Atmospheric Circulation and Dynamic Mechanism for Persistent Haze Events in the Beijing–Tianjin–Hebei Region   总被引：16，自引：0，他引：16  

Ping WU  Yihui DING  Yanju LIU 《大气科学进展》2017,34(4):429-440

In this study, regional persistent haze events(RPHEs) in the Beijing–Tianjin–Hebei(BTH) region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–2013. The formation mechanisms of the severe RPHEs were investigated with focus on the atmospheric circulation and dynamic mechanisms. Results indicated that:(1) 49 RPHEs occurred during the past 34 years.(2) The severe RPHEs could be categorized into two types according to the large-scale circulation, i.e. the zonal westerly airflow(ZWA) type and the high-pressure ridge(HPR) type. When the ZWA-type RPHEs occurred, the BTH region was controlled by near zonal westerly airflow in the mid–upper troposphere.Southwesterly winds prevailed in the lower troposphere, and near-surface wind speeds were only 1–2 ms~(-1). Warm and humid air originating from the northwestern Pacific was transported into the region, where the relative humidity was 70% to 80%, creating favorable moisture conditions. When the HPR-type RPHEs appeared, northwesterly airflow in the mid–upper troposphere controlled the region. Westerly winds prevailed in the lower troposphere and the moisture conditions were relatively weak.(3) Descending motion in the mid-lower troposphere caused by the above two circulation types provided a crucial dynamic mechanism for the formation of the two types of RPHEs. The descending motion contributed to a reduction in the height of the planetary boundary layer(PBL), which generated an inversion in the lower troposphere. This inversion trapped the abundant pollution and moisture in the lower PBL, leading to high concentrations of pollutants.  相似文献   

郊区化背景下居民健身活动时空约束对心理健康影响——以广州为例   总被引：6，自引：6，他引：0  

周素红  何嘉明 《地理科学进展》2017,36(10):1229-1238

本文从健康地理跨学科的视角入手,以广州市典型郊区的102个样本为研究对象,并选择10个城区街道的927个样本作为参照组进行对比研究,重点探讨中国式快速郊区化背景下,郊区居民健身活动时空约束对心理健康状况的影响。通过构建多元线性回归模型,从微观层面探讨居民城市建成环境、健身行为和心理健康之间的相互关系。结果表明：基于WHO-5反映心理健康量表的评分,郊区样本心理健康状况平均分值只有8.411分,远低于城区样本的平均12.788分,郊区居民的心理健康问题需要引起重视。相对于城区居民,郊区居民健身活动受长距离的通勤及不完善的公共交通系统的时空约束更为明显,健身活动频率更低、时间更短、空间上主要集中在住宅附近。这种差异除了受个人经济社会属性、邻里社区融入等因素影响外,还明显受到建成环境因素的影响。研究结论对弥补过度市场化逐利下造成的城市公共性缺失,维护社会空间公平,完善中国式郊区化下的公共服务设施配套体系,改善郊区居民心理健康状况有重要意义,同时也可为郊区规划及公共政策制定提供参考。  相似文献   

Rules and Methods of UAV Activities’ Aerial Lanes Design for (Ultra) Low Airspace in Regional Areas   总被引：1，自引：0，他引：1  

Bai Long  Lu Zi  Du Xinru  Gao Fang 《地球科学进展》2016,31(11):1197-1204

The exploitation of (ultra) low airspace resource has become an important component of optimizing the utilization of airspace and has received worldwide attention. It is the major form for UAV activity, which reveals great socioeconomic prospects. Firstly, the background of exploiting (ultra) low airspace resource and challenge for UAV activities were analyzed in regional areas. Then, legal rights for UAV activities and routes design in overseas and domestic research were reviewed. Second, the forms of regional rules for UAV activities in (ultra) low airspace were summarized, which included height-density rule, coverage area rule and isolation area of rule. Third, based on the air network of UAV(s) and aiming at the demand of aerial lanes for different requirements, the development from the method of 3D city model to the Cost-to-go was prospected. The findings are as follows: UAV activities’ aerial lanes design includes high-density as general rules and coverage area rule, isolation area rule as special rules. On the basis of 3D city model, improved method of Cost-to-go is applied to the choice of the optimal aerial lanes; based on ground buildings and residents’ actual conditions in regional area, the rules and methods are good for the (ultra) low airspace resources development and better solve the problem of UAV activities coordination. Furthermore, the rules and methods play an important role even in the implementation of the national airspace system.  相似文献   

Valuing the health benefits of physical activities in the marine environment and their importance for marine spatial planning     

《Marine Policy》2016

The marine environment provides a number of services which contribute to human well-being including the provision of food, regulation of climate and the provision of settings for cultural gains. To ensure these services continue to be provided, effective management is required and is being strategically implemented through the development of marine spatial plans. These plans require an understanding of the costs and benefits associated with alternative marine uses and how they contribute to human well-being. One benefit which is often difficult to quantify is the health benefit of engaging with the marine environment. To address this, the research develops an approach which can estimate the contribution aquatic physical activities makes to quality adjusted life years (QALYs) in monetary and non-monetary terms. Using data from the Health Survey for England, the research estimates that physical activities undertaken in aquatic environments at a national level provides a total gain of 24,853 QALYs. A conservative estimate of the monetary value of a QALY gain of this magnitude is £176 million. This approach provides estimates of health benefits which can be used in more comprehensive impact assessments, such as cost-benefit analysis, to compare alternative marine spatial plans. The paper concludes by discussing future steps.  相似文献   

饲料蛋白质水平对拟目乌贼生长前期的生长性能、肌肉成分和酶活的影响     

汪元  蒋霞敏  乐可鑫  韩庆喜  彭瑞冰  梁晶晶  王鹏帅 《海洋科学》2016,40(3):87-94

以鱼粉、豆粕和明胶为主要蛋白源配制成蛋白质水平分别为31.5%、35.0%、38.5%、42.0%、45.5%、49.0%的试验饲料。选取初始均重(3.99±0.08)g的拟目乌贼(Sepia lycidas)540只,随机分成6组,每组3个重复,每个重复30只。结果表明:拟目乌贼的生长性能指标(增重率、特定生长率、成活率)均在饲料蛋白质水平为45.91%时达到最佳,除与蛋白质水平为49.72%时差异不显著(P0.05)外,与其他各组均有显著差异(P0.05)。饲料系数随蛋白质水平的升高呈先降后升的趋势,在饲料蛋白质水平为45.91%时达到最低,显著低于除49.72%组外的其他各组;蛋白质效率随着饲料中蛋白质水平的升高而显著下降(P0.05)。饲料蛋白质水平对肥满度与肝体比影响不显著(P0.05)。胃蛋白酶、胰蛋白酶、肠道脂肪酶和肝脏超氧化物歧化酶活性,随饲料蛋白质水平的增加呈先升后降的趋势,均在饲料蛋白质水平为45.91%时达到最高,胃蛋白酶和胰蛋白酶活性除与蛋白质水平为42.22%时差异不显著(P0.05)外,与其他各组均有显著差异(P0.05);脂肪酶和肝脏超氧化物歧化酶活性与其他各组均有显著差异(P0.05),而肠道淀粉酶活性则相反。肝脏谷丙转氨酶和谷草转氨酶活性随饲料蛋白质水平的增加呈先升后稳定的趋势,均在饲料蛋白质水平为49.72%时达到最大,显著高于除45.91%组外的其他各组(P0.05);而饲料蛋白质水平对碱性磷酸酶活性影响不显著(P0.05)。乌贼肌肉粗蛋白质在饲料蛋白质水平45.91%时含量最高,显著高于除49.72%组外的其他各组(P0.05);粗脂肪含量最低,显著低于其他各组(P0.05);而肌肉水分和粗灰分含量不受饲料蛋白质水平的影响(P0.05)。拟目乌贼生长前期(4~10 g)配合饲料适宜的蛋白质水平为45.91%。  相似文献   

华北地区冬季持续性异常低温事件与大气低频振荡活动的关系          下载免费PDF全文

刘樱  郭品文  冯涛 《大气科学学报》2016,39(3):370-380

采用1959—2009年日平均气温观测资料和NCEP/NCAR逐日再分析资料,对华北地区冬季持续性异常低温事件进行了定义,并在此基础上统计分析了该区近50 a来冬季持续性异常低温事件的发生规律及环流特征,然后对华北地区持续性异常低温事件与大气低频振荡之间的关系进行了研究。研究表明,近50 a来华北地区共出现26次持续性异常低温事件;环流场上持续性异常低温过程对应的是乌拉尔山高压脊的建立、发展、消亡以及东亚大槽的维持、加深、减弱过程;同时,分析发现低频波动与持续性异常低温事件密切相关,10~20 d低频环流场上华北、东北地区上空的低频气旋、中西伯利亚的低频反气旋,及30~60 d低频环流场上西西伯利亚附近的低频反气旋及日本海附近的低频气旋是造成持续性异常低温事件的重要低频影响因子,进一步分析发现对流层高层到低层的低频信号主要是由中高纬向低纬且自西向东传播,来影响我国华北地区的。  相似文献   

How Frequently Will the Persistent Heavy Rainfall over the Middle and Lower Yangtze River Basin in Summer 2020 Happen under Global Warming?     

Zi-An GE  Lin CHEN  Tim LI  Lu WANG 《大气科学进展》2022,39(10):1673-1692

The middle and lower Yangtze River basin (MLYRB) suffered persistent heavy rainfall in summer 2020, with nearly continuous rainfall for about six consecutive weeks. How the likelihood of persistent heavy rainfall resembling that which occurred over the MLYRB in summer 2020 (hereafter 2020PHR-like event) would change under global warming is investigated. An index that reflects maximum accumulated precipitation during a consecutive five-week period in summer (Rx35day) is introduced. This accumulated precipitation index in summer 2020 is 60% stronger than the climatology, and a statistical analysis further shows that the 2020 event is a 1-in-70-year event. The model projection results derived from the 50-member ensemble of CanESM2 and the multimodel ensemble (MME) of the CMIP5 and CMIP6 models show that the occurrence probability of the 2020PHR-like event will dramatically increase under global warming. Based on the Kolmogorov–Smirnoff test, one-third of the CMIP5 and CMIP6 models that have reasonable performance in reproducing the 2020PHR-like event in their historical simulations are selected for the future projection study. The CMIP5 and CMIP6 MME results show that the occurrence probability of the 2020PHR-like event under the present-day climate will be double under lower-emission scenarios (CMIP5 RCP4.5, CMIP6 SSP1-2.6, and SSP2-4.5) and 3–5 times greater under higher-emission scenarios (3.0 times for CMIP5 RCP8.5, 2.9 times for CMIP6 SSP3-7.0, and 4.8 times for CMIP6 SSP5-8.5). The inter-model spread of the probability change is small, lending confidence to the projection results. The results provide a scientific reference for mitigation of and adaptation to future climate change.  相似文献   

贵州省2020年秋绵雨过程分析及农业气象服务          下载免费PDF全文

谭文  王方芳  杨世琼  左晋  徐永灵 《中低纬山地气象》2022,46(2):98-101

2020年9月-11月贵州省出现了1961年以来持续时间和影响范围最强的秋绵雨天气,1149站（总数的75.0%）出现特重级秋绵雨。秋绵雨天气造成秋收进度缓慢、秋种进度受阻,同时也不利于水果成熟采摘上市,2020年水稻单产较上年减产1.9%。针对这次秋绵雨天气过程,贵州省山地环境气候研究所及时启动应急保障服务,修正秋收及秋种气象适宜度等级指标,建立6h、12h、24h秋收（抢收）气象适宜度指标,提前预警、及时发布秋收气象适宜度等级、滚动跟进服务,采用多种手段对外发布各种预报、预警信息,减少损失,保障贵州省水稻收获、颗粒归仓以及秋播顺利进行。  相似文献   

Typical Circulation Patterns and Associated Mechanisms for Persistent Heavy Rainfall Events over Yangtze–Huaihe River Valley during 1981–2020※     

Huijie WANG  Jianhua SUN  Shenming FU  Yuanchun ZHANG 《大气科学进展》2021,38(12):2167-2182

Persistent heavy rainfall events (PHREs) over the Yangtze–Huaihe River Valley (YHRV) during 1981–2020 are classified into three types (type-A, type-B and type-C) according to pattern correlation. The characteristics of the synoptic systems for the PHREs and their possible development mechanisms are investigated. The anomalous cyclonic disturbance over the southern part of the YHRV during type-A events is primarily maintained and intensified by the propagation of Rossby wave energy originating from the northeast Atlantic in the mid–upper troposphere and the northward propagation of Rossby wave packets from the western Pacific in the mid–lower troposphere. The zonal propagation of Rossby wave packets and the northward propagation of Rossby wave packets during type-B events are more coherent than those for type-A events, which induces eastward propagation of stronger anomaly centers of geopotential height from the northeast Atlantic Ocean to the YHRV and a meridional anomaly in geopotential height over the Asian continent. Type-C events have "two ridges and one trough" in the high latitudes of the Eurasian continent, but the anomalous intensity of the western Pacific subtropical high (WPSH) and the trough of the YHRV region are weaker than those for type-A and type-B events. The composite synoptic circulation of four PHREs in 2020 is basically consistent with that of the corresponding PHRE type. The location of the South Asian high (SAH) in three of the PHREs in 2020 moves eastward as in the composite of the three types, but the position of the WPSH of the four PHREs is clearly westward and northward. Two water vapor conveyor belts and two cold air conveyor belts are tracked during the four PHREs in 2020, but the water vapor path from the western Pacific is not seen, which may be caused by the westward extension of the WPSH.  相似文献   

广西贺州市里松-贺县地区矿山开发活动及矿山地质环境遥感监测     

倪斌 《地质与勘探》2021,57(3):593-602

以2008年和2017年获取的广西贺州市里松-贺县地区的SPOT-5数据和国产GF-2卫星影像数据作为主要数据源,通过对影像数据进行处理,根据影像特征建立了研究区的矿山遥感解译标志,辅以野外验证,利用Arc GIS平台动态监测与分析了研究区矿山开发占地情况和矿山地质环境等问题,厘清了里松-贺县地区的矿山地质环境现状和变化趋势。研究表明:(1)研究区内2017年矿山开发占地总计1775.03 hm~2,占整个研究区面积的1.26%。其中,矿山开采面占地达992.38 hm~2,为矿山开发占地的55.91%。对比2008年和2017年的2期数据解译成果,得出2017年的矿山开发占损土地面积比2008年增长51.10%。(2)研究区的矿山开采引发了滑坡、崩塌、泥石流、不稳定斜坡等地质灾害共计121处,面积达133.48 hm~2、开采面占用的土地植被破坏严重、矿山开采也引发了水土和粉尘污染等矿山地质环境问题。  相似文献