The Precipitation Process in Convective Cells Embedded in Deep Snow Bands over the Sea of Japan

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概要

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• Convective cells in two deep snow bands were examined over the Sea of Japan with an instrumented aircraft and dual-Doppler radars. A combination of the relatively warm air stream (westerly) at lower levels secluded near the center of the low and the polar air stream (west-southwesterly) at middle and upper levels produced a deep unstable stratification to the southwestern quadrant of a well-developed low, where snow bands A1 and B1 were respectively observed at around 1600 and 1700 JST on 28 Jan. 1993. Radar data showed that both snow bands were in quasi-steady state within a dual Doppler radar observation area. However, the two snow bands showed quite different development; the maximum reflectivities in bands A1 and B1 were 15 dBZ and 30 dBZ, respectively. Aircraft data showed that the accretional growth of snow particles was the primary precipitation formation mechanism in the convective cells embedded in both snow bands. From aircraft and radar data, it appears that vertical wind shear within the cloud layer influenced the precipitation process. In the cell embedded in snow band A1, the updraft at middle and upper levels tilted downshear due to a strong wind shear and precipitation embryos initiated in the updraft were advected downshear from the main supercooled cloud water region. Therefore, these embryos did not grow to large graupel particles. By comparison, in the cell embedded in snow band B1, the updraft tilted upshear at lower levels and stood almost erect at middle and upper levels due to weak wind shear. Therefore, precipitation embryos initiated in the updraft grew into 5 mm graupel particles as they descended through the main supercooled cloud water region. In addition, re-circulation of graupel particles, which had descended in a vicinity of the updraft core, seemed to play an important role to efficiently produce larger graupel particles.

• 社団法人日本気象学会の論文
• 2003-06-25

著者

• Iwanami Koyuru

  National Research Institute For Earth And Disaster Prevention

• Murakami Masataka

  Meteorological Research Institute

• YAMADA Yoshinori

  Meteorological Research Institute

• MATSUO Takayo

  Meteorological Research Institute

• MARWITZ John

  University of Wyoming, Laramie

• GORDON Glenn

  University of Wyoming, Laramie

• Marwitz John

  University Of Wyoming Laramie

• Gordon Glenn

  University Of Wyoming Laramie

• Yamada Yoshinori

  Meteorological Res. Inst.

• GORDON Glenn

  University of Wyoming

• MARWITZ John

  University of Wyoming

関連論文

• Doppler Radar Observations of Orographic Effects of Isolated Echoes during the Baiu Season at Nagasaki Prefecture, on July 14 and 15, 1988
• Retrieval of Microphysical Properties of Water, Ice, and Mixed-Phase Clouds Using a Triple-Wavelength Radar and Microwave Radiometer
• The Precipitation Process in Convective Cells Embedded in Deep Snow Bands over the Sea of Japan
• Relationships among Structures, Development Processes, and Heating Profiles for Two Mesoscale Convective Systems in Inactive Phase of a Large-Scale Disturbance over Northern Australia during the Southern Summer in 1998-1999
• Dual-Doppler Radar Observations on Factors Causing Differences in the Structure of Snow Clouds during Winter Monsoon Surges
• Hydrometeor Size Distribution Estimated by Vertically Pointing Doppler Radar and Polarimetric Radar Measurements : Preliminary Results
• Re-Evaluation of the Collection Efficiency of the Hydrometeor Videosonde for Dry Snow Particles
• Airflow Circulations in the Precipitation Clouds over the Southeastern Slope of the Orofure Mountain Range, Hokkaido, Japan
• Two Case Studies of Heavy Rainfalls from the Stratiform and Convective Precipitation Clouds in the Orofure Mountain Range, Hokkaido, Japan
• A Case Study of Heavy Rainfalls from the Shallow Orographic Precipitating Clouds in the Orofure Mountain Range, Hokkaido, Japan

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