The commencement of the tropical Asian summer monsoon(TASM)in May is a crucial phase in its seasonal evolution,with critical implications for agriculture and water resources.Based on observational and reanalysis data,...The commencement of the tropical Asian summer monsoon(TASM)in May is a crucial phase in its seasonal evolution,with critical implications for agriculture and water resources.Based on observational and reanalysis data,this study finds that the relationship between El Nino-Southern Oscillation(ENSO)and monsoon commencement experiences a notable interdecadal strengthening after 1976/77.While the response of tropical tropospheric temperature to ENSO remains largely unchanged,ENSO induces a stronger Walker circulation,a more pronounced equatorial Rossby wave,and an intensified extratropical Rossby wave train after 1976/77.These enhanced atmospheric processes,which directly reinforce the ENSO-TASM commencement relationship,are likely driven by interdecadal shifts in the structure and variance of ENSO.Post-1976/77,ENSO displays increased variance and a more coherent structure,with more pronounced sea surface temperature anomalies in the western North Pacific and subtropical North Pacific.Given the limitations of observational data,a 1000-year piControl experiment further confirms the role of ENSO variance changes in strengthening its influence on monsoon commencement.Our findings underscore the critical influence of evolving ENSO characteristics on climate anomalies such as monsoon commencement,offering potential insights for short-term climate prediction.展开更多
Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the i...Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the impacts of wildfire on hydrology have been widely assessed at the watershed scale,the underlying mechanisms of the responses of summer low flows remain poorly understood.In this study,we employed an integrated research framework that combines hydrometric monitoring with geochemical tracing to evaluate how the 2021 White Rock Lake Wildfire affected summer low flows,and to identify the underlying mechanisms governing these responses in the Okanagan Valley,British Columbia(BC),Canada.We found that(1)summer low flows,represented by Q90(flows exceeded at 90%of the time in summer)significantly increased following the wildfire(p<0.05);(2)summer low flows were primarily regulated by snow water in early summer(July),while dominated by groundwater in late summer(August and September);and(3)enhanced snow water contribution and reduced evapotranspiration(ET)were two primary contributors to the increased summer low flows.Our results provide insights for developing sustainable water management strategies for the region in the context of climate change and increasing forest disturbance.This study also demonstrates that the combination of hydrometric monitoring and geochemical tracing is an effective approach towards uncovering mechanisms that drive low-flow responses.展开更多
Recent studies have suggested that rapid warming over the Mongolian Plateau(MP) may intensify extreme heat events(EHEs). However, the characteristics and mechanisms driving summer EHEs over the MP(MP-EHEs) remain uncl...Recent studies have suggested that rapid warming over the Mongolian Plateau(MP) may intensify extreme heat events(EHEs). However, the characteristics and mechanisms driving summer EHEs over the MP(MP-EHEs) remain unclear. This study explores the interannual variations in summer MP-EHEs and their relationship with the summer soil moisture over the Inner Tibetan Plateau(TP-SM). The results reveal that changes in the MP-EHEs are linked to descending atmospheric motion induced by a local high-pressure system over the MP region. Descending motion further results in decreased mid-tolow-level cloud cover and increased shortwave radiation, thereby warming the surface and triggering summer MP-EHEs.Further analysis indicates that increased TP-SM results in a greater latent heat flux, triggering a local secondary circulation that reinforces the local high-pressure system over the MP region, thus serving to promote the occurrence of summer MPEHEs. Additionally, model results from the linear baroclinic model(LBM) and CMIP6 further confirm that variations in summer TP-SM contribute to the occurrence of the MP-EHEs.展开更多
Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(EN...Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.展开更多
Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives ...Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives of billions who depend on or are affected by monsoons, as it is essential for the water cycle, food security, ecology, disaster prevention, and the economy of monsoon regions. Given the extensive literature on Asian monsoon climate prediction, we limit our focus to reviewing the seasonal prediction and predictability of the Asian Summer Monsoon (ASM). However, much of this review is also relevant to monsoon predictions in other seasons and regions. Over the past two decades, considerable progress has been made in the seasonal forecasting of the ASM, driven by an enhanced understanding of the sources of predictability and the dynamics of seasonal variability, along with advanced development in sophisticated models and technologies. This review centers on advances in understanding the physical foundation for monsoon climate prediction (section 2), significant findings and insights into the primary and regional sources of predictability arising from feedback processes among various climate components (sections 3 and 4), the effects of global warming and external forcings on predictability (section 5), developments in seasonal prediction models and techniques (section 6), the challenges and limitations of monsoon climate prediction (section 7), and emerging research trends with suggestions for future directions (section 8). We hope this review will stimulate creative activities to enhance monsoon climate prediction.展开更多
The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity...The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity.To clarify the effect of subsoiling before winter wheat on the kernel position effect of densely grown summer maize and its regulatory mechanism,field experiments were conducted during the 2020-2021 and 2021-2022 growing seasons using a split-plot design.The main plots included two tillage practices:conventional tillage practice(CT)and subsoiling before the sowing of winter wheat(SS);and the subplots consisted of three plant densities(D1-D3 at 6.0×10~4,7.5×10~4,and 9.0×10~4 plants ha-1).Compared with CT,SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernels(WR)in the D2 and D3 treated plants.The higher WR of SS treated plants contributed largely to the improved flling of inferior kernels.Under the same plant density,SS signifcantly improved the root dry matter accumulation(DMA)and antioxidant enzyme activities(superoxide dismutase(SOD)and peroxidase(POD)),and it reduced the malondialdehyde(MDA)content,especially for the plants grown under higher plant densities.These results indicated that SS delayed the root senescence,which is associated with the reduced soil bulk density.In addition,compared with CT,SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and the post-silking leaf area duration,and it reduced the post-silking leaf chlorophyll reduction rate and leaf area reduction rate,indicating that the post-silking leaf senescence had been alleviated.Under the same plant density,the post-silking DMA of SS was obviously higher than that of CT,which was probably related to the improved leaf area duration and photosynthetic enzyme activities(phosphoenolpyruvate carboxylase(PEPC)and Rubisco).The correlation analysis revealed that the main mechanism of SS in alleviating the kernel position effect of densely grown summer maize is as follows:SS delays the post-silking root-shoot senescence by regulating soil physical properties,and further improves the post-silking DMA and flling of inferior kernels,which ultimately alleviates the kernel position effect and improves grain yield.The results of this study provide new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.展开更多
During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the s...During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the subtropical Northwestern Pacific(10°-20°N,130°E-175°W).The former is well-documented and considered to be influenced by the ENSO,while the latter has received comparatively less attention and is likely influenced by the Pacific Meridional Mode(PMM),as suggested by partial correlation analysis results.To elucidate the physical processes responsible for the enhanced(weakened)intraseasonal convection over the subtropical northwestern Pacific during warm(cold)PMM years,the authors employed a moisture budget analysis.The findings reveal that during warm PMM years,there is an increase in summer-mean moisture over the subtropical northwestern Pacific.This increase interacts with intensified vertical motion perturbations in the region,leading to greater vertical moisture advection in the lower troposphere and consequently resulting in convective instability.Such a process is pivotal in amplifying intraseasonal convection anomalies.The observational findings were further verified by model experiments forced by PMM-like sea surface temperature patterns.展开更多
一、完形填空阅读短文,掌握其大意,从A、B、C三个选项中选择最佳答案填空。It's a hot summer day.Jake and Harry are working hard in the garden.Their friend Ralph is__1__under a tree.Jake asks Harry,"Why are we here...一、完形填空阅读短文,掌握其大意,从A、B、C三个选项中选择最佳答案填空。It's a hot summer day.Jake and Harry are working hard in the garden.Their friend Ralph is__1__under a tree.Jake asks Harry,"Why are we here in the__2__sun when Ralph is sitting there?"Hary says,"I don't know.I will go and ask him."展开更多
Summer is my favorite season of the year.The weather is hot,but I don’t mind because there are so many fun things to do.In summer,I can swim in the pool with my friends.The cool water makes me feel really comfortable.
Summer residential tourism is the future trend in China because of tourists’living quality improvement,heat crisis,rising market demand,and optimization of the destinations’residential environment,transport and acce...Summer residential tourism is the future trend in China because of tourists’living quality improvement,heat crisis,rising market demand,and optimization of the destinations’residential environment,transport and accessibility.Compared with summer tourism and vacation tourism,summer residential tourism had got less attention and lacks in prospective and preventive research.Hence,this study focused on potential assessment,pattern recognition and phase segmentation of 32 residential tourism destinations in China selected from 4 lists.An index system of 16 indicators from 5 dimensions was established as Summer Residence Index(SRI),and Range method,Entropy weight method and Composite index method were chosen as the core methods.Three main conclusions were as follows.(1)Only 2 typical districts’SRI value were near to 0.6,and 4 destinations were below 0.1,about 26 destinations were at medium-level,which indicated that China’s summer residential tourism was not so popular and only few destinations have stepped into a higher level.(2)Seven patterns could be recognized based on the contribution of the 5 dimensions to SRI value,including 3 single-factor driven patterns and 4 compound factors driven patterns.(3)Like tourist area life cycle(TALC),Unconscious stage,Initial stage,Developmental stage and Maturity stage could be segmented for summer residential destinations with the value of below 0.1,0.1-0.3,0.3-0.5,and above 0.5.Four destinations were under Unconscious stage.Twenty-two destinations were at initiate stage.Only 4 destinations have stepped into development stage and 2 at maturity stage.China’summer residential tourism has just started and has a better prospect.This study is just an attempt and needs further consideration,for example,a tracking study of SRI calculation for each year will be carried to justify the effectiveness of SRI and to check the rationality of the empirical results.As time goes on,policies in housing,residential estate and other aspects should be included as a factor in the SRI index.Data availability should be optimized because of better data sources and new technologies.Some other districts or cities in 2 batches of national Comprehensive Tourism Demonstration Zones(CTDZs)pilots and provincial CTDZs will be further selections of summer residential tourism destinations.展开更多
Hi,I'm Young from Zhangjiagang Yangshe Experimental School,and I'm in Grade Six.I want to share my fantastic summer vacation with you!This summer,I went on a trip to Macao with my family.It was an amazing and ...Hi,I'm Young from Zhangjiagang Yangshe Experimental School,and I'm in Grade Six.I want to share my fantastic summer vacation with you!This summer,I went on a trip to Macao with my family.It was an amazing and unforgettable experience for me!展开更多
This summer holiday,my older brother and I paid a visit to my grandparents by bus.The bus was crowded,but everyone seemed to be friendly and helpful.We enjoyed beautiful views all the way.At first,we saw one hill afte...This summer holiday,my older brother and I paid a visit to my grandparents by bus.The bus was crowded,but everyone seemed to be friendly and helpful.We enjoyed beautiful views all the way.At first,we saw one hill after another.展开更多
Last summer holiday,I went to Nan'ao Island in Shantou with my family.It was a wonderful trip,and I enjoyed it very much.The island is very beautiful.The sea was clear and blue,and the beach had soft golden sand.W...Last summer holiday,I went to Nan'ao Island in Shantou with my family.It was a wonderful trip,and I enjoyed it very much.The island is very beautiful.The sea was clear and blue,and the beach had soft golden sand.We spent the whole morning at Qing'ao Bay.I played frisbee with my brother,built a little sand house,and even collected some pretty seashells.The waves were small and gentle,so I ran into the water and felt very excited.Later,we visited the Nan'ao Island Museum,where we learned many interesting stories about the island's history,the fishermen's lives,and the animals in the sea.展开更多
Tom:Hi,Lily!What's the weather like today?Lily:It's sunny and warm.The sky is blue.Tom:That's great!I like sunny days.We can play outside.Lily:Yes!Let's go to the park after school.Tom:Good idea!What&#...Tom:Hi,Lily!What's the weather like today?Lily:It's sunny and warm.The sky is blue.Tom:That's great!I like sunny days.We can play outside.Lily:Yes!Let's go to the park after school.Tom:Good idea!What's your favourite season?Lily:I like winter.I can play in the snow and make a snowman.Tom:I like spring.The flowers are beautiful,and the weather is nice.Lily:Do you like summer?Tom:It's too hot,but I like eating ice cream!Lily:Haha!Me too.Ice cream is the best in summer!展开更多
一、请根据录音,填写单词。二、听对话,选择正确的答案。1.Where did Lucy go for her summer vacation?A.She stayed in the city.B.She went to the science museum.C.She went to Beijing.2.What did Tom think about climbing the G...一、请根据录音,填写单词。二、听对话,选择正确的答案。1.Where did Lucy go for her summer vacation?A.She stayed in the city.B.She went to the science museum.C.She went to Beijing.2.What did Tom think about climbing the Great Wall?展开更多
In mid-June,the vast,rolling meadow steppe grasslands of Bayanwenduer Sumu in Ar Horqin Banner,Inner Mongolia Autonomous Region,once again stretched into the horizon like green waves with herds of cattle and sheep sca...In mid-June,the vast,rolling meadow steppe grasslands of Bayanwenduer Sumu in Ar Horqin Banner,Inner Mongolia Autonomous Region,once again stretched into the horizon like green waves with herds of cattle and sheep scattered across them like pearls in a green ocean.This flock was driven by herders on horseback,motorcycles,and agricultural vehicles,leading the animals to summer pastures in one of the most important migrations of the year.展开更多
Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the nume...Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the numerical model outputs and historical observations,which can partly predict seasonal precipitation.However,solving a nonlinear problem through linear regression is significantly biased.This study implements a nonlinear optimization of an existing observational constrained correction model using a Light Gradient Boosting Machine(LightGBM)machine learning algorithm based on output from the Beijing National Climate Center Climate System Model(BCC-CSM)and station observations to improve the prediction of summer precipitation in China.The model was trained using a rolling approach,and LightGBM outperformed Linear Regression(LR),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost).Using parameter tuning to optimize the machine learning model and predict future summer precipitation using eight different predictors in BCC-CSM,the mean Anomaly Correlation Coefficient(ACC)score in the 2019–22 summer precipitation predictions was 0.17,and the mean Prediction Score(PS)reached 74.The PS score was improved by 7.87%and 6.63%compared with the BCC-CSM and the linear observational constraint approach,respectively.The observational constraint correction prediction strategy with LightGBM significantly and stably improved the prediction of summer precipitation in China compared to the previous linear observational constraint solution,providing a reference for flood control and drought relief during the flood season(summer)in China.展开更多
The Summer Palace in Beijing is one of Chinas most charming parks,renowned for its natural beauty and historical significance.Its appeal lies in the harmonious blend of lush(茂盛的)gardens,peaceful lakes and magnifice...The Summer Palace in Beijing is one of Chinas most charming parks,renowned for its natural beauty and historical significance.Its appeal lies in the harmonious blend of lush(茂盛的)gardens,peaceful lakes and magnificent architecture,making it a favorite destination for both locals and tourists.展开更多
Not many 17‑year‑old girls know how to join two pipes together or light the pilot light.These are skills I have learned over the past five years as an assistant to my plumber dad.This summer job demands an attitude of...Not many 17‑year‑old girls know how to join two pipes together or light the pilot light.These are skills I have learned over the past five years as an assistant to my plumber dad.This summer job demands an attitude of perseverance and grace that I frequently struggle to adopt.Each humid morning,my dad and I drag awkward and heavy toolboxes into people's dark and damp basements where I usually get lost in mazes of storage boxes.Nevertheless,I stick to it.I am the plumber's daughter and helper.展开更多
Selecting an appropriate planting density is an effective way to improve crop water productivity(WPC).However, there is a lack of research on the balance between evapotranspiration(ET) partitioning, water consumption,...Selecting an appropriate planting density is an effective way to improve crop water productivity(WPC).However, there is a lack of research on the balance between evapotranspiration(ET) partitioning, water consumption, and grain production under different summer maize planting densities. To close this knowledge gap, a two-year field experiment was conducted in the North China Plain(NCP) to reveal the effects of different planting densities(HD: 100,000 plants ha^(-1);MD: 78,000 plants ha^(-1);LD:56,000 plants ha^(-1)) on ET partitioning, grain yield, and water productivity of summer maize. The water-heat-carbon-nitrogen simulator(WHCNS) model was employed to calculate ET partitioning and perform scenario simulation after calibration and validation. The results showed that compared to the LD treatment, ET of the summer maize and grain yield in the MD and HD treatments significantly increased. Model simulations showed that the ratio of evaporation to ET ranged from 25.6% to 30.7%and reduced as increasing planting densities. Increasing planting density enhanced total transpiration of summer maize more than 20 mm, comparing to LD treatment, and the most significant differences between various planting densities appeared at the mid-growth stage(August 1 to 31). Scenario simulations indicated that grain yield and WPCof summer maize were consistently higher in wet and normal years compared to drought years, exhibiting a trend of initially increasing and then decreasing with increasing planting density. The highest grain yield and WPCof summer maize were observed at a planting density of approximately 80,000 plants ha^(-1). The results provide theoretical support for selecting a summer maize planting density and effectively utilizing agricultural water in the NCP.展开更多
基金supported jointly by the Natural Science Foundation of Yunnan Province(Grant No.202501CF070059)the National Natural Science Foundation of China(Grant No.42205021)+5 种基金the Yunnan Provincial Science and Technology Department(Grant Nos.202505AB350001 and202403AP140009)the Yunnan Southwest United Graduate School Science and Technology Special Project(Award No.202302AP370003)the Scientific Research Fund Project of Yunnan Education Department(Grant No.2025Y0111)the Practical Innovation Project of Postgraduate Students in the Academic Degree of Yunnan University(Grant No.KC-24248868)the Practical Innovation Project of Postgraduate Students in the Professional Degree of Yunnan University(Grant No.ZC-24248604)the Youth Science and Technology Fund Project of Gansu Province(Grant No.24JRRA1186)。
文摘The commencement of the tropical Asian summer monsoon(TASM)in May is a crucial phase in its seasonal evolution,with critical implications for agriculture and water resources.Based on observational and reanalysis data,this study finds that the relationship between El Nino-Southern Oscillation(ENSO)and monsoon commencement experiences a notable interdecadal strengthening after 1976/77.While the response of tropical tropospheric temperature to ENSO remains largely unchanged,ENSO induces a stronger Walker circulation,a more pronounced equatorial Rossby wave,and an intensified extratropical Rossby wave train after 1976/77.These enhanced atmospheric processes,which directly reinforce the ENSO-TASM commencement relationship,are likely driven by interdecadal shifts in the structure and variance of ENSO.Post-1976/77,ENSO displays increased variance and a more coherent structure,with more pronounced sea surface temperature anomalies in the western North Pacific and subtropical North Pacific.Given the limitations of observational data,a 1000-year piControl experiment further confirms the role of ENSO variance changes in strengthening its influence on monsoon commencement.Our findings underscore the critical influence of evolving ENSO characteristics on climate anomalies such as monsoon commencement,offering potential insights for short-term climate prediction.
基金the China Scholarship Council(CSC)the Uplifting Reciprocal Research Scholarship Program for sponsoring Shixuan Lyu+1 种基金supported by MITACS Accelerate(No.IT39116)the Okanagan Basin Water Board water conservation and quality improvement grant program。
文摘Forests are experiencing more frequent and intense wildfires in Canada,which pose considerable threats to water quantity and quality,particularly during the summer low-flow period when water demand is high.While the impacts of wildfire on hydrology have been widely assessed at the watershed scale,the underlying mechanisms of the responses of summer low flows remain poorly understood.In this study,we employed an integrated research framework that combines hydrometric monitoring with geochemical tracing to evaluate how the 2021 White Rock Lake Wildfire affected summer low flows,and to identify the underlying mechanisms governing these responses in the Okanagan Valley,British Columbia(BC),Canada.We found that(1)summer low flows,represented by Q90(flows exceeded at 90%of the time in summer)significantly increased following the wildfire(p<0.05);(2)summer low flows were primarily regulated by snow water in early summer(July),while dominated by groundwater in late summer(August and September);and(3)enhanced snow water contribution and reduced evapotranspiration(ET)were two primary contributors to the increased summer low flows.Our results provide insights for developing sustainable water management strategies for the region in the context of climate change and increasing forest disturbance.This study also demonstrates that the combination of hydrometric monitoring and geochemical tracing is an effective approach towards uncovering mechanisms that drive low-flow responses.
基金supported by the National Natural Science Foundation of China (Grant No.42288101)the Young Scientists Fund of the National Natural Science Foundation of China (Grand No.42505018)the Shanghai “Science and Technology Innovation Action Plan” Venus Project (Grant No.23YF1437300)。
文摘Recent studies have suggested that rapid warming over the Mongolian Plateau(MP) may intensify extreme heat events(EHEs). However, the characteristics and mechanisms driving summer EHEs over the MP(MP-EHEs) remain unclear. This study explores the interannual variations in summer MP-EHEs and their relationship with the summer soil moisture over the Inner Tibetan Plateau(TP-SM). The results reveal that changes in the MP-EHEs are linked to descending atmospheric motion induced by a local high-pressure system over the MP region. Descending motion further results in decreased mid-tolow-level cloud cover and increased shortwave radiation, thereby warming the surface and triggering summer MP-EHEs.Further analysis indicates that increased TP-SM results in a greater latent heat flux, triggering a local secondary circulation that reinforces the local high-pressure system over the MP region, thus serving to promote the occurrence of summer MPEHEs. Additionally, model results from the linear baroclinic model(LBM) and CMIP6 further confirm that variations in summer TP-SM contribute to the occurrence of the MP-EHEs.
基金supported by the National Natural Science Foundation of China[grant numbers 41975087,U2242212,and 41975085]supported by the National Natural Science Foundation of China[grant number U2242212]。
文摘Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.
基金supported by the National Natural Science Foundation of China(Grant No.U2342208)support from NSF/Climate Dynamics Award#2025057。
文摘Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives of billions who depend on or are affected by monsoons, as it is essential for the water cycle, food security, ecology, disaster prevention, and the economy of monsoon regions. Given the extensive literature on Asian monsoon climate prediction, we limit our focus to reviewing the seasonal prediction and predictability of the Asian Summer Monsoon (ASM). However, much of this review is also relevant to monsoon predictions in other seasons and regions. Over the past two decades, considerable progress has been made in the seasonal forecasting of the ASM, driven by an enhanced understanding of the sources of predictability and the dynamics of seasonal variability, along with advanced development in sophisticated models and technologies. This review centers on advances in understanding the physical foundation for monsoon climate prediction (section 2), significant findings and insights into the primary and regional sources of predictability arising from feedback processes among various climate components (sections 3 and 4), the effects of global warming and external forcings on predictability (section 5), developments in seasonal prediction models and techniques (section 6), the challenges and limitations of monsoon climate prediction (section 7), and emerging research trends with suggestions for future directions (section 8). We hope this review will stimulate creative activities to enhance monsoon climate prediction.
基金fnancially supported by the Natural Science Foundation of Hebei Province,China(C2021301004)the State Key Laboratory of North China Crop Improvement and Regulation,China(NCCIR2023KF-10)the HAAFS Science and Technology Innovation Special Project,China(2022KJCXZX-LYS-9)。
文摘The intensified kernel position effect is a common phenomenon in maize production under higher plant density,which limits crop productivity.Subsoiling is an effective agronomic practice for improving crop productivity.To clarify the effect of subsoiling before winter wheat on the kernel position effect of densely grown summer maize and its regulatory mechanism,field experiments were conducted during the 2020-2021 and 2021-2022 growing seasons using a split-plot design.The main plots included two tillage practices:conventional tillage practice(CT)and subsoiling before the sowing of winter wheat(SS);and the subplots consisted of three plant densities(D1-D3 at 6.0×10~4,7.5×10~4,and 9.0×10~4 plants ha-1).Compared with CT,SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernels(WR)in the D2 and D3 treated plants.The higher WR of SS treated plants contributed largely to the improved flling of inferior kernels.Under the same plant density,SS signifcantly improved the root dry matter accumulation(DMA)and antioxidant enzyme activities(superoxide dismutase(SOD)and peroxidase(POD)),and it reduced the malondialdehyde(MDA)content,especially for the plants grown under higher plant densities.These results indicated that SS delayed the root senescence,which is associated with the reduced soil bulk density.In addition,compared with CT,SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and the post-silking leaf area duration,and it reduced the post-silking leaf chlorophyll reduction rate and leaf area reduction rate,indicating that the post-silking leaf senescence had been alleviated.Under the same plant density,the post-silking DMA of SS was obviously higher than that of CT,which was probably related to the improved leaf area duration and photosynthetic enzyme activities(phosphoenolpyruvate carboxylase(PEPC)and Rubisco).The correlation analysis revealed that the main mechanism of SS in alleviating the kernel position effect of densely grown summer maize is as follows:SS delays the post-silking root-shoot senescence by regulating soil physical properties,and further improves the post-silking DMA and flling of inferior kernels,which ultimately alleviates the kernel position effect and improves grain yield.The results of this study provide new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.
基金supported by the National Natural Science Foundation of China [grant number 42088101]。
文摘During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the subtropical Northwestern Pacific(10°-20°N,130°E-175°W).The former is well-documented and considered to be influenced by the ENSO,while the latter has received comparatively less attention and is likely influenced by the Pacific Meridional Mode(PMM),as suggested by partial correlation analysis results.To elucidate the physical processes responsible for the enhanced(weakened)intraseasonal convection over the subtropical northwestern Pacific during warm(cold)PMM years,the authors employed a moisture budget analysis.The findings reveal that during warm PMM years,there is an increase in summer-mean moisture over the subtropical northwestern Pacific.This increase interacts with intensified vertical motion perturbations in the region,leading to greater vertical moisture advection in the lower troposphere and consequently resulting in convective instability.Such a process is pivotal in amplifying intraseasonal convection anomalies.The observational findings were further verified by model experiments forced by PMM-like sea surface temperature patterns.
文摘一、完形填空阅读短文,掌握其大意,从A、B、C三个选项中选择最佳答案填空。It's a hot summer day.Jake and Harry are working hard in the garden.Their friend Ralph is__1__under a tree.Jake asks Harry,"Why are we here in the__2__sun when Ralph is sitting there?"Hary says,"I don't know.I will go and ask him."
文摘Summer is my favorite season of the year.The weather is hot,but I don’t mind because there are so many fun things to do.In summer,I can swim in the pool with my friends.The cool water makes me feel really comfortable.
基金Supported by Ningxia Natural Science Foundation(2024AAC03100).
文摘Summer residential tourism is the future trend in China because of tourists’living quality improvement,heat crisis,rising market demand,and optimization of the destinations’residential environment,transport and accessibility.Compared with summer tourism and vacation tourism,summer residential tourism had got less attention and lacks in prospective and preventive research.Hence,this study focused on potential assessment,pattern recognition and phase segmentation of 32 residential tourism destinations in China selected from 4 lists.An index system of 16 indicators from 5 dimensions was established as Summer Residence Index(SRI),and Range method,Entropy weight method and Composite index method were chosen as the core methods.Three main conclusions were as follows.(1)Only 2 typical districts’SRI value were near to 0.6,and 4 destinations were below 0.1,about 26 destinations were at medium-level,which indicated that China’s summer residential tourism was not so popular and only few destinations have stepped into a higher level.(2)Seven patterns could be recognized based on the contribution of the 5 dimensions to SRI value,including 3 single-factor driven patterns and 4 compound factors driven patterns.(3)Like tourist area life cycle(TALC),Unconscious stage,Initial stage,Developmental stage and Maturity stage could be segmented for summer residential destinations with the value of below 0.1,0.1-0.3,0.3-0.5,and above 0.5.Four destinations were under Unconscious stage.Twenty-two destinations were at initiate stage.Only 4 destinations have stepped into development stage and 2 at maturity stage.China’summer residential tourism has just started and has a better prospect.This study is just an attempt and needs further consideration,for example,a tracking study of SRI calculation for each year will be carried to justify the effectiveness of SRI and to check the rationality of the empirical results.As time goes on,policies in housing,residential estate and other aspects should be included as a factor in the SRI index.Data availability should be optimized because of better data sources and new technologies.Some other districts or cities in 2 batches of national Comprehensive Tourism Demonstration Zones(CTDZs)pilots and provincial CTDZs will be further selections of summer residential tourism destinations.
文摘Hi,I'm Young from Zhangjiagang Yangshe Experimental School,and I'm in Grade Six.I want to share my fantastic summer vacation with you!This summer,I went on a trip to Macao with my family.It was an amazing and unforgettable experience for me!
文摘This summer holiday,my older brother and I paid a visit to my grandparents by bus.The bus was crowded,but everyone seemed to be friendly and helpful.We enjoyed beautiful views all the way.At first,we saw one hill after another.
文摘Last summer holiday,I went to Nan'ao Island in Shantou with my family.It was a wonderful trip,and I enjoyed it very much.The island is very beautiful.The sea was clear and blue,and the beach had soft golden sand.We spent the whole morning at Qing'ao Bay.I played frisbee with my brother,built a little sand house,and even collected some pretty seashells.The waves were small and gentle,so I ran into the water and felt very excited.Later,we visited the Nan'ao Island Museum,where we learned many interesting stories about the island's history,the fishermen's lives,and the animals in the sea.
文摘Tom:Hi,Lily!What's the weather like today?Lily:It's sunny and warm.The sky is blue.Tom:That's great!I like sunny days.We can play outside.Lily:Yes!Let's go to the park after school.Tom:Good idea!What's your favourite season?Lily:I like winter.I can play in the snow and make a snowman.Tom:I like spring.The flowers are beautiful,and the weather is nice.Lily:Do you like summer?Tom:It's too hot,but I like eating ice cream!Lily:Haha!Me too.Ice cream is the best in summer!
文摘一、请根据录音,填写单词。二、听对话,选择正确的答案。1.Where did Lucy go for her summer vacation?A.She stayed in the city.B.She went to the science museum.C.She went to Beijing.2.What did Tom think about climbing the Great Wall?
文摘In mid-June,the vast,rolling meadow steppe grasslands of Bayanwenduer Sumu in Ar Horqin Banner,Inner Mongolia Autonomous Region,once again stretched into the horizon like green waves with herds of cattle and sheep scattered across them like pearls in a green ocean.This flock was driven by herders on horseback,motorcycles,and agricultural vehicles,leading the animals to summer pastures in one of the most important migrations of the year.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42122034,42075043,42330609)the Second Tibetan Plateau Scientific Expedition and Research program(2019QZKK0103)+2 种基金Key Talent Project in Gansu and Central Guidance Fund for Local Science and Technology Development Projects in Gansu(No.24ZYQA031)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021427)West Light Foundation of the Chinese Academy of Sciences(xbzg-zdsys-202215)。
文摘Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the numerical model outputs and historical observations,which can partly predict seasonal precipitation.However,solving a nonlinear problem through linear regression is significantly biased.This study implements a nonlinear optimization of an existing observational constrained correction model using a Light Gradient Boosting Machine(LightGBM)machine learning algorithm based on output from the Beijing National Climate Center Climate System Model(BCC-CSM)and station observations to improve the prediction of summer precipitation in China.The model was trained using a rolling approach,and LightGBM outperformed Linear Regression(LR),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost).Using parameter tuning to optimize the machine learning model and predict future summer precipitation using eight different predictors in BCC-CSM,the mean Anomaly Correlation Coefficient(ACC)score in the 2019–22 summer precipitation predictions was 0.17,and the mean Prediction Score(PS)reached 74.The PS score was improved by 7.87%and 6.63%compared with the BCC-CSM and the linear observational constraint approach,respectively.The observational constraint correction prediction strategy with LightGBM significantly and stably improved the prediction of summer precipitation in China compared to the previous linear observational constraint solution,providing a reference for flood control and drought relief during the flood season(summer)in China.
文摘The Summer Palace in Beijing is one of Chinas most charming parks,renowned for its natural beauty and historical significance.Its appeal lies in the harmonious blend of lush(茂盛的)gardens,peaceful lakes and magnificent architecture,making it a favorite destination for both locals and tourists.
文摘Not many 17‑year‑old girls know how to join two pipes together or light the pilot light.These are skills I have learned over the past five years as an assistant to my plumber dad.This summer job demands an attitude of perseverance and grace that I frequently struggle to adopt.Each humid morning,my dad and I drag awkward and heavy toolboxes into people's dark and damp basements where I usually get lost in mazes of storage boxes.Nevertheless,I stick to it.I am the plumber's daughter and helper.
基金supported in part by the Key R&D Program of Shandong Province,China (2023CXGC010703)the National Key Research and Development Program of China (2022YFD2300905-01)the Natural Science Foundation of Shandong Province,China (ZR2021MC123)。
文摘Selecting an appropriate planting density is an effective way to improve crop water productivity(WPC).However, there is a lack of research on the balance between evapotranspiration(ET) partitioning, water consumption, and grain production under different summer maize planting densities. To close this knowledge gap, a two-year field experiment was conducted in the North China Plain(NCP) to reveal the effects of different planting densities(HD: 100,000 plants ha^(-1);MD: 78,000 plants ha^(-1);LD:56,000 plants ha^(-1)) on ET partitioning, grain yield, and water productivity of summer maize. The water-heat-carbon-nitrogen simulator(WHCNS) model was employed to calculate ET partitioning and perform scenario simulation after calibration and validation. The results showed that compared to the LD treatment, ET of the summer maize and grain yield in the MD and HD treatments significantly increased. Model simulations showed that the ratio of evaporation to ET ranged from 25.6% to 30.7%and reduced as increasing planting densities. Increasing planting density enhanced total transpiration of summer maize more than 20 mm, comparing to LD treatment, and the most significant differences between various planting densities appeared at the mid-growth stage(August 1 to 31). Scenario simulations indicated that grain yield and WPCof summer maize were consistently higher in wet and normal years compared to drought years, exhibiting a trend of initially increasing and then decreasing with increasing planting density. The highest grain yield and WPCof summer maize were observed at a planting density of approximately 80,000 plants ha^(-1). The results provide theoretical support for selecting a summer maize planting density and effectively utilizing agricultural water in the NCP.
