{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,12]],"date-time":"2026-06-12T16:58:49Z","timestamp":1781283529691,"version":"3.54.1"},"reference-count":20,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2022,3,30]],"date-time":"2022-03-30T00:00:00Z","timestamp":1648598400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>(1) Raindrop size distribution (DSD) is a vital microphysical characteristic of clouds and precipitations. The vertical evolution of DSD also provides a reference for the microphysical mechanisms and dynamic processes involved in clouds and precipitations. (2) Here we analyzed the characteristics and vertical evolution of DSDs, which were obtained from Micro Rain Radar (MRR) data of two typical stratiform rain cases. (3) First, we compared MRR-observed reflectivity (Z) and DSD at 400 m with data from a distrometer on the ground. This ensured the reliability of the MRR data of the two cases. Then it was found that the DSD was wider just below the 0 \u00b0C level than at lower levels. The larger DSDs width formed a bulge shape in the vertical direction, and large particles in the \u2018bulge\u2019 then constantly collided as they were falling down. The DSD was broadened and the echo of the warm layer was strengthened. We referred to this as the bulge phenomenon (BP), which appeared occasionally, and broader DSD propagated from high to low intermittently during the stratiform rain. Next, by combining the detailed cloud structures detected by cloud radar with BP, we found that a BP was always accompanied by higher developing cloud tops, stronger Z and larger falling velocity. It was inferred that ice particles formed near cloud top intermittently and fell through the underlying cloud, causing the gustiness and instability of particle aggregation, which was reflected by the BP below the 0 \u00b0C layer. BP triggered quick collision and falling down along the warm layer, enhancing the Z and falling velocity transiently. Thus, BP was considered as one of the mechanisms of rain variation in stratocumulus and stratiform rain in North China. Finally, we defined the cycle time of a BP (BPT), which was composed of broadening stage (BS) and stable stage (SS). We found that changes of DSD parameters for both MRR and distrometer responded to each BP occurring, showing the same intermittency. From each BP occurring time to the corresponding BS ending time, Dm basically grew from small to large. After this, Dm decreased immediately or maintained for a while and then decreased. Nw had the opposite trend to Dm. Also, it was found that larger R accelerated the fluency of BP occurring (BPT).<\/jats:p>","DOI":"10.3390\/rs14071655","type":"journal-article","created":{"date-parts":[[2022,3,30]],"date-time":"2022-03-30T21:28:39Z","timestamp":1648675719000},"page":"1655","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Analyses of DSD Vertical Evolution and Rain Variation Mechanism in Stratiform Cloud Cases Using Micro Rain Radar"],"prefix":"10.3390","volume":"14","author":[{"given":"Ningkun","family":"Ma","sequence":"first","affiliation":[{"name":"Beijing Weather Modification Center, Beijing 100089, China"},{"name":"Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources (LCPW), Beijing Meteorological Bureau, Beijing 100089, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6290-5652","authenticated-orcid":false,"given":"Yichen","family":"Chen","sequence":"additional","affiliation":[{"name":"Beijing Weather Modification Center, Beijing 100089, China"},{"name":"Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources (LCPW), Beijing Meteorological Bureau, Beijing 100089, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zuo","family":"Jia","sequence":"additional","affiliation":[{"name":"CSSC Marine Technology Co., Ltd., Beijing 100070, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liping","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Science, Beijing 100089, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xincheng","family":"Ma","sequence":"additional","affiliation":[{"name":"Beijing Weather Modification Center, Beijing 100089, China"},{"name":"Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources (LCPW), Beijing Meteorological Bureau, Beijing 100089, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu","family":"Huang","sequence":"additional","affiliation":[{"name":"Beijing Weather Modification Center, Beijing 100089, China"},{"name":"Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources (LCPW), Beijing Meteorological Bureau, Beijing 100089, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,3,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2417","DOI":"10.1175\/1520-0469(2000)057<2417:TTSIAC>2.0.CO;2","article-title":"The turbulence structure in a continental stratocumulus cloud from millimeter-wavelength Radar observations","volume":"57","author":"Kollias","year":"2000","journal-title":"J. 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