In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are investigated.Results indicated that approximately 72.42%of tropi...In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are investigated.Results indicated that approximately 72.42%of tropical cyclones(TCs)in the Western Pacific produce TRP over China.The peak months for TRP are July and August.The four key regions of TRP are the adjacent areas between the Sichuan and Shaanxi Provinces,the northern coast of the Bohai Sea,the coast of the Yellow Sea,and the southern coast area.The typical distance between the station with TRP and the TC center ranges from 1500 to 2500 km.Most of these stations are situated north to 60°west of north of the TC.The south–west water vapor transportation on the west side of the TC is crucial to TRP.TRP has a decreasing trend because of the decrease in the number of TCs that generate TRP.From the perspective of large-scale environmental conditions,a decrease in the integrated horizontal water vapor transport in China' Mainland,the weakening of upward motion at approximately 25°–35°N,which is inconducive to convection,and an increase in low-level vertical wind shear,which is unfavorable for the development of TC in areas with high frequencies of TRP-related TCs,are the factors that result in the decreasing trend of TRP.展开更多
[Objective]The research aimed to study influence of the 850 hPa WPSH abnormality on rainfall in Jianghuai basin in early summer.[Method]Based on NCEP/NCAR 2.5°×2.5° analysis data,by using composite anal...[Objective]The research aimed to study influence of the 850 hPa WPSH abnormality on rainfall in Jianghuai basin in early summer.[Method]Based on NCEP/NCAR 2.5°×2.5° analysis data,by using composite analysis,correlation analysis,etc.,circulation and rainfall abnormalities were analyzed.Subtropical index related to geopotential height field,zonal wind field,precipitation rate,vertical velocity field and so on.Influence of the 850 hPa WPSH abnormality in early summer on rainfall in Jianghuai basin was discussed.[Result]850 hPa WPSH abnormality in early summer had important influence on rainfall in Jianghuai basin.When WPSH area was small in early summer,and ridge point was by east and north,there was no blocking high in Sea of Okhotsk area at 500 hPa height field,and pathway of the cold air at high latitude was by north.Low-pressure disturbance in plum rain frontal zone weakened,and East Asian summer monsoon circulation strengthened.Cold air in Jianghuai basin was weak,which caused less precipitation in Jianghuai basin.When WPSH area was big in early summer,and ridge point was by west and south,it was controlled by blocking high in Sea of Okhotsk area at 500 hPa height field.Low-pressure disturbance in plum rain frontal zone strengthened,and East Asian summer monsoon circulation weakened.Cold air in Jianghuai basin was strong,which caused more precipitation in Jianghuai basin.[Conclusion]The research played indicative role in precipitation abnormality in Jianghuai basin.展开更多
In this study, Fengyun-3 D(FY-3 D) Micro Wave Radiation Imager(MWRI) radiance data were directly assimilated into the Global/Regional Assimilation and Pr Ediction System(GRAPES) four-dimensional variational(4 DVar) sy...In this study, Fengyun-3 D(FY-3 D) Micro Wave Radiation Imager(MWRI) radiance data were directly assimilated into the Global/Regional Assimilation and Pr Ediction System(GRAPES) four-dimensional variational(4 DVar) system. Quality control procedures were developed for MWRI applications by using algorithms from similar microwave instruments. Compared with the FY-3 C MWRI, the bias of FY-3 D MWRI observations did not show a clear node-dependent difference from the numerical weather prediction background simulation. A conventional bias correction approach can therefore be used to remove systematic biases before the assimilation of data. After assimilating the MWRI radiance data into GRAPES, the geopotential height and humidity analysis fields were improved relative to the control experiment. There was a positive impact on the location of the subtropical high, which led to improvements in forecasts of the track of Typhoon Shanshan.展开更多
It is crucial to maintain the balance of economic development and ecosystem protection. The value of ecosystem services is an indicator to help people understand the importance of ecosystem protection. Traditional mod...It is crucial to maintain the balance of economic development and ecosystem protection. The value of ecosystem services is an indicator to help people understand the importance of ecosystem protection. Traditional models estimate ecosystem service values only according to land use/cover data while ignoring vegetation status differences in the same land use/cover. This study uses the normalized difference vegetation index(NDVI), the leaf area index(LAI),and net primary productivity(NPP) as vegetation status data to describe the differences in the same land use/cover type. The principal component analysis(PCA) approach is used to reduce the correlations among the three types of vegetation status data. Then, the calculated vegetation status index after PCA is input into the estimation model. The case study in China shows that the improved model has two major advantages. First, it can clearly distinguish the differences in ecosystem service values even for the same land use/cover type. Second, it can clearly describe the transitional zones between different land use/cover types through continuous changes in ecosystem service values. This improved model can provide a more detailed description of the distribution characteristics of ecosystem service values in China and help policymakers balance economic development and ecosystem protection.展开更多
Dust aerosol effects on the properties of cirrus and altocumulus cloud in Northwest China were studied for the period March-May 2007 by using the satellite data of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite...Dust aerosol effects on the properties of cirrus and altocumulus cloud in Northwest China were studied for the period March-May 2007 by using the satellite data of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations （CALIPSO）, Aqua, and CloudSat. Dusty clouds were defined as those mixed with dust aerosols or existing in dust aerosol conditions, while pure clouds were those in a dust-free environment. For dusty altocumulus clouds, the mean values of cloud optical depth （OPD）, cloud liquid water path （LWP）, cloud ice water path （IWP）, cloud effective particle radius （Re）, and cloud effective particle diameter （Dr） were 6.40, 40.23 g m-2, 100.70 g m-2, 8.76 μm, and 40.72 μm, respectively. For pure altocumulus clouds, the corresponding mean values were 9.28, 76.70 g m-2, 128.75 g m-2, 14.03 μm, and 48.92 μm, respectively. These results show a significant decrease of OPD, LWP, IWP, Re, and De of approximately 31%, 48%, 22%, 38%, and 17% because of the effects of dust aerosols. Moreover, the effects of dust aerosols on liquid-phase altocumulus clouds were greater than on ice-phase altocumulus clouds. Regarding dusty cirrus clouds, the mean values of OPD, IWP, and De were 5.11, 137.53 g in 2, and 60.44 μm, respectively. In contrast, the mean values were 6.69, 156.17 g m-2, and 66.63 μm, respectively, for pure cirrus clouds, with a 24% decrease in OPD, a 12% decrease in IWP, and a 9% decrease in De. These results indicate that dust aerosols can significantly change cloud properties, leading to a reduction of OPD, LWP, and effective particle size for both altocumulus and cirrus clouds in Northwest China.展开更多
This corrigendum is to report a figure error in Xiao et al.(2020)entitled“Impact of FY-3D MWRI radiance assim-ilation in GRAPES 4DVar on forecasts of Typhoon Shanshan.”In Xiao et al.(2020),the green lines for CTL2 a...This corrigendum is to report a figure error in Xiao et al.(2020)entitled“Impact of FY-3D MWRI radiance assim-ilation in GRAPES 4DVar on forecasts of Typhoon Shanshan.”In Xiao et al.(2020),the green lines for CTL2 and CTL3 in Figs.8b,c were mistakenly plotted the same as that(CTLI)in Fig.8a.Now,they are corrected in the figure(Figs.8b,c)below;i.e.,the green lines are different now.展开更多
Self-organization of typhoon vortex in a baroclinic environment is studied based on eight numerical experiments with the fifth-generation Pennsylvania State University/National Center for Atmospheric Research （PSU/N...Self-organization of typhoon vortex in a baroclinic environment is studied based on eight numerical experiments with the fifth-generation Pennsylvania State University/National Center for Atmospheric Research （PSU/NCAR） Mesoscale Model （MM5）. The results show that, when there are only two 400-km-away mesoscale axisymmetric vortices with a radius of 500 km in the initial field, the two vortices move away from each other during co-rotating till the distance between them greater than a critical distance named co-rotating critical distance. Then, they stop co-rotating. The situation is changed when a small vortex with a radius of 80 kin is introduced in between the two vortices in the initial field, with the two initially separated vortices approaching each other during their co-rotation, and finally self-organizing into a typhoon-like vortex consisting of an inner core and spiral bands. This result supports both Zhou Xiuji＇s view in 1994 and the studies in the barotropic framework concerning the interactions between the same and different scales of vortices. Six other experiments are carried out to study the effects of the initial vortex parameters, including the initial position of the small-scale vortex, the distance and intensity of the initially axisymmetric binary mesoscale vortices. It is found that the distance between the initial axisymmetrie mesoscale vortices is the most important parameter that influences the self-organizing process of the final typhoon-like vortex. This conclusion is similar to that obtained from barotropical model experiments.展开更多
By the 2000s,the winter wheat regions in the North China Plain had undergone six major variety renewals.It is crucial to know how the winter wheat varieties bred across different eras respond to climate change,especia...By the 2000s,the winter wheat regions in the North China Plain had undergone six major variety renewals.It is crucial to know how the winter wheat varieties bred across different eras respond to climate change,especially climate warming.From 2017 to 2022,we conducted a two-factor,two-level field experiment at Gucheng and Raoyang,with a temperature difference of 1℃existing between the two sites.The experiment used ten winter wheat varieties bred from the 1960s to the 2000s and included both fertilization and no fertilization treatments.The experiment aimed to separate the effects of warming and fertilization on the growth and development of the winter wheat varieties,thereby revealing the differences in their responses to warming.All the winter wheat varieties across different eras had higher yields in warmer environments.By separating the effects of warming and fertilization,the rate of yield increase decreased with the breeding eras of varieties due to the impact of warming alone.However,it still increased with the eras due to the combined effects of warming and fertilization.For varieties from the 1980s and 2000s,there is a strong correlation between higher fertility and warmer climate adaptability.Warming has a yield gain effect,significantly amplifying the yield increase under fertilization for the middle and late varieties.Therefore,the average yield increase for varieties from the 2000s reached 67%in warmer environments.Warming has increased the average daily minimum temperature during the winter wheat growing season.It has significantly reduced the number of days below zero degrees Celsius,shortening the overwintering stage and thereby shortening the growth period of winter wheat.However,the effective developmental days(>0℃days)maintained a consistent level.Warming promotes the development of large tillers,increases leaf area and dry matter accumulation,and reduces the ratio of sterile spikelets.The varieties from the 2000s had the lowest ratio of sterile spikelets and the highest harvest index(HI)in warmer environments,resulting in a significant increase in yield.This study reveals the differential responses to the warming of winter wheat varieties across different eras,which have a specific reference for winter wheat breeding to cope with climate change.展开更多
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province (No.KYCX22_1136)the National Natural Scientific Foundation of China (No.42275037)+2 种基金the Basic Research Fund of CAMS (No.2023Z016)the Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province (No.SCSF202202)supported by the Jiangsu Collaborative Innovation Center for Climate Change。
文摘In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are investigated.Results indicated that approximately 72.42%of tropical cyclones(TCs)in the Western Pacific produce TRP over China.The peak months for TRP are July and August.The four key regions of TRP are the adjacent areas between the Sichuan and Shaanxi Provinces,the northern coast of the Bohai Sea,the coast of the Yellow Sea,and the southern coast area.The typical distance between the station with TRP and the TC center ranges from 1500 to 2500 km.Most of these stations are situated north to 60°west of north of the TC.The south–west water vapor transportation on the west side of the TC is crucial to TRP.TRP has a decreasing trend because of the decrease in the number of TCs that generate TRP.From the perspective of large-scale environmental conditions,a decrease in the integrated horizontal water vapor transport in China' Mainland,the weakening of upward motion at approximately 25°–35°N,which is inconducive to convection,and an increase in low-level vertical wind shear,which is unfavorable for the development of TC in areas with high frequencies of TRP-related TCs,are the factors that result in the decreasing trend of TRP.
基金co-funded by the Key Project of the National Natural Science Foundation of China [grant number 42230609 and 41630425]the National Key Research and Development Plan projects [grant number 2022YFC3004101]
文摘[Objective]The research aimed to study influence of the 850 hPa WPSH abnormality on rainfall in Jianghuai basin in early summer.[Method]Based on NCEP/NCAR 2.5°×2.5° analysis data,by using composite analysis,correlation analysis,etc.,circulation and rainfall abnormalities were analyzed.Subtropical index related to geopotential height field,zonal wind field,precipitation rate,vertical velocity field and so on.Influence of the 850 hPa WPSH abnormality in early summer on rainfall in Jianghuai basin was discussed.[Result]850 hPa WPSH abnormality in early summer had important influence on rainfall in Jianghuai basin.When WPSH area was small in early summer,and ridge point was by east and north,there was no blocking high in Sea of Okhotsk area at 500 hPa height field,and pathway of the cold air at high latitude was by north.Low-pressure disturbance in plum rain frontal zone weakened,and East Asian summer monsoon circulation strengthened.Cold air in Jianghuai basin was weak,which caused less precipitation in Jianghuai basin.When WPSH area was big in early summer,and ridge point was by west and south,it was controlled by blocking high in Sea of Okhotsk area at 500 hPa height field.Low-pressure disturbance in plum rain frontal zone strengthened,and East Asian summer monsoon circulation weakened.Cold air in Jianghuai basin was strong,which caused more precipitation in Jianghuai basin.[Conclusion]The research played indicative role in precipitation abnormality in Jianghuai basin.
基金Supported by the National Natural Science Foundation of China(41675108)National Key Research and Development Program(2018YFC1506700)Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0105)。
文摘In this study, Fengyun-3 D(FY-3 D) Micro Wave Radiation Imager(MWRI) radiance data were directly assimilated into the Global/Regional Assimilation and Pr Ediction System(GRAPES) four-dimensional variational(4 DVar) system. Quality control procedures were developed for MWRI applications by using algorithms from similar microwave instruments. Compared with the FY-3 C MWRI, the bias of FY-3 D MWRI observations did not show a clear node-dependent difference from the numerical weather prediction background simulation. A conventional bias correction approach can therefore be used to remove systematic biases before the assimilation of data. After assimilating the MWRI radiance data into GRAPES, the geopotential height and humidity analysis fields were improved relative to the control experiment. There was a positive impact on the location of the subtropical high, which led to improvements in forecasts of the track of Typhoon Shanshan.
基金Supported by the National Key Research and Development Program of China (2018YFC1506503)Meteorological Collaborative Innovation Foundation in Huadong Area (QYHZ201815)。
文摘It is crucial to maintain the balance of economic development and ecosystem protection. The value of ecosystem services is an indicator to help people understand the importance of ecosystem protection. Traditional models estimate ecosystem service values only according to land use/cover data while ignoring vegetation status differences in the same land use/cover. This study uses the normalized difference vegetation index(NDVI), the leaf area index(LAI),and net primary productivity(NPP) as vegetation status data to describe the differences in the same land use/cover type. The principal component analysis(PCA) approach is used to reduce the correlations among the three types of vegetation status data. Then, the calculated vegetation status index after PCA is input into the estimation model. The case study in China shows that the improved model has two major advantages. First, it can clearly distinguish the differences in ecosystem service values even for the same land use/cover type. Second, it can clearly describe the transitional zones between different land use/cover types through continuous changes in ecosystem service values. This improved model can provide a more detailed description of the distribution characteristics of ecosystem service values in China and help policymakers balance economic development and ecosystem protection.
基金Supported by the National Natural Science Foundation of China(41505013,41375032,and 41175026)China Postdoctoral Science Fund(2014M552506)
文摘Dust aerosol effects on the properties of cirrus and altocumulus cloud in Northwest China were studied for the period March-May 2007 by using the satellite data of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations （CALIPSO）, Aqua, and CloudSat. Dusty clouds were defined as those mixed with dust aerosols or existing in dust aerosol conditions, while pure clouds were those in a dust-free environment. For dusty altocumulus clouds, the mean values of cloud optical depth （OPD）, cloud liquid water path （LWP）, cloud ice water path （IWP）, cloud effective particle radius （Re）, and cloud effective particle diameter （Dr） were 6.40, 40.23 g m-2, 100.70 g m-2, 8.76 μm, and 40.72 μm, respectively. For pure altocumulus clouds, the corresponding mean values were 9.28, 76.70 g m-2, 128.75 g m-2, 14.03 μm, and 48.92 μm, respectively. These results show a significant decrease of OPD, LWP, IWP, Re, and De of approximately 31%, 48%, 22%, 38%, and 17% because of the effects of dust aerosols. Moreover, the effects of dust aerosols on liquid-phase altocumulus clouds were greater than on ice-phase altocumulus clouds. Regarding dusty cirrus clouds, the mean values of OPD, IWP, and De were 5.11, 137.53 g in 2, and 60.44 μm, respectively. In contrast, the mean values were 6.69, 156.17 g m-2, and 66.63 μm, respectively, for pure cirrus clouds, with a 24% decrease in OPD, a 12% decrease in IWP, and a 9% decrease in De. These results indicate that dust aerosols can significantly change cloud properties, leading to a reduction of OPD, LWP, and effective particle size for both altocumulus and cirrus clouds in Northwest China.
文摘This corrigendum is to report a figure error in Xiao et al.(2020)entitled“Impact of FY-3D MWRI radiance assim-ilation in GRAPES 4DVar on forecasts of Typhoon Shanshan.”In Xiao et al.(2020),the green lines for CTL2 and CTL3 in Figs.8b,c were mistakenly plotted the same as that(CTLI)in Fig.8a.Now,they are corrected in the figure(Figs.8b,c)below;i.e.,the green lines are different now.
基金Supported by the Natural Science Foundation of China under Grant No.40333028the Key Project of Science and Technology Department of Zhejiang Province under Grant No.2007C13G1610002
文摘Self-organization of typhoon vortex in a baroclinic environment is studied based on eight numerical experiments with the fifth-generation Pennsylvania State University/National Center for Atmospheric Research （PSU/NCAR） Mesoscale Model （MM5）. The results show that, when there are only two 400-km-away mesoscale axisymmetric vortices with a radius of 500 km in the initial field, the two vortices move away from each other during co-rotating till the distance between them greater than a critical distance named co-rotating critical distance. Then, they stop co-rotating. The situation is changed when a small vortex with a radius of 80 kin is introduced in between the two vortices in the initial field, with the two initially separated vortices approaching each other during their co-rotation, and finally self-organizing into a typhoon-like vortex consisting of an inner core and spiral bands. This result supports both Zhou Xiuji＇s view in 1994 and the studies in the barotropic framework concerning the interactions between the same and different scales of vortices. Six other experiments are carried out to study the effects of the initial vortex parameters, including the initial position of the small-scale vortex, the distance and intensity of the initially axisymmetric binary mesoscale vortices. It is found that the distance between the initial axisymmetrie mesoscale vortices is the most important parameter that influences the self-organizing process of the final typhoon-like vortex. This conclusion is similar to that obtained from barotropical model experiments.
基金supported by the Development Program of China(Grant No.2023YFE0122200)the National Natural Science Foundation of China(Grant No.42075193)。
文摘By the 2000s,the winter wheat regions in the North China Plain had undergone six major variety renewals.It is crucial to know how the winter wheat varieties bred across different eras respond to climate change,especially climate warming.From 2017 to 2022,we conducted a two-factor,two-level field experiment at Gucheng and Raoyang,with a temperature difference of 1℃existing between the two sites.The experiment used ten winter wheat varieties bred from the 1960s to the 2000s and included both fertilization and no fertilization treatments.The experiment aimed to separate the effects of warming and fertilization on the growth and development of the winter wheat varieties,thereby revealing the differences in their responses to warming.All the winter wheat varieties across different eras had higher yields in warmer environments.By separating the effects of warming and fertilization,the rate of yield increase decreased with the breeding eras of varieties due to the impact of warming alone.However,it still increased with the eras due to the combined effects of warming and fertilization.For varieties from the 1980s and 2000s,there is a strong correlation between higher fertility and warmer climate adaptability.Warming has a yield gain effect,significantly amplifying the yield increase under fertilization for the middle and late varieties.Therefore,the average yield increase for varieties from the 2000s reached 67%in warmer environments.Warming has increased the average daily minimum temperature during the winter wheat growing season.It has significantly reduced the number of days below zero degrees Celsius,shortening the overwintering stage and thereby shortening the growth period of winter wheat.However,the effective developmental days(>0℃days)maintained a consistent level.Warming promotes the development of large tillers,increases leaf area and dry matter accumulation,and reduces the ratio of sterile spikelets.The varieties from the 2000s had the lowest ratio of sterile spikelets and the highest harvest index(HI)in warmer environments,resulting in a significant increase in yield.This study reveals the differential responses to the warming of winter wheat varieties across different eras,which have a specific reference for winter wheat breeding to cope with climate change.
