The air quality in China has improved significantly in the last decade and,correspondingly,the characteristics of PM_(2.5)have also changed.We studied the interannual variation of PM_(2.5)in Chengdu,one of the most he...The air quality in China has improved significantly in the last decade and,correspondingly,the characteristics of PM_(2.5)have also changed.We studied the interannual variation of PM_(2.5)in Chengdu,one of the most heavily polluted megacities in southwest China,during the most polluted season(winter).Our results show that the mass concentrations of PM_(2.5)decreased significantly year-by-year,from 195.8±91.0μg/m~3in winter 2016 to 96.1±39.3μg/m^(3)in winter 2020.The mass concentrations of organic matter(OM),SO_()4^(2-),NH_(4)^(+)and NO_(3)^(-)decreased by 49.6%,57.1%,49.7% and 28.7%,respectively.The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO_(3)^(-)and there was a larger contribution from mobile sources.The contribution of OM and NO_(3)^(-)not only increased with increasing levels of pollution,but also increased year-by-year at the same level of pollution.Four sources of PM_(2.5)were identified:combustion sources,vehicular emissions,dust and secondary aerosols.Secondary aerosols made the highest contribution and increased year-by-year,from 40.6%in winter 2016 to 46.3% in winter 2020.By contrast,the contribution from combustion sources decreased from 14.4% to 8.7%.Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants(e.g.,OM and NO_(3)^(-))and sources(secondary aerosols and vehicular emissions)in future policies for the reduction of pollution in Chengdu during the winter months.展开更多
With the advent of climate change,winter temperatures have been steadily increasing in the middle-to-high latitudes of the world.However,we have not found a corresponding decrease in the number of extremely cold winte...With the advent of climate change,winter temperatures have been steadily increasing in the middle-to-high latitudes of the world.However,we have not found a corresponding decrease in the number of extremely cold winters.This paper,based on Climatic Research Unit(CRU)re-analysis data,and methods of trend analysis,mutation analysis,correlation analysis,reports on the effects of Arctic warming on winter temperatures in Heilongjiang Province,Northeast China.The results show that:(1)during the period 1961-2018,winter temperatures in the Arctic increased considerably,that is,3.5 times those of the Equator,which has led to an increasing temperature gradient between the Arctic and the Equator.An abrupt change in winter temperatures in the Arctic was observed in 2000.(2)Due to the global warming,an extremely significant warming occurred in Heilongjiang in winter,in particular,after the Arctic mutation in 2000,although there were two warm winters,more cold winters were observed and the interannual variability of winter temperature also increased.(3)Affected by the warming trend in the Arctic,the Siberian High has intensified,and both the Arctic Vortex and the Eurasian Zonal Circulation Index has weakened.This explains the decrease in winter temperatures in Heilongjiang,and why cold winters still dominate.Moreover,the increase in temperature difference between the Arctic and the Equator is another reason for the decrease in winter temperatures in Heilongjiang.展开更多
The 2022 Beijing Winter Olympic Games are only a year away.Three years ago,at the closing ceremony of the 23rd Winter Olympics in PyeongChang,South Korea,Chinese President Xi Jinping extended a warm invitation to peop...The 2022 Beijing Winter Olympic Games are only a year away.Three years ago,at the closing ceremony of the 23rd Winter Olympics in PyeongChang,South Korea,Chinese President Xi Jinping extended a warm invitation to people from all over the world:“See you in Beijing in 2022!”He pledged that Beijing would strive to deliver on its commitment to present an exciting,extraordinary,and outstanding Winter Olympic Games.展开更多
Human activities have unintentionally helped rats grow rapidly worldwide.Beyond food waste and heated buildings,expanding cities and poorly maintained underground systems create endless shelters for rats.Now,climate c...Human activities have unintentionally helped rats grow rapidly worldwide.Beyond food waste and heated buildings,expanding cities and poorly maintained underground systems create endless shelters for rats.Now,climate change adds another challenge.A recent study in Science Advances reveals that warmer winters are boosting rat populations in cities.Researchers analyzed 16 cities across North America and Europe,finding that regions with faster temperature rises reported more frequent rat sightings.For example,Washington,D.C.saw a 25%increase in rat activity per 1℃ winter warming.展开更多
Increasing the grain yield(GY) and water use efficiency(WUE) of winter wheat in the Huaibei Plain(HP), China are essential. However, the effects of micro-sprinkler irrigation and topsoil compaction after wheat seed so...Increasing the grain yield(GY) and water use efficiency(WUE) of winter wheat in the Huaibei Plain(HP), China are essential. However, the effects of micro-sprinkler irrigation and topsoil compaction after wheat seed sowing on the GY and WUE are unclear. Therefore, a two-year field experiment was conducted during the 2021–2023 winter wheat growing seasons with a total six treatments: rain-fed(RF), conventional irrigation(CI) and micro-sprinkler irrigation(MI), as well as topsoil compaction after seed sowing under these three irrigation methods(RFC, CIC, and MIC). The results in the two years indicated that MI significantly increased GY compared to CI and RF, by averages of 17.9 and 42.1%, respectively. The increase in GY of MI was due to its significant increases in the number of spikes, kernels per spike, and grain weight. The chlorophyll concentration in flag leaves of MI after the anthesis stage maintained higher levels than with CI and RF, and was the lowest in RF. This was due to the dramatically enhanced catalase and peroxidase activities and lower malondialdehyde content under MI. Compared with RF and CI, MI significantly promoted dry matter remobilization and production after anthesis, as well as its contribution to GY. In addition, MI significantly boosted root growth, and root activity during the grain-filling stage was remarkably enhanced compared to CI and RF. In 2021–2022, there was no significant difference in WUE between MI and RF, but the WUE of RF was significantly lower than that of MI in 2022–2023. However, the WUE in MI was significantly improved compared to CI, and it increased by averages of 15.1 and 17.6% for the two years. Topsoil compaction significantly increased GY and WUE under rain-fed conditions due to improved spike numbers and dry matter production. Overall, topsoil compaction is advisable for enhancing GY and WUE in rain-fed conditions, whereas micro-sprinkler irrigation can be adopted to simultaneously achieve high GY and WUE in the HP.展开更多
Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two ...Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two diseases to appear simultaneously in some main production areas.It is necessary to discriminate wheat YR and FHB at the regional scale to accurately locate the disease in space,conduct detailed disease severity monitoring,and scientific control.Four images on different dates were acquired from Sentinel-2,Landsat-8,and Gaofen-1 during the critical period of winter wheat,and 22 remote sensing features that characterize the wheat growth status were then calculated.Meanwhile,6 meteorological parameters that reflect the wheat phenological information were also obtained by combining the site meteorological data and spatial interpolation technology.Then,the principal components(PCs)of comprehensive remote sensing and meteorological features were extracted with principal component analysis(PCA).The PCs-based discrimination models were established to map YR and FHB damage using the random forest(RF)and backpropagation neural network(BPNN).The models’performance was verified based on the disease field truth data(57 plots during the filling period)and 5-fold cross-validation.The results revealed that the PCs obtained after PCA dimensionality reduction outperformed the initial features(IFs)from remote sensing and meteorology in discriminating between the two diseases.Compared to the IFs,the average area under the curve for both micro-average and macro-average ROC curves increased by 0.07 in the PCs-based RF models and increased by 0.16 and 0.13,respectively,in the PCs-based BPNN models.Notably,the PCs-based BPNN discrimination model emerged as the most effective,achieving an overall accuracy of 83.9%.Our proposed discrimination model for wheat YR and FHB,coupled with multi-source remote sensing images and meteorological data,overcomes the limitations of a single-sensor and single-phase remote sensing information in multiple stress discrimination in cloudy and rainy areas.It performs well in revealing the damage spatial distribution of the two diseases at a regional scale,providing a basis for detailed disease severity monitoring,and scientific prevention and control.展开更多
The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skil...The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skills and strong will in different kinds of winter sports,such as skiing,skating and ice hockey.展开更多
In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads he...In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads here and there and it makes the whitesnow shine like diamonds.Although the trees are usually bare in winter,but(2)they look beautiful with the sunlight falling on them.展开更多
The South China Sea winter monsoon(SCSWM),an integral component of the East Asian winter monsoon,connects extratropical and tropical regions.Utilizing ERA5 reanalysis and PAMIP simulations,the relationship between Arc...The South China Sea winter monsoon(SCSWM),an integral component of the East Asian winter monsoon,connects extratropical and tropical regions.Utilizing ERA5 reanalysis and PAMIP simulations,the relationship between Arctic sea ice and the SCSWM is investigated.The authors reveal that its strongest relationship with Arctic sea ice occurs in the North Pacific sector,i.e.,the Sea of Okhotsk and western Bering Sea.This link persists throughout the cold season,peaks when sea ice precedes the SCSWM by one month,and is independent of ENSO.North Pacific sea-ice loss weakens the meridional temperature gradient(MTG)and vertical wind shear in midlatitudes,reducing baroclinic eddy formation.Given the reduced zonal wind according to the thermal wind relation,the reduced wave activity flux in the upper troposphere must be balanced by equatorward wind based on the quasi-geostrophic momentum equation.This generates an anomalous meridional overturning circulation with descent and low-level divergence around 30°N,which intensifies the divergent component of the SCSWM.The divergent northerly anomalies also lead to cold advection and subtropical cooling.The enhanced MTG due to the subtropical cooling and weakened MTG due to high-latitude warming closely tied to reduced North Pacific sea ice displace the westerly jet southward,creating cyclonic shears over the North Pacific and intensifying the rotational component of the SCSWM.These findings establish North Pacific sea ice as a non-ENSO driver of the SCSWM,holding substantial implications for the predictability of the SCSWM.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42205100 and 41805095)the Sichuan Science and Technology Program(Nos.2019YFS0476and 2022NSFSC0982)support from the Sichuan comprehensive monitoring station for environmental air quality。
文摘The air quality in China has improved significantly in the last decade and,correspondingly,the characteristics of PM_(2.5)have also changed.We studied the interannual variation of PM_(2.5)in Chengdu,one of the most heavily polluted megacities in southwest China,during the most polluted season(winter).Our results show that the mass concentrations of PM_(2.5)decreased significantly year-by-year,from 195.8±91.0μg/m~3in winter 2016 to 96.1±39.3μg/m^(3)in winter 2020.The mass concentrations of organic matter(OM),SO_()4^(2-),NH_(4)^(+)and NO_(3)^(-)decreased by 49.6%,57.1%,49.7% and 28.7%,respectively.The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO_(3)^(-)and there was a larger contribution from mobile sources.The contribution of OM and NO_(3)^(-)not only increased with increasing levels of pollution,but also increased year-by-year at the same level of pollution.Four sources of PM_(2.5)were identified:combustion sources,vehicular emissions,dust and secondary aerosols.Secondary aerosols made the highest contribution and increased year-by-year,from 40.6%in winter 2016 to 46.3% in winter 2020.By contrast,the contribution from combustion sources decreased from 14.4% to 8.7%.Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants(e.g.,OM and NO_(3)^(-))and sources(secondary aerosols and vehicular emissions)in future policies for the reduction of pollution in Chengdu during the winter months.
基金National Natural Science Foundation of China,No.41771067,No.U20A2082Key Project of Natural Science Foundation of Heilongjiang Province,No.ZD2020D002。
文摘With the advent of climate change,winter temperatures have been steadily increasing in the middle-to-high latitudes of the world.However,we have not found a corresponding decrease in the number of extremely cold winters.This paper,based on Climatic Research Unit(CRU)re-analysis data,and methods of trend analysis,mutation analysis,correlation analysis,reports on the effects of Arctic warming on winter temperatures in Heilongjiang Province,Northeast China.The results show that:(1)during the period 1961-2018,winter temperatures in the Arctic increased considerably,that is,3.5 times those of the Equator,which has led to an increasing temperature gradient between the Arctic and the Equator.An abrupt change in winter temperatures in the Arctic was observed in 2000.(2)Due to the global warming,an extremely significant warming occurred in Heilongjiang in winter,in particular,after the Arctic mutation in 2000,although there were two warm winters,more cold winters were observed and the interannual variability of winter temperature also increased.(3)Affected by the warming trend in the Arctic,the Siberian High has intensified,and both the Arctic Vortex and the Eurasian Zonal Circulation Index has weakened.This explains the decrease in winter temperatures in Heilongjiang,and why cold winters still dominate.Moreover,the increase in temperature difference between the Arctic and the Equator is another reason for the decrease in winter temperatures in Heilongjiang.
文摘The 2022 Beijing Winter Olympic Games are only a year away.Three years ago,at the closing ceremony of the 23rd Winter Olympics in PyeongChang,South Korea,Chinese President Xi Jinping extended a warm invitation to people from all over the world:“See you in Beijing in 2022!”He pledged that Beijing would strive to deliver on its commitment to present an exciting,extraordinary,and outstanding Winter Olympic Games.
文摘Human activities have unintentionally helped rats grow rapidly worldwide.Beyond food waste and heated buildings,expanding cities and poorly maintained underground systems create endless shelters for rats.Now,climate change adds another challenge.A recent study in Science Advances reveals that warmer winters are boosting rat populations in cities.Researchers analyzed 16 cities across North America and Europe,finding that regions with faster temperature rises reported more frequent rat sightings.For example,Washington,D.C.saw a 25%increase in rat activity per 1℃ winter warming.
基金funding from the Scientific Research Program of the Higher Educational Institutions in Anhui Province, China (2023AH050986)the Natural Science Foundation of Anhui Province, China (240805MC063)+1 种基金the National Natural Science Foundation of China (32172119)the Talent Introduction Project of Anhui Agricultural University, China (rc312212 and yj2019-01)。
文摘Increasing the grain yield(GY) and water use efficiency(WUE) of winter wheat in the Huaibei Plain(HP), China are essential. However, the effects of micro-sprinkler irrigation and topsoil compaction after wheat seed sowing on the GY and WUE are unclear. Therefore, a two-year field experiment was conducted during the 2021–2023 winter wheat growing seasons with a total six treatments: rain-fed(RF), conventional irrigation(CI) and micro-sprinkler irrigation(MI), as well as topsoil compaction after seed sowing under these three irrigation methods(RFC, CIC, and MIC). The results in the two years indicated that MI significantly increased GY compared to CI and RF, by averages of 17.9 and 42.1%, respectively. The increase in GY of MI was due to its significant increases in the number of spikes, kernels per spike, and grain weight. The chlorophyll concentration in flag leaves of MI after the anthesis stage maintained higher levels than with CI and RF, and was the lowest in RF. This was due to the dramatically enhanced catalase and peroxidase activities and lower malondialdehyde content under MI. Compared with RF and CI, MI significantly promoted dry matter remobilization and production after anthesis, as well as its contribution to GY. In addition, MI significantly boosted root growth, and root activity during the grain-filling stage was remarkably enhanced compared to CI and RF. In 2021–2022, there was no significant difference in WUE between MI and RF, but the WUE of RF was significantly lower than that of MI in 2022–2023. However, the WUE in MI was significantly improved compared to CI, and it increased by averages of 15.1 and 17.6% for the two years. Topsoil compaction significantly increased GY and WUE under rain-fed conditions due to improved spike numbers and dry matter production. Overall, topsoil compaction is advisable for enhancing GY and WUE in rain-fed conditions, whereas micro-sprinkler irrigation can be adopted to simultaneously achieve high GY and WUE in the HP.
基金supported by National Key R&D Program of China(2022YFD2000100)National Natural Science Foundation of China(42401400)Zhejiang Provincial Key Research and Development Program(2023C02018).
文摘Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two diseases to appear simultaneously in some main production areas.It is necessary to discriminate wheat YR and FHB at the regional scale to accurately locate the disease in space,conduct detailed disease severity monitoring,and scientific control.Four images on different dates were acquired from Sentinel-2,Landsat-8,and Gaofen-1 during the critical period of winter wheat,and 22 remote sensing features that characterize the wheat growth status were then calculated.Meanwhile,6 meteorological parameters that reflect the wheat phenological information were also obtained by combining the site meteorological data and spatial interpolation technology.Then,the principal components(PCs)of comprehensive remote sensing and meteorological features were extracted with principal component analysis(PCA).The PCs-based discrimination models were established to map YR and FHB damage using the random forest(RF)and backpropagation neural network(BPNN).The models’performance was verified based on the disease field truth data(57 plots during the filling period)and 5-fold cross-validation.The results revealed that the PCs obtained after PCA dimensionality reduction outperformed the initial features(IFs)from remote sensing and meteorology in discriminating between the two diseases.Compared to the IFs,the average area under the curve for both micro-average and macro-average ROC curves increased by 0.07 in the PCs-based RF models and increased by 0.16 and 0.13,respectively,in the PCs-based BPNN models.Notably,the PCs-based BPNN discrimination model emerged as the most effective,achieving an overall accuracy of 83.9%.Our proposed discrimination model for wheat YR and FHB,coupled with multi-source remote sensing images and meteorological data,overcomes the limitations of a single-sensor and single-phase remote sensing information in multiple stress discrimination in cloudy and rainy areas.It performs well in revealing the damage spatial distribution of the two diseases at a regional scale,providing a basis for detailed disease severity monitoring,and scientific prevention and control.
文摘The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skills and strong will in different kinds of winter sports,such as skiing,skating and ice hockey.
文摘In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads here and there and it makes the whitesnow shine like diamonds.Although the trees are usually bare in winter,but(2)they look beautiful with the sunlight falling on them.
基金supported by the National Key Research and Development Program of China[grant number 2022YFF0801701]the National Natural Science Foundation of China[grant number 42105017].
文摘The South China Sea winter monsoon(SCSWM),an integral component of the East Asian winter monsoon,connects extratropical and tropical regions.Utilizing ERA5 reanalysis and PAMIP simulations,the relationship between Arctic sea ice and the SCSWM is investigated.The authors reveal that its strongest relationship with Arctic sea ice occurs in the North Pacific sector,i.e.,the Sea of Okhotsk and western Bering Sea.This link persists throughout the cold season,peaks when sea ice precedes the SCSWM by one month,and is independent of ENSO.North Pacific sea-ice loss weakens the meridional temperature gradient(MTG)and vertical wind shear in midlatitudes,reducing baroclinic eddy formation.Given the reduced zonal wind according to the thermal wind relation,the reduced wave activity flux in the upper troposphere must be balanced by equatorward wind based on the quasi-geostrophic momentum equation.This generates an anomalous meridional overturning circulation with descent and low-level divergence around 30°N,which intensifies the divergent component of the SCSWM.The divergent northerly anomalies also lead to cold advection and subtropical cooling.The enhanced MTG due to the subtropical cooling and weakened MTG due to high-latitude warming closely tied to reduced North Pacific sea ice displace the westerly jet southward,creating cyclonic shears over the North Pacific and intensifying the rotational component of the SCSWM.These findings establish North Pacific sea ice as a non-ENSO driver of the SCSWM,holding substantial implications for the predictability of the SCSWM.
