The effect of urbanization on temperature indices in the Philippines

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.

Automated summary

This study provides a comprehensive analysis of the impact of urbanization on surface air temperature trends in the Philippines from 1951 to 2018. Results indicate significant differences in SAT trends between urban and rural stations, with urbanization showing a greater effect on T-min-related indices.