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Doppler Radar Observations on the structure and Characteristics of Tropical Clouds during the TOGA-COARE IOP in Manus, Papua New Guinea : Meso-γ Scale Structures of Stratiform Region in Tropical Cloud Cluster
| Content Provider | Semantic Scholar |
|---|---|
| Author | Shimizu, Shuji Uyeda, Hiroshi Kinoshita, Atsushi |
| Copyright Year | 1998 |
| Abstract | We attempted to investigate the structure of a stratiform region of a tropical cloud cluster on Manus Island during the Intensive Observation Period (IOP) of the Tropical Ocean-Global Atmosphere program, a Coupled Ocean-Atmosphere Response Experiment (TOGA-COARE). Time series of Velocity Azimuth Display (V AD) and Extended V AD (EV AD) analyses for the two X -band radars were used to obtain horizontal wind profiles and convergence profiles for comparison with time series of the Integrated Sounding System (ISS) horizontal wind profiles. Two types of stratiform clouds on Manus Island were analyzed. In Case A, northerly winds dominated at high level and northwesterly winds dominated the low and middle level throughout the period analyzed. The height of vertical shear between northerly winds and northwesterly winds gradually descended from 3.5 km to 1.5 km. A sudden ascent and descent of the vertical shear was • Present affiliation: Earth Observation Research Center, National Space Development Agency of Japan, Tokyo 106-0032, Japan. ,. Present affiliation: Betsukai High School, Betsukai, Hokkaido 086-0214, Japan. 302 S. Shimizu et al. associated with convergence and divergence in the middle level within the analysis area of the X -band radar. This rapid change of the height of the vertical shear corresponded to southeastward passage of a convective part. The convection contributed to initiating precipitation (10 mm/h) over Manus Island in the dissipating cloud cluster. This temporal change of the wind profiles may have caused by a southeastward wave in the boundary between the two layers. In Case B, a variation in the divergence profiles was associated with the interaction between convective cloud lines. When two linear echoes merged and changed to a stratiform echo, divergence was analyzed above 2 km. Convergence in the lower level then ascended with northeasterly winds and divergence developed in the lower level. Case A was caused by development and passage of a convective part in the stratiform region. Case B was caused by merger of linear convection and transition to stratiform echoes. Similar divergence profile patterns with the dissipating stratiform regions were observed in both cases. These patterns were also similar to that of the anvil region of a squall line. However the scale, process to the stratiform precipitation and detailed structures of these cases were quite different from those of the anvil region. |
| Starting Page | 301 |
| Ending Page | 322 |
| Page Count | 22 |
| File Format | PDF HTM / HTML |
| DOI | 10.2151/jmsj1965.73.2b_415 |
| Alternate Webpage(s) | https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/8836/1/11(1)_p301-322.pdf |
| Alternate Webpage(s) | https://doi.org/10.2151/jmsj1965.73.2b_415 |
| Volume Number | 11 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
