The Change in Rainfall from Tropical Cyclones Due to Orographic Effect of the
Sierra Madre Mountain Range in Luzon, Philippines

Bernard Alan B. Racoma1,2*, Carlos Primo C. David1,
Irene A. Crisologo1, and Gerry Bagtasa3

1National Institute of Geological Sciences, College of Science,
University of the Philippines, Diliman, Quezon City, Philippines
2Nationwide Operational Assessment of Hazards,
University of the Philippines, Diliman, Quezon City, Philippines
3Institute of Environmental Science and Meteorology, College of Science,
University of the Philippines, Diliman, Quezon City, Philippines

This paper discusses the Sierra Madre Mountain Range of the Philippines and its associated influence on the intensity and distribution of rainfall during  tropical cyclones. Based on Weather and Research Forecasting model simulations, a shift in rainfall was observed in different portions of the country, due to the reduction of the topography of the mountain. Besides increasing the rainfall along the mountain range, a shift in precipitation was observed during Tropical Storm Ondoy, Typhoon Labuyo, and Tropical Storm Mario. It was also observed that the presence of the Sierra Madre Mountain Range slows down the movement of a tropical cyclones, and as such allowing more time for precipitation to form over the country. Wind profiles also suggest that the windward and leeward sides  of mountain ranges during Tropical Cyclones changes depending on the storm path. It has been suggested that in predicting the distribution of rainfall, the direction of movement of a tropical cyclones as well as its adjacent areas be taken into great consideration. While the study shows high amounts of variation in the characteristics of different tropical cyclones with respect of the Sierra Madre Mountain Range, the results of this study can provide insights to pre-disaster operations before tropical cyclones approaches land. The decrease in tropical cyclones speed introduced by the Sierra Madre Mountain Range can be used to identify the possible areas that can experience prolonged rains due to the mountain range. Disaster management authorities can also prepare in advance by identifying which locations can experience orographic enhanced precipitation. However, due to the lack of available data and resources, further studies are recommended due to the study presenting limited cases.

Key words: geomorphology, numerical weather prediction, orographic effect, precipitation, tropical
                 cyclones, weather and research forecasting modelling

The Philippines is in constant exposure to tropical cyclones (TCs) that originate from the West Pacific Ocean (WPO). Out of all storms that form in the WPO,  an  average of 30.3% of these TCs make landfall in the Philippines (David et al. 2013). Correspondingly, every year as much as 19.4 TCs enter the Philippine Area of Responsibility, with 9 of these TCs actually making landfall (Cinco et al. 2016). Packing both strong winds and bringing extreme rainfall, most of these cause direct and indirect effects to the country, resulting to loss of lives and large damage to property. While the Intergovernmental Panel on Climate Change (IPCC) projects a decrease in the number of TCs over the West Philippine Sea (a part of the WPO) in the future, it conversely projects an increase in activity near subtropical Asia (Kirtman et al. 2013; Wang et al. 2011). Similarly, a significant increase in number of Category 4-5 TCs is expected between the years 2000 to 2050 in the neighboring southwest Pacific Ocean Basin (Leslie et al. 2007).


ABON C, DAVID C,  PELLEJERA  N. 2011. Reconstructing the Tropical Storm Ketsana flood event in Marikina River, Philippines, Hydrology and Earth System Sciences, 15:1283–1289
BRAND S, BLELLOCH J. 1973. Changes in the Characteristics of Typhoons Crossing the Philippines. Journal of Applied Meteorology., 12, 104–109
CINCO TA, DE GUZMAN RG, ORTIZ AMD, DELFINO RJP, LASCO RD, HILARIO FD, JUANILLIO EL, BARBA R, ARES ED. 2016. Observed trends and impacts of tropical cyclones in the Philippines: observed trends and impacts of tropical cyclones in the philippines. International Journal of Climatology, n/a–n/a.
CRISOLOGO I, VULPIANI G, ABON CC, DAVID CPC, BRONSTERT, A, HEISTERMANN M. 2014. Polarimetric rainfall retrieval from a C-Band weather radar in a tropical environment (The Philippines). Asia-Pacific Journal of Atmospheric Sciences, 50(S1), 595–607.  
DAVID CC, RACOMA BB, GONZALES J, CLUTARIO M. 2013. A Manifestation of Climate Change? A Look at Typhoon Yolanda in Relation to the Historical Tropical Cyclone Archive. Science Diliman, Vol 25, No 2. 79-86
FANG X, KUO YH, WANG A. 2011. The Impacts of Taiwan Topography on the Predictability of Typhoon Morakot’s Record-Breaking Rainfall: A High-Resolution Ensemble Simulation. Weather and Forecasting, 26(5), 613–633.  
GERMANN U, GALLI G, BOSCACCI M, BOLLIGER M. 2006. Radar precipitation measurement in a mountainous region. Quarterly Journal of the Royal Meteorological Society, 132(618), 1669–1692.  
HONG SY, LIM JOJ. 2006. The WRF single-moment 6-class microphysics scheme (WSM6). Journal of Korean Meteorological Society. (42):129–151.
JAMANDRE CA, NARISMA GT. 2013. Spatio-temporal validation of satellite- based rainfall estimates in the Philippines. Atmospheric Research, 122, 599–608.
JOYCE RJ, JANOWIAK JE, ARKIN PA, XIE P. 2004. CMORPH: A method that produces global precipitation estimates from passive  microwave  and  infrared data at high spatial and temporal resolution. Journal of Hydrometeorology. (5): 487-503.
JUANICO MB, AGNOLN. 1987. Physical Geography. Quezon City: JMC Press, Inc., 1987.
KAIN JS. 2004. The Kain-Fritsch convective parameterization: an update. Journal of Applied Meteorology, 43(1), 170–181.
KIRTMAN B, POWER SB, ADEDOYIN JA, BOER GJ, BOJARIU R, CAMILLONI I, DOBLAS- REYES FJ, FIORE AM, KIMOTO M, MEEHL GA, PRATHER M, SARR A, SCHÄR C, SUTTON R, VAN OLDENBORGH GJ, VECCHI G, WANG HJ. 2013. Near-term Climate Change: Projections and Predictability. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New    York,    NY,    USA,    pp.    953–1028,  
KNAPP KR, KRUK MC, LEVINSON V, DIAMOND HJ, NEUMANN  CJ. 2010. The International Best Track Archive for Climate Stewardship  (IBTrACS):  Unifying tropical cyclone best track data. Bulletin of the American Meteorological Society,    91,    363-376.    non-government    domain  
LAGMAY AMF, BAGTASA G, CRISOLOGO IA, RACOMA BAB, DAVID CPC. 2015. Volcanoes magnify Metro Manila's southwest monsoon rains and lethal floods. Frontiers of Earth Science, 2:36.
LAPEÑA C. 2010: Super typhoon Juan makes landfall in Northern Sierra Madre. GMA News Online. Web. 18 Oct. 2010. Retrieved from
LESLIE LM, KAROLY DJ, LEPLASTRIER M, BUCKLEY BW. 2007. Variability of tropical cyclones over the southwest Pacific Ocean using a high-resolution  climate  model. Meteorology and Atmospheric Physics, 97(1-4), 171–180.  
MINAMIDE M, YOSHIMURA K. 2014. Orographic Effect on the Precipitation with Typhoon Washi in the Mindanao Island of the Philippines. Scientific  Online Letters on the Atmosphere, 10(0), 67–71.    
[NSO] NATIONAL STATISTICS OFFICE. 2010. Population and Annual Growth Rates for The  Philippines and Its Regions, Provinces, and Highly Urbanized Cities. 2010  Census and Housing Population. Retrieved from
National Oceanic and Atmospheric Administration National Climatic Data Center International Best Track Archive for Climate Stewardship (IBTrACS). Retrieved from on 2014-08-18
RAKTHAM C, BRUYÈRE C, KREASUWUN J, DONE J, THONGBAI C, PROMNOPAS W. 2015. Simulation sensitivities of the major weather regimes of the Southeast Asia region. Climate Dynamics, 44(5-6), 1403–1417.
RANTUCCI G. 1994. Geological Disasters In The Philippines: The July 1990 Earthquake And The June 1991 Eruption of Mount Pinatubo. Description, effects and lessons learned. Philippine Institute of Volcanology and Seismology (PHIVOLCS). ISBN 978-0-7881-2075-6
ROE GH. 2005. OROGRAPHIC PRECIPITATION. Annual Review of Earth and Planetary Sciences 33(1), 645–671.
SKAMAROCK WC, KLEMP JB, DUDHIA J, GILL DO, BARKER DM, WANG W, POWERS JG. 2005. A description of the advanced research WRF version 2. DTIC Document. Retrieved from on 2014-08-28
 Terry JP, Feng CC. 2010. On quantifying the sinuosity of typhoon tracks in the western North Pacific basin. Applied Geography, 30(4), 678–686.  
WANG R, WU L, WANG C. 2011. Typhoon Track Changes Associated with Global Warming. Journal of Climate, 24(14), 3748–3752.
YANG MJ, ZHANG DL, HUANG HL. 2008. A Modeling Study of Typhoon Nari (2001) at Landfall. Part I: Topographic Effects. Journal of the Atmospheric Sciences, 65(10), 3095–3115.  
ZHANG X, ANAGNOSTOU EN, FREDIANI M, SOLOMOS S, KALLOS G. 2013. Using NWP Simulations in Satellite Rainfall Estimation of Heavy Precipitation Events over Mountainous Areas. Journal of Hydrometeorology, 14(6), 1844–1858.