ANALYSIS ON MICROPHYSICAL AND CHEMICAL CHARACTERISTICS OF A SEA FOG ON THE SEA SURFACE IN THE NORTHWESTERN SOUTH CHINA SEA
-
摘要: 利用2017年3月MICAPS资料、欧洲气象中心再分析ERA-Interim数据及在南海西北部海上的海雾观测数据,分析了南海西北部一次海上海雾的微物理特征和雾水化学特性,并将海上海雾与南海岸边海雾进行对比分析。结果表明:此次海雾为南海偏南暖气流移至冷海面发生冷却并达到饱和而形成。海雾过程中气压与气温变化趋势相反,相对湿度不断增加,雾滴数浓度、液态含水量和平均直径的平均值分别为198 cm-3、0.116 g/cm3和5.6 μm。相比广东湛江东海岛和广东茂名博贺地区岸边海雾个例,本次海上海雾水汽充足,雾滴偏大。本次海雾属于酸性海雾,pH值变化范围为2.51~3.50,海雾后的雨水样本pH值则为4.05。海雾发生初期电导率比其它阶段高很多,说明海雾发生的初始阶段雾水溶解了大量的气溶胶。海上雾水中Na+和Cl-浓度最高,浓度分别为32 535 μmol/L和53 466 μmol/L,K+浓度远高于Mg2+和Ca2+,而东海岛岸边海雾相反。Abstract: By using Micaps data, European Meteorological Center reanalysis data and sea fog observation data in March 2017, we investigated the microphysical and chemical characteristics of a sea fog on the sea surface in the northwestern South China Sea. Furthermore, the comparisons between the sea fog on the sea surface and the sea fog on the South China Sea coast were analyzed. The main results are as follow. The observed fog occurred when the warm and moist southward airflows from the South China Sea was cooled and saturated after contacting the cold water on the sea surface. The relative humidity increased during the sea fog process, whereas the pressure and temperature decreased. The average values of fog droplets number concentration (N), liquid water content (LWC), average diameter (D) were 198 cm-3, 0.116g/cm3 and 5.6 μm, respectively. Compared with the coastal sea fog in the Donghai Island and the Bohe region, the water vapors of sea fog on sea surface was more sufficient, and the droplets was larger. The sea fog on sea surface was acidic, with pH within the range of 2.51~3.50. The pH of the rain sample collected after the sea fog was 4.05. The electrical conductivity of the fog water during the formation stage was higher than that during other stages, indicating that a large number of aerosols dissolved in the fog water when fog formed. Na+ and Cl- concentrations in the fog water on the sea surface was the highest; the values were 53466 and 32535 μmol/L, respectively. The concentration of K+ in the fog water on the sea surface was much higher than that of Mg2+and Ca2+, while the concentration of K+ in the coastal sea fog in the Donghai Island was lower than that of Mg2+ and Ca2+.
-
表 1 2017年3月10—11日南海西北部海上海雾微物理结构参量及与湛江东海岛、茂名博贺岸边观测值比较
观测地点/时间 数浓度N/(个/cm3) 含水量W/(g/m3) 平均直径D /μm 范围 平均 范围 平均 范围 平均 湛江东海岛/2011年2月23—24日 3~354 248 0.001~0.257 0.102 3.1~7.8 5.2 茂名博贺/2008年3月18—19日 33~396 261 0.011~0.335 0.144 2.8~6.8 4.6 南海西北部/2017年3月10—11日 42~445 198 0.012~0.484 0.116 3.8~12.8 5.6 表 2 南海西北部雾水和雨水的pH值和电导率
阶段 采集时间 pH EC/(μS/cm) 第一次振荡期 3月10日21:01—22:00 3.07 5 400 3月10日22:01—23:00 3.5 541 3月10日23:01—11日00:00 3.3 425 第二次振荡期 3月11日00:01—02:00 2.58 1 745 3月11日02:01—03:00 2.56 1 595 3月11日03:01—04:00 2.51 1 721 第三次振荡期及消散期 3月11日04:01—05:00 2.76 1 063 3月11日05:01—06:00 2.86 938 3月11日06:01—07:00 2.76 1 260 小雨 3月11日07:01—10:00 4.05 810 表 3 南海西北部海上雾水中各离子浓度与湛江东海岛岸边观测值的比较
过程序号 采样时段 阳离子(μmol/L) 阴离子(μmol/L) Na+ K+ Mg2+ Ca2+ NH4+ F- Cl- NO3- SO42- NO2- 岸边1 2010-3-22 23:00—11:00 35 940.35 1 875.130 6 311.18 14 636.76 2 214.40 308.15 35 431.36 21 308.06 6 797.52 53.7 岸边2 2010-3-23 23:00—10:00 12 383.97 1 378.500 2 016.04 2 658.51 1 241.46 199.65 13 209.21 4 712.49 1 165.85 13.9 岸边3 2010-3-31 19:20—09:00 78 629.30 4 305.653 1 1491.94 6 577.43 5 098.97 644.54 87 931.49 16 741.91 6 920.39 1.63 岸边4 2010-4-1 17:40—09:00 30 169.11 1 424.038 4 491.90 2 911.31 3 865.53 280.73 31 838.24 11 536.55 2 770.40 — 岸边5 2010-4-6 03:00—07:00 53 725.76 1 870.589 7 739.67 2 943.38 2 003.44 327.48 59 581.36 10 269.17 4 495.22 — 海上1 2017-3-10 21:20—06:40 32 535.34 7 838.790 4 667.06 3 012.78 21 806.86 570.32 53 465.94 37 256.28 10 757.90 * 注:—表示缺测值;*表示未检测到。 -
[1] 牛生杰, 陆春松, 吕晶晶, 等.近年来中国雾研究进展[J].气象科技进展, 2016, 6(2): 6-19. [2] DARKO K, CLIVE E D. Marine Fog: Challenges and advancements in observations, modeling, and forecasting[M]. Springer Progress. 2017: 1-6. [3] PILIÉ R, MACK E, ROGERS C, et al. The formation of marine fog and the development of fog-stratus systems along the California coast[J]. Appl Meteor, 1979, 18(10): 1 275-1 286. [4] LEIPPER D F. Fog on the U.S. west coast, review[J]. Bull Amer Meteor Soc, 1994, 75(2): 229-348. [5] FUZZI S, FACCHINI M C, ORSI G, et al. The Po valley fog experiment 1989, an overview[J]. Tellus, 1992, 44(5): 448-468. [6] FINDLATER J, ROACH W T, MCHUGH B C. The harr of north-east Scotland[J]. Quart J Roy Meteor Soc, 1989, 115:581-608. [7] GULTEPE I, PEARSON G, MILBRANDT J A. The fog remote sensing and modeling field project[J]. Bull Amer Meteor Soc, 2009, 90:341-359. [8] 张舒婷, 牛生杰, 赵丽娟.一次南海海雾微物理结构个例分析[J].大气科学, 2013, 37(3): 552-562. [9] 岳岩裕, 牛生杰, 赵丽娟, 等.湛江地区近海岸雾产生的天气条件及宏微观特征分析[J].大气科学, 2013, 37(3): 609-622. [10] 岳岩裕, 牛生杰, 张羽, 等.南海沿岸海雾特征的观测研究[J].大气科学学报, 2015, 38(5) : 694-702. [11] 吕晶晶, 牛生杰, 赵丽娟, 等.湛江地区一次冷锋型海雾微物理特征[J].大气科学学报, 2014, 37(2): 208-215. [12] 岳岩裕, 牛生杰, 张羽, 等.湛江东海岛海雾雾水化学特征的对比分析[J].环境科学学报, 2016, 36(5): 1 573-1 580. [13] 徐峰, 牛生杰, 张羽, 等.湛江东海岛春季海雾雾水化学特性分析[J].中国环境科学, 2011, 31(3):353-360. [14] 吕晶晶, 牛生杰, 张羽, 徐峰.湛江东海岛一次春季海雾的宏微观结构及边界层演变特征[J].气象学报, 2014, 72(2): 350-365. [15] 黄辉军, 黄健, 毛伟康, 等.茂名地区海雾含水量的演变特征及其与大气水平能见度的关系[J].海洋学报, 2010, 32(2): 40-53. [16] 黄辉军, 黄健, 刘春霞, 等.茂名地区海雾的微物理结构特征[J].海洋学报, 2009, 31(2): 17-23. [17] 黄辉军, 詹国伟, 刘春霞, 等.一次华南沿海海雾个例的数值模拟研究[J].热带气象学报, 2015, 31(5): 643-654. [18] 黄彬, 王睛, 陆雪, 等.黄渤海一次持续性大雾过程的边界层特征及生消机理分析[J].气象, 2014, 40(11):1324-1337. [19] 史得道, 吴振玲, 罗凯, 等. 2015-04-28渤海海雾形成过程中的海气相互作用分析[J].热带气象学报, 2018, 34(3): 324-331. [20] 杨中秋, 许绍祖, 耿骠.舟山地区春季海雾的形成和微物理结构[J].海洋学报, 1989, 11(4): 431-438. [21] 张悦, 樊曙先, 张舒婷, 等.海峡西岸一次雾过程微结构及其起伏特征研究[J].热带气象学报, 2015, 31(3): 385-394. [22] 王彬华.海雾[M].北京:海洋出版社, 1983: 1-352. [23] DRAXLER R R, HESS G D. An overview of HYSPLIT-4 modeling system of trajectories, dispersion, and deposition[J]. Aust Meteor Mag, 1998, 47: 295-308. [24] FU G, LI P, JOSEPH G, et al. An observational and modeling study of a sea fog event over the Yellow Sea on 1 August 2003[J]. Meteor Atmos Phys, 2010, 107(3-4): 149-159. [25] ELDRIDGE R G. The relationship between fog condensation nuclei and fog microstructure[J]. J Atmos Sci, 1971, 28: 1 183-1 186. [26] 牛生杰.雾物理化学研究[M].北京:气象出版社, 2014: 104-107. [27] 唐孝炎, 张远航, 邵敏.大气环境化学[M].北京:高等教育出版社, 2006: 104-107.