Analysis on Spatio-temporal Distribution of Lightning in Dalian Area of China between 2007 and 2008

The cloud-to-ground lightning data between 2007 and 2008 were collected by lightning detection and location system,which was composed of four lightning detectors in four different sites of Dalian area.The spatio-temporal distribution of cloud-to-ground lightning in surrounding areas of Dalian was analyzed from several aspects of polarity distribution,diurnal variation,lightning intensity and lightning density.The results showed that the number of negative lightning accounted for 93.9% of the total number of lightning,and its average lightning intensity was 27.99 kA.The number of positive lightning accounted for 6.1% of the total number of lightning,and its average lightning intensity was 35.56 kA.The diurnal variation of lightning frequency showed an obvious structure of two peaks (17:00-18:00 and 04:00-05:00) and two valleys (09:00-10:00 and 00:00-01:00).The number of lightning between May and September was 91.5% of the annual number,and the lightning occurred the most frequently between June and August.Most of positive and negative lightning was at the intensity of 15-35 kA,80.0% lower than 40 kA,and 99.3% lower than 100 kA.The lightning density had obvious regional differences in distribution,high in the Liaodong Bay and the Dalian Bay and low in inland areas.Therefore,coastal areas should attract more attention in lightning disaster defense in the surrounding areas of Dalian.

Integrated approach for understanding spatio-temporal changes in forest resource distribution in the central Himalaya

Intense anthropogenic exploitation has altered distribution of forest resources. This change was analyzed using visual interpretation of satellite data of 1979, 1999 and 2009. Field and interactive social surveys were conducted to identify spatial trends in forest degradation and data were mapped on forest cover and land use maps. Perceptions of villagers were compiled in a pictorial representation to understand changes in forest resource distribution in central Himalaya from 1970 to 2010. For- ested areas were subject to degradation and isolation due to loss of con- necting forest stands. Species like Lantana camara and Eupatorium adenophorum invaded forest landscapes. Intensity of human pressure differed by forest type and elevation. An integrated approach is needed to monitor forest resource distribution and disturbance.

Response of Spatio-temporal Distribution of Fishery Resources to Mairne Environment in the Northern South China Sea

[Objective] The paper was to investigate the spatio-temporal distribution of fishery resources in the northern South China Sea and to provide reference for scientific evaluation and effective protection of fishery resources in the northern South China Sea. [Methods] Based on monitoring data and satellite remote sensing data [including Sea Surface Temperature(SST), Chlorophyll a concentration(Chl a) and Sea Surface Wind(SSW)] in winter(January to February) and summer(August to September) in the northern South China Sea, the relationship between spatio-temporal distribution of fishery resources and marine environment was investigated by using Generalized Linear Models(GLM), fishing ground gravity and correlation analysis. [Results] The suitable SST and Chl a of light falling-net fishing ground in winter were 17-23°C and 0.2-0.6 mg/m3, respectively. The suitable SST and Chl a in summer were approximately 28°C and 0.2-1.0 mg/m3. Standardized Catch Per Unit Effort(SCPUE) was higher in summer(2-4) and lower in winter(1-3). From winter to summer, the fishing ground gravity migrated to the east about 1 °E. [Conclusion] The spatio-temporal distribution of fishery resources is related to eastern Hainan-western Guangdong upwelling and the coastal flow, caused by the monsoon in the northern South China Sea, and the major catch species of light falling-net.

Spatio-Temporal Distribution of Agricultural Non-Point Source Pollution in Binzhou City Based on Large Computer Data

Based on the relevant statistics on the agricultural non-point source pollution in Binzhou City,we studied the spatio-temporal variation in agricultural non-point source nitrogen pollution and phosphorus pollution in Binzhou City during 2008-2015. The results showed that the agricultural non-point source nitrogen pollution and phosphorus pollution in Binzhou City changed from 114400 t and 28800 t in 2008 to110600 t and 24400 t in 2015,respectively; for the non-point source nitrogen pollution sources,the proportion of chemical fertilizer,manure and domestic sewage changed from 80. 41%,10. 47% and 9. 13% in 2008 to 82. 94%,4. 77% and 12. 29% in 2015,respectively; for the non-point source phosphorus pollution sources,the proportion of chemical fertilizer,manure and domestic sewage changed from 89. 29%,8. 32% and 2. 39% in 2008 to 91. 6%,4. 78% and 3. 62% in 2015,respectively; in 2015,the non-point source nitrogen pollution was most serious in Wudi County and Huimin County and least serious in Zhanhua County; the non-point source phosphorus pollution was most serious in Zouping County and least serious in Wudi County.

Spatial-temporal distribution of debris flow impact pressure on rigid barrier

Grain composition plays a vital role in impact pressure of debris flow. Current approaches treat debris flow as uniform fluid and almost ignore its granular effects. A series of flume experiments have been carried out to explore the granular influence on the impact process of debris flow by using a contact surface pressure gauge sensor(Tactilus~?, produced by Sensor Products LLC). It is found that the maximum impact pressure for debris flow of low density fluctuates drastically with a long duration time while the fluctuation for flow of high density is short in time, respectively presenting logarithmic and linear form in longitudinal attenuation. This can be ascribed to the turbulence effect in the former and grain collisions and grainfluid interaction in the latter. The horizontal distribution of the impact pressure can be considered as the equivalent distribution. For engineering purposes, the longitudinal distribution of the pressure can be generalized to a triangular distribution, from which a new impact method considering granular effects is proposed.

Spatiotemporal Distribution of Cladocera and Rotifer of the Mangrove Waters of Mouanko (Coastal Cameroon): Influence of Some Abiotic Variables

The Mouanko mangrove is subjected to major anthropogenic activities such as agriculture, fishing and deforestation, hence information on Cladocerans and Rotifers amongst other aquatic organisms in order to monitor and manage this ecosystem is vital. The aim of this work is to study the physicochemical parameters of the environment that influence the diversity and spatiotemporal distribution of Cladocerans and Rotifers in the mangrove waters of Mouanko. This study was carried out from November 2019 to October 2020 at 8 sampling stations. Both biological and physico-chemical sampling and analyses were done following standard recommendations. The results of the phyico-chemical analyses revealed that the waters of the Mouanko mangroves were slightly basic (7.64 ± 0.71 UC), moderately oxygenated (69.56% ± 14.29%) with low levels of nutrients [ NO -2 (0. 06 ± 0.05 mg/L), NH+4 (0.39 ± 0.3 mg/L) and PO3-4 (up to 0.12 mg/L)] and high values of electrical conductivity (up to 6531.04 μS/cm), salinity (up to 3.71‰). 15 species of Cladocerans and 30 species of Rotifers were identified accounting for a total abundance of 612 ind/L. The species richness was higher in freshwater influenced zones (40 taxa) compared to marinewater influenced zones (17 taxa). Among these species, the Cladocera, Penilia avirostris was the most abundant in marinewater influenced zones (84 ind/L) while the Rotifer, Keratella tecta was the most abundant in freshwater influenced zones (64 ind/L). Shannon-Weaver’s diversity and Pielou’s equitability indices indicated that freshwater influenced zones host a diverse community with a tendency towards equi-partition of species while marinewater influenced zones revealed the opposite. The low levels of organic pollution indicator variables recorded and the high diversity of the freshwater influenced zones population studied attested to the low level of anthropization in this environment. High salinity and electrical conductivity values influence the distribution of these organisms.

基于时空关联特征与B-LSTM模型的分布式光伏功率区间预测

提出一种基于时空关联特征与贝叶斯-长短期记忆神经网络(bayesian long short-term memory,B-LSTM)模型的分布式光伏功率区间预测方法。以长短期记忆神经网络(long short-term memory,LSTM)为基础构建近似贝叶斯神经网络,建立考虑时空关联特征的B-LSTM模型,利用其强大的记忆能力和特征提取不同特征尺度的模态分量,并进行分布式光伏功率区间预测。以某地区实际分布式光伏数据集进行算例分析,验证了所提方法的优越性。

1971-2022年河南省水汽压与能见度的时空分布及其关联

为探究河南省水汽压和能见度的时空分布特征和相关性,利用1971-2022年河南省118个国家级气象站的日最高水汽压和日最小能见度数据,分析了河南省年平均最高水汽压和最小能见度的时空变化特征及二者的相关性。结果表明:(1)年平均最高水汽压呈显著上升趋势,其气候倾向率达0.25 hPa/10a;最高水汽压在1998年发生由低到高的突变;豫中南、豫东及豫北水汽压上升最为显著;最高水汽压变化幅度大值区主要位于豫中南大部、豫西南部分县市。(2)年平均最小能见度呈显著下降趋势,其气候倾向率为-0.56 km/10a;最小能见度在2014年出现下降突变;豫西、豫西南、豫北部分县市及商丘、信阳局部能见度下降显著,变化幅度较大。(3)河南省大部分地区年平均最高水汽压与最小能见度存在显著的负相关(区域平均相关系数约为-0.41),水汽压升高(降低)易引起能见度降低(升高)。

基于CRITIC-TOPSIS的深基坑风险分区动态评价

为解决深基坑工程风险评价中的主观性影响及场地风险的细化分区与跟踪问题,本文提出了一种基于现场实测数据的相关性赋权法(CRITIC)与优劣解距离法(TOPSIS)相结合的深基坑施工风险分区动态评价方法。首先根据基坑测点布置划分子区域,以周边环境变形、基坑变形及地下水位变化等为评价指标,以现场实测数据为基础,采用CRITIC法确定指标权重,基于TOPSIS方法与模糊理论实现对基坑各分区施工风险的动态评价,最后通过上海某地铁深基坑工程案例应用,验证了该方法的有效性。结果表明:(1)本案例在深基坑施工风险评价中起主导作用的指标为地表沉降累计、地表沉降变化速率、坑外水位累计、坑外水位变化速率和地下连续墙顶水平位移变化速率;(2)随着基坑开挖施工的进行,累计类指标的权重计算值总体上在增大,而速率类指标的权重计算值总体上在减小;(3)空间分布上,基坑各分区风险为长边区域风险>短边区域风险>角部区域风险;(4)时间变化上,基坑各分区的风险等级变化不大,基坑开挖过程中基坑本身与周边环境均处于比较稳定的状态。以上风险评价结论与现场符合度较高,表明CRITIC-TOPSIS法能够有效避免专家赋权的主观性,可用于深基坑工程的施工全过程风险评价。

基于组合权重-TOPSIS模型的贵州省水资源承载力评价

以贵州省为研究对象,基于2010—2020年水资源公报、统计年鉴数据等相关数据,从水资源、社会、经济、生态环境4个方面选取16项指标,构建水资源承载力评价指标体系,采用组合权重-TOPSIS模型对研究区88个县进行水资源承载力评价分析。结果表明:1)贵州省2020年县域水资源承载变化范围为0.329~0.716,总体水资源承载状况差异显著,较2010年水资源承载力有明显提升,且2020年水资源承载力呈现黔中区域的水资源承载力较低、周边区域较高的变化趋势,黔东区域水资源承载力最高。2)利用ArcGIS对贵州省县域的水资源承载指数进行全局莫兰指数分析,贵州省县域水资源承载力的莫兰指数为0.515,z值显著大于临界值2.58,p值小于显著性水平,贵州省水资源承载指数呈现空间集聚趋势。3)通过地理探测器分析可知,单因子对水资源承载力影响解释力最大的是人均水资源占有量;双因子交互作用下对水资源承载力的影响程度结果显示,人均水资源占有量是水资源承载力的主导因子。

基于Sentinel-5P的华北地区大气CH_(4)时空分布特征

基于Sentinel-5P遥感卫星反演的CH_(4)柱浓度数据,探究了2019—2022年华北地区CH_(4)柱浓度的时空分布特征,并分析了其影响因素。结果表明:华北地区CH_(4)柱浓度空间分布呈现西北低、东南高的特点,且京津冀与山西中东部地区具有明显的高浓度连片特征,时间上CH_(4)柱浓度逐年上升,并呈现出明显的秋高春低、夏冬过渡的季节性特征;回归分析表明,华北地区CH_(4)柱浓度受到气温、降雨量、植被指数、路网密度、风速、地形的影响,且气温、降雨量、植被指数影响最甚。

基于时序NPP-VIIRS夜间灯光和土地利用数据的福州市GDP时空分布研究

基于时序NPP-VIIRS夜间灯光、社会经济统计等数据,构建GDP空间化模型,并结合空间分辨率为30 m×30 m的土地利用数据对模型进行修正,研究2013—2020年福州市经济空间差异性及演变趋势。结果表明:(1)利用土地利用数据对GDP空间化模型进行修正以提高单元网格精度和效度的方法是可行的,对较小尺度的经济空间分析具有意义。(2)将土地利用数据对应的各产业产值用于对GDP空间化模型修正,能够进一步提升单元网格的模拟精度。(3)从共时性比对来看,福州市的经济空间呈现东部GDP较高,西部和北部GDP以低值为主、高值零星分布的格局。从历时性来看,自2015年起,福州市GDP高值区域的扩张与GDP总值的增长速度明显提高,2018年后整体出现略微下降趋势。

云南省2000-2020年石漠化时空演变分析

【目的】在宏观尺度利用遥感手段识别和提取石漠化斑块信息,定量分析石漠化的空间分布特征和时序演变过程,可为中国西南地区石漠化的发生、发展过程研究提供技术手段和数据支撑。【方法】以云南省为研究区,基于谷歌地球引擎(Google Earth Engine)平台,以2000、2010和2020年为研究时段,采用决策树分类法定量提取石漠化斑块信息;通过时空演变模型分析云南省石漠化的时空演变过程和特征。【结果】(1)研究时段内,云南省石漠化状况整体得到改善,石漠化占国土面积比例从9.65%下降至6.48%,但局部地区仍在恶化。(2)云南省石漠化空间分布呈东多西少的特征,其中昭通、曲靖、文山、红河和昆明等地区的石漠化分布面积较大,占全省石漠化发生面积的65.42%~72.14%。(3)石漠化演变流向复杂,既转移至石漠化程度高的等级又向石漠化程度低的等级转移,边治理边破坏的现象未被遏制。(4)极重度石漠化修复所需的周期较长,近20 a间云南省极重度石漠化大部分转移至重度石漠化。(5)石漠化内部演变过程剧烈,轻度石漠化和中度石漠化的综合变化速率较快,易于改善的同时亦存在较高的恶化风险,需加以重视。【结论】依据相关规程中的石漠化等级判定标准,采用决策树分类法,可准确提取宏观尺度的石漠化斑块信息。云南省石漠化土地面积呈减少趋势,空间分布不均匀,不同石漠化等级之间存在相互转化的现象。

Spatio-temporal distribution and transformation of cropland in geomorphologic regions of China during 1990–2015

Landforms are an important factor determining the spatial pattern of cropland through allocation of surface water and heat. Therefore, it is of great importance to study the change in cropland distribution from the perspective of geomorphologic divisions. Based on China's multi-year land cover data(1990, 1995, 2000, 2005, 2010 and 2015) and geomorphologic regionalization data, we analyzed the change in cropland area and its distribution pattern in six geomorphologic regions of China over the period of 1990-2015 with the aid of GIS techniques. Our results showed that the total cropland area increased from 177.1 to 178.5 million ha with an average increase rate of 0.03%. Cropland area decreased in southern China and increased in northern China. Region I(Eastern hilly plains) had the highest cropland increase rate, while the cropland dynamic degree of Region IV(Northwestern middle and high mountains, basins and plateaus) was significantly higher than that of other regions. The barycenter of China's cropland shifted from northern China to the northwest over the 25-year period. Regions IV and I were the two regions with the greatest increase of cropland. Region II(Southeastern low and middle mountains) and Region V(Southwestern middle and low mountains, plateaus and basins) were the main decreasing cropland regions. The area of cropland remained almost unchanged in Region III(Northern China and Inner Mongolia eastern-central mountains and plateaus) and Region VI(Tibetan Plateau). The loss of cropland occurred mostly in Regions I and II as a result of growing industrialization and urbanization, while the increase of cropland occurred mainly in Region IV because of reclamation of grassland and other wasteland. These analyzing results would provide fundamental information for further studies of urban planning, ecosystem management, and natural resourcesconservation in China.

青海省太阳能-风能发电潜力评估及时空格局

为定量评估青海省太阳能、风能资源开发潜力,该文基于地形条件、土地利用、生态保护区等地理空间分析,在10 m×10 m空间分辨率上提取光风电站可开发利用区域,考虑了地形条件对装机折减影响及真实电场设计参数,采用1980—2020年MERRA-2再分析数据,评估了青海省光风理论和技术发电潜力,分析了时空格局,识别了开发利用现状。研究表明:(1)1980—2020年青海省太阳能多年平均理论发电潜力1881.1 kWh/m^(2),技术发电潜力301.7 kWh/m^(2);空间上,呈西高东低的分布格局,且东部变化更为显著;时间上,全省呈波动减少特征,整体下降速率为-337.9亿kWh/a,各地区增减不一,其中果洛和玉树缓慢上升,其他地区呈下降趋势。(2)1980—2020年青海省风能多年平均理论发电潜力121.1 kWh/m^(2),技术发电潜力21.9 kWh/m^(2);空间上,呈西北高东南低的分布格局,且西南部变化更为显著;时间上,全省呈先增加后减少的趋势特征,整体下降速率为-27.0亿kWh/a,各地区增减不一,其中海西减少最快,玉树有小幅增加。(3)青海省太阳能和风能2020年发电量分别为167亿kWh和81亿kWh,分别占技术发电潜力的1.1%和9.2%,仍具有较大挖潜空间。

2016-2019年泰安市近地面大气臭氧污染特征及敏感性分析

为揭示泰安市大气臭氧污染特征,利用泰安市2016-2019年地面气象观测资料、大气污染物监测资料及NECP/NCAR提供的FNL资料,采用信息流、后向轨迹模拟、WRF-Chem数值模拟等方法对泰安市臭氧污染时空分布特征、气象影响因子、污染源及敏感性前体物进行分析。结果表明:泰安市臭氧超标高发期主要出现在夏季的7、8月份,O_(3)日浓度最大值出现在14:00-16:00,并且其浓度变化具有工作日的高于周末的,而前体物浓度工作日的低于周末的“周末效应”。空间上,泰安市臭氧浓度分布呈现出西高东低、南高北低的分布趋势,受地形影响明显。泰安市臭氧污染受多种气象因子共同影响,日平均气温为22~26℃,日最高气温为30~32℃,相对湿度为70%~80%,东南风风速为1.0~1.5 m·s^(-1)时,臭氧浓度更容易超标。臭氧污染期间,气流主要来源于鲁东南(65%)和鲁北渤海(23%),PSCF和CWT对泰安市臭氧前体物潜在源区分析结果表明,臭氧前体物主要来源于山东省内鲁南地区,包括泰安、济案、枣庄和临沂等地。利用WRF-Chem模式对2016年9月2-5日重污染过程模拟结果表明,泰安市本次污染过程的臭氧敏感性前体物为VOCs。

青藏高原土壤湿度-气候相互影响研究进展

土壤湿度作为一个具有“记忆性”的重要气候变量,可以通过改变地表的能量和水分交换,进而影响局地乃至全球的大气环流,因此受到全球气候观测系统计划的重视。近年来青藏高原土壤湿度观测网(站)建设发展迅速,为局地陆气相互作用研究提供了可靠的数据支撑。本文从不同的土壤湿度资料在青藏高原的适用性、高原土壤湿度的时空变化特征及其对气候的影响综述了近年来的国内外研究进展。由于土壤湿度在时空上的高度变异性,现有相关研究大多使用再分析资料、陆面数据同化资料和卫星遥感数据来补充观测资料进行青藏高原土壤湿度与气候的相互影响研究。但模式选择、算法和实验方案的不同,导致青藏高原土壤湿度的补充资料适用性不同,使得前人对高原土壤湿度如何影响中国及全球气候得出不同结论,故相关问题需要进一步讨论,并提出了后期青藏高原土壤湿度研究需要解决的关键问题。

考虑数据中心用能时空可调的电-气互联综合能源系统分布式光伏最大准入容量计算

在数字经济背景下,数据中心日益增长的用能规模和灵活迅速的负荷调节能力引起了广泛关注。为促进分布式清洁能源的消纳,本文提出一种考虑数据中心用能时空可调的电-气互联综合能源系统分布式光伏最大准入容量计算方法。首先,对数据中心能耗及运行特性进行建模,并分析数据中心用能时空可调特性;然后,在计及电-气能源网络安全约束的前提下,构建集成数据中心的电-气互联综合能源系统分布式光伏最大准入容量优化模型,利用凸松弛技术和增量分段线性化方法将模型转化为混合整数二阶锥模型求解。最后,在97节点电网和11节点气网算例中,验证了考虑数据中心用能时空可调特性对分布式光伏消纳的促进作用,并分析了电-气能源网络安全约束对分布式光伏最大准入容量的影响。

基于配电网-路网融合的移动储能车多场景时空协同优化调度策略

移动储能车(MESV)具有电池容量大、机动灵活等特性。针对现有研究未能充分挖掘MESV多场景应用潜力的问题,提出一种基于配电网-路网融合的MESV多场景时空协同优化调度策略。首先,建立MESV在配电网-路网融合系统中的时-空网络移动模型;然后,以配电网运行的综合效益最大化为目标,考虑MESV的移动与充放电功率与荷电状态约束及配电网运行约束,构建MESV的多场景应用协同调度模型;最后,针对混合整数二阶锥规划模型求解复杂的问题,采用改进哈里斯鹰算法(HHO)提高优化问题的求解效率。算例分析表明,所提策略能够有效地优化配电网运行的经济效益,实现削峰填谷、促进新能源消纳及提高供电可靠性。

Spatio-temporal distribution of vascular plant species abundance on Qinghai-Tibet Plateau

For quantitatively explaining the correlations between the vascular plant species abundance (VPSA) and habitat factors, a spatial simulation method has been developed to simulate the distribution of VPSA on the Qinghai-Tibet Plateau. In this paper, the vascular plant type, land cover, mean annual biotemperature, average total annual precipitation, topographic relief, patch connectivity and ecological diversity index were selected to screen the best correlation equation between the VPSA and habitat factors on the basis of 37 national nature reserves on the Qinghai-Tibet Plateau. The research results show that the coefficient of determination between VPSA and habitat factors is 0.94, and the mean error is 2.21 types per km2. The distribution of VPSA gradually decreases from southeast to northwest, and reduces with increasing altitude except the desert area of Qaidam Basin. Furthermore, the scenarios of VPSA on the Qinghai-Tibet Plateau during the periods from 1981 to 2010 (T0), from 2011 to 2040 (T2), from 2041 to 2070 (T3) and from 2071 to 2100 (T4) were simulated by combining the land cover change and the climatic scenarios of CMIP5 RCP2.6, RCP4.5 and RCP8.5. The simulated results show that the VPSA would generally decrease on the Qinghai-Tibet Plateau from T0 to T4. The VPSA has the largest change ratio under RCP8.5 scenario, and the smallest change ratio under RCP2.6 scenario. In general, the dynamic change of habitat factors would directly affect the spatial distribution of VPSA on the Qinghai- Tibet Plateau in the future.