Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm Pool
In the Western North Pacific (WNP), the atmospheric low-level convergence is one of the main factors that influences the genesis of tropical cyclones (TC). It has been observed that the timing of the seasonal maxima in the low-level convergence and TC genesis has shifted since the mid-1990s from mid...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-04-01
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| Series: | Atmosphere |
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| Online Access: | http://www.mdpi.com/2073-4433/9/5/158 |
| _version_ | 1819129052664954880 |
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| author | Yen-Heng Lin S.-Y. Simon Wang |
| author_facet | Yen-Heng Lin S.-Y. Simon Wang |
| author_sort | Yen-Heng Lin |
| collection | DOAJ |
| description | In the Western North Pacific (WNP), the atmospheric low-level convergence is one of the main factors that influences the genesis of tropical cyclones (TC). It has been observed that the timing of the seasonal maxima in the low-level convergence and TC genesis has shifted since the mid-1990s from mid-August to late-July, with this shift having also affected the number of TC. A multidecadal frequency of 20 years was revealed in the timing variation of the tropical intraseasonal oscillation (ISO) in the Western Pacific, in which a weak WNP low-level convergence in spring may trigger an advanced ISO phase in summer and vice versa. The present diagnostic analysis does not identify any prominent oceanic variations associated with these multidecadal variations in the summer ISO or in the spring setup of the ISO. The atmospheric circulation does show an anomaly, which suggests an intensified extension of the subtropical high. The possible mechanism may be related to stochastic low-frequency variability of the atmosphere, which acts to influence the seasonal evolution of the WNP low-level convergence. |
| first_indexed | 2024-12-22T08:37:35Z |
| format | Article |
| id | doaj.art-618c282183784c85a70a5e997fb0030f |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-12-22T08:37:35Z |
| publishDate | 2018-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-618c282183784c85a70a5e997fb0030f2022-12-21T18:32:19ZengMDPI AGAtmosphere2073-44332018-04-019515810.3390/atmos9050158atmos9050158Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm PoolYen-Heng Lin0S.-Y. Simon Wang1Department of Plants, Soils, and Climate, Utah State University, Logan, UT 84322, USADepartment of Plants, Soils, and Climate, Utah State University, Logan, UT 84322, USAIn the Western North Pacific (WNP), the atmospheric low-level convergence is one of the main factors that influences the genesis of tropical cyclones (TC). It has been observed that the timing of the seasonal maxima in the low-level convergence and TC genesis has shifted since the mid-1990s from mid-August to late-July, with this shift having also affected the number of TC. A multidecadal frequency of 20 years was revealed in the timing variation of the tropical intraseasonal oscillation (ISO) in the Western Pacific, in which a weak WNP low-level convergence in spring may trigger an advanced ISO phase in summer and vice versa. The present diagnostic analysis does not identify any prominent oceanic variations associated with these multidecadal variations in the summer ISO or in the spring setup of the ISO. The atmospheric circulation does show an anomaly, which suggests an intensified extension of the subtropical high. The possible mechanism may be related to stochastic low-frequency variability of the atmosphere, which acts to influence the seasonal evolution of the WNP low-level convergence.http://www.mdpi.com/2073-4433/9/5/158East Asian summer monsoonmultidecadal variabilitylow-level convergence |
| spellingShingle | Yen-Heng Lin S.-Y. Simon Wang Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm Pool Atmosphere East Asian summer monsoon multidecadal variability low-level convergence |
| title | Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm Pool |
| title_full | Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm Pool |
| title_fullStr | Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm Pool |
| title_full_unstemmed | Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm Pool |
| title_short | Multidecadal Variability in the Subseasonal Peak of Low-Level Convergence over the Pacific Warm Pool |
| title_sort | multidecadal variability in the subseasonal peak of low level convergence over the pacific warm pool |
| topic | East Asian summer monsoon multidecadal variability low-level convergence |
| url | http://www.mdpi.com/2073-4433/9/5/158 |
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