碩士 / 國立臺灣大學 / 大氣科學研究所 / 104 / The South China Sea (SCS) summer monsoon is the bridge between the south Asia and East Asia systems. The better understanding of the evolution of precipitation and cloud patterns during monsoon onset period can help to understand the relationships between convection and environment, as well as the physical mechanisms of the Asian monsoon transition. Precipitation over the SCS exhibits significant diurnal variation during both pre- and post-onset periods. The post-onset southwesterly winds and land-sea breeze enhances the convergence at the low level and generates the convection.
To better understand the changes of diurnal variation of convection during monsoon onset period, this study analyzed multiple datasets including the reanalysis data, the TRMM precipitation estimates, and the DARDAR-MASK and 2B-FLXHR-LIDAR cloud products. Climatological statistics for analyzed periods were derived for (1) temporal and spatial distribution of precipitation diurnal cycle, (2) the vertical cloud frequency, cloud types, and size of convection clouds, and (3) the cloud radiative effects. The post-onset precipitation diurnal cycle (DC) exhibits enhanced amplitude and the peak time over ocean becomes more synchronized. After monsoon onset, over the northern SCS, the cloud frequency, number, and size of convective cloud shows a significant increase. The cloud radiative effect becomes stronger. Over the southern SCS, the change in cloud frequency is more significant than the change in rainfall. The number and size of convective cloud both decrease. The present results indicate a change in convection organization after the monsoon onset. Future study can be focused on the investigation of the mechanisms of such organization, including the roles of environmental moisture and vertical wind shear, the interactions between local land-sea breeze and mean wind, and effects of topography.
| Identifer | oai:union.ndltd.org:TW/104NTU05022029 |
| Date | January 2016 |
| Creators | Peng-Jen Chen, 陳鵬任 |
| Contributors | Wei-Ting Chen, 陳維婷 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 67 |
Page generated in 0.0021 seconds