A landscape connectivity model to quantify contributions of heat sources and sinks in urban regions

•Landscape source-sink index was developed to quantify landscape configuration.•Water served as heat sinks during the day and heat sources at night.•Landscape impact on temperature varied seasonally at daytime and remained stable at night.•Large distance between green-impervious increased diurnal temperature variations.•Large distance between water-impervious decreased diurnal temperature variations.