The dominant frequency modes of pre-summer extreme precipitation events(EPEs)over South China(SC)between1998 and 2018 were investigated.The 67 identified EPEs were all characterized by the 3-8-d(synoptic)frequency ban...The dominant frequency modes of pre-summer extreme precipitation events(EPEs)over South China(SC)between1998 and 2018 were investigated.The 67 identified EPEs were all characterized by the 3-8-d(synoptic)frequency band.However,multiscale combined modes of the synoptic and three low-frequency bands[10-20-d(quasi-biweekly,QBW);15-40-d(quasi-monthly,QM);and 20-60-d(intraseasonal)]accounted for the majority(63%)of the EPEs,and the precipitation intensity on the peak wet day was larger than that of the single synoptic mode.It was found that EPEs form within strong southwesterly anomalous flows characterized by either lower-level cyclonic circulation over SC or a deep trough over eastern China.Bandpass-filtered disturbances revealed the direct precipitating systems and their life cycles.Synoptic-scale disturbances are dominated by mid-high latitude troughs,and the cyclonic anomalies originate from downstream of the Tibetan Plateau(TP).Given the warm and moist climate state,synoptic-scale northeasterly flows can even induce EPEs.At the QBW and QM scales,the disturbances originate from the tropical Pacific,downstream of the TP,or mid-high latitudes(QBW only).Each is characterized by cyclonic-anticyclonic wave trains and intense southwesterly flows between them within a region of large horizontal pressure gradient.The intraseasonal disturbances are confined to tropical regions and influence SC by marginal southwesterly flows.It is concluded that low-frequency disturbances provide favorable background conditions for EPEs over SC and synoptic-scale disturbances ultimately induce EPEs on the peak wet days.Both should be simultaneously considered for EPE predictions over SC.展开更多
Root-knot nematodes(RKNs)cause severe diseases in peppers annually around the world.In pepper,the Me3 gene provides a heat-stable and broad-spectrum resistance to RKNs.In this study,several simple sequence repeat(SSR)...Root-knot nematodes(RKNs)cause severe diseases in peppers annually around the world.In pepper,the Me3 gene provides a heat-stable and broad-spectrum resistance to RKNs.In this study,several simple sequence repeat(SSR)markers and insertion/deletion(In Del)markers were developed to fine map the Me3 gene.Analysis of 2272 individuals(F2progenies)revealed that Me3 was located in a 45-kb DNA region between markers SSR784 and SSR339,in which there were three candidate genes.Among them,as a novel nucleotide binding site and leucine rich repeat(NBS-LRR)family gene,the DNA sequence of Capana09g000163 of pepper line‘HDA149’was 6348 bp in length,with a 2802-bp open reading frame encoding 933 amino acids,including NB-ARC and LRR domains.Tobacco transient expression assays demonstrated that expression of Capana09g000163 triggered a hypersensitive response(HR)in Nicotiana benthamiana leaves.Subcellular localization results showed that the Capana09g000163 protein was localized in the cell nucleus.Ectopic expression of Capana09g000163 in Arabidopsis significantly increased resistance against Meloidogyne incognita compared with the wild-type(WT)Arabidopsis.Furthermore,M.incognita was almost unable to develop in transgenic Arabidopsis expressing Capana09g000163.Taken together,we cloned the Me3 gene and verified that it induced resistance against M.incognita with the methods of map-based cloning and transgenic technology,which may be of great significance to pepper breeding for resistance against RKNs.展开更多
A new local kinetic energy(KE)budget for the Madden−Julian Oscillation(MJO)is constructed in a multi-scale framework.This energy budget framework allows us to analyze the local energy conversion processes of the MJO w...A new local kinetic energy(KE)budget for the Madden−Julian Oscillation(MJO)is constructed in a multi-scale framework.This energy budget framework allows us to analyze the local energy conversion processes of the MJO with the high-frequency disturbances and the low-frequency background state.The KE budget analysis is applied to a pronounced MJO event during the DYNAMO field campaign to investigate the KE transport path of the MJO.The work done by the pressure gradient force and the conversion of available potential energy at the MJO scale are the two dominant processes that affect the MJO KE tendency.The MJO winds transport MJO KE into the MJO convection region in the lower troposphere while it is transported away from the MJO convection region in the upper troposphere.The energy cascade process is relatively weak,but the interaction between high-frequency disturbances and the MJO plays an important role in maintaining the high-frequency disturbances within the MJO convection.The MJO KE mainly converts to interaction KE between MJO and high-frequency disturbances over the area where the MJO zonal wind is strong.This interaction KE over the MJO convection region is enhanced through its flux convergence and further transport KE to the high-frequency disturbances.This process is conducive to maintaining the MJO convection.This study highlights the importance of KE interaction between the MJO and the high-frequency disturbances in maintaining the MJO convection.展开更多
In this review article,we pay primary attention to innovative works in the Madden–Julian Oscillation(MJO)field done by Chinese scientists.The historical aspect of discovery of the MJO and earlier studies of its dynam...In this review article,we pay primary attention to innovative works in the Madden–Julian Oscillation(MJO)field done by Chinese scientists.The historical aspect of discovery of the MJO and earlier studies of its dynamics by Chinese scientists are first described.It is followed by the description of recent advances in MJO propagation and initiation dynamics.For MJO eastward propagation,two types of the moisture mode theory are introduced.The first one emphasizes the effect of zonal asymmetry of perturbation moisture in the atmospheric boundary layer and the second one emphasizes the zonal asymmetry of column integrated moisture static energy(MSE)tendency.The mechanisms for MJO initiation over the western Indian Ocean include three distinctive processes:lower tropospheric moistening due to horizontal advection caused by preceding suppressed-phase MJO,midlatitude Rossby wave activity flux convergence in the upper troposphere originated from the Southern Hemisphere,and a delayed sea surface temperature feedback in association with a preceding opposite-phase MJO.The impacts of MJO on low-frequency variability of precipitation and temperature and associated extreme events in East Asia are also discussed.展开更多
Winter rainfall over southern China is usually enhanced when Madden–Julian oscillation(MJO) is active over the Indian Ocean, but it can be weakened under certain conditions. Here, the diversity of MJO impacts on wint...Winter rainfall over southern China is usually enhanced when Madden–Julian oscillation(MJO) is active over the Indian Ocean, but it can be weakened under certain conditions. Here, the diversity of MJO impacts on winter rainfall and its mechanisms are explored by using scenarios of enhanced and suppressed rainfall anomalies over southern China when MJO is active over the Indian Ocean. The combined effects of low-frequency background moisture and intraseasonal winds are the major contributors to the different rainfall anomalies. Anomalous circulation in mid–high latitudes, especially on intraseasonal timescales, is almost opposite in the two scenarios, which can modulate the response of extratropical atmosphere to MJO heating and then induces the different circulations over southern China. In the enhanced scenario, mid–high latitudes of Eurasia and southern China are dominated by positive and negative sea level pressure anomalies, respectively. The southerly over southern China and the South China Sea induced by MJO heating promotes the anomalous moisture convergence and ascending motion over southern China, resulting in the enhanced rainfall. In the suppressed scenario, however, the circulation in mid–high latitudes does not favor rainfall over southern China and leads to the northerly response to MJO heating over southern China, which enhances moisture divergence and weakens rainfall over southern China.展开更多
In this study,we established a simple colorimetric method for visual detection of chromium(Ⅲ)ions using aggregated silver nanoprisms induced by monohydrogen phosphate.The detection strategy had two steps,selective ag...In this study,we established a simple colorimetric method for visual detection of chromium(Ⅲ)ions using aggregated silver nanoprisms induced by monohydrogen phosphate.The detection strategy had two steps,selective aggregation of silver nanoprisms with monohydrogen phosphate at high temperature,and anti aggregation of silver nanoprisms in the presence of chromium(Ⅲ)ions.In this strategy,significant spectral shift of the localized surface plasmon resonance(LSPR)absorption peak of silver nanoprisms could be visualized with the color changed from yellow to blue.The spectral peak shift of silver nanoprisms in the anti-aggregation process was linear with the concentrations of the added chromium(Ⅲ)ions in the range of 20.0-800.0 nM.Thus,a colorimetric method for chromium(Ⅲ)ions detection was established with the detection limit of 3.6 nM.The experimental results of real water samples indicated that the colorimetric sensor was potential in environmental monitoring.展开更多
基金supported by the National Key R&D Program of China(Grant No.2018YFC1507403)。
文摘The dominant frequency modes of pre-summer extreme precipitation events(EPEs)over South China(SC)between1998 and 2018 were investigated.The 67 identified EPEs were all characterized by the 3-8-d(synoptic)frequency band.However,multiscale combined modes of the synoptic and three low-frequency bands[10-20-d(quasi-biweekly,QBW);15-40-d(quasi-monthly,QM);and 20-60-d(intraseasonal)]accounted for the majority(63%)of the EPEs,and the precipitation intensity on the peak wet day was larger than that of the single synoptic mode.It was found that EPEs form within strong southwesterly anomalous flows characterized by either lower-level cyclonic circulation over SC or a deep trough over eastern China.Bandpass-filtered disturbances revealed the direct precipitating systems and their life cycles.Synoptic-scale disturbances are dominated by mid-high latitude troughs,and the cyclonic anomalies originate from downstream of the Tibetan Plateau(TP).Given the warm and moist climate state,synoptic-scale northeasterly flows can even induce EPEs.At the QBW and QM scales,the disturbances originate from the tropical Pacific,downstream of the TP,or mid-high latitudes(QBW only).Each is characterized by cyclonic-anticyclonic wave trains and intense southwesterly flows between them within a region of large horizontal pressure gradient.The intraseasonal disturbances are confined to tropical regions and influence SC by marginal southwesterly flows.It is concluded that low-frequency disturbances provide favorable background conditions for EPEs over SC and synoptic-scale disturbances ultimately induce EPEs on the peak wet days.Both should be simultaneously considered for EPE predictions over SC.
基金supported by the National Natural Science Foundation of China(Grant Nos.31672010,31871942 and 32172366)Hainan Yazhou Bay Seed Lab(Grant No.B21HJ0214)China Agriculture Research System(Grant No.CARS-25)。
文摘Root-knot nematodes(RKNs)cause severe diseases in peppers annually around the world.In pepper,the Me3 gene provides a heat-stable and broad-spectrum resistance to RKNs.In this study,several simple sequence repeat(SSR)markers and insertion/deletion(In Del)markers were developed to fine map the Me3 gene.Analysis of 2272 individuals(F2progenies)revealed that Me3 was located in a 45-kb DNA region between markers SSR784 and SSR339,in which there were three candidate genes.Among them,as a novel nucleotide binding site and leucine rich repeat(NBS-LRR)family gene,the DNA sequence of Capana09g000163 of pepper line‘HDA149’was 6348 bp in length,with a 2802-bp open reading frame encoding 933 amino acids,including NB-ARC and LRR domains.Tobacco transient expression assays demonstrated that expression of Capana09g000163 triggered a hypersensitive response(HR)in Nicotiana benthamiana leaves.Subcellular localization results showed that the Capana09g000163 protein was localized in the cell nucleus.Ectopic expression of Capana09g000163 in Arabidopsis significantly increased resistance against Meloidogyne incognita compared with the wild-type(WT)Arabidopsis.Furthermore,M.incognita was almost unable to develop in transgenic Arabidopsis expressing Capana09g000163.Taken together,we cloned the Me3 gene and verified that it induced resistance against M.incognita with the methods of map-based cloning and transgenic technology,which may be of great significance to pepper breeding for resistance against RKNs.
基金This study was supported by the National Key R&D Program of China through Grant Nos.2018YFC1505901 and 2018YFA0606203the National Nature Science Foundation of China through Grant Nos.41922035,41575062,41520104008+1 种基金Key Research Program of Frontier Sciences of CAS through Grant No.QYZDB-SSW-DQC017the Youth Innovation Promotion Association,Chinese Academy of Sciences.The first author acknowledges the support from the China Scholarship Council(CSC)Grant No.201904910516.
文摘A new local kinetic energy(KE)budget for the Madden−Julian Oscillation(MJO)is constructed in a multi-scale framework.This energy budget framework allows us to analyze the local energy conversion processes of the MJO with the high-frequency disturbances and the low-frequency background state.The KE budget analysis is applied to a pronounced MJO event during the DYNAMO field campaign to investigate the KE transport path of the MJO.The work done by the pressure gradient force and the conversion of available potential energy at the MJO scale are the two dominant processes that affect the MJO KE tendency.The MJO winds transport MJO KE into the MJO convection region in the lower troposphere while it is transported away from the MJO convection region in the upper troposphere.The energy cascade process is relatively weak,but the interaction between high-frequency disturbances and the MJO plays an important role in maintaining the high-frequency disturbances within the MJO convection.The MJO KE mainly converts to interaction KE between MJO and high-frequency disturbances over the area where the MJO zonal wind is strong.This interaction KE over the MJO convection region is enhanced through its flux convergence and further transport KE to the high-frequency disturbances.This process is conducive to maintaining the MJO convection.This study highlights the importance of KE interaction between the MJO and the high-frequency disturbances in maintaining the MJO convection.
基金Supported by the National Key Research and Development Program of China(2018YFC1505804)National Natural Science Foundation of China(41875069,41575043,41575052,41922035,41520104,and 41575062)+1 种基金US NSF AGS-1643297NOAA NA18OAR4310298.
文摘In this review article,we pay primary attention to innovative works in the Madden–Julian Oscillation(MJO)field done by Chinese scientists.The historical aspect of discovery of the MJO and earlier studies of its dynamics by Chinese scientists are first described.It is followed by the description of recent advances in MJO propagation and initiation dynamics.For MJO eastward propagation,two types of the moisture mode theory are introduced.The first one emphasizes the effect of zonal asymmetry of perturbation moisture in the atmospheric boundary layer and the second one emphasizes the zonal asymmetry of column integrated moisture static energy(MSE)tendency.The mechanisms for MJO initiation over the western Indian Ocean include three distinctive processes:lower tropospheric moistening due to horizontal advection caused by preceding suppressed-phase MJO,midlatitude Rossby wave activity flux convergence in the upper troposphere originated from the Southern Hemisphere,and a delayed sea surface temperature feedback in association with a preceding opposite-phase MJO.The impacts of MJO on low-frequency variability of precipitation and temperature and associated extreme events in East Asia are also discussed.
基金the National Key Research and Development Program of China (2018YFA0606203 and 2018YFC1505901)National Natural Science Foundation of China (41520104008, 41922035, 41575062, and 41475070)Key Research Program of Frontier Sciences of Chinese Academy of Sciences (QYZDB-SSW-DQC017)。
文摘Winter rainfall over southern China is usually enhanced when Madden–Julian oscillation(MJO) is active over the Indian Ocean, but it can be weakened under certain conditions. Here, the diversity of MJO impacts on winter rainfall and its mechanisms are explored by using scenarios of enhanced and suppressed rainfall anomalies over southern China when MJO is active over the Indian Ocean. The combined effects of low-frequency background moisture and intraseasonal winds are the major contributors to the different rainfall anomalies. Anomalous circulation in mid–high latitudes, especially on intraseasonal timescales, is almost opposite in the two scenarios, which can modulate the response of extratropical atmosphere to MJO heating and then induces the different circulations over southern China. In the enhanced scenario, mid–high latitudes of Eurasia and southern China are dominated by positive and negative sea level pressure anomalies, respectively. The southerly over southern China and the South China Sea induced by MJO heating promotes the anomalous moisture convergence and ascending motion over southern China, resulting in the enhanced rainfall. In the suppressed scenario, however, the circulation in mid–high latitudes does not favor rainfall over southern China and leads to the northerly response to MJO heating over southern China, which enhances moisture divergence and weakens rainfall over southern China.
基金financially supported by the National Natural Science Foundation of China(21565030 and 21465025)Program for Excellent Young Talents of Yunnan UniversityFoundation of National Demonstration Center for Experimental Chemistry and Chemical Engineering Education(Yunnan University)
文摘In this study,we established a simple colorimetric method for visual detection of chromium(Ⅲ)ions using aggregated silver nanoprisms induced by monohydrogen phosphate.The detection strategy had two steps,selective aggregation of silver nanoprisms with monohydrogen phosphate at high temperature,and anti aggregation of silver nanoprisms in the presence of chromium(Ⅲ)ions.In this strategy,significant spectral shift of the localized surface plasmon resonance(LSPR)absorption peak of silver nanoprisms could be visualized with the color changed from yellow to blue.The spectral peak shift of silver nanoprisms in the anti-aggregation process was linear with the concentrations of the added chromium(Ⅲ)ions in the range of 20.0-800.0 nM.Thus,a colorimetric method for chromium(Ⅲ)ions detection was established with the detection limit of 3.6 nM.The experimental results of real water samples indicated that the colorimetric sensor was potential in environmental monitoring.
