Multi-year Precipitable Water Vapor Observations in East Manila, Philippines using Radiosonde and Global Navigation Satellite System

Precipitable water vapor (PWV) is a parameter that used to describe the water vapor content in the atmosphere has the potential to become a precipitation. Thus, it is important to measure PWV and investigate its trends and variability for potential forecasting precipitation. This study presents the variation of PWV at Tanay Upper Station (14°34’52.8”N, 121°22’08.9”E) from radiosonde operated by the Philippine Atmospheric, Geophysical and Astronomical Services Administration and at PIMO station (14°38’08.5”N, 121°04’39.4”E) using Global Navigation Satellite System (GNSS) operated by NASAJet Propulsion Laboratory under the International GNSS Service (IGS) network from 2015-2017. Moreover, there is no significant difference (p-values < 0.05) among PWV radiosonde, GNSS-PWV and rainfall as a function of year of observation. Monthly mean variation conforms to the Coronas climate classification, Climate Type I, in terms of the amount of precipitation. It is shown that PWV is high during wet months and least during dry months (November to April). Further, monthly mean variation is moderate correlated with surface temperature from radiosonde (R = +0.589). Evaporation rate depends on the surface temperature, which contributes in forming water vapor. The results showed that PWV from radiosonde gave reasonable values to be considered during wet and dry season as well as the seasonal variation of rainfall

Development of a low-cost sunphotometer tracking and data acquisition system

A low-cost sun tracking and data acquisition system for the SPO 2 and SP10 1 sun photometers were developed. The sun-tracking system has a 1-degree pointing error and was based on a mathematical algorithm that depends on the position of the observer and the time of observation. A virtual instrument software called The Sun photometer Data Acquisition System (SunDAPS) was developed using LabVIEW6.1TM. It was used to acquire analog signals from the sun photometers and control the tracking system through the NI PCI-6023 ETM DAQ card

Two-Dimensional Mapping of Ionospheric Total Electron Content over the Philippines Using Kriging Interpolation

Monitoring of ionospheric total electron content (TEC) was made possible with the help of satellite data, albeit in one dimension. However, ionospheric TEC maps can be produced from a collection of one-dimensional satellite data over a geographic area. Multiple mapping methods have been recognized; however, this study tried to test one of those methods: kriging interpolation. An algorithm was developed and used to reconstruct GIMs. The optimum number of stations and the semivariogram model were evaluated using GIM maps modeling 12 days of March 2015, accounting for different ionospheric conditions. This includes days of high scintillation and an ionospheric storm due to the St. Patrick’s Day geomagnetic storm of 2015. It was found that 12 stations and the linear semivariogram model had the least mean error in 5 days and had the least standard deviation in 7 days, making it the optimum parameter set. This optimum set was then used to map and analyze the ionosphere using actual satellite data from the Philippine Active Geodetic Network (PAGeNet). From this, it was observed that there is a north–south gradient in VTEC in the region during the day. The VTEC in the north reaches more than 100 TECU, and, in the south, generally around 60–90 TECU depending on the ionospheric condition. VTEC was at a minimum during the night when the VTEC level decreases to around 10 TECU

Retrieval of boundary layer and cloud base heights in Manila from a two-wavelength lidar measurement

The boundary layer and cloud heights were determined from two wavelength lidar measurement in Manila. Normalized concentration gradient (NCG) method was implemented in the boundary layer height retrieval and from the slope of the range squared corrected signal (RSCS), the cloud base heights were retrieved. During the time of the measurement from 1500 to 2200 HR local time, the boundary layer height was found to be stable at around 370 m, which is considered as period of stable stratification. The cloud heights from the slope method during the measurement period was 800 m up to 1.2 km and the other layer starting from 1.6 km to 1.8 km. The calculated cloud heights matched the clouds that can be determined visually from the range-squared corrected signal THI plot

A climatological study of typhoons over the Philippine Area of Responsibility from 1989–2018

The Philippines is in the Western North Pacific region, where it is a recipient of several weather disturbances such as tropical cyclones. This study aims to determine trends and periodicities of typhoons (TY) within the Philippine Area of Responsibility (PAR), and the rainfall they brought in a 30-year period (1989–2018) for future forecast and disaster risk mitigation efforts of these TY. These TYs are raised when TC’s sustained winds are 118 kph and above. Frequency analysis of TY is done to determine the trends and periodicities in terms of the yearly total occurrence, number of TY that made landfall, distribution of TY classification, and their seasonal variation. The results showed that with PAR the yearly total occurrence of TY seems to have an approximately 12-year periodicity where maximum occurrence was observed around the years 1994, 2004, and 2014 while minimum occurrence was observed in years 1989, 1999, and 2010. Also, track data shows that only 32 % of these TY made a landfall within PAR. Out of the three regions in the Philippines, Luzon Island is the region where most of the severe typhoons made landfall at 80 %. Moreover, TYs occurred mostly during September to November where the transition period between the northeast monsoon and south west monsoon usually occurs. Also, rainfall during which these TYs have occurred were obtained from five synoptic stations across the Philippines. It showed from 1989 to 1998, the total yearly rainfall brought by these TYs ranged from 804 mm to 1 912 mm. But from 1999 to 2018, these TYs brought more rain where their total yearly rainfall ranged from 2 844 mm to 4 941 mm

Simultaneous scanning lidar measurement and air sampling using a personal cascade impactor for traffic aerosol characterization

Simultaneous vertical scanning lidar measurement and air sampling using a personal cascade impactor was presented in this paper. The fine particulate matters collected using the personal cascade impactor were characterized for their morphology and elemental composition using a scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The scanning Lidar provided a two-dimensional profile of the traffic aerosol showing the spatial distribution of the aerosol horizontally and vertically as indicated by the strong backscattering signal. SEM image showed that the particles collected from the sampling site were irregularly shaped particles. Elemental analysis showed the presence of C and O, in all particles are with traces of Ca, Si, Cu, V, Zn, Sb, Fe, Mg, K, Ba, Co, Cl, Sn, Ni, and Br. Most of these elements are typically associated with anthropogenic emissions such as traffic and combustion of fossil fuels. The study showed that a combined Lidar and air sampling with SEM-EDX analysis can give a better understanding of the characteristics of aerosols such as its spatial distribution, shape, morphology, and chemical composition, and possibly the source

Multi-angle lidar sensing of traffic aerosol in Manila

Multi-angle lidar sensing of traffic aerosols was conducted in a very busy Manila area. The backscatter coefficients for 355 nm and 532 nm were calculated from Fernald\u27s inversion method using calibration results retrieved from the slant-path method. An aerosol extinction-to-backscatter ratio of 30 sr was assumed in the calculation. Several scans were conducted on 31 July 2003 during peak traffic hours to observe the two-dimensional spatial and temporal distribution of traffic aerosols. The presence of a constant aerosol mass near a busy intersection was observed throughout the scanning period. The calculated backscatter coefficient for these aerosol mass ranged from 3.56×10 -6 m-1sr-1 to 5.01×10-6 m -1sr-1 for 532 nm and 1.76×10-5 m -1sr-1 to 2.02×10-5m-1sr -1 for 355 nm

Temporal and spectral variation of aerosol optical depth (AOD) over Manila

Aerosol optical depths for four wavelengths (368, 500, 675, 862 nm) were obtained using a commercial sunphotometer over Manila. A total of 33 values of mean AOD were calculated in the morning (11) and afternoon (22) sessions from 1 March to 2 April 2004 in DLSU-Manila. The more of the shorter wavelengths than the longer ones