In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in th...In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.展开更多
Efficient CO_(2) electroreduction requires catalysts for enhanced energy conversion efficiency and carbon product selectivity with low overpotential,in consideration of the interference of competitive H_(2) evolution ...Efficient CO_(2) electroreduction requires catalysts for enhanced energy conversion efficiency and carbon product selectivity with low overpotential,in consideration of the interference of competitive H_(2) evolution reaction and complex intermediate species involved.We proposed that adaptive electronic structures based on dynamic mixed-valence interconversion would facilitate electron transfer and intermediate turnover during the catalysis,ensuring high activity,selectivity,and durability.Herein,a novel mixed-valence Cu-based metal-organic framework was prepared using an electron-rich linker for electrocatalytic reduction of CO_(2).The designed material delivered a remarkable Faradaic efficiency of 99.2%for C_(1) liquid fuels at a low reduction potential of -0.1 V versus reversible hydrogen electrode,considerably higher than that of the commercial copper foam and competitive to the Cu-based electrocatalysts reported.The experimental data and theoretical calculations verified the Cu(Ⅰ)/Cu(Ⅱ)interconversion and the much higher energy barrier of H2 evolution than carbon product generation.Such a feasible strategy,simultaneously improving energy conversion efficiency,carbon product selectivity,and structural robustness,provides great insights into rational catalyst customization for sustainable CO_(2) conversion.展开更多
Compound heatwaves with both daytime and nighttime hot extremes(hereafter compound heatwaves)have been occurring frequently worldwide,threatening human health and ecosystems.Land-air coupling(LAC)has been identified a...Compound heatwaves with both daytime and nighttime hot extremes(hereafter compound heatwaves)have been occurring frequently worldwide,threatening human health and ecosystems.Land-air coupling(LAC)has been identified as a key factor in amplifying the intensity and frequency of purely daytime heatwaves,but it remains unclear whether it affects the frequency and structure of compound heatwaves.Here,using CMIP6 models,we reveal that LAC will cause an increase in concurrent daytime-nighttime hot extremes and independent hot days,with a decrease in independent hot nights during a compound heatwave event in most areas of the globe during 1995–2099.This change in the structure of compound heatwaves is particularly pronounced in the long-term future(2080–2099)under the high-emission scenario.With the uncontrolled greenhouse-gases emissions,enhanced LAC appears to intensify the daytime surface sensible heat flux and nighttime surface upwelling longwave radiation,thereby raising near-surface temperatures.With more non-hot days/nights,independent hot days and nights converted into concurrent daytime-nighttime hot extremes,short-term compound heatwaves will be merged into longer ones,exacerbating their risks.The intensity of concurrent daytime-nighttime hot extremes due to LAC during a compound heatwave in the long-term future maybe 39,101,42,and 7 times higher than in the historical period in hotspots such as central North America,northern South America,the Mediterranean coast,and northern Australia,respectively.In contrast,under other scenarios,the limited influence of LAC may cause a higher frequency of short-term compound heatwaves,which in turn would increase the frequency of compound heatwaves.Our results provide a scientific foundation for the policy decisions related to compound heatwaves under the non-emission-reduction scenarios.展开更多
Meiyu is the main rainy season in the middle and lower reaches of the Yangtze River basin.However,the mechanism and predictability of atypical Meiyu are not clear.In 2022,an atypical“hot-and-dry”Meiyu occurred in th...Meiyu is the main rainy season in the middle and lower reaches of the Yangtze River basin.However,the mechanism and predictability of atypical Meiyu are not clear.In 2022,an atypical“hot-and-dry”Meiyu occurred in the lower Yangtze River basin(LYRB).By taking the 2022 Meiyu as an example,causes of the atypical Meiyu are diagnosed from the perspective of subseasonal evolution,and its predictability is further evaluated with ECMWF and NCEP Climate Forecast System version 2(CFSv2)forecast models.The 2022 atypical Meiyu featured an early onset and a three-stage back-and-forth swing through LYRB,with two sudden meridional rainband shifts,i.e.,a southward withdrawal in early June and a northward leap in late June.Influenced by the active phases of the boreal summer intraseasonal oscillation(BSISO)and the“cold vortex-heat dome(CVHD)”pattern in northern East Asia,the Meiyu rainband was suppressed and retreated southward to South China in early June.A northwestward expansion of western Pacific subtropical high(WPSH)and an abrupt northward leap of the rainband terminated Meiyu near early July due to a sudden northward displacement of the East Asian summer westerly jet and the BSISO2(10-30 day BSISO)-modulated anomalous cyclone in the subtropics.Two eastward-propagating intraseasonal wave trains along the polar front and subtropical westerly jets that are responsible for the jet displacement played crucial roles in triggering the CVHD pattern and forming an enormous upper-tropospheric anomalous anticyclone over western East Asia.Both ECMWF and CFSv2 models exhibited lower prediction skills on extratropical intraseasonal oscillations(ISOs)than on tropical ISOs.The models well predicted the rainband position in the first and third stages,but overestimated the LYRB rainfall in the second stage,which was caused by poor representation of the two intraseasonal wave trains and the CVHD pattern.These results highlight the cooperative effects of tropical and extratropical intraseasonal variabilities on atypical Meiyu events.展开更多
Rainfall-runoff modeling is essential for addressing a wide range of issues in urban drainage system design and operation in both scientific research and engineering practice.Recently,it has become increasingly attrac...Rainfall-runoff modeling is essential for addressing a wide range of issues in urban drainage system design and operation in both scientific research and engineering practice.Recently,it has become increasingly attractive to use the smoothed particle hydrodynamics(SPH)method to model rainfall-runoff because of its inherent features such as mesh-free and automatic adaptiveness for wet-dry interfaces.However,one of its inadequacies is the lack of an infiltration effect within rainfall-runoff modeling.Hence,we propose a new methodology that innovatively integrates the infiltration effect into the shallow water equation(SWE)system with the SPH method(SPH-SWE)to represent a more complete rainfall-runoff process.In the proposed method,the mass-varied SPH-SWE(MVSPH-SWE)method is enhanced by integrating the infiltration model.A naked area treatment(NAT)method is subsequently proposed to improve the modeling efficiency and accuracy.The obtained numerical results are validated using experimental data from the literature.The results demonstrate that the proposed method is accurate and reliable.The achievements and findings of this study are expected to improve and extend the use of existing hydrological process models.展开更多
Given extensive and rapid urbanization globally,assessing regional urban thermal effects(UTE)in both canopy and boundary layers under extreme weather/climate conditions is of significant interest.Rapid population and ...Given extensive and rapid urbanization globally,assessing regional urban thermal effects(UTE)in both canopy and boundary layers under extreme weather/climate conditions is of significant interest.Rapid population and economic growth in the Yangtze River Delta(YRD)have made it one of the largest city clusters in China.Here,we explore the three-dimensional(3D)UTE in the YRD using multi-source observations from high-resolution automatic weather stations,radiosondes,and eddy covariance sensors during the record-setting heat wave(HW)of July-August 2013.It is found that the regional canopy layer UTE is up to 0.6-1.2℃,and the nocturnal UTE(0.7-1.6℃)is larger than daytime UTE(0.2-0.5℃)during the HW.The regional canopy layer UTE is enhanced and expanded northwards,with some rural sites contaminated by the urban influences,especially at night.In the boundary layer,the strengthened regional UTE extends vertically to at least 925 hPa(~750 m)during this HW.The strengthened 3D UTE in the YRD is associated with an enlarged Bowen ratio difference between urban and non-urban areas.These findings about the 3D UTE are beneficial for better understanding of the thermal environment of large city clusters under HW and for more appropriate adaption and mitigation strategies.展开更多
基金the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030004)the National Natural Science Foundation of China(Grant No.42175056)+3 种基金the Natural Science Foundation of Shanghai(Grant No.21ZR1457600)Review and Summary Project of China Meteorological Administration(Grant No.FPZJ2023-044)the China Meteorological Administration Innovation and Development Project(Grant No.CXFZ2022J009)the Key Innovation Team of Climate Prediction of the China Meteorological Administration(Grant No.CMA2023ZD03).
文摘In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.
基金granted by the National Natural Science Foundation of China(Nos.22376161 and 52373216)the National Key Research and Development Program of China(No.2022YFE0110500)the Fundamental Research Funds for the Central Universities of China.
文摘Efficient CO_(2) electroreduction requires catalysts for enhanced energy conversion efficiency and carbon product selectivity with low overpotential,in consideration of the interference of competitive H_(2) evolution reaction and complex intermediate species involved.We proposed that adaptive electronic structures based on dynamic mixed-valence interconversion would facilitate electron transfer and intermediate turnover during the catalysis,ensuring high activity,selectivity,and durability.Herein,a novel mixed-valence Cu-based metal-organic framework was prepared using an electron-rich linker for electrocatalytic reduction of CO_(2).The designed material delivered a remarkable Faradaic efficiency of 99.2%for C_(1) liquid fuels at a low reduction potential of -0.1 V versus reversible hydrogen electrode,considerably higher than that of the commercial copper foam and competitive to the Cu-based electrocatalysts reported.The experimental data and theoretical calculations verified the Cu(Ⅰ)/Cu(Ⅱ)interconversion and the much higher energy barrier of H2 evolution than carbon product generation.Such a feasible strategy,simultaneously improving energy conversion efficiency,carbon product selectivity,and structural robustness,provides great insights into rational catalyst customization for sustainable CO_(2) conversion.
基金supported by the National Natural Science Foundation of China(Grant Nos.42288101,42175053)the National Key Research and Development Program of China(Grant No.2022YFF0801703)+1 种基金the Science and Technology Commission of Shanghai Municipality(Grant No.24YF2738900)the Undergraduate Research Grant Program of Fudan University(Grant No.22033)。
文摘Compound heatwaves with both daytime and nighttime hot extremes(hereafter compound heatwaves)have been occurring frequently worldwide,threatening human health and ecosystems.Land-air coupling(LAC)has been identified as a key factor in amplifying the intensity and frequency of purely daytime heatwaves,but it remains unclear whether it affects the frequency and structure of compound heatwaves.Here,using CMIP6 models,we reveal that LAC will cause an increase in concurrent daytime-nighttime hot extremes and independent hot days,with a decrease in independent hot nights during a compound heatwave event in most areas of the globe during 1995–2099.This change in the structure of compound heatwaves is particularly pronounced in the long-term future(2080–2099)under the high-emission scenario.With the uncontrolled greenhouse-gases emissions,enhanced LAC appears to intensify the daytime surface sensible heat flux and nighttime surface upwelling longwave radiation,thereby raising near-surface temperatures.With more non-hot days/nights,independent hot days and nights converted into concurrent daytime-nighttime hot extremes,short-term compound heatwaves will be merged into longer ones,exacerbating their risks.The intensity of concurrent daytime-nighttime hot extremes due to LAC during a compound heatwave in the long-term future maybe 39,101,42,and 7 times higher than in the historical period in hotspots such as central North America,northern South America,the Mediterranean coast,and northern Australia,respectively.In contrast,under other scenarios,the limited influence of LAC may cause a higher frequency of short-term compound heatwaves,which in turn would increase the frequency of compound heatwaves.Our results provide a scientific foundation for the policy decisions related to compound heatwaves under the non-emission-reduction scenarios.
基金Supported by the National Natural Science Foundation of China(42175056)China Meteorological Administration(CMA)Joint Research Project for Meteorological Capacity Improvement(23NLTSQ006)+4 种基金Shanghai Sailing Program(23YF1440100)Natural Science Foundation of Shanghai(21ZR1457600)CMA Innovation and Development Project(CXFZ2022J009)CMA Youth Innovation Group Program(CMA2024QN06)CMA Key Innovation Team Project(CMA2023ZD03).
文摘Meiyu is the main rainy season in the middle and lower reaches of the Yangtze River basin.However,the mechanism and predictability of atypical Meiyu are not clear.In 2022,an atypical“hot-and-dry”Meiyu occurred in the lower Yangtze River basin(LYRB).By taking the 2022 Meiyu as an example,causes of the atypical Meiyu are diagnosed from the perspective of subseasonal evolution,and its predictability is further evaluated with ECMWF and NCEP Climate Forecast System version 2(CFSv2)forecast models.The 2022 atypical Meiyu featured an early onset and a three-stage back-and-forth swing through LYRB,with two sudden meridional rainband shifts,i.e.,a southward withdrawal in early June and a northward leap in late June.Influenced by the active phases of the boreal summer intraseasonal oscillation(BSISO)and the“cold vortex-heat dome(CVHD)”pattern in northern East Asia,the Meiyu rainband was suppressed and retreated southward to South China in early June.A northwestward expansion of western Pacific subtropical high(WPSH)and an abrupt northward leap of the rainband terminated Meiyu near early July due to a sudden northward displacement of the East Asian summer westerly jet and the BSISO2(10-30 day BSISO)-modulated anomalous cyclone in the subtropics.Two eastward-propagating intraseasonal wave trains along the polar front and subtropical westerly jets that are responsible for the jet displacement played crucial roles in triggering the CVHD pattern and forming an enormous upper-tropospheric anomalous anticyclone over western East Asia.Both ECMWF and CFSv2 models exhibited lower prediction skills on extratropical intraseasonal oscillations(ISOs)than on tropical ISOs.The models well predicted the rainband position in the first and third stages,but overestimated the LYRB rainfall in the second stage,which was caused by poor representation of the two intraseasonal wave trains and the CVHD pattern.These results highlight the cooperative effects of tropical and extratropical intraseasonal variabilities on atypical Meiyu events.
基金Projects supported by the National Natural Science Foundation of China(Grant Nos.51778452,51978493,52000142).
文摘Rainfall-runoff modeling is essential for addressing a wide range of issues in urban drainage system design and operation in both scientific research and engineering practice.Recently,it has become increasingly attractive to use the smoothed particle hydrodynamics(SPH)method to model rainfall-runoff because of its inherent features such as mesh-free and automatic adaptiveness for wet-dry interfaces.However,one of its inadequacies is the lack of an infiltration effect within rainfall-runoff modeling.Hence,we propose a new methodology that innovatively integrates the infiltration effect into the shallow water equation(SWE)system with the SPH method(SPH-SWE)to represent a more complete rainfall-runoff process.In the proposed method,the mass-varied SPH-SWE(MVSPH-SWE)method is enhanced by integrating the infiltration model.A naked area treatment(NAT)method is subsequently proposed to improve the modeling efficiency and accuracy.The obtained numerical results are validated using experimental data from the literature.The results demonstrate that the proposed method is accurate and reliable.The achievements and findings of this study are expected to improve and extend the use of existing hydrological process models.
基金Supported by the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)National Natural Science Foundation of China(42175056,41790471)+2 种基金Natural Science Foundation of Shanghai(21ZR1457600)China Meteorological Administration Innovation and Development Project(CXFZ2022J009)UK-China Research and Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP)China as part of the Newton Fund.
文摘Given extensive and rapid urbanization globally,assessing regional urban thermal effects(UTE)in both canopy and boundary layers under extreme weather/climate conditions is of significant interest.Rapid population and economic growth in the Yangtze River Delta(YRD)have made it one of the largest city clusters in China.Here,we explore the three-dimensional(3D)UTE in the YRD using multi-source observations from high-resolution automatic weather stations,radiosondes,and eddy covariance sensors during the record-setting heat wave(HW)of July-August 2013.It is found that the regional canopy layer UTE is up to 0.6-1.2℃,and the nocturnal UTE(0.7-1.6℃)is larger than daytime UTE(0.2-0.5℃)during the HW.The regional canopy layer UTE is enhanced and expanded northwards,with some rural sites contaminated by the urban influences,especially at night.In the boundary layer,the strengthened regional UTE extends vertically to at least 925 hPa(~750 m)during this HW.The strengthened 3D UTE in the YRD is associated with an enlarged Bowen ratio difference between urban and non-urban areas.These findings about the 3D UTE are beneficial for better understanding of the thermal environment of large city clusters under HW and for more appropriate adaption and mitigation strategies.
