Remote sensing of the Davao Atmosphere using a stand-alone GNSS Receiver and Radiosonde for 2013-2015

Date of Publication


Document Type

Master's Thesis

Degree Name

Master of Science in Physics


College of Science



Thesis Adviser

Maria Cecilia D. Galvez

Defense Panel Member

Edgar A. Vallar
Christopher T. Que
Ernest P. Macalalad
Jose Santos R. Carandang, VI


A standalone GNSS receiver was utilized to get an estimate of the atmospheric water vapor content in Davao City for the years 2013-2015. The datasets from the local radiosonde station was used to verify the measured GNSS-derived precipitable water vapor (PWV) where a significantly strong correlation (R=0.871) was obtained. A local, water vapor weighted mean temperature, Tm, model utilizing the datasets from the Davao City radiosonde station was derived and validated by comparison to the global and regional models. This local Tm model was utilized in the GNSS PWV calculations in the study as it is tuned to the local climate as well as its geographic condition.

Time series plots were made out of the calculated GNSS PWV values for the years 2013, 2014 and 2015 to test for any annual, seasonal and monthly variations. Results from analysis of variance (ANOVA) with post-hoc tests showed that significant difference were measured in the PWV means for the three years tested. There were also significant differences in the PWV means for the dry and wet season as well as between the cool dry, hot dry and wet seasons. The results for the monthly variations agree well with the wet and dry seasons with the month of February (2013-2015) getting the lowest average monthly value of GNSS PWV and the months of May (2013, 2015) and June (2014) the highest. Finally, the temporal behavior of GNSS PWV was also evaluated for moderate to torrential rain events. It was shown that while moderate rain follows small variations in PWV, heavy torrential rains usually follow a peak in the PWV value with a time lag ranging from 2 10 hours and a decrease in PWV that ranges from 5-15 mm.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer disc ; 4 3/4 in.


Atmosphere--Research--Philippines; Atmospheric science--Philippines; Climatology

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