Vertical Profiles of Raindrop Size Distribution Observed by Micro Rain Radar
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摘要: 雨滴谱的垂直变化特征对于认识降水过程、改进模式和雷达定量估计降水等具有重要意义。利用2016年6月1日-9月30日雨量筒、微雨雷达(micro rain radar,简称MRR)和PARSIVEL雨滴谱仪连续4个月的观测数据,在对比3种仪器观测结果的基础上,研究了层状云降水不同降水强度下微物理特征量和雨滴谱垂直演变特征。结果表明:MRR与PARSIVEL雨滴谱仪观测降水强度相关性较好,且两种仪器观测的雨滴谱在中等粒子段(0.5~2.5 mm)表现出较好的一致性,而对于小粒子段(雨滴直径小于0.5 mm)PARSIVEL雨滴谱仪观测的数浓度明显低于MRR。对于弱降水(降水强度R ≤ 0.2 mm·h-1),液水含量和降水强度随高度降低减小,雨滴在下落过程中蒸发明显。对于较强降水(R>2 mm·h-1),随高度降低,雷达反射率因子增大,小滴数浓度减小的同时大滴数浓度增加明显,雨滴下落过程碰并作用明显。所有高度直径不超过0.5 mm的小滴对数浓度贡献均为最大。高层雨滴直径不小于1 mm的小粒子对降水强度的贡献可达50%,小粒子对降水强度贡献随高度降低减小。Abstract: Raindrop size distribution (DSD) is of great importance for understanding the microphysical process of precipitation, as well as improving the microphysical parameterization scheme in numerical model. Most studies of DSD focus on precipitation characteristics on the surface. However, vertical profiles of DSD and rain parameters are important for quantitatively accurate precipitation estimation from weather radars. Based on data observed by the ground-based PARSIVEL disdrometer and a vertical pointing micro rain radar (MRR) at Xingtai, Hebei Province located in North China from June to September in 2016, the vertical evolution of precipitation microphysical parameters and DSD of different rain rate classed for stratiform precipitation are analyzed. Measurements from MRR, rain gauge and ground PARSIVEL disdrometer are compared. Results show that measurements from MRR, rain gauge and PARSIVEL disdrometer have good agreement in rain rate. MRR and PARSIVEL disdrometer show good consistency in medium sized (1-2.5 mm) range of DSD but have slight differences for small and large raindrops. MRR observes much more small particles than PARSIVEL disdrometer. When the rain rate is low, with low relative humidity around the ground, both large and small drops decrease with the altitude decreasing, so as to the liquid water content and rain rate, which is explained by the evaporation. When the rain rate is high, the concentration of particles for precipitation is much larger, and the vertical variation of DSD is more obvious. The profiles of radar reflectivity show a positive slope(dZ/dH>0). The concentration of medium-sized and large raindrops increases obviously with decreasing altitude at the cost of reducing small raindrops for precipitation with rain rate between 2-20 mm·h-1, indicating that the coalescence is the dominant process for 2-20 mm·h-1. The largest contribution to the total number concentration is small drops (0-0.5 mm) with diameters between 0-1 mm and can reach up to 50% above altitude of 2 km. Small particles contribute less to the precipitation intensity as the altitude decreasing. These small raindrops account only 15% to the surface precipitation, while the medium-sized raindrops can contribute 60% with rain rate between 2-20 mm·h-1. Large raindrops (>2 mm) is about 50% of the surface rainfall for the largest rain rate class. These results provide useful information for better understanding rain processes and quantitative estimation of precipitation in the future.
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图 4 2016年6月1日—9月30日邢台MRR观测层状云不同降水强度下雨滴谱垂直分布(a)0.1 mm·h-1≤R≤0.2 mm·h-1, (b)0.2 mm·h-1 < R≤2 mm·h-1, (c)2 mm·h-1 < R≤20 mm·h-1, (d)R>20 mm·h-1
Fig. 4 Averaged profiles of drop size distributions for stratiform precipitation cases with different subgroups at Xingtai during 1 Jun-30 Sep in 2016 (a)0.1 mm·h-1≤R≤0.2 mm·h-1, (b)0.2 mm·h-1 < R≤2 mm·h-1, (c)2 mm·h-1 < R≤20 mm·h-1, (d)R>20 mm·h-1
表 1 MRR主要参数
Table 1 Main parameters of MRR
参数 取值 发射频率 24.23 GHz 功率 50 mW 波束宽度 2° 时间分辨率 10~3600 s(可调节) 高度分辨率 10~1000 m(可调节) 距离库数 31 速度分辨率 0.191 m·s-1 速度范围 0~12.3 m·s-1 -
[1] Sarkar T, Das S, Maitra A.Assessment of different raindrop size measuring techniques:Inter-comparison of Doppler radar, impact and optical disdrometer.Atmos Res, 2015, 160(160):15-27. http://cn.bing.com/academic/profile?id=81c9821b92a91896ed216be864f7c040&encoded=0&v=paper_preview&mkt=zh-cn [2] 周毓荃, 刘晓天, 周非非, 等.河南干旱年地面雨滴谱特征.应用气象学报, 2001, 12(增刊Ⅰ):39-47. http://d.old.wanfangdata.com.cn/Periodical/yyqxxb2001z1006 [3] 尚博, 周毓荃, 刘建朝, 等.基于Cloudsat的降水云和非降水云垂直特征.应用气象学报, 2012, 23(1):1-9. doi: 10.3969/j.issn.1001-7313.2012.01.001 [4] Jakob C.Accelerating progress in global atmospheric model development through improved parameterizations:Challenges, opportunities, and strategies.Bull Amer Meteor Soc, 2010, 91(7):869-875. doi: 10.1175/2009BAMS2898.1 [5] Atlas D, Srivastava R C, Sekhon R S.Doppler radar characteristics of precipitation at vertical incidence.Rev Geophys, 1973, 11(1):1-35. http://cn.bing.com/academic/profile?id=f5ccd9a145023565a775a054a52ec1d5&encoded=0&v=paper_preview&mkt=zh-cn [6] Doelling I G, Joss J, Riedl J.Systematic variations of Z-R-relationships from drop size distributions measured in northern Germany during seven years.Atmos Res, 1998, 47-48:635-649. doi: 10.1016/S0169-8095(98)00043-X [7] Zhang G, Sun J, Brandes E A.Improving parameterization of rain microphysics with disdrometer and radar observations.J Atmos Sci, 2006, 63(4):1273-1290. doi: 10.1175/JAS3680.1 [8] Bringi V N, Chandrasekar V, Hubbert J, et al.Raindrop size distribution in different climatic regimes from disdrometer and dual-polarized radar analysis.J Atmos Sci, 2003, 60(2):354-365. doi: 10.1175/1520-0469(2003)060<0354:RSDIDC>2.0.CO;2 [9] Ulbrich C W, Atlas D.Microphysics of raindrop size spectra:tropical continental and maritime storms.J Appl Meteor Climatol, 2007, 46(11):1777-1791. doi: 10.1175/2007JAMC1649.1 [10] Chen B, Yang J, Pu J.Statistical characteristics of raindrop size distribution in the Meiyu season observed in eastern China.J Meterol Soc Japan, 2013, 91(2):215-227. doi: 10.2151/jmsj.2013-208 [11] Niu S, Jia X, Sang J, et al.Distributions of raindrop sizes and fall velocities in a semiarid plateau climate:Convective versus stratiform rains.J Appl Meteor Climatol, 2010, 49(4):632-645. doi: 10.1175/2009JAMC2208.1 [12] 柳臣中, 周筠珺, 谷娟, 等.成都地区雨滴谱特征.应用气象学报, 2015, 26(1):112-121. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20150112&flag=1 [13] 林文, 林长城, 李白良, 等.登陆台风麦德姆不同部位降水强度及谱特征.应用气象学报, 2016, 27(2):239-248. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20160212&flag=1 [14] 金祺, 袁野, 纪雷, 等.安徽滁州夏季一次飑线过程的雨滴谱特征.应用气象学报, 2015, 26(6):725-734. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20150609&flag=1 [15] 陈聪, 银燕, 陈宝君.黄山不同高度雨滴谱的演变特征.大气科学学报, 2015, 38(3):388-395. http://d.old.wanfangdata.com.cn/Periodical/njqxxyxb201503011 [16] 李慧, 银燕, 单云鹏, 等.黄山层状云和对流云降水不同高度的雨滴谱统计特征分析.大气科学, 2018, 42(2):268-280. http://d.old.wanfangdata.com.cn/Periodical/daqikx201802003 [17] 袁野, 朱士超, 李爱华.黄山雨滴下落过程滴谱变化特征.应用气象学报, 2016, 27(6):734-740. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20160610&flag=1 [18] 贾星灿, 牛生杰.空中、地面雨滴谱特征的观测分析.南京气象学院学报, 2008, 31(6):865-870. doi: 10.3969/j.issn.1674-7097.2008.06.015 [19] 封秋娟, 李培仁, 丁建芳, 等.山西地区一次层状云降水过程的微观特征观测分析.大气科学学报, 2013, 36(5):537-545. doi: 10.3969/j.issn.1674-7097.2013.05.003 [20] 何越, 何平, 林晓萌.基于双高斯拟合的风廓线雷达反演雨滴谱.应用气象学报, 2014, 25(5):570-580. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20140506&flag=1 [21] 何平, 李柏, 吴蕾, 等.确定风廓线雷达功率谱噪声功率方法.应用气象学报, 2013, 24(3):297-303. doi: 10.3969/j.issn.1001-7313.2013.03.005 [22] Peters G, Fischer B, Andersson T.Rain observations with a vertically looking micro rain radar (MRR).Boreal Environment Research, 2002, 7(4):353-362. http://cn.bing.com/academic/profile?id=ad1a97b79566b1f887a063ce4fa461eb&encoded=0&v=paper_preview&mkt=zh-cn [23] Das S, Shukla A K, Maitra A.Investigation of vertical profile of rain microstructure at Ahmedabad in Indian tropical region.Adv Space Res, 2010, 45(10):1235-1243. doi: 10.1016/j.asr.2010.01.001 [24] Wen L, Zhao K, Zhang G, et al.Statistical characteristics of raindrop size distributions observed in East China during the Asian summer monsoon season using 2D-Video disdrometer and Micro-rain Radar data.J Geophys Res Atmos, 2016, 121:2265-2282. doi: 10.1002/2015JD024160 [25] Harikumar R, Sampath S, Sasi Kumar V.Altitudinal and temporal evolution of raindrop size distribution observed over a tropical station using a K-band radar.Int J Remote Sens, 2011, 33(10):3286-3300. http://cn.bing.com/academic/profile?id=43b9d436e34b3eac98c63676c16ab7b1&encoded=0&v=paper_preview&mkt=zh-cn [26] Das S, Maitra A.Vertical profile of rain:Ka band radar observations at tropical locations.J Hydrol, 2016, 534:31-41. doi: 10.1016/j.jhydrol.2015.12.053 [27] Wang H, Lei H, Yang J.Microphysical processes of a stratiform precipitation event over eastern China:Analysis using micro rain radar data.Adv Atmos Sci, 2017, 34(12):1472-1482. doi: 10.1007/s00376-017-7005-6 [28] 崔云扬.利用微雨雷达研究不同云系降水的垂直结构分布与演变特征.南京: 南京信息工程大学, 2018. http://cdmd.cnki.com.cn/Article/CDMD-10300-1018140361.htm [29] Kinzer G G D.The terminal velocity of fall for water droplets in stagnant air.J Atmos Sci, 1949, 6(4):243-248. http://cn.bing.com/academic/profile?id=8d845c2027999be2548b59314ac43ac8&encoded=0&v=paper_preview&mkt=zh-cn [30] Peters G, Fischer B, Münster H, et al.Profiles of raindrop size distributions as retrieved by micro rain radars.J Appl Meteor Climatol, 2005, 44(12):1930-1949. doi: 10.1175/JAM2316.1 [31] Peters G, Fischer B, Clemens M.Rain attenuation of radar echoes considering finite-range resolution and using drop size distributions.J Atmos Ocean Tech, 2010, 27(5):829-842. doi: 10.1175/2009JTECHA1342.1 [32] Tokay A, Bashor P G.An experimental study of small-scale variability of raindrop size distribution.J Appl Meteor Climatol, 2010, 49(11):2348-2365. doi: 10.1175/2010JAMC2269.1 [33] Gamache J F, Houze R A.Mesoscale air motions associated with a tropical squall line.Mon Wea Rev, 1982, 110:118-135. doi: 10.1175/1520-0493(1982)110<0118:MAMAWA>2.0.CO;2 [34] Wen L, Zhao K, Zhang G, et al.Impacts of instrument limitations on estimated raindrop size distribution, radar parameters, and model microphysics during Mei-Yu season in East China.J Atmos Oceanic Technol, 2017, 34(5):1021-1037. doi: 10.1175/JTECH-D-16-0225.1 [35] 李淘, 阮征, 葛润生, 等.激光雨滴谱仪测速误差对雨滴谱分布的影响.应用气象学报, 2016, 27(1):25-34. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20160103&flag=1 [36] 宫福久, 刘吉成, 李子华.三类降水云雨滴谱特征研究.大气科学, 1997, 21(5):607-614. doi: 10.3878/j.issn.1006-9895.1997.05.12 [37] 陈宝君, 李子华, 刘吉成, 等.三类降水云雨滴谱分布模式.气象学报, 1998, 56(4):506-512. doi: 10.3321/j.issn:0577-6619.1998.04.013 [38] 李其琛, 杜金林.下落过程中雨滴谱和雨的雷达反射率的变化.北京大学学报(自然科学版), 1964(3):79-85. http://www.cnki.com.cn/Article/CJFDTOTAL-BJDZ196403006.htm [39] 吴兑.关于雨滴在云下蒸发的数值试验.气象学报, 1991, 49(1):116-121. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB199101017.htm [40] Steiner M, Smith J A, Uijlenhoet R.A microphysical interpretation of Radar reflectivity-rain rate relationships.J Atmos Sci, 2004, 61(10):1114-1131. doi: 10.1175/1520-0469(2004)061<1114:AMIORR>2.0.CO;2