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​Atmospheric water vapor in the eye of the Sumatran GPS Array (SuGAr): A case study of the 2008 northern summer

Published on: 30-Aug-2019

Event Type: Seminar
Event Date: 30 August 2019 - 4:00pm to 5:00pm
Venue: ASE 3D Viz Laboratory Room (N2-B1c-16c)
Speaker: Dr. Feng Lujia

About the speaker:

Dr. FENG Lujia is a Senior Research Fellow at the Earth Observatory of Singapore (EOS), Nanyang Technological University (NTU), Singapore. She received her B.Sc. in Geology and M.Sc. in Structural Geology from Zhejiang University in China, and her Ph.D. in Geophysics from Georgia Institute of Technology in USA. She is a geodesist who has various experiences in using GPS to study tectonic, seismic, and volcanic deformation. Much of her work at EOS has involved analysis and modeling of the deformation signals from the Sumatran GPS Array (SuGAr). She has recently developed her interest in using the atmospheric water vapor information collected by the SuGAr to study the weather and climate over Southeast Asia. Known as “Tectonic Squirrel”, Lujia is hoping to become a “Climate Squirrel” in the near future.

About the event:

Although originally designed for positioning, navigation, and timing, the Global Positioning System (GPS) can be used as a powerful tool for observing the amount of water vapor in an atmospheric column. Over the past three decades, an exponentially growing number of continuously operating GPS (cGPS) stations have been built for recording tectonic and earthquake deformation; however, the rich trove of information about atmospheric water vapor (AWV) from these stations has yet to be widely investigated.

In the Ph.D. dissertation of Dr. ZHANG Tengfei, he conducted a case study using the zenith wet delay data from the SuGAr for the northern summer of 2008, which was not strongly influenced by either the El Niño-Southern Oscillation (ENSO) or Indian Ocean Dipole (IOD). His results show that the summer intra-seasonal variability over Sumatra in a year without strong inter-annual variability is dominated by the Indian monsoon and further influenced by dry-air intrusions due to Rossby waves originating in the Southern Hemisphere.

In this talk, I will present an update on this case study. Our new results reveal an intra-seasonal connection between the Indian monsoon and the western North Pacific monsoon. When the Indian monsoon is strong, it pumps AWV over Sumatra and the eastern Indian Ocean to feed into the convection in the western North Pacific monsoon region. Additionally, our results suggest a teleconnection in which the southern Maritime Continent - including southern Sumatra - is influenced by quasi-biweekly activity of Rossby waves in the Southern Hemisphere mid-latitudes. I would also like to acknowledge the contribution of Tengfei to SuGAr meteorology.

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