forecast of other atmospheric and ocean phenomena in the future.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141372669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-07DOI: 10.1088/1748-9326/ad5573
Yeonsoo Cho, Jin-Ho Yoon, Jee-Hoon Jeong, J. Kug, Baek-Min Kim, Hyungjun Kim, Rokjin Park, Sang-Woo Kim
Wildfires in Northeast (NE) Siberia have become more frequent owing to the warming climate, exerting a profound impact on the global carbon cycle. While an increase in global temperature is recognized as a primary driver of unprecedented wildfires, the role of precipitation during wildfire season is relatively unexplored. Here, we present evidence that an increase in summer precipitation led to a sudden decrease in NE Siberian wildfires, especially in 2022, notwithstanding the persistent warming trend in the northern high latitudes. The interannual variability of summer precipitation, linked to the large-scale atmospheric circulation, known as the Scandinavia (SCAND) pattern, significantly impacts the regulation of wildfires. Climate models project enhanced variability in summer precipitation, potentially amplifying year-to-year fluctuations in wildfire occurrences. The interplay between the temperature and precipitation patterns in NE Siberia under ongoing warming may increase the occurrence of extreme wildfires, leading to a substantial release of carbon and further contributing to climate warming.
{"title":"Precipitation-induced abrupt decrease of Siberian wildfire in summer 2022 under continued warming","authors":"Yeonsoo Cho, Jin-Ho Yoon, Jee-Hoon Jeong, J. Kug, Baek-Min Kim, Hyungjun Kim, Rokjin Park, Sang-Woo Kim","doi":"10.1088/1748-9326/ad5573","DOIUrl":"https://doi.org/10.1088/1748-9326/ad5573","url":null,"abstract":"\u0000 Wildfires in Northeast (NE) Siberia have become more frequent owing to the warming climate, exerting a profound impact on the global carbon cycle. While an increase in global temperature is recognized as a primary driver of unprecedented wildfires, the role of precipitation during wildfire season is relatively unexplored. Here, we present evidence that an increase in summer precipitation led to a sudden decrease in NE Siberian wildfires, especially in 2022, notwithstanding the persistent warming trend in the northern high latitudes. The interannual variability of summer precipitation, linked to the large-scale atmospheric circulation, known as the Scandinavia (SCAND) pattern, significantly impacts the regulation of wildfires. Climate models project enhanced variability in summer precipitation, potentially amplifying year-to-year fluctuations in wildfire occurrences. The interplay between the temperature and precipitation patterns in NE Siberia under ongoing warming may increase the occurrence of extreme wildfires, leading to a substantial release of carbon and further contributing to climate warming.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141374514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-07DOI: 10.1088/1748-9326/ad5575
Yao Wu, Danijela Gasevic, R. Xu, Zhengyu Yang, P. Yu, Bo Wen, Guowei Zhou, Yan Zhang, Jiangning Song, Hong Liu, Shanshan Li, Yu-Ming Guo
Background Floods have been the most common type of disaster and are expected to increase in frequency and intensity due to climate change. Although there is growing evidence on the impacts of floods on human health, none has so far investigated the association between flooding exposure and biological aging acceleration. Methods We collected data from 364,841 participants from the UK Biobank project. Flooding data before baseline were retrieved from the Dartmouth Flood Observatory and linked to each participant. A novel index termed the "flood index" was developed for this study, which incorporates both the duration of exposure to floods and the severity of each flood event. We calculated the two biological aging measures at baseline: PhenoAge and Klemera-Doubal method biological age (KDM-BA) and assessed their associations with flooding exposure using mixed-effects linear regression models. Results We observed that participants exposed to higher levels of floods were more likely to have accelerated biological aging. The risks associated with flooding exposure could last for several years, with the highest cumulative effect observed over 0–4 years. In the fully adjusted model, per interquartile increase in flood index was associated with an increase of 0.24 years (95% CI: 0.14, 0.34) in PhenoAge acceleration and 0.14 years (95% CI: 0.07, 0.21) in KDM-BA acceleration over lag 0–4 years. The associations were consistent regardless of lifestyles, demographics, and socio-economic status. Conclusions Our findings suggest that exposure to floods may lead to accelerated biological aging. Our work provides the basis for further understanding of the flood-related health impacts and suggests that public-health policies and adaptation measures should be initiated in the short-, medium- and even long- terms after flooding.
{"title":"Flooding exposure accelerated biological aging: a population-based study in the UK","authors":"Yao Wu, Danijela Gasevic, R. Xu, Zhengyu Yang, P. Yu, Bo Wen, Guowei Zhou, Yan Zhang, Jiangning Song, Hong Liu, Shanshan Li, Yu-Ming Guo","doi":"10.1088/1748-9326/ad5575","DOIUrl":"https://doi.org/10.1088/1748-9326/ad5575","url":null,"abstract":"\u0000 Background Floods have been the most common type of disaster and are expected to increase in frequency and intensity due to climate change. Although there is growing evidence on the impacts of floods on human health, none has so far investigated the association between flooding exposure and biological aging acceleration. Methods We collected data from 364,841 participants from the UK Biobank project. Flooding data before baseline were retrieved from the Dartmouth Flood Observatory and linked to each participant. A novel index termed the \"flood index\" was developed for this study, which incorporates both the duration of exposure to floods and the severity of each flood event. We calculated the two biological aging measures at baseline: PhenoAge and Klemera-Doubal method biological age (KDM-BA) and assessed their associations with flooding exposure using mixed-effects linear regression models. Results We observed that participants exposed to higher levels of floods were more likely to have accelerated biological aging. The risks associated with flooding exposure could last for several years, with the highest cumulative effect observed over 0–4 years. In the fully adjusted model, per interquartile increase in flood index was associated with an increase of 0.24 years (95% CI: 0.14, 0.34) in PhenoAge acceleration and 0.14 years (95% CI: 0.07, 0.21) in KDM-BA acceleration over lag 0–4 years. The associations were consistent regardless of lifestyles, demographics, and socio-economic status. Conclusions Our findings suggest that exposure to floods may lead to accelerated biological aging. Our work provides the basis for further understanding of the flood-related health impacts and suggests that public-health policies and adaptation measures should be initiated in the short-, medium- and even long- terms after flooding.","PeriodicalId":11747,"journal":{"name":"Environmental Research Letters","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141372537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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