The effect of urbanization on temperature indices in the Philippines. (12th July 2021)

• Record Type: Journal Article
• Authors: Manalo, John A.; Matsumoto, Jun; Takahashi, Hiroshi G.; Villafuerte, Marcelino Q.; Olaguera, Lyndon Mark P.; Ren, Guoyu; Cinco, Thelma A.
• Is Part Of: International journal of climatology. Volume 42:Number 2(2022)
• Page Start: 850
• Page End: 867
• Publication Date: 2021-07-12
• Subjects: extreme temperature indices -- satellite night‐light -- surface air temperature -- urbanization; Climatology -- Periodicals; Climat -- Périodiques; Climatologie -- Périodiques; 551.605
• DOI: 10.1002/joc.7276
• Languages: English
• ISSNs: 0899-8418

Abstract

Abstract: This paper presents a comprehensive analysis of the effect of urbanization on the surface air temperature (SAT) from 1951 to 2018 in the Philippines. The daily minimum temperature ( T min ) and daily maximum temperature ( T max ) records from 34 meteorological stations were used to derive extreme temperature indices. These stations were then classified as urban or rural based on satellite night‐lights. The results showed a significant difference in the SAT trends between urban and rural stations, indicative of the effect of urbanization in the country. Larger and more significant warming trends were observed in indices related to T min than those related to T max . In particular, the effects of urbanization were significant in the annual index series of T min, diurnal temperature range, minimum T min, percentage of days when T min was less than the 10th percentile ( T N10p ), percentage of days when T min was greater than 90th percentile ( T N90p ), and the number of coldest nights. The effects of urbanization were not as clear on the index series of maximum T max ( T Xx ), minimum T max ( T Xn ), percentage of days when T max was less than 10th percentile ( T X10p ), and the number of hottest days. The effects of urbanization on the annual series of extreme temperature indices were statistically significant at the 95% confidence level, with the exception of T max, T Xn, T Xx, T X10p, and the number of hottest days. Further analysis revealed that the effect of urbanization was the greatest during the DJF (December–January–February) season. These findings serve as a baseline study that focuses on the countrywide effect of urbanization on SAT trends in the Philippines. Abstract : The 34 synoptic stations in the Philippines were classified into urban and rural stations based on the satellite nightlights to estimate the effect of urbanization on the trends of extreme temperature indices (e.g., (a) T min and (b) T max ) in the country for the first time. The results show that larger and significant effects of urbanization were found in the annual indices related to T min as compared to those indices related to T max . Further analysis reveals that the maximum urbanization effect occurred during the winter season.