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EVOLUTION OF LIQUID WATER CONTENT IN A SEA FOG CONTROLLED BY A HIGH-PRESSURE PATTERN 被引量:3
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作者 李晓娜 黄健 +2 位作者 申双和 刘寿东 吕卫华 《Journal of Tropical Meteorology》 SCIE 2010年第4期409-416,共8页
On March 16–17, 2008, a sea fog occurred in Dianbai in the west of Guangdong Province and was accompanied by a high-pressure synoptic system. Using comprehensive observation datasets, this study analyzes the evolutio... On March 16–17, 2008, a sea fog occurred in Dianbai in the west of Guangdong Province and was accompanied by a high-pressure synoptic system. Using comprehensive observation datasets, this study analyzes the evolution of liquid water content during this sea fog and investigates the relationships between liquid water content and the average diameters and count densities of fog droplets, air temperature, wind speed and turbulence exchanges. The main results are presented as follows. (1) The sea fog showed a quasi-periodic oscillation characteristic, i.e., it developed, disappeared and then developed again. (2) During the sea fog, the number of fog droplets changed significantly while the changes in average diameter of the fog droplets were relatively small. The development and disappearance of the sea fog correlated significantly with the fog droplet numbers. (3) The air-cooling mechanism played a significant role in sea fog formation and development. However, the influences of this mechanism were not evident during fog persistence. (4) During sea fog formation, weak turbulence exchanges were helpful for fog formation. During sea fog development and persistence, liquid water content increased when turbulence exchanges weakened, and vice versa. The changes in turbulence exchanges were closely related to the quasi-periodic oscillations observed in sea fog presence. 展开更多
关键词 high-pressure pattern sea fog liquid water content count density of fog droplets average diameter of fog droplets turbulence exchanges
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Comparison of Liquid Water Content Retrievals for Airborne Millimeter-Wave Radar with Different Particle Parameter Schemes
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作者 CUI Xin-dong YAO Zhi-gang +3 位作者 ZHAO Zeng-liang WANG Min-wei FAN Chun-hui SU Tao 《Journal of Tropical Meteorology》 SCIE 2020年第2期188-198,共11页
In the application of the physical iterative method to retrieve millimeter-wave radar liquid water content(LWC)and liquid water path(LWP),particle parameter scheme is the main factor affecting retrieval performance.In... In the application of the physical iterative method to retrieve millimeter-wave radar liquid water content(LWC)and liquid water path(LWP),particle parameter scheme is the main factor affecting retrieval performance.In this paper,synchronous measurements of an airborne millimeter-wave radar and a hot-wire probe in stratus cloud are used to compare the LWC retrievals of the oceanic and continental particle parameter scheme with diameter less than 50μm and the particle parameter scheme with diameter less than 500μm and 1500μm(scheme 1,scheme 2,scheme 3,and scheme4,respectively).The results show that the particle parameter scheme needs to be selected according to the reflectivity factor when using the physical iterative method to retrieve the LWC and LWP.When the reflectivity factor is less than-30 d BZ,the retrieval error of scheme 1 is the minimum.When the reflectivity factor is greater than-30 d BZ,the retrieval error of scheme 4 is the minimum.Based on the reflectance factor value,the LWP retrievals of scheme 4 are closer to the measurements,the average relative bias is 5.2%,and the minimum relative bias is 4.4%.Compared with other schemes,scheme 4 seems to be more useful for the LWC and LWP retrieval of stratus cloud in China. 展开更多
关键词 millimeter-wave radar physical iterative method particle parameter scheme liquid water content liquid water path
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Influence of liquid water content on wind turbine blade icing by numerical simulation
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作者 LI Yan SUN Ce +4 位作者 JIANG Yu YI Xian GUO Wenfeng WANG Shaolong FENG Fang 《排灌机械工程学报》 EI CSCD 北大核心 2019年第6期513-520,共8页
In order to research the influence of liquid water content ( LWC ) on blade icing of wind turbine, a numerical simulation method for blade icing was established. The numerical simulation was based on low speed viscous... In order to research the influence of liquid water content ( LWC ) on blade icing of wind turbine, a numerical simulation method for blade icing was established. The numerical simulation was based on low speed viscous N-S equation. The trajectory equation of water droplets was established by Lagrangian method. The mass and energy conservation equations of the water droplets impacting on the surface of the blade were solved based on control body theory. Three sections along blade span wise of a 1.5 MW wind turbine were decided to simulate icing. Five kinds of LWC were selected for simulation including 0.2,0.4,0.6,0.8 and 1.0 g/m^3 under two ambient temperatures of -10 ℃ and -20 ℃. The medium volume droplet diameter ( MVD ) was 30μm. The simulations included icing shape on blade surface, dimensionless icing area and dimensionless maximum stagnation thickness. Furthermore, the flow fields around both the iced blade airfoil and the original one were simulated and analyzed. Accor-ding to the results, the typical icing characteristics of icing shape, icing area and thickness were greatly affected by the difference of LWCs. This study can provide theoretical reference for the research on antiicing and deicing of wind turbine blade. 展开更多
关键词 WIND TURBINE ICING AIRFOIL NUMERICAL simulation liquid water content
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A Comparative Study of Cloud Liquid Water Content from Radiosonde Data at a Tropical Location
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作者 Swastika Chakraborty Animesh Maitra 《International Journal of Geosciences》 2012年第1期44-49,共6页
In this paper, some features of cloud liquid water content with respect to rain and water vapor are presented. Cloud liquid water density profile is obtained from radiosonde observation with Salonen's model and Ka... In this paper, some features of cloud liquid water content with respect to rain and water vapor are presented. Cloud liquid water density profile is obtained from radiosonde observation with Salonen's model and Karsten's model at Kolkata, a tropical location in the Indian region. Cloud liquid water contents (LWC) are obtained from these profiles which show a prominent seasonal variation. The monsoon months exhibit much higher values of LWC than in other months. However Salonen's model yields higher LWC values than that obtained with Karsten's model. The variation of daily total rainfall with LWC shows a positive relationship indicating the role of LWC in controlling the rainfall. Also the variation pattern of LWC with integrated water vapor (IWV) content of the atmosphere indicates that a threshold value of water vapor is required for cloud to form and once cloud is formed LWC increases with IWV. 展开更多
关键词 CLOUD liquid water contentS (LWC) Integrated water Vapor (IWV)
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Analysis of Vertical Profiles of Precipitable Liquid Water Content in a Tropical Climate Using Micro Rain Radar
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作者 Joseph S. Ojo Omololu O. Daodu Olalekan L. Ojo 《Journal of Geoscience and Environment Protection》 2019年第2期140-155,共16页
In this paper, some distinctive features of the vertical profile of precipitable liquid water content (LWC) with considerable respect to rain rates (R) and radar reflectivity (Z) obtained in a tropical location are pr... In this paper, some distinctive features of the vertical profile of precipitable liquid water content (LWC) with considerable respect to rain rates (R) and radar reflectivity (Z) obtained in a tropical location are presented. Assessment of LWC allows applications in the specific area of flight icing severity, aviation safety as well as signals traversing through the atmosphere. The parameters were typically measured using vertically-pointing Micro Rain Radar (MRR) over a period of 2 years (2011-2012) at Akure, a tropical location of Nigeria. The radar scanned at every 10 seconds and integrated over one minute samples to reduce event logging error associated with the instrument. The vertical profile of the LWC typically reveals a prominent seasonal variation. However, majority of the LWC profiles has low LWC, less than 0.1 gm?3 while the maximum observed LWC is about 3.18 gm?3. A strong like hood relation was observed between the melting layer height and the LWC, with the LWC reaches peak at the considerable height of about 4160 m which coincides precisely with the freezing height level (rain height of ~4520 m) of the study location. Good correlation was also observed between the LWC and R in most of the heights considered. The results obtained will assist system engineers to assess the level of absorption, reflection and attenuation of electromagnetic signals as a result of precipitable LWC along the transmitting paths. The novelty of the present work is in the area of linking LWC and Z as against usual relation between Z and R. 展开更多
关键词 liquid water content MICRO RAIN RADAR Vertical Profile TROPICAL CLIMATE RADAR REFLECTIVITY Factor
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NUMERICAL STUDY OF REMOTE SENSING OF CLOUD LIQUID WATER CONTENT BY SPACE-BORNE COMBINED RADAR-RADIOMETER 被引量:1
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作者 刘锦丽 张凌 +1 位作者 陈洪滨 吕达仁 《Acta meteorologica Sinica》 SCIE 1998年第4期435-442,共8页
A retrieval method of microwave(MW)space-borne remote sensing of cloud liquid water content by the combined radar-radiometer is suggested.A three-layer cloud model is chosen to represent the typical stratified precipi... A retrieval method of microwave(MW)space-borne remote sensing of cloud liquid water content by the combined radar-radiometer is suggested.A three-layer cloud model is chosen to represent the typical stratified precipitating cloud.The retrieval method mainly follows our previously suggested scheme with some modifications.Numerical comparative study shows that in space-borne remote sensing of cloud liquid water content by the combined method is much better than by radar only;Also the retrieval accuracy of cloud liquid water content may be improved when using the three-layer cloud model in the combined method. 展开更多
关键词 space-borne MW remote sensing cloud liquid water content combined radar-radiometer
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Molecular dynamics study of room temperature ionic liquids with water at mica surface
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作者 Huanhuan Zhang Mengyang Zhu +2 位作者 Wei Zhao Song Li Guang Feng 《Green Energy & Environment》 SCIE 2018年第2期120-128,共9页
Water in room temperature ionic liquids(RTILs) could impose significant effects on their interfacial properties at a charged surface. Although the interfaces between RTILs and mica surfaces exhibit rich microstructure... Water in room temperature ionic liquids(RTILs) could impose significant effects on their interfacial properties at a charged surface. Although the interfaces between RTILs and mica surfaces exhibit rich microstructure, the influence of water content on such interfaces is little understood,in particular, considering the fact that RTILs are always associated with water due to their hygroscopicity. In this work, we studied how different types of RTILs and different amounts of water molecules affect the RTIL-mica interfaces, especially the water distribution at mica surfaces,using molecular dynamics(MD) simulation. MD results showed that(1) there is more water and a thicker water layer adsorbed on the mica surface as the water content increases, and correspondingly the average location of K^+ ions is farther from mica surface;(2) more water accumulated at the interface with the hydrophobic [Emim][TFSI] than in case of the hydrophilic [Emim][BF4] due to the respective RTIL hydrophobicity and ion size. A similar trend was also observed in the hydrogen bonds formed between water molecules. Moreover, the 2D number density map of adsorbed water revealed that the high-density areas of water seem to be related to K^+ ions and silicon/aluminum atoms on mica surface. These results are of great importance to understand the effects of hydrophobicity/hydrophicility of RTIL and water on the interfacial microstructure at electrified surfaces. 展开更多
关键词 Room temperature ionic liquids Hydrophobicity/hydrophicility water content Electrical double layer Mica surface
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Yangtze River Delta Aerosol liquid water in PM_(2.5)and its roles in secondary aerosol formation at a regional site of Yangtze River Delta 被引量:1
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作者 Ruifang Shi Fei Zhang +8 位作者 Yemin Shen Jiasi Shen Bingye Xu Binyu Kuang Zhengning Xu Lingling Jin Qian Tang Xudong Tian Zhibin Wang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第4期684-696,共13页
Aerosol liquid water content(ALWC)plays an important role in secondary aerosol formation.In this study,a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021.ALWC estimated by ISORR... Aerosol liquid water content(ALWC)plays an important role in secondary aerosol formation.In this study,a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021.ALWC estimated by ISORROPIA-Ⅱ was then investigated to explore its characteristics and relationship with secondary aerosols.ALWC exhibited a highest value in spring(66.38μg/m^(3)),followed by winter(45.08μg/m^(3)),summer(41.64μg/m^(3)),and autumn(35.01μg/m^(3)),respectively.It was supposed that the secondary inorganic aerosols(SIA)were facilitated under higher ALWC conditions(RH>80%),while the secondary organic species tended to form under lower ALWC levels.Higher RH(>80%)promoted the NO_(3)^(-)formation via gas-particle partitioning,while SO_(4)^(2-)was generated at a relative lower RH(>50%).The ALWC was more sensitive to NO_(3)^(-)(R=0.94)than SO_(4)^(2-)(R=0.90).Thus,the self-amplifying processes between the ALWC and SIA enhanced the particle mass growth.The sensitivity of ALWC and OX(NO_(2)+O_(3))to secondary organic carbon(SOC)varied in different seasons at Shanxi,more sensitive to aqueous-phase reactions(daytime R=0.84;nighttime R=0.54)than photochemical oxidation(daytime R=0.23;nighttime R=0.41)in wintertime with a high level of OX(daytime:130-140μg/m^(3);nighttime:100-140μg/m^(3)).The self-amplifying process of ALWC and SIA and the aqueous-phase formation of SOC will enhance aerosol formation,contributing to air pollution and reduction of visibility. 展开更多
关键词 Aerosol liquid water content NITRATE SULFATE Secondary organic compounds Aqueous-phase reaction
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长江三角洲地区高空云过程气溶胶——云相互作用的观测研究
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作者 陈怡欣 杜荣光 +9 位作者 张佃国 滕晓咪 王玥 刘磊 徐亮 王文青 谢筠 齐冰 方双喜 李卫军 《大气科学》 CSCD 北大核心 2024年第4期1283-1296,共14页
气溶胶—云相互作用过程对于评估大气云和气溶胶的寿命及气候效应至关重要。目前关于气溶胶—云相互作用的研究主要以飞机航测、卫星反演和模式模拟为主,地基直接观测由于布置难度大、实验时间长、人力物力耗费等原因开展得较少。当前... 气溶胶—云相互作用过程对于评估大气云和气溶胶的寿命及气候效应至关重要。目前关于气溶胶—云相互作用的研究主要以飞机航测、卫星反演和模式模拟为主,地基直接观测由于布置难度大、实验时间长、人力物力耗费等原因开展得较少。当前针对气溶胶—云相互作用机制的理解还比较低,亟需外场观测资料深入认识其过程。本研究以长江三角洲地区高山站点的云雾为背景,利用雾滴谱仪、地用逆流虚拟撞击器、混合凝聚核粒子计数器、扫描电迁移率颗粒物粒径谱仪等仪器,研究了大明山顶(海拔1483 m)7月份多云雾期间云滴和气溶胶的特性,探讨了气溶胶对云形成和发展的影响以及云对气溶胶颗粒物的清除作用。云形成初期对气溶胶颗粒物的清除率约为20%~50%。研究显示水汽过饱和度越高且颗粒物粒径越大,清除率越高,这表明粒径较大的吸湿性颗粒物容易活化为云凝结核。对比同一云雾事件中气溶胶数浓度差异较大的三个阶段,我们发现较低的气溶胶数浓度有利于形成液态水含量高的浓云,此时云团由数量相对较少而粒径大的云滴组成,而大气颗粒物数量增多会使云雾变淡,此时的云团由大量细小的云滴组成。本研究分析了8μm以上云滴的云凝结核数量分布特征,发现大云滴的云凝结核几乎都是100 nm以上的颗粒物;随着气溶胶数浓度升高,8μm以上大云滴的数量减少,且大云滴云凝结核的平均直径变大。这些结果显示气溶胶数浓度升高会促使云滴的数量增多而等效直径变小,在水汽有限的自然环境中,气溶胶数浓度越高,颗粒物的临界活化直径越大。总之,我们发现大气气溶胶的数浓度—粒径分布特性影响着云滴的数量和粒径,云的形成和发展也对气溶胶颗粒物有较强的清除作用。 展开更多
关键词 气溶胶 外场观测 云清除作用 粒径分布 液态水含量
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生物炭施用对冻结期退化黑土水热盐动态变化的影响
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作者 魏志淼 张少良 +4 位作者 闫思华 闫鹏科 冯兰茜 肖梓良 刘志华 《水土保持学报》 CSCD 北大核心 2024年第4期322-334,共13页
[目的]生物炭施用可改变土壤理化性状,研究不同生物炭施用方式对土壤水、热及电导率(EC)分布的影响,可为季节性冻土科学管理提供依据。[方法]利用田间定位试验,通过长期观测,研究东北黑土区不同生物炭施用方式对冻结期的土壤液态水含量... [目的]生物炭施用可改变土壤理化性状,研究不同生物炭施用方式对土壤水、热及电导率(EC)分布的影响,可为季节性冻土科学管理提供依据。[方法]利用田间定位试验,通过长期观测,研究东北黑土区不同生物炭施用方式对冻结期的土壤液态水含量、温度及EC的影响差异。生物炭施用方式包括一次性生物炭混施40 t/hm^(2)(HO)、生物炭底施40 t/hm^(2)(HE),空白为0 t/hm^(2)(CK)。[结果]2种生物炭施用方式均增加冻结期土壤平均液态水含量(p<0.05),表现为HO>HE>CK;整个试验周期内生物炭施用均显著增加土壤EC,且HO和HE处理土壤平均EC分别比CK增加17.73%,6.89%;2种生物炭施用方式对土壤温度影响不同,与CK相比,HE处理土壤平均温度提高0.32℃,而HO处理土壤平均温度降低0.46℃。此外,HE处理相较于HO和CK处理减弱冻结期土壤液态水、温度及EC的变化幅度。[结论]生物炭混施和底施均有利于提高冻结期退化黑土液态水含量和EC,特别是生物炭底施还有利于提升冻结期耕层土壤温度,而生物炭混施在同时期还有利于减缓土壤冻结作用,2种生物炭施用方式均可能对冻结期土壤水盐运移和物质转化过程有重要影响,甚至对春季作物出苗和早期生长产生重要影响。 展开更多
关键词 生物炭 冻结期 退化黑土 土壤液态水含量 土壤温度 EC
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Aircraft Observations of Liquid and Ice in Midlatitude Mixed-Phase Clouds 被引量:5
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作者 ZHAO Zhen LEI Hengchi 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2014年第3期604-610,共7页
ABSTRACT This paper reports airborne measurements of midlatitude altostratus clouds observed over Zhengzhou, Henan Province, China on 3 March 2007. The case demonstrates mixed-phase conditions at altitudes from 3200 ... ABSTRACT This paper reports airborne measurements of midlatitude altostratus clouds observed over Zhengzhou, Henan Province, China on 3 March 2007. The case demonstrates mixed-phase conditions at altitudes from 3200 to 4600 m (0°C to -7.6°C), with liquid water content ranging from 0.01 to 0.09 g m-3. In the observed mixed-phase cloud, liquid water content exhibited a bimodal distribution, whereas the maximum ice particle concentration was located in the middle part of the cloud. The liquid and ice particle data showed significant horizontal variability on the scale of a few hundred meters. The cloud droplet concentration varied greatly over the horizontal sampling area. There was an inverse relationship between the cloud droplet concentration and ice particle concentration. A gamma distribution provided the best description of the cloud droplet spectra. The liquid droplet distributions were found to increase in both size and concentration with altitude. It was inferred from the profile of the spectra parameters that the cloud droplet sizes tend to form a quasi-monodisperse distribution. Ice particle spectra in the cloud were fitted well by an exponential distribution. Finally, a remarkable power law relationship was found between the slope (λ) and intercept (No) parameters of the exponential size distribution. 展开更多
关键词 cloud structure liquid water content droplet spectra particle measuring systems
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真空作用下高含水率疏浚泥颗粒迁移规律试验研究 被引量:1
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作者 曾玲玲 王其忠 林晓鑫 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第8期1776-1782,共7页
研制了高含水率疏浚泥真空固结模型装置,针对两种具有不同液限的疏浚泥,开展不同初始状态下的真空固结试验,探究真空作用下疏浚泥初始状态对细颗粒迁移性状的影响规律。研究结果表明,引入初始含水率与液限比值作为无量纲化的初始状态指... 研制了高含水率疏浚泥真空固结模型装置,针对两种具有不同液限的疏浚泥,开展不同初始状态下的真空固结试验,探究真空作用下疏浚泥初始状态对细颗粒迁移性状的影响规律。研究结果表明,引入初始含水率与液限比值作为无量纲化的初始状态指标,能够作为确定细颗粒迁移与否的一个临界阈值。当初始含水率与液限比值不大于临界阈值,真空作用下高含水率疏浚泥没有发生颗粒迁移;当初始含水率与液限比值大于临界阈值,真空作用下高含水率疏浚泥发生颗粒迁移,黏粒向排水面附近聚集。一旦发生颗粒迁移,黏粒向排水面附近富集的程度随着初始含水率与液限比值的增大而愈发显著。 展开更多
关键词 疏浚泥 真空预压 颗粒迁移 液限 初始含水率
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考虑水盐相变的盐渍土基质吸力的温度效应
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作者 肖泽岸 段杰云 +2 位作者 李康良 王启航 郭茂亮 《农业工程学报》 EI CAS CSCD 北大核心 2024年第15期287-292,共6页
基质吸力是引起土体中水分迁移的驱动力,对探究土体中水盐迁移动态具有重要的意义。为研究由温度变化诱发的盐渍土孔隙溶液相变对土体基质吸力的影响,用pF meter测试了不同NaCl和Na_(2)SO_(4)比例的盐渍土在不同温度条件下的基质吸力。... 基质吸力是引起土体中水分迁移的驱动力,对探究土体中水盐迁移动态具有重要的意义。为研究由温度变化诱发的盐渍土孔隙溶液相变对土体基质吸力的影响,用pF meter测试了不同NaCl和Na_(2)SO_(4)比例的盐渍土在不同温度条件下的基质吸力。试验结果表明:在水盐相变发生前,盐渍土基质吸力随温度的降低呈线性增加;而当降温过程中有水盐相变发生时,土体基质吸力随温度的变化趋势会发生明显突变。NaCl和Na_(2)SO_(4)对土体水盐相变规律影响不同,使得含不同比例NaCl和Na_(2)SO_(4)的复合盐渍土基质吸力呈现较大的区别。2%NaCl+4%Na_(2)SO_(4)的盐渍土在19和-9℃附近发生盐结晶相变和二次相变,而4%NaCl+2%Na_(2)SO_(4)的盐渍土两次相变分别发生在11和-16℃附近。水盐相变导致土体液态含水率明显降低,进而引起复合盐渍土基质吸力在两个相变阶段均有明显增加。NaCl抑制土体中液态水发生冰水相变,Na_(2)SO_(4)容易在正温结晶,故Na_(2)SO_(4)主要影响土体正温时的盐结晶规律,NaCl则主要影响土体在负温条件下的冰晶产生规律;二者比例不同造成土体盐结晶温度和二次相变温度有明显差异,使得复合盐渍土的水盐相变规律更加复杂,其基质吸力随温度的变化更加难以预测。此外,该研究进一步探究了冰、盐结晶量对基质吸力变化的贡献,为深入理解盐渍土的相变过程和基质吸力之间的关系提供了有效参考。 展开更多
关键词 盐渍土 基质吸力 水盐相变 液态含水率 温度效应
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结冰气象探测飞行及数据符合性分析方法研究
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作者 丁军亮 《航空工程进展》 CSCD 2024年第4期152-161,共10页
结冰气象捕获、最优气象条件选取准则、符合性数据处理方法等一直是飞机自然结冰试飞过程中亟待攻克的难题。通过分析CCAR25部附录C结冰气象标准的形成背景及其局限性,提出一种利用结冰试验研究机开展结冰探测的飞行方法,该方法包括试... 结冰气象捕获、最优气象条件选取准则、符合性数据处理方法等一直是飞机自然结冰试飞过程中亟待攻克的难题。通过分析CCAR25部附录C结冰气象标准的形成背景及其局限性,提出一种利用结冰试验研究机开展结冰探测的飞行方法,该方法包括试验研究机的选型、改装、探测目标区域确定、飞行操作策略、飞行安全管理、数据处理等。依据对探测数据的统计分析,确定民用运输机自然结冰试飞的气象条件选取准则,规范云隙、液态水含量、总水收集率、积冰速率、积冰厚度和冰脱落程度等一系列结冰气象的数据处理方法和符合性判据,校验国内结冰气象预测算法,探索自然结冰试飞的安全管控策略和风险降解措施。大量飞行实测表明:该方法通用性强,效果显著,已经成功应用于C919大型客机合格取证试飞工作,并有力支撑了国内结冰适航标准自主。 展开更多
关键词 自然结冰 飞行试验 结冰气象探测 液态水含量 中值水滴直径
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基于地基微波辐射计的羊卓雍错地区云水特征分析
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作者 唐利琴 刘俊卿 +3 位作者 豆永丽 央金卓玛 益西卓玛 德吉白玛 《科技创新与应用》 2024年第33期87-90,共4页
基于2020年1—10月西藏浪卡子气象站地基微波辐射计观测的水汽总量和路径液水含量数据,该文分析西藏羊卓雍错地区大气云水特征并探讨其在人工影响天气中的应用。结果表明,羊卓雍错地区大气水汽总量和路径液水含量呈单峰分布,峰值出现在7... 基于2020年1—10月西藏浪卡子气象站地基微波辐射计观测的水汽总量和路径液水含量数据,该文分析西藏羊卓雍错地区大气云水特征并探讨其在人工影响天气中的应用。结果表明,羊卓雍错地区大气水汽总量和路径液水含量呈单峰分布,峰值出现在7月,年均值分别为7.88 mm和0.53 mm;5—9月羊卓雍错地区大气水汽总量平均值大于11 mm,降水日和非降水日的差值不大,表明雨季大气水汽总量充沛且稳定;干季,羊卓雍错地区大气水汽总量的日变化表现为白天高夜间低,而雨季则表现为中午低傍晚高;降水开始前1个小时大气水汽总量、路径液水含量存在突增现象,可作为降水预报的参考量之一。 展开更多
关键词 羊卓雍错地区 微波辐射计 大气水汽总量 路径液水含量 峰值
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Magnitude and Trends of High-elevation Cloud Water Pollutant Concentrations and Modeled Deposition Fluxes
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作者 Selma Isil Thomas Lavery +2 位作者 Kristi Gebhart Christopher Rogers Carol Armbrust Wanta 《Journal of Environmental Science and Engineering(B)》 2017年第3期127-143,共17页
Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 th... Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 through 2011. This paper presents results from 2000 through the conclusion of the study in 2011. Samples were analyzed for SO42", NO3, NH4+ and H+. These measurements were supplemented by measurements of ambient air and precipitation concentrations to estimate dry and wet deposition. Cloud water concentrations, LWC, cloud frequency, various meteorological measurements and information on nearby forest canopy were used to model cloud water deposition to gauge trends in deposition. Total deposition was calculated as the sum of cloud, dry and wet deposition estimates. Concentrations and deposition fluxes declined over the study period. The decreases in cloud water SO42" and NO3 concentrations were 40 percent and 26 percent, respectively. Three-year mean 5042 and NO3 deposition rates decreased by 71 percent and 70 percent, respectively. Trends in concentrations and depositions were comparable with trends in SO2 and NOx emissions from Tennessee Valley Authority power plants and aggregated emission reductions from electric generating units in adjacent states. Back trajectories were simulated with the HYSPLIT model and aggregated over cloud sampling periods from 2000 through 2007 and 2009 through 2011. Trajectories during periods with high H+ concentrations traveled over local EGU (Electric Generating Unit) emission sources in Tennessee and Kentucky to the Ohio River Valley, Alabama and Georgia with the conclusion that these source regions contributed to acidic cloud water deposition at Clingmans Dome. This work was supported by U.S. Environmental Protection Agency and the Tennessee Valley Authority with infrastructure support provided by the National Park Service. 展开更多
关键词 Cloud water acid deposition liquid water content EMISSIONS back trajectory high elevation.
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泵叶片结冰后的特性数值模拟研究
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作者 马飞 张永昇 《区域供热》 2024年第5期106-111,共6页
通过数值模拟探讨了电厂工作环境中泵叶片结冰对其特性的影响。考察了不同来流温度和液态水含量(LWC)下的结冰特性和传热系数(HTC)的变化规律。结果表明,随着来流温度的降低,泵叶片表面逐渐出现结冰现象,导致传热系数增加。同时,增加LW... 通过数值模拟探讨了电厂工作环境中泵叶片结冰对其特性的影响。考察了不同来流温度和液态水含量(LWC)下的结冰特性和传热系数(HTC)的变化规律。结果表明,随着来流温度的降低,泵叶片表面逐渐出现结冰现象,导致传热系数增加。同时,增加LWC显著提高了结冰区域的传热系数,表现为局部热传递的尖锐峰值。结合来流温度和LWC的影响,揭示了在寒冷高湿环境下结冰的复杂特性。研究结果为深入理解泵叶片结冰机理和设计防冰系统提供了重要参考。 展开更多
关键词 泵叶片 结冰特性 传热系数 液态水含量 来流温度
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二氧化碳吞吐采出液处理用破乳剂的研究与应用
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作者 王丽娟 王丽伟 +1 位作者 韩志峰 赵永刚 《化工管理》 2024年第7期136-139,共4页
二氧化碳吞吐作为增产的一种重要措施,在油田得到越来越广泛的应用。但是随之而来的是采出液中因含有二氧化碳而导致的污水发黑、含油高的问题,给集输系统油水处理带来较大的困难。文章根据油水分离的原理,对破乳剂的配方进行了优化,在... 二氧化碳吞吐作为增产的一种重要措施,在油田得到越来越广泛的应用。但是随之而来的是采出液中因含有二氧化碳而导致的污水发黑、含油高的问题,给集输系统油水处理带来较大的困难。文章根据油水分离的原理,对破乳剂的配方进行了优化,在破乳剂中引入了具有清水作用的成分。室内试验表明,极大降低了脱出污水含油,投入现场应用后,现场破乳剂的用量从原来的300 mg/L降至160 mg/L,水含油由原来的200 mg/L降至140 mg/L,现场运行稳定。后期还将继续降低药剂用量,该项工作每年可为NP2-3节省破乳剂费用47%,同时为油田含二氧化碳污水的处理提供了借鉴。 展开更多
关键词 二氧化碳吞吐 采出液 破乳剂 水含油
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华东一次极端冰雹天气过程雷达回波特征的比较分析 被引量:6
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作者 汤兴芝 俞小鼎 +1 位作者 姚瑶 王金兰 《高原气象》 CSCD 北大核心 2023年第4期1078-1092,共15页
2005年6月14日到15日凌晨,受东北冷涡影响,华东出现了一次历史上罕见的冰雹天气过程,最大冰雹直径达15~18 cm,并伴有雷暴大风和龙卷。本文利用2005年6月14日08:00(北京时,下同)至15日08:00新一代多普勒天气雷达资料,统计分析了这次过程... 2005年6月14日到15日凌晨,受东北冷涡影响,华东出现了一次历史上罕见的冰雹天气过程,最大冰雹直径达15~18 cm,并伴有雷暴大风和龙卷。本文利用2005年6月14日08:00(北京时,下同)至15日08:00新一代多普勒天气雷达资料,统计分析了这次过程中江苏沭阳、江苏泗阳、安徽固镇三地极端冰雹的雷达回波特征,结果如下:(1)极端冰雹过程是由不同超级单体造成,由于环境CAPE、深层垂直风切变和低层相对风暴螺旋度都很强,导致三个超级单体都具有强中气旋,而强中气旋与环境相互作用导致向上的扰动气压梯度力,使得超级单体上升气流大大增强并强烈发展。(2)三地超级单体雹暴回波最大反射率因子超过70 dBZ,60 dBZ以上强回波持续时间超过3 h,60 dBZ最大高度超过11 km。比较而言,沭阳超级单体持续时间最长,泗阳超级单体回波强度最大,固镇超级单体雹暴60 dBZ以上的反射率因子垂直扩展高度最高。从上述雹暴例子初步得到线索:当最大反射率因子超过68 dBZ、60 dBZ回波扩展高度在10 km以上预示有极端冰雹出现。(3)有界弱回波区(BWER)或弱回波区(WER)以及位于其上的回波悬垂是超级单体雹暴的典型结构。泗阳雹暴显示有WER和宽广的回波悬垂,沭阳和固镇雹暴则显示出BWER和宽广的回波悬垂,固镇雹暴中气旋切变值的持续上升伴随着雹暴的强盛发展。(4)三个超级单体雹暴的垂直液态水含量(VIL)异常高,分别为88 kg·m^(-2)、102 kg·m^(-2)、89 kg·m^(-2),远超过6月大冰雹的VIL阈值65 kg·m^(-2)。固镇雹暴显示出强烈的风暴顶辐散特征,辐散速度差值最高达80 m·s^(-1)。(5)固镇雹暴出现近1 h的三体散射长钉(TBSS),沭阳、固镇雹暴出现旁瓣回波,都表明雹暴中存在大冰雹。 展开更多
关键词 极端冰雹 超级单体 高悬强回波 垂直液态水含量 三体散射 风暴顶辐散
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基于Ka波段云雷达观测的中国西天山降雨云宏微观物理特征研究 被引量:2
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作者 张晋茹 杨莲梅 +2 位作者 刘凡 李建刚 周玉淑 《大气科学》 CSCD 北大核心 2023年第3期756-768,共13页
利用Ka毫米波云雷达与自动气象站降雨资料,研究了西天山地区2019年和2020年5~8月的降雨云宏微观特性。结果表明:(1)降雨主要发生在夜间,累积降雨量集中在21:00(北京时间,下同)至次日07:00,降雨频次和累积降雨量相关系数为0.71。大雨强... 利用Ka毫米波云雷达与自动气象站降雨资料,研究了西天山地区2019年和2020年5~8月的降雨云宏微观特性。结果表明:(1)降雨主要发生在夜间,累积降雨量集中在21:00(北京时间,下同)至次日07:00,降雨频次和累积降雨量相关系数为0.71。大雨强频次虽最少,但对总累积降雨量贡献较显著。(2)小雨强、中雨强、大雨强平均反射率因子最大值分别为30 dBZ、35.8 dBZ和39.5 dBZ,最大平均液态水含量分别为1.5 g m^(-3)、4.2 g m^(-3)和7.3 g m^(-3)。(3)不同降雨强度对应的反射率因子都有两个集中区域,2.0~4.4 km反射率因子集中在15~26 dBZ,地面附近的小雨强、中雨强、大雨强对应的反射率因子分别集中在24~32 dBZ、29~38 dBZ和31~42 dBZ。1.75 km以下中雨强和大雨强液态含水量小于1gm^(-3)的频率明显少于小雨强,降雨强度的越大降雨粒子径向速度越集中。 展开更多
关键词 西天山地区 毫米波云雷达 降雨云 反射率因子 液态水含量
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