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Boehmeria nivea var. strigosa (Urticaceae), a new variety from Southwest China
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作者 ZHAO Ying Richard I.MILNE +2 位作者 LI Zhipeng Amos KIPKOECH WU Zengyuan 《广西植物》 CAS CSCD 北大核心 2024年第9期1617-1624,I0001-I0006,共14页
Boehmeria nivea var.strigosa Zeng Y.Wu&Y.Zhao,a new variety of B.nivea(Urticaceae)from Southwest China,is here described based on evidence from morphology and molecular phylogeny.This new variety is mainly charact... Boehmeria nivea var.strigosa Zeng Y.Wu&Y.Zhao,a new variety of B.nivea(Urticaceae)from Southwest China,is here described based on evidence from morphology and molecular phylogeny.This new variety is mainly characterized by its green abaxial leaf blade,partly connate stipules,and densely patent strigose hairs on stems and potioles.The phylogenetic analysis based on rbc L,nrDNA and rbc L+nrDNA datasets,revealed that all individuals of B.nivea var.strigosa formed a monophyletic group.The conservation status of B.nivea var.strigosa is assessed as“Near Threatened”(NT)according to IUCN evaluation criteria.The discovery of this new variety is not only crucial for the taxonomy of ramie,but also provides reference for the exploration and utilization of ramie. 展开更多
关键词 Boehmeria nivea MORPHOLOGY molecular phylogeny new variety southwest China YUNNAN
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Comparative Analysis of Energy Characteristics of Two Southwest Vortices in Sichuan Under Similar Circulation Backgrounds
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作者 周春花 张驹 肖红茹 《Journal of Tropical Meteorology》 SCIE 2024年第2期168-179,共12页
Based on ERA5 reanalysis data,the present study analyzed the thermal energy development mechanism and kinetic energy conversion characteristics of two extreme rainstorm processes in relation to the shallow southwest v... Based on ERA5 reanalysis data,the present study analyzed the thermal energy development mechanism and kinetic energy conversion characteristics of two extreme rainstorm processes in relation to the shallow southwest vortex in the warm-sector during a“rain-generated vortex”process and the deep southwest vortex in a“vortex-generated rain”process.The findings were as follows:(1)During the extreme rainstorm on August 11,2020(hereinafter referred to as the“8·11”process),intense surface heating and a high-energy unstable environment were observed.The mesoscale convergence system triggered convection to produce heavy rainfall,and the release of latent condensation heat generated by the rainfall promoted the formation of a southwest vortex.The significant increase(decrease)in atmospheric diabatic heating and kinetic energy preceded the increase(decrease)in vorticity.By contrast,the extreme rainstorm on August 16,2020(hereinafter referred to as the“8·16”process)involved the generation of southwest vortex in a low-energy and highhumidity environment.The dynamic uplift of the southwest vortex triggered rainfall,and the release of condensation latent heat from rainfall further strengthened the development of the southwest vortex.The significant increase(decrease)in atmospheric diabatic heating and kinetic energy exhibited a delayed progression compared to the increase(decrease)in vorticity.(2)The heating effect around the southwest vortex region was non-uniform,and the heating intensity varied in different stages.In the“8·11”process,the heating effect was the strongest in the initial stage,but weakened during the vortex's development.On the contrary,the heating effect was initially weak in the“8·16”process,and intensified during the development stage.(3)The available potential energy of the“8·11”process significantly increased in kinetic energy converted from rotational and divergent winds through baroclinic action,and the divergent wind energy continued to convert into rotational wind energy.By contrast,the“8·16”process involved the conversion of rotational wind energy into divergent wind energy,which in turn converted kinetic energy back into available potential energy,thereby impeding the further development and maintenance of the southwest vortex. 展开更多
关键词 southwest vortex similar circulation background diabatic heating kinetic energy spatial non-uniform heating effect
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The Spatial-Temporal Characteristics of Meteorological Disasters in the Southwest Region of Zhejiang Province during 1953-2022
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作者 Qi Zhang Yifan Wang +3 位作者 Zhidan Zhu Hongxia Shi Wenhao Yang Shujie Yuan 《Journal of Geoscience and Environment Protection》 2024年第3期16-27,共12页
Meteorological disasters are some of the most serious and costly natural disasters, which have larger effects on economic and social activity. Liuchun Lake is an ecotourism area in the southwest region of Zhejiang pro... Meteorological disasters are some of the most serious and costly natural disasters, which have larger effects on economic and social activity. Liuchun Lake is an ecotourism area in the southwest region of Zhejiang province, where also has experienced meteorological disasters including rainstorm and cold wave. Understanding the temporal-spatial characteristics of meteorological disasters is important for the local tourism and economic development. Based on the daily temperature and precipitation from 18 meteorological stations in the southwest of Zhejiang province during 1953-2022 and some statistical approaches, the temporal and spatial characteristics of meteorological disasters (Freezing, Rainstorm, Cold wave) are analyzed. The results indicate that 1) Rainstorm occurred frequently around the Liuchun lake, the frequency was about 8 times/a, it can also reach about 3 times/a in the other region. Freezing and cold wave (including strong cold wave and extremely cold wave) had the same spatial distribution as rainstorm, however, except for Liuchun lake, they occurred less than one time in the other regions;2) The trend of rainstorm had larger spatial difference, it increased in all the study area, but it increased more significantly around the study area than around Liuchun lake. Freezing was on the downtrend in the whole region, with 93.3% of the stations passed the 95% significant level. Cold wave also showed a declined trend, but it was insignificantly at most of the stations, only 33% of the stations passed the 90% significant level. Compared with cold wave, strong cold wave and extremely strong cold wave had weaker decline in all the regions. In general, from 1953 to 2022 rainstorm showed an increasing trend, it was the main meteorological disaster in the study area, cold wave displayed a decreasing trend, but it still occurred about 2 - 3 times/a in most regions. 展开更多
关键词 southwest of Zhejiang Province RAINSTORM Cold Wave Spatial Distribution Trend Analysis
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Genomic analysis of indigenous goats in Southwest Asia reveals evidence of ancient adaptive introgression related to desert climate 被引量:1
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作者 Hojjat Asadollahpour Nanaei Yudong Cai +8 位作者 Akil Alshawi Jiayue Wen Tanveer Hussain Wei-Wei Fu Nai-Yi Xu Abdulameer Essa Johannes ALenstra Xihong Wang Yu Jiang 《Zoological Research》 SCIE CAS CSCD 2023年第1期20-29,共10页
Understanding how evolutionary pressures related to climate change have shaped the current genetic background of domestic animals is a fundamental pursuit of biology. Here, we generated wholegenome sequencing data fro... Understanding how evolutionary pressures related to climate change have shaped the current genetic background of domestic animals is a fundamental pursuit of biology. Here, we generated wholegenome sequencing data from native goat populations in Iraq and Pakistan. Combined with previously published data on modern, ancient(Late Neolithic to Medieval periods), and wild Capra species worldwide, we explored the genetic population structure, ancestry components, and signatures of natural positive selection in native goat populations in Southwest Asia(SWA). Results revealed that the genetic structure of SWA goats was deeply influenced by gene flow from the eastern Mediterranean during the Chalcolithic period, which may reflect adaptation to gradual warming and aridity in the region. Furthermore, comparative genomic analysis revealed adaptive introgression of the KITLG locus from the Nubian ibex(C. nubiana) into African and SWA goats. The frequency of the selected allele at this locus was significantly higher among goat populations located near northeastern Africa. These results provide new insights into the genetic composition and history of goat populations in the SWA region. 展开更多
关键词 GOAT Adaptation KITLG southwest Asia Nubian ibex
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A comparative study of seismic tomography models of Southwest China 被引量:1
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作者 Xuezhen Zhang Xiaodong Song Feiyi Wang 《Earthquake Science》 2023年第1期15-39,共25页
The margin of the Tibetan Plateau of Southwest China is one of the most seismically active regions of China and is the location of the China Seismic Experimental Site(CSES).Many studies have developed seismic velocity... The margin of the Tibetan Plateau of Southwest China is one of the most seismically active regions of China and is the location of the China Seismic Experimental Site(CSES).Many studies have developed seismic velocity models of Southwest China,but few have compared and evaluated these models which is important for further model improvement.Thus,we compared six published seismic shear-wave velocity models of Southwest China on absolute velocity and velocity perturbation patterns.The models are derived from different types of data(e.g.,surface waves from ambient noise and earthquakes,body-wave travel times,receiver functions) and inversion methods.We interpolated the models into a uniform horizontal grid(0.5° × 0.5°) and vertically sampled them at 5,10,20,30,40,and 60 km depths.We found significant differences between the six models.Then,we selected three of them that showed greater consistency for further comparison.Our further comparisons revealed systematic biases between models in absolute velocity that may be related to different data types.The perturbation pattern of the model is especially divergent in the shallow part,but more consistent in the deep part.We conducted synthetic and inversion tests to explore possible causes and our results imply that systematic differences between the data,differences in methods,and other factors may directly affect the model.Therefore,the Southwest China velocity model still has considerable room for improvement,and the impact of inconsistency between different data types on the model needs further research.Finally,we proposed a new reference shear-wave velocity model of Southwest China(SwCM-S1.0) based on the three selected models with high consistency.We believe that this model is a better representation of more robust features of the models that are based on different data sets. 展开更多
关键词 model comparison shear-wave velocity model southwest China
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Deep learning-based subseasonal to seasonal precipitation prediction in southwest China:Algorithm comparison and sensitivity to input features 被引量:1
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作者 GuoLu Gao Yang Li +3 位作者 XueYun Zhou XiaoMing Xiang JiaQi Li ShuCheng Yin 《Earth and Planetary Physics》 CAS CSCD 2023年第4期471-486,共16页
The prediction of precipitation at subseasonal to seasonal(S2S)timescales remains an enormous challenge because of the gap between weather and climate predictions.This study compares three deep learning algorithms,nam... The prediction of precipitation at subseasonal to seasonal(S2S)timescales remains an enormous challenge because of the gap between weather and climate predictions.This study compares three deep learning algorithms,namely,the long short-term memory recurrent(LSTM),gated recurrent unit(GRU),and recurrent neural network(RNN),and selects the optimal algorithm to establish an S2S precipitation prediction model.The models were evaluated in four subregions of the Sichuan Province:the Plateau,Valley,eastern Basin,and western Basin.The results showed that the RNN model had better performance than the LSTM and GRU models.This could be because the RNN model had an advantage over the LSTM model in the transformation of climate indices with positive and negative variations.In the validation of test datasets,the RNN model successfully predicted the precipitation trend in most years during the wet season(May-October).The RNN model had a lower prediction bias(within±10%),higher sign accuracy of the precipitation trend(~88.95%),and greater accuracy of the maximum precipitation month(>0.85).For the prediction of different lead times,the RNN model was able to provide a stable trend prediction for summer precipitation,and the time correlation coefficient score was higher than that of the National Climate Center of China.Furthermore,this study proposed a method to measure the sensitivity of the RNN model to different input features,which may provide unprecedented insights into the nonlinear relationship and complicated feedback process among climate systems.The results of the sensitivity distribution are as follows.First,the Niño 4 and Niño 3.4 indices were equally important for the prediction of wet season precipitation.Second,the sensitivity of the snow cover on the Tibetan Plateau was higher than that in the Northern Hemisphere.Third,an opposite sensitivity appeared in two different patterns of the Indian Ocean and sea ice concentrations in the Arctic and the Barents Sea. 展开更多
关键词 recurrent neural network long short-term memory recurrent sensitivity analysis artificial intelligence explainability complex terrain southwest China
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An extraordinary multielement apparatus of conodont Nicoraella from the Middle Triassic Luoping Biota,southwest China
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作者 Jin-yuan Huang 《China Geology》 CAS CSCD 2023年第1期183-184,共2页
Conodont animal is an extinct group of marine animals.The conodont elements and their hard skeletal remains are originally from the head region of this kind of animal,and they are considered to be functioned as“teeth... Conodont animal is an extinct group of marine animals.The conodont elements and their hard skeletal remains are originally from the head region of this kind of animal,and they are considered to be functioned as“teeth”.The“multielement apparatus”can also be called the“(conodont)apparatus”,“multimembrate(skeletal)apparatus”. 展开更多
关键词 apparatus southwest MIDDLE
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Prevalence, Aetiology, and Clinical Profile of Acute Abdomen in Pregnancy in Southwest Cameroon: A 5-Year Retrospective Study
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作者 Yannick Mahamat Ekani Boukar Divine Mokake +9 位作者 Felix Adolphe Elong Terence Dze Enah Moussa Adam Adami Eric Patrick Savom Anutebeh Verdo Zisuh Guy Aristide Bang Alain Chichom Mefire Arthur Essomba Marcellin Ngowe Ngowe Maurice Aurelien Sosso 《Surgical Science》 2023年第1期1-9,共9页
Background: Acute abdomen is one of the commonest reasons for presentation at the emergency department. The physiologic changes of pregnancy increase the chances of developing acute abdomen. The global incidence of ac... Background: Acute abdomen is one of the commonest reasons for presentation at the emergency department. The physiologic changes of pregnancy increase the chances of developing acute abdomen. The global incidence of acute abdomen in pregnancy range from 1 in 500 to 1 in 635 pregnant women. In 2018, a study in Azerbaijan reported a prevalence of 25%. However, to the best of our knowledge, very few studies have been carried out on this subject in Cameroon. Objectives: To determine the prevalence, assess the aetiologies, and review clinical profile of acute abdomen in pregnancy in the Southwest Cameroon. Methods: We conducted a 5-year retrospective study at the Obst/Gyn and Surgical units of Kumba, Buea, and Limbe Regional Hospitals. We included all files of pregnant women that were admitted for acute abdomen within the study period (1<sup>st</sup> Jan 2017 to 31<sup>st</sup> Dec 2021). Data was collected using a structured checklist adapted from previous studies. Descriptive statistics and statistical testing was done using SPSS version 25.0. Chi-square was used to compare categorical variables. p Results: Over 14,106 pregnant women were admitted to the aforementioned hospitals within the study period. 335 (2.4%) met our inclusion criteria. The patients’ age ranged from 17 to 43 years. The mean age was 27 years. Acute abdomen was more frequent (65%) in the first trimester. Ectopic pregnancy was the commonest obstetric aetiology while appendicitis was the commonest non obstetric surgical aetiology. Abdominal pain and tenderness were the most common presentation. Conclusion: The prevalence of acute abdomen in pregnancy in the Southwest Cameroon is 10 times higher than the global prevalence. Our study also confirmed the numerous aetiologies and varied clinical presentations of acute abdomen in pregnancy. Hence a wake-up call for primary care physicians. 展开更多
关键词 Acute Abdomen PREGNANCY southwest Cameroon
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The Spatial-Temporal Change of Extreme Precipitation in the Southwest Region of Zhejiang Province during 1953-2022
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作者 Wenhao Yang Shujie Yuan Hongxia Shi 《Journal of Geoscience and Environment Protection》 2023年第11期91-102,共12页
Based on the daily precipitation from 17 meteorological stations in the southwest of Zhejiang from 1953 to 2022, 11 extreme precipitation indices were calculated, and the temporal-spatial characteristic of extreme pre... Based on the daily precipitation from 17 meteorological stations in the southwest of Zhejiang from 1953 to 2022, 11 extreme precipitation indices were calculated, and the temporal-spatial characteristic of extreme precipitation were analyzed. The results indicate that 1) Except for the number of consecutive dry days (CDD), all the other extreme precipitation indices had low values in the northeast of the study area and high value around Liuchun Lake;2) CDD had a decreasing trend in most part of study area, while the other indices were on the rise, especially at Suichang (SC) and Tonglu (TL) stations, the change was significant (p 0.05);3) The annual variation showed that CDD declined with the trend of 0.83 d/10a, however, all the other indices increased, especially after 2000, the increase was more obvious. In general, the extreme precipitation mount, the extreme precipitation days showed an increasing trend, drought was less likely to happen, and the possibility of heavy precipitation is less, however, at some individual station such as SC, heavy precipitation and storm is much more likely to occur. 展开更多
关键词 southwest of Zhejiang Province Extreme Precipitation Indices Temporal-Spatial Characteristic
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Record of hydrothermal activity in the Yuhuang hydrothermal field and its implications for the Southwest Indian Ridge:evidence from sulfide chronology
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作者 Weifang Yang Chunhui Tao +6 位作者 Shili Liao Jin Liang Wei Li Teng Ding Ágata Alveirinho Dias Xuefeng Wang Lisheng Wang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第11期59-68,共10页
The Yuhuang hydrothermal field(YHF)is located between the Indomed and Gallieni fracture zones near the top of the off-axis slope on the south rift wall of Segment 29 on the ultraslow Southwest Indian Ridge(SWIR).Previ... The Yuhuang hydrothermal field(YHF)is located between the Indomed and Gallieni fracture zones near the top of the off-axis slope on the south rift wall of Segment 29 on the ultraslow Southwest Indian Ridge(SWIR).Previous studies have shown that sulfides in the YHF formed during different mineralization episodes and the YHF has the greatest potential for the formation of large-scale seafloor massive sulfide deposits.However,the sulfide chronology and hydrothermal activity of the YHF remain poorly constrained.In this study,mineralogical analyses and 230Th/U dating were performed.Hydrothermal activity may start about(35.9±2.3)ka from the southwest part of the YHF and may cease about(708±81)a ago from the northeast part of the YHF.The 74 nonzero chronological data from hydrothermal sulfide samples provide the first quantitative characterization of the spatial and temporal history along the SWIR.Hydrothermal activity in the SWIR has been relatively active over the past20 ka.In contrast,between 40 ka and 100 ka,hydrothermal activity was relatively infrequently and short in duration.The maximum activity occurred at 15–11 ka,9–7 ka,6–0.2 ka.There was a slight positive correlation between the maximal age and estimated surface area or estimated tonnage.The minimum mass accumulation rate of YHF is about 278 t/a,which is higher than most HFs related to ultramafic systems.The ultraslow spreading SWIR has the greatest potential to form large-scale seafloor massive sulfides(SMS)deposits.The results of this study provide new insights into the metallogenic mechanism of hydrothermal sulfides along ultraslow-spreading ridges. 展开更多
关键词 southwest Indian Ridge seafloor massive sulfides 230Th/U dating hydrothermal activity mass accumulation
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Moisture Sources and Their Contributions to Summer Precipitation in the East of Southwest China
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作者 李永华 黄丁安 +3 位作者 卢楚翰 向波 周杰 何卷雄 《Journal of Tropical Meteorology》 SCIE 2023年第2期153-167,共15页
Complex topography,special geographical location and sea-land-air interactions lead to high interannual variability of summer precipitation in the east of Southwest China(ESWC).However,the contributions,influencing fa... Complex topography,special geographical location and sea-land-air interactions lead to high interannual variability of summer precipitation in the east of Southwest China(ESWC).However,the contributions,influencing factors and mechanisms of remote and local evaporation remain to be further investigated.Using clustering analysis and Hybrid Single-Particle Lagrangian Integrated Trajectory version 5 model,we analyze the contributions of remote moisture transport and local evaporation to summer precipitation in the ESWC and their causes.There are mainly five remote moisture channels in the ESWC,namely the Arabian Sea channel,Bay of Bengal channel,western Pacific channel,Northwest channel 1 and Northwest channel 2.Among the five channels,the western Pacific channel has the largest number of trajectories,while the Bay of Bengal channel has the largest contribution rate of specific humidity(33.33%)and moisture flux(33.14%).The amount of regional average precipitation is close to that of the precipitation caused by remote moisture transport,and both are considerably greater than the rainfall amount caused by local evaporation.However,on interannual time scales,precipitation recirculation rates are negatively correlated to regional average precipitation and precipitation caused by remote moisture transport but are consistent with that caused by local evaporation.An apparent"+-+"wave train can be found on the height anomaly field in East Asia,and the sea surface temperature anomalies are positive in the equatorial Middle-East Pacific,the South China Sea,the Bay of Bengal and the Arabian Sea.These phenomena cause southwest-northeast moisture transport with strong updrafts,thereby resulting in more precipitation in the ESWC. 展开更多
关键词 east of southwest China summer precipitation moisture sources local evaporation contributions of moisture
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西南水稻主产区用水现状与绿色高效灌排技术 被引量:2
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作者 崔宁博 尹飞虎 +6 位作者 龚道枝 贺秀斌 陈飞 赵璐 郑顺生 张艺璇 吴宗俊 《中国工程科学》 CSCD 北大核心 2024年第2期132-141,共10页
西南水稻主产区面临季节性干旱、工程性缺水等生产问题,绿色高效灌排技术是该区域实现节水稳产增效的关键举措,对保障国家粮食安全具有重要意义。本文系统梳理了包括云南省、贵州省、四川省、重庆市在内的西南地区水稻生产用水现状和灌... 西南水稻主产区面临季节性干旱、工程性缺水等生产问题,绿色高效灌排技术是该区域实现节水稳产增效的关键举措,对保障国家粮食安全具有重要意义。本文系统梳理了包括云南省、贵州省、四川省、重庆市在内的西南地区水稻生产用水现状和灌排技术现状,阐述了西南水稻主产区绿色高效灌排体系的基本特征、绿色高效灌排的具体技术类型,提出了由稻田精准需水预报、灌区精量配水管理、田间高效用水管理、田间高效排水管理构成的绿色高效灌排技术模式。研究发现,西南水稻主产区水资源丰富但时空分布不均,节水灌溉和排水技术落后且对各地区气候条件、水资源量、地形的适用性有较大差异。建议研发稻田灌排高效协同调控新技术、推广绿色高效灌排技术体系、优化稻田水肥运筹模式、开发稻田智能灌排与信息化管理系统、构建水稻绿色高效灌排技术多维推广体系,据此推动西南水稻主产区节水提质增效与绿色减污降排多赢。 展开更多
关键词 水稻 灌排技术 西南地区 绿色高效 节水
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Evaluation and Quantitative Attribution Analysis of Water Yield Services in the Peak-cluster Depression Basins in Southwest of Guangxi,China
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作者 WANG Donghua TIAN Yichao +5 位作者 ZHANG Yali HUANG Liangliang TAO Jin YANG Yongwei LIN Junliang ZHANG Qiang 《Chinese Geographical Science》 SCIE CSCD 2023年第1期116-130,共15页
Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression ... Karst environmental issues have become one of the hot spots in contemporary international geological research. The same problem of water shortage is one of the hot spots of global concern. The peak-cluster depression basins in southwest of Guangxi is an important water connotation and ecological barrier areas in the Pearl River Basin of China. Thus, studying the spatial and temporal variations and the influencing factors of its water yield services is critical to achieve the sustainable development of water resources and ecological environmental protection in this region. As such, this paper uses the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model to assess the spatial and temporal variabilities of water yield services and its trends in the peak-cluster depression basins in southwest of Guangxi from 2000 to 2020. This work also integrates precipitation(Pre), reference evapotranspiration(ET), temperature(Tem), digital elevation model(DEM), slope, normalized difference vegetation index(NDVI), land use/land cover(LULC) and soil type to reveal the main factors that influence water yield services with the help of Geodetector. Results show that: 1) in time scale,the total annual water yield in the study area show a fluctuating and increasing trend from 2000 to 2020, with a growth rate of 7.3753 × 10^(8)m^(3)/yr, and its multi-year average water yield was 538.07 mm;2) in spatial pattern, with high yield areas mainly distributed in the south of the study area(mainly including Shangsi County, Pingxiang City, Ningming County, Longzhou County and Jingxi County), and low yield areas mainly distributed in Baise City and Nanning City;3) the dominant factor of water yield within karst and non-karst landforms is not necessarily controlled by precipitation, and the explanation degree of DEM factors in karst areas is significantly higher than that in non-karst areas;4) amongst the climatic factors, Pre, ET and Tem are dominant in the spatial pattern of region water yield capacity. among which Pre has the highest explanatory power for the spatial heterogeneity of annual water production, with q values above0.8, and each driver showed a significant interaction on the spatial distribution of water yield, with Pre exhibiting the strongest interaction with LULC. 展开更多
关键词 water yield Integrated Valuation of Ecosystem Services and Trade-offs(InVEST) Geodetector peak-cluster depression basins in southwest of Guangxi China
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“23·8”黑龙江极端强降水过程特征与成因 被引量:1
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作者 齐铎 王承伟 +5 位作者 白雪梅 公衍铎 孙琪 栾晨 唐凯 赵玉洁 《应用气象学报》 CSCD 北大核心 2024年第3期257-271,共15页
利用多源观测资料及ERA5(ECMWF reanalysis version 5)再分析资料,从气候统计、天气分析及物理量诊断等角度,分析2023年8月2—4日黑龙江省东南部一次极端强降水过程。高空持续辐散、副热带高压和东北北部冷涡稳定少动、西南低空急流持... 利用多源观测资料及ERA5(ECMWF reanalysis version 5)再分析资料,从气候统计、天气分析及物理量诊断等角度,分析2023年8月2—4日黑龙江省东南部一次极端强降水过程。高空持续辐散、副热带高压和东北北部冷涡稳定少动、西南低空急流持续水汽输送等有利条件是此次强降水过程持续时间较长的主要原因。该过程可分为两个阶段:第1阶段,经向水汽净收入层和大气饱和层深厚,大气层结为弱对流不稳定;中层受西北气流控制,低层西南急流发展、伴随弱低涡东移,形成水平风速辐合及系统性上升运动,产生大范围持续性降水;该阶段以层积混合云为主,降水效率高,个别时段伴有列车效应,造成极端小时降水量及较大累积降水量。第2阶段,经向水汽净收入集中在对流层低层,且中心强度较大,对流层低层暖湿、饱和,中高层干冷,大气具有较强对流不稳定;在中层槽和低层暖式切变的系统性抬升以及地形辐合抬升的共同作用下,局地有积云发展,引发短时强降水,降水强度分布不均。 展开更多
关键词 极端强降水 西南急流 列车效应 地形效应
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Contribution of external forcing to summer precipitation trends over the Qinghai-Tibet Plateau and Southwest China
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作者 Yuying Xiang Tao Wang +1 位作者 Hongna Xu Huijun Wang 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第5期29-34,共6页
在过去的60年中,全球气候经历了快速变暖和短暂的变暖停滞,而中国的区域降水也经历了多样而复杂的变化.本文分析了1961年至2014年外强迫因子对青藏高原和中国西南地区夏季降水趋势的影响.观测数据显示,青藏高原的夏季降水呈增加趋势,而... 在过去的60年中,全球气候经历了快速变暖和短暂的变暖停滞,而中国的区域降水也经历了多样而复杂的变化.本文分析了1961年至2014年外强迫因子对青藏高原和中国西南地区夏季降水趋势的影响.观测数据显示,青藏高原的夏季降水呈增加趋势,而中国西南地区的夏季降水呈减少趋势,这两个相邻地区的夏季降水变化趋势相反.利用CMIP6数据,本文研究了不同外强迫因子对两个区域夏季降水趋势的影响.结果表明,温室气体对青藏高原夏季降水的增加具有显著影响,而气溶胶在中国西南地区夏季降水减少中起主要作用。 展开更多
关键词 夏季降水 青藏高原 中国西南 CMIP6 外强迫因子
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The dry and hot American Southwest under the present and future climates
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作者 Wei Zhang 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第6期48-51,共4页
由于正在持续的特大干旱,更频繁的洪水,热浪以及导致空气污染的山火,美国西南部目前正在经历气候危机.这些气候危机主要与水文气候过程相关,尤其是气候系统各圈层之间的水汽通量.本研究主要讨论目前一些水文系统的科学基站以及物理驱动... 由于正在持续的特大干旱,更频繁的洪水,热浪以及导致空气污染的山火,美国西南部目前正在经历气候危机.这些气候危机主要与水文气候过程相关,尤其是气候系统各圈层之间的水汽通量.本研究主要讨论目前一些水文系统的科学基站以及物理驱动因素,比如北美夏季风以及太平洋北美遥相关.本研究指出降水以及气温对于干旱的相对作用的理论和工具.确定内部变率和外部强迫对于美国西南部水文气候系统的相对作用尤为重要.展望未来,需要研究高分辨率模拟系统,加强降水以及温度对于水文气候系统相对作用的理解,外部强迫的作用以及通过科学家以及其他利益相关者之间的合作. 展开更多
关键词 美国西南部 热浪 干旱 气候变化 内部变率 外部强迫
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西南山区乡村贫困地域系统时空演化格局研究——以云南省镇沅县为例 被引量:1
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作者 潘卓 廖和平 +1 位作者 刘愿理 朱琳 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第3期2-14,共13页
在梳理总结国内外关于贫困地理与农村多维空间贫困、乡村地域系统与贫困地域系统理论前沿研究的基础上,提出“乡村贫困地域系统”研究视角,并对乡村贫困地域系统理论内涵进行了初步探析.以云南省镇沅县109个村域为评价分析单元,构建了... 在梳理总结国内外关于贫困地理与农村多维空间贫困、乡村地域系统与贫困地域系统理论前沿研究的基础上,提出“乡村贫困地域系统”研究视角,并对乡村贫困地域系统理论内涵进行了初步探析.以云南省镇沅县109个村域为评价分析单元,构建了乡村贫困地域系统演化发展评价指标体系,设计了乡村贫困地域系统演化发展指数测度模型和基于“时空立方体—新兴时空热点分析”的时空演化模式识别方法.研究显示:(1)镇沅县2013-2021年乡村贫困地域系统演化时序阶段性特征经历了“差异波动演化(2013-2015年)—快速演化(2016-2019年)—增长滞缓趋稳(2020-2021年)”3个主要阶段.(2)镇沅县乡村贫困地域系统时空演化模式以连续热点模式为主,加强的热点模式呈零星分布,表征2013-2021年镇沅县乡村贫困地域系统整体上经历了较快且连续稳定的减贫演化过程,是减贫政策普惠作用在时空演化模式上的具体表现;连续冷点模式和持续冷点模式呈现出县域东西两端集聚分布态势.(3)多维空间贫困陷阱主要集中在和平镇、者东镇、振太镇的部分村域,相关村域脱贫稳定性相对较差、返贫风险较高.乡村发展是乡村地域系统循环累积与动态演化的结果,深入刻画分析乡村贫困地域系统时空演化格局与特征,对于科学推动脱贫地区转型发展具有重要意义. 展开更多
关键词 乡村贫困地域系统 时空演化格局 西南山区 镇沅县
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新气候态下西南地区夏季气候变化特点及其成因
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作者 唐红玉 吴遥 +1 位作者 董新宁 魏麟骁 《气候与环境研究》 CSCD 北大核心 2024年第1期45-58,共14页
利用1981~2020年中国西南地区云南、贵州、四川、重庆393站气象观测台站夏季气温、降水和NCEP/NCAR再分析资料,分析了西南地区夏季气温、降水的气候值在新旧气候态下的不同特征和变化差异,并从大气环流影响角度,对变化成因进行了分析。... 利用1981~2020年中国西南地区云南、贵州、四川、重庆393站气象观测台站夏季气温、降水和NCEP/NCAR再分析资料,分析了西南地区夏季气温、降水的气候值在新旧气候态下的不同特征和变化差异,并从大气环流影响角度,对变化成因进行了分析。结果表明:相对于旧气候态,新气候态下西南地区夏季降水总体呈略减少的变化,气温具有一致性变暖的变化特征。相对于旧气候态,新气候态下四川盆地东部降水的减少和云南北部、四川西部及贵州夏季降水的增多与西太平洋副热带高压的相对偏西偏北有关。同时中高纬阻高等系统的相对不活跃、贝加尔湖槽的减弱,对西南大部地区的暖干变化起到了积极作用。新气候态下,西南地区夏季贵州呈弱暖湿变化、而云南为较强的暖干变化、四川和重庆则呈强的暖干变化,这与西太平洋和印度洋地区水汽的变化密切相关。 展开更多
关键词 新气候态 西南地区 夏季 成因
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中国西南地区旱坡地碳减排研究进展与展望
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作者 王谢 杨琴 +7 位作者 刘禹池 李芹 杨勤 陈冠陶 岳丽杰 张建华 陈新平 刘永红 《作物学报》 CAS CSCD 北大核心 2024年第7期1635-1646,共12页
农田生态系统既是碳源,又是碳汇,具备很强的减排固碳潜力,对全球碳循环贡献巨大。西南地区旱坡地长期小规模、碎片化的农业生产方式给区域碳排放带来极大的不确定性。探索西南旱坡地的碳排放特征和减排途径对于改善环境、提升区域农业... 农田生态系统既是碳源,又是碳汇,具备很强的减排固碳潜力,对全球碳循环贡献巨大。西南地区旱坡地长期小规模、碎片化的农业生产方式给区域碳排放带来极大的不确定性。探索西南旱坡地的碳排放特征和减排途径对于改善环境、提升区域农业生产潜力具有重要意义。本研究系统总结了我国西南地区旱坡地农田生态系统主要温室气体(CO_(2)、N_(2)O)的产生环节,探讨了旱坡地固碳减排新材料与新技术的应用效果,提出了未来西南地区旱坡地的固碳减排策略。(1)鉴于西南地区旱坡地的区域资源禀赋、产业基础、生产规模、经营方式、生态功能等差异巨大,应结合地区特殊的农业生产条件,集成研发适宜的固碳减排措施和监测体系,探索全球变暖背景下西南旱坡地碳排放过程及其内在机制,以全面提升地区农业生产应对气候变化的韧性。(2)鉴于西南地区农作物复种指数较高且作物空间分布斑块化,应依据国家战略和地方规划,以绿色高产优质为目标导向,改进农业生产方式,优化产业空间布局。(3)由于西南地区旱坡地碳减排是一个复合过程,亟需根据今后较长一段时间内区域农业生产的实际结构和功能需求,有针对性地对各项成熟的减排技术、固碳产品和固碳模式进行优化组合,形成综合性的固碳减排方案。综上,本综述期望为进一步研究西南地区旱坡地农田生态系统的碳源和碳汇特征,以及合理调整农田管理措施提供全面的有效参考。 展开更多
关键词 温室气体 旱坡地 固碳减排 中国西南地区
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西南高山峡谷区水土流失综合防治技术与示范
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作者 周金星 关颖慧 +6 位作者 汪亚峰 秦伟 何丙辉 王克勤 吴秀芹 万龙 丁亚丽 《生态学报》 CAS CSCD 北大核心 2024年第18期7937-7943,共7页
西南高山峡谷区覆盖大横断“七脉六江”地区,是国家“三区四带”重要生态安全屏障,对保障国家生态安全和区域高质量发展具有重要作用。针对西南高山峡谷区存在的水土流失分异演变地带性规律及其关键驱动机制,水土流失对农业耕作、高陡... 西南高山峡谷区覆盖大横断“七脉六江”地区,是国家“三区四带”重要生态安全屏障,对保障国家生态安全和区域高质量发展具有重要作用。针对西南高山峡谷区存在的水土流失分异演变地带性规律及其关键驱动机制,水土流失对农业耕作、高陡地形、岩溶地质及冻融作用等复杂驱动条件的响应及其防控机制,民族聚集区生态系统服务功能整体提升及生态生产协同的理论与对策等问题,选取兰坪、云龙、永胜、康定以及波密县为典型示范区,开展国家重点研发计划活动,以西南高山峡谷不同类型区水土流失分异规律和综合防治为主线,按照三个层次开展水土流失综合防治与示范研究,攻克高精度土壤侵蚀预报模型与监测技术瓶颈,形成生态系统服务整体提升的“水土流失防治-生态系统服务-民族经济发展”的多目标水土流失综合防治技术体系,最终为西南高山峡谷区生态系统恢复提供科学依据与技术支撑。 展开更多
关键词 西南高山峡谷区 水土流失 民族聚集 生态系统服务
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