First simultaneous measurement of vertical air velocity, particle fall velocity, and hydrometeor sphericity in stratiform precipitation: Results from 47 MHz wind-profiling radar and 532 nm polarization lidar observations

作者：Mega Tomoaki^*; Yamamoto Masayuki K; Abo Makoto; Shibata Yasukuni; Hashiguchi Hiroyuki; Nishi Noriyuki; Shimomai Toyoshi; Shibagaki Yoshiaki; Yamamoto Mamoru; Yamanaka Manabu D; Fukao Shoichiro; Manik Timbul

来源：Radio Science, 2012, 47: RS3002.

DOI：10.1029/2011RS004823

Results from simultaneous measurements of vertical air velocity (W), particle fall velocity, and hydrometeor sphericity in stratiform precipitation are reported for the first time. Cases of stratiform precipitation on 8 (case A) and 16 December 2008 (case B) observed at Sumatra, Indonesia (0.2 degrees S, 100.32 degrees E), are described. A 47 MHz wind-profiling radar measured W and reflectivity-weighted particle fall velocity relative to the air (V-Z) simultaneously. Upward W above similar to 6.0 km altitude in case B (%26gt;0.2 m s(-1)) was greater than in case A (%26lt;0.1 m s(-1)). V-Z at 300 m above the 0 degrees C altitude in case B (1.8 m s(-1)) was greater than in case A (1.3 m s(-1)). The thickness of melting layer (ML) in case B (900 m) was greater than in case A (300 m). Because the large-sized aggregates contribute to produce greater V-Z and thicker ML, it is likely that entangled growth of dendritic crystals under the presence of significant upward W and enhanced aggregation occurrence by the well-developed dendritic crystals produced the large-sized aggregates. Lidar measured an increase of linear depolarization ratio (delta) and lidar dark band in the ML. Volume delta of raindrops was 0.08-0.10 in case B and close to zero in case A. Stronger multiple scattering in case B is likely a cause that produced the greater delta. In case B, a dip of delta was measured at the bottom of ML. The decrease of hydrometeor nonsphericity at the final stage of melting explains the dip.

• 出版日期2012-5-8