Understanding the relationship between fire activity and climate variability is a major concern for the scientific community and is essential for reducing economic losses and life-threatening fire hazards.However,the ...Understanding the relationship between fire activity and climate variability is a major concern for the scientific community and is essential for reducing economic losses and life-threatening fire hazards.However,the drivers of fire activity and the influence of climate variability remain uncertain.Here,we show that the Madden–Julian Oscillation(MJO)—a dominant tropical subseasonal variability—influences fire activity by modulating local fire-supporting weather through atmospheric teleconnections.Our results show that midlatitude fire emissions exhibit significant subseasonal variability,with MJO-related weather influencing the fire intensity and contributing to large fire events.MJO-related fire events account for about 10%–20%of total midlatitude fire events,suggesting that if MJO teleconnections strengthen in the future,fire emissions and associated economic losses could worsen.展开更多
Written by Julian Barnes,a well-known contemporary British writer,The Porcupine is a novel with a touch on Bulgaria’s social realities in the early 1990s.However,it is not a realistic novel in a conventional sense.It...Written by Julian Barnes,a well-known contemporary British writer,The Porcupine is a novel with a touch on Bulgaria’s social realities in the early 1990s.However,it is not a realistic novel in a conventional sense.It is composed of forty-three sections,long or short,fragmented in form and laid out by means of montage strategies.In the novel,Barnes used“continuous montage”and“parallel montage”strategies to unveil the plot and tell the story and employed“psychological montage”and“contrast montage”strategies to showcase characters’consciousness and personalities.The ingenious use of different montage strategies in the novel challenges the linear narrative paradigm in traditionally realistic novels,enriches its narrative structures and textual dimensions,and highlights its dramatic conflict,hence reflecting the narrative innovation in Barnes’s fictional writing and providing new space for the studies of his novels from the viewpoint of narratology and/or postmodernism.展开更多
The Madden-Julian Oscillation (MJO) is investigated in two sets of 11-year records of observed precipitation, the daily mean Microwave Sounding Units (MSU) oceanic rainfall (Spencer, 1993) data and the pentad Climate ...The Madden-Julian Oscillation (MJO) is investigated in two sets of 11-year records of observed precipitation, the daily mean Microwave Sounding Units (MSU) oceanic rainfall (Spencer, 1993) data and the pentad Climate Prediction Center Merged Analysis of Precipitation (CMAP) data (Xie and Arkin, 1997). Obvious interannual variability is found in the MJO in the tropical Pacific. MJO is limited to the west of dateline in normal years while extends more east during the year of warm sea surface temperature (SST) appeared in the eastern Pacific (i.e., El Ni?o years of 1982–1983, 1986–1988, 1991–1992) and manifested in the central-eastern Pacific for several months. The most significant correlation between interannual variability of MJO in the central-eastern Pacific and SST was found in the vicinity of the Ni?o3 region. Forced by observed SST, CCM3 presents a realistic trend of interannual variability to MJO in the 11 years, with a smaller magnitude than that from the observation. Comparison between the two realizations of the CCM3 simulation, which are forced by weekly and monthly mean SST respectively, showed that the MJO activities resemble each other in central-eastern Pacific while there is discrepancy in the western Pacific. It is suggested that the interannual variability of MJO is controlled, to certain extent bythe powerful interannual variability of SST in the central-eastern Pacific. In the western Pacific, however, there were remarkable impacts of the intraseasonal oscillation of SST on the MJO, where there was active MJO around the year. The notable disagreement between simulated and observed MJO in the western Pacific may come from the lack of high frequency variation of SST force, or from the shortage of air sea interaction for the intraseasonal time scale. It might be of importance to the MJO which is unable to be represented in the atmospheric model. Key words Madden-Julian Oscillation - Precipitation - Sea surface temperature - Interannual variability This study was sponsored by Chinese Academy of Sciences under grant “Hundred Talents” for “Validation of Coupled Climate Models”, the National Natural Science Foundation of China (Grant No. 49823002), and Project G1999043808.展开更多
We investigate the Madden-Julian Oscillation （MJO） signal in wintertime stratospheric ozone over the Tibetan Plateau and East Asia using the harmonized dataset of satellite ozone profiles. Two different MJO indices ...We investigate the Madden-Julian Oscillation （MJO） signal in wintertime stratospheric ozone over the Tibetan Plateau and East Asia using the harmonized dataset of satellite ozone profiles. Two different MJO indices -- the all-season Real-Time multivariate MJO index （RMM） and outgoing longwave radiation-based MJO index （OMI） -- are used to compare the MJO- related ozone anomalies. The results show that there are pronounced eastward-propagating MJO-related stratospheric ozone anomalies （mainly within 20-200 hPa） over the subtropics, The negative stratospheric ozone anomalies are over the Tibetan Plateau and East Asia in MJO phases 4-7, when MJO-related tropical deep convective anomalies move from the equatorial Indian Ocean towards the western Pacific Ocean. Compared with the results based on RMM, the MJO-related stratospheric column ozone anomalies based on OM1 are stronger and one phase ahead. Further analysis suggests that different sampling errors, observation principles and retrieval algorithms may be responsible for the discrepancies among different satellite measurements. The MJO-related stratospheric ozone anomalies can be attributed to the MJO-related circulation anomalies, i.e., the uplifted tropopanse and the northward shifted westerly jet in the upper troposphere. Compared to the result based on RMM, the upper tropospheric westerly jet may play a less important role in generating the stratospheric column ozone anomalies based on OMI. Our study indicates that the circulation-based MJO index （RMM） can better characterize the MJO- related anomalies in tropopause pressure and thus the MJO influence on atmospheric trace gases in the upper troposphere and lower stratosphere, especially over subtropical East Asia.展开更多
The authors examined the Madden-Julian Oscillation(MJO) in stratospheric ozone during boreal winter using a simulation from the Specified Dynamics version of the Whole Atmosphere Community Climate Model(SD-WACCM) in 2...The authors examined the Madden-Julian Oscillation(MJO) in stratospheric ozone during boreal winter using a simulation from the Specified Dynamics version of the Whole Atmosphere Community Climate Model(SD-WACCM) in 2004 and 2010. Comparison with European Centre for Medium-Range Weather Forecasts Interim Reanalysis(ERA-Interim) data suggested that the model simulation represented well the three-dimensional structure of the MJO-related ozone anomalies in the upper troposphere and stratosphere(i.e., between 200 and 20 h Pa). The negative ozone anomalies were over the Tibetan Plateau and East Asia in MJO phases 3–7, when the MJO convective anomalies travelled from the equatorial Indian Ocean towards the equatorial western Pacific Ocean. Due to the different vertical structures of the MJO-related circulation anomalies, the MJO-related stratospheric ozone anomalies showed different vertical structure over the Tibetan Plateau(25–40°N, 75–105°E) and East Asia(25–40°N, 105–135°E). As a result of the positive bias in the model-calculated ozone in the upper troposphere and lower stratosphere, the amplitude of MJO-related stratospheric ozone column anomalies(10–16 Dobson Units(DU)) in the SD-WACCM simulation was slightly larger than that(8–14 DU) in the ERA-Interim reanalysis.展开更多
The intra-seasonal variability plays a major role in the inter-annual variability of weather parameters such as rainfall, temperature and pressure which lead to extreme weather events in certain years. The active (mor...The intra-seasonal variability plays a major role in the inter-annual variability of weather parameters such as rainfall, temperature and pressure which lead to extreme weather events in certain years. The active (more rainy days) and break (less rainy days) periods of Indian summer monsoon heavily depend on the intra-seasonal variability of weather parameters such as wind, pressure and temperature oscillations during the monsoon season. In the present analysis daily total column ozone, surface temperature and surface pressure measured over Cochin using Microtop II Ozonometer (sun Photometer) were used to study the Intra-Seasonal Variations (ISV) of the above parameters during the monsoon season, 2015. The dominant and significant intra-seasonal oscillations (ISOs) were identified using an advanced statistical method called the Discrete Mayer’s Wavelet (DMW) analysis. Two major ISOs such as Madden Julian Oscillations (MJO, 30 - 60 days) and quasi-bi weekly (12 - 16 days) oscillations were found in TCO, surface temperature and pressure. In TCO an additional mode of ISO with quasi tri-weekly periodicity was also found (16 - 22 day). It is observed that MJO mode is the dominant among all other modes and its positive and negative phases correlate with positive and negative anomalies of the above parameters. The ISO mode in the surface pressure shows an out of phase relation with the Indian summer monsoon rainfall which indicates the active and break periods of Indian summer monsoon. The contribution of MJO mode is dominant in the tropical atmosphere, which modulates the intra-seasonal variability. It is found that for the year 2015 total column ozone, surface pressure and surface temperature show an annual range of 30 DU, 4 hPa and 1°C, respectively.展开更多
The aim of this study was to understand the cause of Madden–Julian oscillation(MJO)bias in the High Resolution AtmosphericModel(HiRAM)driven by observed SST through process-oriented diagnosis.Wavenumber-frequency pow...The aim of this study was to understand the cause of Madden–Julian oscillation(MJO)bias in the High Resolution AtmosphericModel(HiRAM)driven by observed SST through process-oriented diagnosis.Wavenumber-frequency power spectrum and composite analyses indicate that HiRAM underestimates the spectral amplitude over theMJO band and mainly produces non-propagating rather than eastward-propagating intraseasonal rainfall anomalies,as observed.Column-integrated moist static energy(MSE)budget analysis is conducted to understand the MJO propagation bias in the simulation.It is found that the bias is due to the lack of a zonally asymmetric distribution of the MSE tendency anomaly in respect to the MJO convective center,which is mainly attributable to the bias in vertical MSE advection and surface turbulent flux.Further analysis suggests that it is the unrealistic simulation of MJO vertical circulation anomalies in the upper troposphere as well as overestimation of the Rossby wave response that results in the bias.展开更多
基金supported by the National Science Foundation of China(Grant No.42088101)by a National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(Grant Nos.RS-2024-00416848 and NRF-2022R1A2C1013296)。
文摘Understanding the relationship between fire activity and climate variability is a major concern for the scientific community and is essential for reducing economic losses and life-threatening fire hazards.However,the drivers of fire activity and the influence of climate variability remain uncertain.Here,we show that the Madden–Julian Oscillation(MJO)—a dominant tropical subseasonal variability—influences fire activity by modulating local fire-supporting weather through atmospheric teleconnections.Our results show that midlatitude fire emissions exhibit significant subseasonal variability,with MJO-related weather influencing the fire intensity and contributing to large fire events.MJO-related fire events account for about 10%–20%of total midlatitude fire events,suggesting that if MJO teleconnections strengthen in the future,fire emissions and associated economic losses could worsen.
文摘Written by Julian Barnes,a well-known contemporary British writer,The Porcupine is a novel with a touch on Bulgaria’s social realities in the early 1990s.However,it is not a realistic novel in a conventional sense.It is composed of forty-three sections,long or short,fragmented in form and laid out by means of montage strategies.In the novel,Barnes used“continuous montage”and“parallel montage”strategies to unveil the plot and tell the story and employed“psychological montage”and“contrast montage”strategies to showcase characters’consciousness and personalities.The ingenious use of different montage strategies in the novel challenges the linear narrative paradigm in traditionally realistic novels,enriches its narrative structures and textual dimensions,and highlights its dramatic conflict,hence reflecting the narrative innovation in Barnes’s fictional writing and providing new space for the studies of his novels from the viewpoint of narratology and/or postmodernism.
基金Chinese Academy of Sciences under grant "Hundred Talents" for"Validation of Coupled Climate Models", the National Natural Scie
文摘The Madden-Julian Oscillation (MJO) is investigated in two sets of 11-year records of observed precipitation, the daily mean Microwave Sounding Units (MSU) oceanic rainfall (Spencer, 1993) data and the pentad Climate Prediction Center Merged Analysis of Precipitation (CMAP) data (Xie and Arkin, 1997). Obvious interannual variability is found in the MJO in the tropical Pacific. MJO is limited to the west of dateline in normal years while extends more east during the year of warm sea surface temperature (SST) appeared in the eastern Pacific (i.e., El Ni?o years of 1982–1983, 1986–1988, 1991–1992) and manifested in the central-eastern Pacific for several months. The most significant correlation between interannual variability of MJO in the central-eastern Pacific and SST was found in the vicinity of the Ni?o3 region. Forced by observed SST, CCM3 presents a realistic trend of interannual variability to MJO in the 11 years, with a smaller magnitude than that from the observation. Comparison between the two realizations of the CCM3 simulation, which are forced by weekly and monthly mean SST respectively, showed that the MJO activities resemble each other in central-eastern Pacific while there is discrepancy in the western Pacific. It is suggested that the interannual variability of MJO is controlled, to certain extent bythe powerful interannual variability of SST in the central-eastern Pacific. In the western Pacific, however, there were remarkable impacts of the intraseasonal oscillation of SST on the MJO, where there was active MJO around the year. The notable disagreement between simulated and observed MJO in the western Pacific may come from the lack of high frequency variation of SST force, or from the shortage of air sea interaction for the intraseasonal time scale. It might be of importance to the MJO which is unable to be represented in the atmospheric model. Key words Madden-Julian Oscillation - Precipitation - Sea surface temperature - Interannual variability This study was sponsored by Chinese Academy of Sciences under grant “Hundred Talents” for “Validation of Coupled Climate Models”, the National Natural Science Foundation of China (Grant No. 49823002), and Project G1999043808.
基金funded by the National Natural Science Foundation of China(Grant No.41105025)the Dragon 3 Programme(ID:10577)the High Resolution Earth Observation Funds for Young Scientists(Grant No.GFZX04060103)
文摘We investigate the Madden-Julian Oscillation （MJO） signal in wintertime stratospheric ozone over the Tibetan Plateau and East Asia using the harmonized dataset of satellite ozone profiles. Two different MJO indices -- the all-season Real-Time multivariate MJO index （RMM） and outgoing longwave radiation-based MJO index （OMI） -- are used to compare the MJO- related ozone anomalies. The results show that there are pronounced eastward-propagating MJO-related stratospheric ozone anomalies （mainly within 20-200 hPa） over the subtropics, The negative stratospheric ozone anomalies are over the Tibetan Plateau and East Asia in MJO phases 4-7, when MJO-related tropical deep convective anomalies move from the equatorial Indian Ocean towards the western Pacific Ocean. Compared with the results based on RMM, the MJO-related stratospheric column ozone anomalies based on OM1 are stronger and one phase ahead. Further analysis suggests that different sampling errors, observation principles and retrieval algorithms may be responsible for the discrepancies among different satellite measurements. The MJO-related stratospheric ozone anomalies can be attributed to the MJO-related circulation anomalies, i.e., the uplifted tropopanse and the northward shifted westerly jet in the upper troposphere. Compared to the result based on RMM, the upper tropospheric westerly jet may play a less important role in generating the stratospheric column ozone anomalies based on OMI. Our study indicates that the circulation-based MJO index （RMM） can better characterize the MJO- related anomalies in tropopause pressure and thus the MJO influence on atmospheric trace gases in the upper troposphere and lower stratosphere, especially over subtropical East Asia.
基金funded by the National Natural Science Foundation of China (Grant No. 41105025)the Dragon 3 Programme (ID: 10577)
文摘The authors examined the Madden-Julian Oscillation(MJO) in stratospheric ozone during boreal winter using a simulation from the Specified Dynamics version of the Whole Atmosphere Community Climate Model(SD-WACCM) in 2004 and 2010. Comparison with European Centre for Medium-Range Weather Forecasts Interim Reanalysis(ERA-Interim) data suggested that the model simulation represented well the three-dimensional structure of the MJO-related ozone anomalies in the upper troposphere and stratosphere(i.e., between 200 and 20 h Pa). The negative ozone anomalies were over the Tibetan Plateau and East Asia in MJO phases 3–7, when the MJO convective anomalies travelled from the equatorial Indian Ocean towards the equatorial western Pacific Ocean. Due to the different vertical structures of the MJO-related circulation anomalies, the MJO-related stratospheric ozone anomalies showed different vertical structure over the Tibetan Plateau(25–40°N, 75–105°E) and East Asia(25–40°N, 105–135°E). As a result of the positive bias in the model-calculated ozone in the upper troposphere and lower stratosphere, the amplitude of MJO-related stratospheric ozone column anomalies(10–16 Dobson Units(DU)) in the SD-WACCM simulation was slightly larger than that(8–14 DU) in the ERA-Interim reanalysis.
文摘The intra-seasonal variability plays a major role in the inter-annual variability of weather parameters such as rainfall, temperature and pressure which lead to extreme weather events in certain years. The active (more rainy days) and break (less rainy days) periods of Indian summer monsoon heavily depend on the intra-seasonal variability of weather parameters such as wind, pressure and temperature oscillations during the monsoon season. In the present analysis daily total column ozone, surface temperature and surface pressure measured over Cochin using Microtop II Ozonometer (sun Photometer) were used to study the Intra-Seasonal Variations (ISV) of the above parameters during the monsoon season, 2015. The dominant and significant intra-seasonal oscillations (ISOs) were identified using an advanced statistical method called the Discrete Mayer’s Wavelet (DMW) analysis. Two major ISOs such as Madden Julian Oscillations (MJO, 30 - 60 days) and quasi-bi weekly (12 - 16 days) oscillations were found in TCO, surface temperature and pressure. In TCO an additional mode of ISO with quasi tri-weekly periodicity was also found (16 - 22 day). It is observed that MJO mode is the dominant among all other modes and its positive and negative phases correlate with positive and negative anomalies of the above parameters. The ISO mode in the surface pressure shows an out of phase relation with the Indian summer monsoon rainfall which indicates the active and break periods of Indian summer monsoon. The contribution of MJO mode is dominant in the tropical atmosphere, which modulates the intra-seasonal variability. It is found that for the year 2015 total column ozone, surface pressure and surface temperature show an annual range of 30 DU, 4 hPa and 1°C, respectively.
基金This work was supported by the National Key Research and Development Program on Monitoring,Early Warning and Prevention of Major Natural Disaster[Grant No.2019YFC1510004]the National Natural Science Foundation of China[Grant Nos.41975108 and 42105022]+2 种基金NOAA[Grant No.NA18OAR4310298]the Natural Science Foundation of Jiangsu[Grant No.BK20190781]the National Natural Science Foundation of China–Shandong Joint Fund for Marine Science Research Centers[Grant No.U1606405].
文摘The aim of this study was to understand the cause of Madden–Julian oscillation(MJO)bias in the High Resolution AtmosphericModel(HiRAM)driven by observed SST through process-oriented diagnosis.Wavenumber-frequency power spectrum and composite analyses indicate that HiRAM underestimates the spectral amplitude over theMJO band and mainly produces non-propagating rather than eastward-propagating intraseasonal rainfall anomalies,as observed.Column-integrated moist static energy(MSE)budget analysis is conducted to understand the MJO propagation bias in the simulation.It is found that the bias is due to the lack of a zonally asymmetric distribution of the MSE tendency anomaly in respect to the MJO convective center,which is mainly attributable to the bias in vertical MSE advection and surface turbulent flux.Further analysis suggests that it is the unrealistic simulation of MJO vertical circulation anomalies in the upper troposphere as well as overestimation of the Rossby wave response that results in the bias.
