Rainfall Enhancement and Fog Dissipation Experiments in Wuling Mountain in 2020 Using Artificial Strong Sound Wave
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摘要: 为了研究人工低频强声波增雨和消雾作业手段的效果, 使用最大声压级为155 dB的电声低频强声波装置原型机, 于2020年8—9月在河北省雾灵山开展增雨和消雾外场作业观测试验。具有明显消雾效果的两个典型个例显示:作业开始后2~3 min内尺度小于10 μm的雾滴减少, 尺度大于10 μm的雾滴增多;随后大部分尺度的雾滴明显减少, 10 min内能见度可从小于100 m回升至最高1000 m。在风速、风向与消雾效果的关系方面, 消雾效果明显的个例均发生在平均风速小于1.5 m·s-1且风向可使雾能够途经声波装置影响范围近侧的条件下, 而平均风速大于2 m·s-1的个例能见度几乎未出现趋势性变化。在一次地面平均风速为1.4 m·s-1的对流云增雨作业中观测到符合试验预期的结果, 开始作业后的3 min内地面雨强从0.3 mm·h-1迅速增至7 mm·h-1以上, 并观测到出现迅速但维持时间较短的大雨滴。其他增雨个例在作业时段的平均风速均超过3 m·s-1, 可能受风速偏大和观测点单一的影响, 未能观测到明确且一致的增雨证据。Abstract: Low-frequency sound wave is a new type of operational approach that has the potential for enhancing rainfall and dissipating fog. To investigate the impact of this type of equipment, field operations and observational experiments are conducted in Wuling Mountain from August to September 2020. Wuling Mountain is located at Chengde of Hebei outside the northeastern boundary of Beijing. The main peak of the Yanshan Mountains is renowned for its foggy summers with an altitude of 2118 m. In the experiment, a prototype of an electronic acoustic low-frequency strong sound wave device is used. This device has a maximum sound pressure level of 155 dB. Meanwhile, observation instruments such as a disdrometer, visibility meter, fog droplet spectrometer, and automatic weather station with an ultrasonic anemometer are deployed. These instruments are used to obtain the background conditions and to monitor macro and micro changes during rainfall enhancement and fog dissipation operations for evaluating the effectiveness.In two typical cases with an obvious defogging effect, within 2 to 3 minutes after the start of the operation, the number of droplets smaller than 10 μm decreased, while the number of droplets larger than 10 μm increased. Subsequently, the size of the droplets on most scales decreased significantly, resulting in improved visibility. Within a span of 10 minutes, visibility could increase from less than 100 m to a maximum of 1000 m. The relationship between wind speed, wind direction, and the dissipation effect of fog shows that cases with a noticeable defogging effect occur when the average wind speed is less than 1.5 m·s-1 and the wind direction causes the fog to pass through the near side of the influence range of the sound wave device, while cases with an average wind speed greater than 2 m·s-1 hardly show any change in visibility trends. Results, which align with the experimental expectations, are observed during an operation on a convective cloud precipitation when the surface mean wind speed is 1.4 m·s-1. In this case, the rainfall intensity increases rapidly from 0.3 mm·h-1 to more than 7 mm·h-1 within 3 min of operation, and large raindrops with rapid occurrence but short duration are observed. In other rainfall enhancement experimental cases, the average wind speed exceeded 3 m·s-1 during the operation period, and no clear and consistent evidence of increased rainfall is observed, which may be affected by the high wind speeds and only one single observation point.
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图 1 雾灵山顶临时试验场的位置
(方框,填色为海拔高度) (a)与仪器分布(A为架设在地面平台上的人工强声波装置,B为架设在屋顶的激光雨滴谱仪和自动气象站,C为雾滴谱仪和能见度仪观测点;蓝色箭头为消雾试验时云雾从南坡爬上山顶的方向示意,红色箭头为低频强声波装置消雾发射时的声波朝向) (b)
Fig. 1 Location of temporary experiment site on the top of Wuling Mountain
(the box, the shaded denotes altitude) (a) and placement of observation instruments (A denotes the placement of artificial strong sound wave device on the ground platform, B denotes the placement of laser disdrometer and automatic weather station on the roof, C denotes the placement of fog droplet spectrometer and visibility meter; the blue arrow denotes the fog moving direction, the red arrow denotes the direction of artificial sound wave for fog dissipation) (b)
图 1 雾灵山顶临时试验场的位置
(方框,填色为海拔高度) (a)与仪器分布(A为架设在地面平台上的人工强声波装置,B为架设在屋顶的激光雨滴谱仪和自动气象站,C为雾滴谱仪和能见度仪观测点;蓝色箭头为消雾试验时云雾从南坡爬上山顶的方向示意,红色箭头为低频强声波装置消雾发射时的声波朝向) (b)
Fig. 1 Location of temporary experiment site on the top of Wuling Mountain
(the box, the shaded denotes altitude) (a) and placement of observation instruments (A denotes the placement of artificial strong sound wave device on the ground platform, B denotes the placement of laser disdrometer and automatic weather station on the roof, C denotes the placement of fog droplet spectrometer and visibility meter; the blue arrow denotes the fog moving direction, the red arrow denotes the direction of artificial sound wave for fog dissipation) (b)
表 1 2020年增雨试验的风速和云信息
Table 1 Information of wind and cloud during rainfall enhancement experiments in 2020
试验时段 开机次数 平均风速/(m·s-1) 云类型 09-07T15:38—16:00 4 1.4 对流云 09-10T06:54—07:20 3 3.1 层状云 09-10T08:46—10:11 9 3.3 层状云 09-11T11:23—12:03 3 3.0 层状云 09-11T16:53—17:33 3 3.6 层状云 表 1 2020年增雨试验的风速和云信息
Table 1 Information of wind and cloud during rainfall enhancement experiments in 2020
试验时段 开机次数 平均风速/(m·s-1) 云类型 09-07T15:38—16:00 4 1.4 对流云 09-10T06:54—07:20 3 3.1 层状云 09-10T08:46—10:11 9 3.3 层状云 09-11T11:23—12:03 3 3.0 层状云 09-11T16:53—17:33 3 3.6 层状云 -
[1] 肖辉, 舒未希, 付丹红, 等.声波对气溶胶和云雾粒子聚并影响研究进展.应用气象学报, 2021, 32(3):257-271. doi: 10.11898/1001-7313.20210301Xiao H, Shu W X, Fu D H, et al. A review on the effect of sound waves upon the coalescence of aerosol and cloud and fog particles. J Appl Meteor Sci, 2021, 32(3): 257-271. doi: 10.11898/1001-7313.20210301 [2] Mednikov E P, Larrick C V. Acoustic Coagulation and Precipitation of Aerosols. New York: Consultants Bureau, 1965: 1-180. [3] 吴学利. 悬浮细颗粒声波团聚的理论与实验研究. 长沙: 国防科学技术大学研究生院, 2014.Wu X L. The Theoretical and Experimental Study on Acoustic Agglomerattion of Fine Particles. Changsha: Graduate School of National University of Defense Technology, 2014. [4] Dianov D B, Podolskii A A, Turubarov V I. Calculation of the hydrodynamic interaction of aerosol particles in a sound field under Oseen flow conditions. Sov Phys Acoust, 1968, 13(3): 314-319. [5] Zhou D, Luo Z Y, Fang M X, et al. Numerical calculation of particle movement in sound wave fields and experimental verification through high-speed photography. Appl Energy, 2017, 185: 2245-2250. doi: 10.1016/j.apenergy.2016.02.006 [6] 许焕斌. 中国的防雹实践和理论提炼. 北京: 气象出版社, 2021.Xu H B. Practice and Theory Hail Suppression in China. Beijing: China Meteorological Press, 2021. [7] Volk M, Moroz W J. Sonic agglomeration of aerosol particles. Water Air Soil Pollut, 1976, 5(3): 319-334. doi: 10.1007/BF00158347 [8] Rajendran N, Wegrzyn J, Cheng M T, et al. Acoustic precipitation of aerosol under standing-wave condition. J Aerosol Sci, 1979, 10(3): 329-338. doi: 10.1016/0021-8502(79)90048-X [9] Chou K H, Lee P S, Wegrzyn J, et al. Aerosol deposition in acoustically induced turbulent flow. Atmos Environ, 1967, 1982, 16(6): 1513-1522. [10] Tiwary R, Reethof G. Hydrodynamic interaction of spherical aerosol particles in a high intensity acoustic field. J Sound Vib, 1986, 108(1): 33-49. doi: 10.1016/S0022-460X(86)80309-1 [11] Hoffmann T L, Koopmann G H. Visualization of acoustic particle interaction and agglomeration: Theory evaluation. J Acoust Soc Am, 1997, 101(6): 3421-3429. doi: 10.1121/1.418352 [12] Riera-Franco de Sarabia E, Gallego-Juárez J A, Acosta-Aparicio V M, et al. Acoustic agglomeration of submicron particles in diesel exhausts: First results of the influence of humidity at two acoustic frequencies. J Aerosol Sci, 2000, 31: 827-828. doi: 10.1016/S0021-8502(00)90837-1 [13] Liu J Z, Zhang G X, Zhou J H, et al. Experimental study of acoustic agglomeration of coal-fired fly ash particles at low frequencies. Powder Technol, 2009, 193(1): 20-25. doi: 10.1016/j.powtec.2009.02.002 [14] Hoffmann T L, Koopmann G H. A new technique for visualization of acoustic particle agglomeration. Rev Sci Instrum, 1994, 65(5): 1527-1536. doi: 10.1063/1.1144887 [15] Hoffmann T L. An extended kernel for acoustic agglomeration simulation based on the acoustic wake effect. J Aerosol Sci, 1997, 28(6): 919-936. doi: 10.1016/S0021-8502(96)00489-2 [16] González I, Hoffmann T L, Gallego-Juárez J A. Theory and calculation of sound induced particle interactions of viscous origin. Acustica, 2000, 86(5): 784-797. [17] González I, Elvira L, Hoffmann T L, et al. Numerical study of the hydrodynamic interaction between aerosol particles due to the acoustic wake effect. Acta Acust U Acust, 2001, 87(4): 454-460. [18] Zhang G X, Zhang L L, Wang J Q, et al. A new model for the acoustic wake effect in aerosol acoustic agglomeration processes. Appl Math Model, 2018, 61: 124-140. doi: 10.1016/j.apm.2018.03.027 [19] Zhang G X, Wang J Q, Chi Z H, et al. Acoustic agglomeration with addition of sprayed liquid droplets: Three-dimensional discrete element modeling and experimental verification. Chem Eng Sci, 2018, 187: 342-353. doi: 10.1016/j.ces.2018.05.012 [20] Zhang G X, Zhang L L, Wang J Q, et al. A new multiple-time-step three-dimensional discrete element modeling of aerosol acoustic agglomeration. Powder Technol, 2018, 323: 393-402. doi: 10.1016/j.powtec.2017.10.036 [21] Zhang G X, Ma Z F, Shen J, et al. Experimental study on eliminating fire smokes using acoustic agglomeration technology. J Hazard Mater, 2020, 382: 121089. doi: 10.1016/j.jhazmat.2019.121089 [22] 魏荣爵, 章肖融, 王耀俊. 气悬微粒在声场中所受的作用力对凝聚的贡献. 南京大学学报(自然科学版), 1964, 8(2): 249-265.Wei R J, Zhang X R, Wang Y J. Aerosol agglomeration due to forces in sound field. J Nanjing Univ(Nat Sci Ed), 1964, 8(2): 249-265. [23] 章肖融, 干昌明, 魏荣爵. 声波对水雾消散作用的初步实验研究. 南京大学学报(自然科学版), 1963, 7(5): 21-28.Zhang X R, Gan C M, Wei R J. Sonic dissipation of water fog-A preliminary experimental study. J Nanjing Univ(Nat Sci Ed), 1963, 7(5): 21-28. [24] 顾震潮. 云雾降水物理基础. 北京: 科学出版社, 1980.Gu Z C. Physical Basis of Cloud Precipitation. Beijing: Science Press, 1980. [25] 侯双全, 吴嘉, 席葆树. 低频声波对水雾消散作用的实验研究. 流体力学实验与测量, 2002, 16(4): 52-56. doi: 10.3969/j.issn.1672-9897.2002.04.010Hou S Q, Wu J, Xi B S. Experiments on acoustic dissipation of water fog at low frequency. Exp Meas Fluid Mech, 2002, 16(4): 52-56. doi: 10.3969/j.issn.1672-9897.2002.04.010 [26] Shi Y, Wei J H, Li Q, et al. Investigation of vertical microphysical characteristics of precipitation under the action of low-frequency acoustic waves. Atmos Res, 2021, 249: 105283. doi: 10.1016/j.atmosres.2020.105283 [27] 王庆, 李季, 樊明月, 等. 济南一次平流辐射雾的微物理结构及演变特征. 气象, 2019, 45(9): 1299-1309.Wang Q, Li J, Fan M Y, et al. Microphysical structure and evolution characteristics of an advection-radiation fog event in Jinan. Meteor Mon, 2019, 45(9): 1299-1309. [28] 王俊, 王文青, 王洪, 等. 山东北部一次夏末雹暴地面降水粒子谱特征. 应用气象学报, 2021, 32(3): 370-384. doi: 10.11898/1001-7313.20210309Wang J, Wang W Q, Wang H, et al. Hydrometeor particle characteristics during a late summer hailstorm in northern Shandong. J Appl Meteor Sci, 2021, 32(3): 370-384. doi: 10.11898/1001-7313.20210309 [29] 黄泽文, 彭思越, 张浩然, 等. 福建安溪雨滴谱特征. 应用气象学报, 2022, 33(2): 205-217. doi: 10.11898/1001-7313.20220207Huang Z W, Peng S Y, Zhang H R, et al. Characteristics of raindrop size distribution at Anxi of Fujian. J Appl Meteor Sci, 2022, 33(2): 205-217. doi: 10.11898/1001-7313.20220207 [30] 胡淑萍, 林文, 林长城, 等. 2014—2022年古田人工增雨随机试验物理检验. 应用气象学报, 2023, 34(6): 706-716. doi: 10.11898/1001-7313.20230606Hu S P, Lin W, Lin C C, et al. Physical inspection of randomized trial for the artificial rain enhancement experiment at Gutian from 2014 to 2022. J Appl Meteor Sci, 2023, 34(6): 706-716. doi: 10.11898/1001-7313.20230606 [31] 葛黎黎, 吕国真, 赵桂香, 等. 太原地区雨滴谱季节分布特征. 应用气象学报, 2023, 34(4): 489-502. doi: 10.11898/1001-7313.20230409Ge L L, Lü G Z, Zhao G X, et al. Seasonal distribution characteristics of raindrop spectrum in Taiyuan. J Appl Meteor Sci, 2023, 34(4): 489-502. doi: 10.11898/1001-7313.20230409 [32] 孙钦宏, 马洪波, 齐彦斌, 等. 2021年夏季长白山麓雨滴谱分布特征. 应用气象学报, 2023, 34(3): 336-347. doi: 10.11898/1001-7313.20230307Sun Q H, Ma H B, Qi Y B, et al. Distribution characteristics of raindrop spectrum at Changbai Mountain foothills in summer of 2021. J Appl Meteor Sci, 2023, 34(3): 336-347. doi: 10.11898/1001-7313.20230307 [33] 王俊, 郑丽娜, 王洪, 等. 山东6次台风暴雨雨滴谱统计特征及区域差异. 应用气象学报, 2023, 34(4): 475-488. doi: 10.11898/1001-7313.20230408Wang J, Zheng L N, Wang H, et al. Statistical characteristics and regional differences of raindrop size distribution during 6 typhoon rainstorms in Shandong. J Appl Meteor Sci, 2023, 34(4): 475-488. doi: 10.11898/1001-7313.20230408 [34] Luo L, Xiao H, Yang H L, et al. Raindrop size distribution and microphysical characteristics of a great rainstorm in 2016 in Beijing, China. Atmos Res, 2020, 239: 104895. doi: 10.1016/j.atmosres.2020.104895 [35] 王俊, 姚展予, 侯淑梅, 等. 山东夏季两次极端雨强暴雨的滴谱特征研究. 大气科学, 2023, 47(2): 311-326.Wang J, Yao Z Y, Hou S M, et al. The characteristics of raindrop size distribution in two rainstorms with extreme rainfall rates in summer in Shandong Province. Chinese J Atmos Sci, 2023, 47(2): 311-326. [36] Ding J F, Tian W S, Xiao H, et al. Raindrop size distribution and microphysical features of the extremely severe rainstorm on 20 July 2021 in Zhengzhou, China. Atmos Res, 2023, 289: 106739. [37] 宋灿, 周毓荃, 吴志会. 雨滴谱垂直演变特征的微雨雷达观测研究. 应用气象学报, 2019, 30(4): 479-490. doi: 10.11898/1001-7313.20190408Song C, Zhou Y Q, Wu Z H. Vertical profiles of raindrop size distribution observed by micro rain radar. J Appl Meteor Sci, 2019, 30(4): 479-490. doi: 10.11898/1001-7313.20190408 [38] 常祎, 郭学良, 唐洁, 等. 青藏高原夏季对流云微物理特征和降水形成机制. 应用气象学报, 2021, 32(6): 720-734. doi: 10.11898/1001-7313.20210607Chang Y, Guo X L, Tang J, et al. Microphysical characteristics and precipitation formation mechanisms of convective clouds over the Tibetan Plateau in summer. J Appl Meteor Sci, 2021, 32(6): 720-734. doi: 10.11898/1001-7313.20210607