目的:建立上颌窦内提升的山羊动物实验模型,比较IBS内提骨凿与Summers骨凿进行山羊上颌窦内提升的效果。方法:大量预实验对山羊上颌窦解剖分析,结合山羊CBCT对上颌窦提升位点探讨,建立上颌窦内提升的山羊动物实验模型。对18只本地山羊3...目的:建立上颌窦内提升的山羊动物实验模型,比较IBS内提骨凿与Summers骨凿进行山羊上颌窦内提升的效果。方法:大量预实验对山羊上颌窦解剖分析,结合山羊CBCT对上颌窦提升位点探讨,建立上颌窦内提升的山羊动物实验模型。对18只本地山羊36个上颌窦左右随机分为实验组与对照组,实验组运用IBS内提骨凿,对照组运用Summers骨凿,18只山羊依据上颌窦提升高度为5,8,10mm随机分为3组,每组6只羊头,统计每组实验组与对照组的穿孔数并记录穿孔时上颌窦提升的高度。结果:建立了以山羊上颌第一磨牙腭侧6-8mm的位点进行上颌窦内提升的动物实验模型。每组实验组6个上颌窦穿孔数分别为0、1、3;对照组6个上颌窦穿孔数分别为1、5、6。实验组与对照组行上颌窦内提升高度为5mm时两者安全性无明显差异[(5.00±0.00) mm vs(4.92±0.20) mm,P>0.05],实验组与对照组行上颌窦内提升高度为8mm时两者差异显著[(7.83±0.41) mm vs (6.58±1.32) mm,P<0.05],实验组与对照组行上颌窦内提升高度为10mm时两者安全性差异显著[(9.17±1.57) mm vs (6.08±0.97) mm,P<0.05]。结论:山羊上颌第一磨牙腭侧6-8mm的位点进行上颌窦内提升效果显著,当提升高度小于5mm,两者提升效果无明显差异,提升高度大于5mm,两骨凿相较而言,IBS内提骨凿较Summers骨凿有更好的提升效果及安全性。展开更多
Watching the winds in northwest Iowa during more than 30 summers has led me to two conclusions about the local atmosphere at ground level: there is a net northward transport of heat and water taking place throughout t...Watching the winds in northwest Iowa during more than 30 summers has led me to two conclusions about the local atmosphere at ground level: there is a net northward transport of heat and water taking place throughout the summer;warm humid winds from the south continually alternate with cool dry winds from the north. The proposed northward heat transfer is consistent with the constraint, placed on the motions of the oceans and the atmosphere, of the earth’s heat balance due to the increased absorption of solar radiation at low latitudes compared to that at high latitudes. At mid-latitudes in the interior of continents, like North America, it is the job of the atmosphere alone to constantly help satisfy the global heat balance. Although qualitative in nature, the predicted northward heat flux is strongly based on frequent observations over lengthy time intervals.展开更多
This study unveils the evolution of two major early signals in the North Pacific atmosphere-ocean system that heralded abnormal high-pressure blockings and cold-vortex activities across Northeast China, based on an an...This study unveils the evolution of two major early signals in the North Pacific atmosphere-ocean system that heralded abnormal high-pressure blockings and cold-vortex activities across Northeast China, based on an analysis of the configurations of major modes including the polar vortex, the North Pacific Oscillation （NPO）, and SST in the preceding winter and spring and atmospheric low-frequency disturbances in Northeast China. We analyzed these aspects to understand the atmosphere ocean physical coupling processes characterized by the two early signals, and here we explain the possible mechanisms through which dipole circulation anomalies affect the summer low-temperature processes in Northeast China. We further analyzed the interdecadal variation background and associated physical processes of the two early signals.展开更多
A set of numerical experiments designed to analyze the oceanic forcing in spring show that the combined forcing of cold （warm） El Ni（n）o （La Ni（n）a） phases in the Ni（n）o4 region and sea surface temperature a...A set of numerical experiments designed to analyze the oceanic forcing in spring show that the combined forcing of cold （warm） El Ni（n）o （La Ni（n）a） phases in the Ni（n）o4 region and sea surface temperature anomalies （SSTA） in the westerly drifts region would result in abnormally enhanced NorthEast Cold Vortex （NECV） activities in early summer.In spring,the central equatorial Pacific El Ni（n）o phase and westerly drift SSTA forcing would lead to the retreat of non-adiabatic waves,inducing elliptic low-frequency anomalies of tropical air flows.This would enhance the anomalous cyclone-anticyclonecyclone-anticyclone low-frequency wave train that propagates from the tropics to the extratropics and further to the mid-high latitudes,constituting a major physical mechanism that contributes to the early summer circulation anomalies in the subtropics and in the North Pacific mid-high latitudes.The central equatorial Pacific La Ni（n）a forcing in the spring would,on the one hand,induce teleconnection anomalies of high pressure from the Sea of Okhotsk to the Sea of Japan in early summer,and on the other hand indirectly trigger a positive low-frequency East Asia-Pacific teleconnection （EAP） wave train in the lower troposphere.展开更多
The performances of CMIP5 atmospheric general circulation models （AGCMs） in simulating the western North Pacific subtropical high （WNPSH） in El Nino decaying summers are examined in this study. Results show that m...The performances of CMIP5 atmospheric general circulation models （AGCMs） in simulating the western North Pacific subtropical high （WNPSH） in El Nino decaying summers are examined in this study. Results show that most models can reproduce the spatial pattern of both climatological and anomalous circulation associated with the WNPSH in El Nino decaying summers. Most CMIP5 AGCMs can capture the westward shift of the WNPSH in El Nino decaying summers compared with the climatological location. With respect to the sub-seasonal variation of the WNPSH, the performances of these AGCMs in reproducing the northward jump of the WNPSH are better than simulating the eastward retreat of the WNPSH from July to August. Twenty-one out of twenty-two （20 out of 22） models can reasonably reproduce the northward jump of the WNPSH in El Nino decaying summers （climatology）, while only 7 out of 22 （8 out of 22） AGCMs can reasonably reproduce the eastward retreat of the WNPSH in El Nino decaying summers （climatology）. In addition, there is a close connection between the climatological WNPSH location bias and that in El Nino decaying summers.展开更多
Atmospheric Rivers(ARs) are narrow and elongated water vapor belts in troposphere with meridional transport across the mid-latitudes towards high-latitudes. Compared with ARs occurred over the northeastern Pacific, th...Atmospheric Rivers(ARs) are narrow and elongated water vapor belts in troposphere with meridional transport across the mid-latitudes towards high-latitudes. Compared with ARs occurred over the northeastern Pacific, the western coast of North America and Europe, the ARs over the East Asia have received less attention. In this paper, the characteristics of ARs which affected China in the area 20?–60?N, 95?–165?E in the middle summer season from 2001 to 2016 were investigated by using European Center for Medium-Range Weather Forecasts(ECMWF) ERA-Interim reanalysis data and Multi-functional Transport Satellites-1 R(MTSAT-1 R) infrared data. Totally, 134 ARs occurred during that period, and averagely 8.4 ARs occurred per year. Statistically, 101 ARs were in east-west orientation, and 33 ARs were in north-south orientation, which accounts for about 75% and 25%, respectively. Herein we report the occurrence number, duration time, intensity, length, width, ratio of length to width, and extension orientation of these ARs, which provide the basic information for those who have interest in ARs over the East Asia.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
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
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
文摘目的:建立上颌窦内提升的山羊动物实验模型,比较IBS内提骨凿与Summers骨凿进行山羊上颌窦内提升的效果。方法:大量预实验对山羊上颌窦解剖分析,结合山羊CBCT对上颌窦提升位点探讨,建立上颌窦内提升的山羊动物实验模型。对18只本地山羊36个上颌窦左右随机分为实验组与对照组,实验组运用IBS内提骨凿,对照组运用Summers骨凿,18只山羊依据上颌窦提升高度为5,8,10mm随机分为3组,每组6只羊头,统计每组实验组与对照组的穿孔数并记录穿孔时上颌窦提升的高度。结果:建立了以山羊上颌第一磨牙腭侧6-8mm的位点进行上颌窦内提升的动物实验模型。每组实验组6个上颌窦穿孔数分别为0、1、3;对照组6个上颌窦穿孔数分别为1、5、6。实验组与对照组行上颌窦内提升高度为5mm时两者安全性无明显差异[(5.00±0.00) mm vs(4.92±0.20) mm,P>0.05],实验组与对照组行上颌窦内提升高度为8mm时两者差异显著[(7.83±0.41) mm vs (6.58±1.32) mm,P<0.05],实验组与对照组行上颌窦内提升高度为10mm时两者安全性差异显著[(9.17±1.57) mm vs (6.08±0.97) mm,P<0.05]。结论:山羊上颌第一磨牙腭侧6-8mm的位点进行上颌窦内提升效果显著,当提升高度小于5mm,两者提升效果无明显差异,提升高度大于5mm,两骨凿相较而言,IBS内提骨凿较Summers骨凿有更好的提升效果及安全性。
文摘Watching the winds in northwest Iowa during more than 30 summers has led me to two conclusions about the local atmosphere at ground level: there is a net northward transport of heat and water taking place throughout the summer;warm humid winds from the south continually alternate with cool dry winds from the north. The proposed northward heat transfer is consistent with the constraint, placed on the motions of the oceans and the atmosphere, of the earth’s heat balance due to the increased absorption of solar radiation at low latitudes compared to that at high latitudes. At mid-latitudes in the interior of continents, like North America, it is the job of the atmosphere alone to constantly help satisfy the global heat balance. Although qualitative in nature, the predicted northward heat flux is strongly based on frequent observations over lengthy time intervals.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41175083 and 41275096)the Special Fund for Meteorological Scientific Research in the Public Interest (Grant Nos. GYHY201006020,GYHY201106016,and GYHY201106015)
文摘This study unveils the evolution of two major early signals in the North Pacific atmosphere-ocean system that heralded abnormal high-pressure blockings and cold-vortex activities across Northeast China, based on an analysis of the configurations of major modes including the polar vortex, the North Pacific Oscillation （NPO）, and SST in the preceding winter and spring and atmospheric low-frequency disturbances in Northeast China. We analyzed these aspects to understand the atmosphere ocean physical coupling processes characterized by the two early signals, and here we explain the possible mechanisms through which dipole circulation anomalies affect the summer low-temperature processes in Northeast China. We further analyzed the interdecadal variation background and associated physical processes of the two early signals.
基金supported by a National Natural Science Foundation project approved under Grant Nos.41175083,41275096 and 41305091a China Meteorological Administration special public welfare reserch funds registeredunder Grant Nos.GYHY201006020,GYHY 201106016,and GYHY201106015
文摘A set of numerical experiments designed to analyze the oceanic forcing in spring show that the combined forcing of cold （warm） El Ni（n）o （La Ni（n）a） phases in the Ni（n）o4 region and sea surface temperature anomalies （SSTA） in the westerly drifts region would result in abnormally enhanced NorthEast Cold Vortex （NECV） activities in early summer.In spring,the central equatorial Pacific El Ni（n）o phase and westerly drift SSTA forcing would lead to the retreat of non-adiabatic waves,inducing elliptic low-frequency anomalies of tropical air flows.This would enhance the anomalous cyclone-anticyclonecyclone-anticyclone low-frequency wave train that propagates from the tropics to the extratropics and further to the mid-high latitudes,constituting a major physical mechanism that contributes to the early summer circulation anomalies in the subtropics and in the North Pacific mid-high latitudes.The central equatorial Pacific La Ni（n）a forcing in the spring would,on the one hand,induce teleconnection anomalies of high pressure from the Sea of Okhotsk to the Sea of Japan in early summer,and on the other hand indirectly trigger a positive low-frequency East Asia-Pacific teleconnection （EAP） wave train in the lower troposphere.
基金supported by the National Natural Science Foundation of China[grant numbers 41475052,41405058]China Postdoctoral Science Foundation[grant number 2015M571095]Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA11010403]
文摘The performances of CMIP5 atmospheric general circulation models （AGCMs） in simulating the western North Pacific subtropical high （WNPSH） in El Nino decaying summers are examined in this study. Results show that most models can reproduce the spatial pattern of both climatological and anomalous circulation associated with the WNPSH in El Nino decaying summers. Most CMIP5 AGCMs can capture the westward shift of the WNPSH in El Nino decaying summers compared with the climatological location. With respect to the sub-seasonal variation of the WNPSH, the performances of these AGCMs in reproducing the northward jump of the WNPSH are better than simulating the eastward retreat of the WNPSH from July to August. Twenty-one out of twenty-two （20 out of 22） models can reasonably reproduce the northward jump of the WNPSH in El Nino decaying summers （climatology）, while only 7 out of 22 （8 out of 22） AGCMs can reasonably reproduce the eastward retreat of the WNPSH in El Nino decaying summers （climatology）. In addition, there is a close connection between the climatological WNPSH location bias and that in El Nino decaying summers.
基金supported by the National Na-tural Science Foundation of China (Nos. 41775042 and 41275049)。
文摘Atmospheric Rivers(ARs) are narrow and elongated water vapor belts in troposphere with meridional transport across the mid-latitudes towards high-latitudes. Compared with ARs occurred over the northeastern Pacific, the western coast of North America and Europe, the ARs over the East Asia have received less attention. In this paper, the characteristics of ARs which affected China in the area 20?–60?N, 95?–165?E in the middle summer season from 2001 to 2016 were investigated by using European Center for Medium-Range Weather Forecasts(ECMWF) ERA-Interim reanalysis data and Multi-functional Transport Satellites-1 R(MTSAT-1 R) infrared data. Totally, 134 ARs occurred during that period, and averagely 8.4 ARs occurred per year. Statistically, 101 ARs were in east-west orientation, and 33 ARs were in north-south orientation, which accounts for about 75% and 25%, respectively. Herein we report the occurrence number, duration time, intensity, length, width, ratio of length to width, and extension orientation of these ARs, which provide the basic information for those who have interest in ARs over the East Asia.
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.
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.
