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Quezon City, Philippines

Chen T.-C.,Iowa State University | Tsay J.-D.,Iowa State University | Yen M.-C.,National Central University | Cayanan E.O.,Philippine Atmospheric
Weather and Forecasting | Year: 2010

Stretched from Indochina, across the South China Sea, to the Philippine Sea, a monsoon cyclonic shear flow was formed by easterlies of the cold surge-like flow in the north and monsoon westerlies in the south before the onset of the tropical Southeast Asian monsoon on 12 May 2008. On this date, two named tropical cyclones (Halong and Matmo) evolved with a 12-h lag from a closed vortex adjacent to the coast of central Vietnam and another closed vortex near Palawan Island (Philippines) within this shear flow. These two cyclones, named the twin Philippine tropical cyclones, moved almost on the same track, along the anomalous shear line (departure from the climatological one) across the Philippines, and turned northeastward to the ocean south of Japan. It was revealed from synoptic analysis that the cold surge-like flow was coupled with the midlatitude eastward-propagating short wave in northeast Asia, and part of the monsoon westerlies were fed by the cross-equatorial flow, the downstream flow of easterlies around the northern rim of the Southern Hemisphere subtropical high. The environment favorable for the formation of the twin cyclones was developed from the tropics-midlatitude interaction between synoptic systems in these two latitudinal zones. Formations of these cyclones were a result of drastic spinups of the two closed vortices (within the monsoon shear flow) following the surge of monsoon westerlies, which coincided with those of easterlies of the cold surge-like flow, and the cross-equatorial flow originating from easterlies between the Southern Hemisphere subtropical high and the Southern Hemisphere shear flow. © 2010 American Meteorological Society. Source

Yumul Jr. G.P.,University of the Philippines at Diliman | Servando N.T.,Philippine Atmospheric | Suerte L.O.,Mines and Geosciences Bureau Regional Office 6 | Magarzo M.Y.,Mines and Geosciences Bureau Regional Office 6 | And 2 more authors.
Natural Hazards | Year: 2012

An unusual amount of precipitation fell in Panay island during the passage of Typhoon Fengshen (local name: Typhoon Frank) in June 2008. The voluminous amount of rain is attributed to the interaction of the tropical cyclone and southwest monsoon as the latter was enhanced by the former during its passage across central Philippines. Ground and aerial surveys were conducted to document the extensive flooding and landslides that occurred in the island. Artificial damming of rivers followed by breaching resulted to flooding, whereas steep slopes, fractured lithologies and intense precipitation were recognized to have led to the occurrence of landslides. These natural hazards and their causes are presented to contribute to our understanding of how weather systems evolve and what the corresponding effects are on the ground. This, hopefully, can provide significant inputs in improving disaster risk reduction and preparedness programs. © 2012 Springer Science+Business Media B.V. Source

Faustino-Eslava D.V.,University of the Philippines at Diliman | Yumul G.P.,University of the Philippines at Diliman | Servando N.T.,Philippine Atmospheric | Dimalanta C.B.,University of the Philippines at Diliman
Global and Planetary Change | Year: 2011

In the first half of January 2009, the southern Philippine island of Mindanao was overwhelmed by numerous natural disasters caused by the passage of the tail-end of the cold front. This otherwise ordinary weather condition was accompanied by unusually heavy precipitation sustained over a period of several days. This triggered numerous landslides and caused many drainage systems to swell, flooding huge tracts of low lying areas that have not experienced similar events in the recent past. Many communities were caught unprepared for the calamity. The amount and extent of damage reflect both the magnitude of the natural disaster itself and the community's nominal level of disaster-preparedness. In view of the increasing atmospheric moisture levels and the likelihood that global warming will affect the weather patterns, there is a possibility that similar weather disturbances can become more frequent. Therefore, there is an urgent need for disaster risk management programs to be developed or enhanced at the local community level especially in areas most vulnerable to weather-related natural hazards, in light of changing global climatic patterns. © 2010 Elsevier B.V. Source

Lapidez J.P.,Nationwide Operational Assessment of Hazards | Tablazon J.,Nationwide Operational Assessment of Hazards | Dasallas L.,Nationwide Operational Assessment of Hazards | Gonzalo L.A.,Nationwide Operational Assessment of Hazards | And 7 more authors.
Natural Hazards and Earth System Sciences | Year: 2015

Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR) on 7 November 2013, causing tremendous damage to infrastructure and loss of lives mainly due to the storm surge and strong winds. Storm surges up to a height of 7 m were reported in the hardest hit areas. The threat imposed by this kind of natural calamity compelled researchers of the Nationwide Operational Assessment of Hazards (Project NOAH) which is the flagship disaster mitigation program of the Department of Science and Technology (DOST) of the Philippine government to undertake a study to determine the vulnerability of all Philippine coastal communities to storm surges of the same magnitude as those generated by Haiyan. This study calculates the maximum probable storm surge height for every coastal locality by running simulations of Haiyan-type conditions but with tracks of tropical cyclones that entered PAR from 1948-2013. One product of this study is a list of the 30 most vulnerable coastal areas that can be used as a basis for choosing priority sites for further studies to implement appropriate site-specific solutions for flood risk management. Another product is the storm tide inundation maps that the local government units can use to develop a risk-sensitive land use plan for identifying appropriate areas to build residential buildings, evacuation sites, and other critical facilities and lifelines. The maps can also be used to develop a disaster response plan and evacuation scheme. © Author(s) 2015. Source

Cayanan E.O.,Philippine Atmospheric | Chen T.-C.,Iowa State University | Argete J.C.,University of the Philippines | Yen M.-C.,National Central University | Nilo P.D.,Philippine Atmospheric
Journal of the Meteorological Society of Japan | Year: 2011

Intense southwest monsoon (SWM) rainfall events causing massive landslides and flash floods along the western sections of the Philippines were studied. These rainfall events, are not directly coming from the tropical cyclones (TCs) for they are situated far north to northeast of Luzon Island. The heavy rainfall is hypothesized as caused by the interaction of strong westerlies with the mountain ranges along the west coast of Luzon that produces strong vertical motion and consequently generates heavy rainfall. Four of heavy SWM rainfall cases were examined to determine how the presence and position of tropical cyclones in the Philippine vicinity affect these SWM rainfall events; three cases with TC of varying positions within the Philippine area of responsibility (PAR) and the fourth case without TC. Using a spatial Fourier decomposition approach, the total streamfunction is decomposed into two flow regimes: monsoon basic flow (Waves 0-1) and tropical cyclone perturbation flow (Waves 2-23) over a domain of (20°E-140°W, 5°S-35°N). The purpose of this flow decomposition is to determine the latter's effect on or contribution to the monsoon activity. The analysis utilized the NCEP Final (FNL) data with 1° long. x 1° lat. resolution. Results show that the tropical cyclones over the Pacific Ocean located northeast of Luzon generate strong southwesterly winds over the west coast of Luzon. These in addition to the southwesterlies from the basic flow strengthened the southwest winds that interact with the high Cordillera Mountain ranges. © 2011, Meteorological Society of Japan. Source

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