Mapping meteorological drought hazard in the Philippines using SPI and SPEI

Salvacion Arnold R. 대한공간정보학회 2021 Spatial Information Research Vol.29 No.6

Drought is a natural hazard with a severe and long-lasting impact on both human and natural systems. Among different drought categories, assessment of meteorological drought is imperative because it is the root cause of other types of drought. In the Philippines, there are limitations (access, availability, and spatial coverage) of long-term climate records to assess drought on the national scale. This paper aims to use the free high spatial resolution and long-term monthly climate data (i.e. rainfall and temperature) from TerraClimate to characterize meteorological drought hazard in the Philippines. The study used two commonly used drought hazard index such as the Standard Precipitation Index, and Standardized Precipitation Evapotranspiration Index to derive different drought characteristics. Based on the results, drought characteristics vary spatially across the country. There are areas in the country where drought duration can last up to 11 months. The magnitude of drought Philippines ranges from 47 to 677 mm with strength of 60 to 800 mm/month. Lastly, this study showed similar results compared to previous drought records and similar studies in the Philippines.

Exploring spatial patterns of trends in monthly rainfall and temperature in the Philippines based on Climate Research Unit grid

Arnold R. Salvacion,Damasa B. Magcale-Macandog,Pompe C. Sta. Cruz,Ronaldo B. Saludes,Ireneo B. Pangga,Christian Joseph R. Cumagun 대한공간정보학회 2018 Spatial Information Research Vol.26 No.5

This study assessed spatial pattern of trends in monthly rainfall and temperature in the Philippines using Climate Research Unit time series data. Based on the results, there are significant trends in monthly rainfall and temperature in the country. On the average, monthly rainfall in the country is increasing by 0.34 mm/year. In the case of monthly temperature, the average increases per year were 0.008 and 0.019 C, for maximum and minimum temperature, respectively. In terms of proportion, larger portion of the country showed significant trends in monthly temperature ([80%) compared to rainfall (\10%). Shift in wettest, driest, warmest, and coldest months were also observed between the periods of 1951–1980 to 1986–2015.

Banana suitability and Fusarium wilt distribution in the Philippines under climate change

Arnold R. Salvacion,Christian Joseph R. Cumagun,Ireneo B. Pangga,Damasa B. Magcale-Macandog,Pompe C. Sta. Cruz,Ronaldo B. Saludes,Tamie C. Solpot,Edna A. Aguilar 대한공간정보학회 2019 Spatial Information Research Vol.27 No.3

Climate change is expected to affect crop production directly and indirectly due to changes in crop suitability, decrease in productivity, and higher incidence of pest and diseases. In the case of banana, change in suitability and distribution of Fusarium wilt due to climate change can pose a major threat on its production system. Being a major dollar earner for the Philippines, these threats can greatly affect the country’s economic and food production system. This study assessed banana suitability and the potential distribution of Fusarium wilt in the Philippines under current and future climate condition using fuzzy logic and maximum entropy approach. Based on the results, climate change might have limited impact on banana suitability in the country. But the projected changes in rainfall in the future can increase the areas that are favorable for Fusarium wilt occurrence. From 21% under baseline climate condition, favorable areas for Fusarium wilt in the Philippines is estimated to increase to 27% covering 91.2% and 28.5% of the country’s highly and moderately suitable areas for banana, respectively. Such coverage accounts for approximately 67% of the country’s total harvested area for banana.

Climate Change Impact on Corn Suitability in Isabela Province, Philippines

Arnold R. Salvacion,Artemio A. Martin Jr. 한국작물학회 2016 Journal of crop science and biotechnology Vol.19 No.3

Climate change is expected to affect agricultural crop production in the Philippines. Several studies were already done to quantify the effect of climate change on agricultural crop production in the country. Most of these studies focus only on the effect of climate change on crop yield. This study estimated the effect of climate change on the area (suitable area) for corn production. Using the Land Use Suitability Evaluation Tool (LUSET), change in corn suitability in the province of Isabela was estimated for the years 2050, 2060, and 2070. Based on the results, climate change will negatively impact corn suitability in the province. Decreasing trend in corn suitability rating was observed due to increasing temperature resulting to loss of highly suitable areas for corn production. For example, during the first cropping season the estimated average decreases in suitability scores due to an increase in temperature were 6.7, 11.4, and 20.7% in the years 2050, 2060, and 2070, respectively. These decreases in suitability resulted in the loss of 6,777 ha highly suitable areas for corn production.

Fuzzy logic approach to explore climatic limitation on corn production in the Philippines

Arnold R. Salvacion 대한공간정보학회 2017 Spatial Information Research Vol.25 No.3

Corn production in the Philippines is highly sensitive to climate. However, to date, no assessment was done to determine which climate parameter (i.e. rainfall and temperature) limits corn production in the country. Using publicly available climatic surface data and fuzzy suitability assessment spatio-temporal mapping of climatic limitation on corn production was done for the entire Philippines. Based on the analysis, monthly rainfall is the major limitation of corn production in the country, specifically the rainfall during the first month of the growing period. For example, planting corn during the month of February, March, and April is not highly recommended for more than 40% of the country because monthly rainfall in these areas are lower than the minimum rainfall requirement (100 mm) of corn during the first month of its growing period.

COVID-19 susceptibility mapping: a case study for Marinduque Island, Philippines

Arnold R. Salvacion 대한공간정보학회 2022 Spatial Information Research Vol.30 No.5

Small islands are highly susceptible to infectious disease outbreak and other health emergencies because of their remoteness, small physical size, and poorly developed infrastructure. These are true in the case of Marinduque, an island province around 200 km south of the National Capital Region (NCR), which is the “epidemiological epicenter” of the COVID-19 pandemic in the Philippines. This study utilized GIS and Principal Component Analysis (PCA) using demographic, socio-economic, and geographic indicators to map susceptibility of different villages in the island province of Marinduque, the Philippines. Based on the results, the northwestern and northeastern portion of Marinduque has a higher susceptibility score. Also, villages in the town centers have relatively high susceptibility scores compared to other villages in each municipality.

A crop rotation model for Marinduque, Philippines

Emerson R. Rico,Destiny S. Lutero,Allen L. Nazareno,Arnold R. Salvacion 대한공간정보학회 2022 Spatial Information Research Vol.30 No.4

Crop production faces an increasing threat due to anthropogenic activities and natural hazards. Crop rotation is a tool that can address these issues in crop production. This study proposes an optimization model that generates a crop rotation plan using spatiotemporal suitability scores given a set of crops, with an objective to maximize the total suitability of the assignment of crops while satisfying principles of crop rotation such as suitability threshold and crop succession requirements. Biophysical and climatic characteristic data from Marinduque, Philippines, with upland rice, corn, and mungbean as crops, were used to validate the model. The results show that with a minimum suitability threshold of 0.6, an optimal crop rotation plan for one annual cycle included corn and mungbean for one (May to October) and two (June to August, September to November) cropping periods, respectively. Throughout each cropping period, the corn and mungbean will cover 46.64% and 10.33% of the arable land, respectively. Based on the crop rotation plan, corn can be cultivated along the shorelines except in the southeast area of the island, where mungbean is more suitable. The results suggest that other crops should be considered since the current set of crops leaves 43% of the arable land unutilized. This model can be used for any combination of crops and other spatiotemporal suitability factors, allowing it to be applied to different sites and scenarios.

Characterizing malaria spatial distribution in the province of Palawan, Philippines

Nicole Faith D. Blanco,Arnold R. Salvacion,Ma. Catriona E. Devanadera,Edwin R. Abucay,Ricardo A. Sandalo 대한공간정보학회 2022 Spatial Information Research Vol.30 No.2

Palawan, an island province in the Philippines, accounts for ninety percent of the country’s malaria cases. A total of 18 of 23 municipalities and one city in Palawan remain malaria-endemic, placing the population at risk of infection despite continuous preventive measures. This study describes trends and analyzes the spatial distribution of confirmed malaria cases in Palawan during eleven-year period (2005–2015). The reported monthly positive malaria cases per municipality from 2005 to 2015 were obtained from the Provincial Health Office, which was aggregated and used in trend and spatial analysis. High malaria risk areas were determined using the Moran’s I and Getis-Ord Gi*. The Mann–Kendall test results revealed that there had been a significant downward trend of confirmed positive cases from 2005 to 2015, with transmission peaks in 2007 and 2010. Among the three districts in the province, district 2 reported the highest total cases comprising 65 percent of the province’s total reported malaria cases, followed by district 3 with 20 percent, and 15 percent were from district 1. High malaria concentration was observed in municipalities located in the southern part of the province, including Rizal, Narra, Brooke’s Point, Sofronio Espan˜ola, and Bataraza (in district 2). Puerto Princesa City (in District 3) was among the municipalities with high malaria transmission during 2005–2011. The results of this study could help in determining targeted malaria control interventions and prioritizing resource allocation for areas with high malaria transmission for future public health planning. This would also contribute to efforts of the public and private sectors to eliminate malaria in Palawan Province by 2030.

Optimal route planning for day tours in Marinduque, Philippines

Destiny S. Lutero,Gilbert Elvis A. Cerilo,Allyssa M. Eustaquio,Christian Alvin H. Buhat,Aldrin O. Nazareno,Allen L. Nazareno,Arnold R. Salvacion 대한공간정보학회 2022 Spatial Information Research Vol.30 No.2

Island day tours have become a ubiquitous inclusion in travel itineraries. Marinduque is one of the Philippine islands where its major tourist attractions can be covered by day tours. This study determines an itinerary of select tourist spots for island day tours in Marinduque. The longitude, latitude of each tourist spot and the pairwise road distances were determined. Every tour was assumed to start and end at the same point, either at Marinduque Airport or at Balanacan Port, and would last for at most 8 h. To determine the optimal route for the different types of tours (general and themed), an integer programming model was formulated. Balanacan port is the point of origin for three of the four identified tours. The general tour is the ideal choice for those who want to maximize theme diversity. The history-themed and church-themed tours are covered in at least three of the four tours. All tours ran from 7.5 to 8 h. All themed-tours covered their themed points except for the cave-themed. All points except one were visited in at least one tour. Three of the four pilgrim points were visited in all tours, while the cave sites were only visited in the cave-themed tour. The results of this study are beneficial to the community of Marinduque, as these will contribute to the tourism management plan of the province. The model may be extended to consider other tourist destinations.