Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia
Using data from the Sumatran GPS Array in Indonesia–a hero network in tectonic and earthquake studies– we study the summer intra-seasonal variability of precipitable water vapor (PWV) over Sumatra in years without strong inter-annual variability. Unlike most other studies that used external meteorol...
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| Format: | Journal Article |
| Language: | English |
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2022
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| Online Access: | https://hdl.handle.net/10356/161385 |
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| author | Feng, Lujia Zhang, Tengfei Koh, Tieh-Yong Hill, Emma M. |
| author2 | Asian School of the Environment |
| author_facet | Asian School of the Environment Feng, Lujia Zhang, Tengfei Koh, Tieh-Yong Hill, Emma M. |
| author_sort | Feng, Lujia |
| collection | NTU |
| description | Using data from the Sumatran GPS Array in Indonesia–a hero network in tectonic and earthquake studies– we study the summer intra-seasonal variability of precipitable water vapor (PWV) over Sumatra in years without strong inter-annual variability. Unlike most other studies that used external meteorological data to derive PWV from Global Positioning System (GPS) signal delays, we use the zenith wet delay (ZWD) time series estimated from a regular geodetic-quality processing routine as a proxy for PWV variations without using auxiliary meteorological data. We decompose the ZWD space-time field into modes of variability using rotated Empirical Orthogonal Function (EOF) analysis and investigate the mechanisms behind the two most important modes using linear regression analysis both with and without lags. We show that the summer intra-seasonal variability of daily ZWD over Sumatra in 2008, 2016, and 2017 was dominated by the South Asian Summer Monsoon and further influenced by dry-air intrusions associated with Rossby waves propagating in the Southern Hemisphere midlatitudes. Both active South Asian monsoons and dry-air intrusions contribute to the dryness over Sumatra during northern summer. Our results indicate an intra-seasonal connection between the South Asian and western North Pacific Summer Monsoons: when the South Asian monsoon is strong, it pumps atmospheric water vapor over the eastern Indian Ocean to feed into the western North Pacific monsoon. We also show a tropical-extratropical teleconnection where PWV over the southern Maritime Continent can be modulated by the activity of eastwardtraveling Rossby waves in the southern midlatitudes. Our case study demonstrates the use of regional continuously operating GPS (cGPS) networks for investigating atmospheric processes that govern intra-seasonal variability in atmospheric water vapor. |
| first_indexed | 2024-10-01T03:01:48Z |
| format | Journal Article |
| id | ntu-10356/161385 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T03:01:48Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | ntu-10356/1613852022-09-03T20:11:06Z Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia Feng, Lujia Zhang, Tengfei Koh, Tieh-Yong Hill, Emma M. Asian School of the Environment Science::Geology Precipitable Water Vapor Intra-Seasonal Variability Using data from the Sumatran GPS Array in Indonesia–a hero network in tectonic and earthquake studies– we study the summer intra-seasonal variability of precipitable water vapor (PWV) over Sumatra in years without strong inter-annual variability. Unlike most other studies that used external meteorological data to derive PWV from Global Positioning System (GPS) signal delays, we use the zenith wet delay (ZWD) time series estimated from a regular geodetic-quality processing routine as a proxy for PWV variations without using auxiliary meteorological data. We decompose the ZWD space-time field into modes of variability using rotated Empirical Orthogonal Function (EOF) analysis and investigate the mechanisms behind the two most important modes using linear regression analysis both with and without lags. We show that the summer intra-seasonal variability of daily ZWD over Sumatra in 2008, 2016, and 2017 was dominated by the South Asian Summer Monsoon and further influenced by dry-air intrusions associated with Rossby waves propagating in the Southern Hemisphere midlatitudes. Both active South Asian monsoons and dry-air intrusions contribute to the dryness over Sumatra during northern summer. Our results indicate an intra-seasonal connection between the South Asian and western North Pacific Summer Monsoons: when the South Asian monsoon is strong, it pumps atmospheric water vapor over the eastern Indian Ocean to feed into the western North Pacific monsoon. We also show a tropical-extratropical teleconnection where PWV over the southern Maritime Continent can be modulated by the activity of eastwardtraveling Rossby waves in the southern midlatitudes. Our case study demonstrates the use of regional continuously operating GPS (cGPS) networks for investigating atmospheric processes that govern intra-seasonal variability in atmospheric water vapor. Ministry of Education (MOE) National Research Foundation (NRF) Published version This work comprises EOS contribution no. 295. This research was supported by the National Research Foundation Singapore under its NRF Investigatorship scheme (National Research Investigatorship Award No. NRF-NRFI05-2019-0009 to E.M.H.), and by the EOS via its funding from the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centers of Excellence initiative. Figures were made using Generic Mapping Tools (Wessel et al. 2013). 2022-08-30T06:37:22Z 2022-08-30T06:37:22Z 2021 Journal Article Feng, L., Zhang, T., Koh, T. & Hill, E. M. (2021). Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia. Journal of the Meteorological Society of Japan, 99(2), 505-536. https://dx.doi.org/10.2151/jmsj.2021-026 0026-1165 https://hdl.handle.net/10356/161385 10.2151/jmsj.2021-026 2-s2.0-85107411630 2 99 505 536 en NRF-NRFI05-2019-0009 Journal of the Meteorological Society of Japan © 2021 The Author(s). This is an open access article published by the Meteorological Society of Japan under a Creative Commons Attribution 4.0 International (CC BY 4.0) license (https://creativecommons.org/licenses/by/4.0) application/pdf |
| spellingShingle | Science::Geology Precipitable Water Vapor Intra-Seasonal Variability Feng, Lujia Zhang, Tengfei Koh, Tieh-Yong Hill, Emma M. Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia |
| title | Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia |
| title_full | Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia |
| title_fullStr | Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia |
| title_full_unstemmed | Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia |
| title_short | Selected years of monsoon variations and extratropical dry-air intrusions compared with the sumatran gps array observations in Indonesia |
| title_sort | selected years of monsoon variations and extratropical dry air intrusions compared with the sumatran gps array observations in indonesia |
| topic | Science::Geology Precipitable Water Vapor Intra-Seasonal Variability |
| url | https://hdl.handle.net/10356/161385 |
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