https://scholars.lib.ntu.edu.tw/handle/123456789/606320
標題: | Quasi-2-Day and Diurnal Cloud Variation Timescales Over Convectively Active Regions | 作者: | Yu H Rasmussen K.L HUNG-CHI KUO |
關鍵字: | brightness temperature;climatology;cloud;convective system;diurnal variation;El Nino-Southern Oscillation;Indian Ocean Dipole;land-sea interaction;mesoscale meteorology;quasi-biennial oscillation;satellite altimetry;sea surface temperature;timescale;Amazonia;Congo;South America;United States | 公開日期: | 2021 | 卷: | 126 | 期: | 21 | 來源出版物: | Journal of Geophysical Research: Atmospheres | 摘要: | Climatological features of the cloud variability on quasi-2-day (Q2D) and diurnal cycle (DC) timescales are investigated by utilizing the high-resolution satellite infrared brightness temperature (IRBT) observations from January 1998 to December 2019. A distinct land-sea contrast between the distributions of Q2D and DC signals is evident. Diurnally driven cloud activity mainly occurs over land and mountainous regions, and the Q2D timescale is more prominent over tropical ocean basins and land where organized convection is usually observed, for example, Congo and Amazon Rainforests, the United States and subtropical South America during warm seasons. The long-term relationship between the Q2D variability and sea surface temperature (SST) shows that the clouds are more active on Q2D timescales over higher SST environments. The Q2D variability correlates well with both the Indian Ocean Dipole (IOD) and El Ni?o/Southern Oscillation (ENSO) from 1998 to 2019. The cloud variability associated with a range of convective available potential energy (CAPE) values is analyzed. The result over land shows that increased Q2D cloud variability emerges with higher CAPE, suggesting the coincidence of Q2D and organized convection, particularly given that this effect is strongest over regions with frequent mesoscale convective systems (MCSs) around the world. The cloud variability and the Q2D timescale analyses provide an alternative perspective to understand the global features of mesoscale convective systems. Overall, this study objectively examines the global variability of convective timescales related to the diurnal cycle and longer-lived convective systems to provide a greater understanding of how the global convection population varies in space and time. ? 2021. American Geophysical Union. All Rights Reserved. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85118767804&doi=10.1029%2f2021JD035426&partnerID=40&md5=ada4523fd73848bb35b9a3eca24cc19e https://scholars.lib.ntu.edu.tw/handle/123456789/606320 |
ISSN: | 2169897X | DOI: | 10.1029/2021JD035426 |
顯示於: | 大氣科學系 |
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