12.07.2015 Views

Proceedings with Extended Abstracts (single PDF file) - Radio ...

Proceedings with Extended Abstracts (single PDF file) - Radio ...

Proceedings with Extended Abstracts (single PDF file) - Radio ...

SHOW MORE
SHOW LESS
  • No tags were found...

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

3. Characteristics of precipitation system <strong>with</strong>in the westward-propagating cloudFigure 3 presents horizontal distribution of 2-km CAPPI echoes at 10-min intervals in theperiod of 16-19 LST. A meso-scale precipitation system consists of several smaller convectioncells. The lifetime of their cells is 30-40 min. It is evident that they propagate westwardaccording to the environmental wind. While the pre-existing cell in the west part of theconvective precipitation decays, new cell forms in the east part of one. As a result, themeso-scale precipitation system propagates eastward. The moving direction is opposite for thecloud system in relation to the environmental wind.A lower-level wind behavior in relation to the evolution of the precipitation system isexamined. Figure 4 presents the time-height cross-section of zonal wind observed by the BLR.When the precipitation system appears around the EAR site, the lower-level zonal windsuddenly changed from easterly to westerly. The westerly wind lasts while the precipitationsystem is passing over the EAR site. The increase of westerly wind component in the earlyevening is confirmed in other days. Thus the low-level westerly wind is considered to be a partof a local circulation around the EAR site. It is also suggested that the formation of the newconvection cells in the precipitation system results in the convergence of this westerly windand the environmental wind.4. ConclusionsWind field and precipitation associated <strong>with</strong> westward-propagating cloud clusters inNovember 2002 is investigated by utilizing the EAR, BLR and rain radar at Kototabang, westSumatera Indonesia. The moving cloud systems are seen <strong>with</strong>in a synoptic-scale cloud systemin relation to the ISO. We mainly study a case on 10 Nov, as an example of thewestward-propagating meso-scale cloud cluster. Convective precipitation system appearswhen the cloud cluster passes around the EAR site. A remarkable updrafts extendingvertically are found in the precipitation system. The precipitation system consists of severalconvection cells. The complicated evolution of the precipitation system is related to theinteraction of the westward-propagating cloud cluster and the local circulation occurringaround the EAR.315

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!