Abstract: Greenspace and water could mitigate the urban heat island effect through their cooling island effect. Evaluation of greenspace and water cool island demand is of great significance to optimizing spatial distribution of greenspace and water. We integrated Landsat remote sensing images, NPP/VIIRS nighttime light data, GDP and population density data of Fujian Delta urban agglomeration in 2017, and constructed an evaluation index system of cool island demand based on three dimensions, including heat island stress degree, land vulnerability degree, and social sensitivity degree. Further, we examined the spatial distribution and heterogeneity of cool island demand degree, and identified demand area and dominant factor types. The results showed that heat island stress degree, land vulnerability degree, and social sensitivity degree in Fujian Delta urban agglomeration had a significant spatial autocorrelation in 2017, with positive correlations among the three parameters. The high demand area and sub-high demand area for cool island were 2820.02 and 2078.31 km², respectively. Cool island demand degree had a significant positive correlation in space, and its spatial pattern was closely related with geographical location and terrain. The high value area was in urban areas along the east coast, and the low value area was in the western inland areas with high elevations. The results of dominant factor partitioning showed that comprehensive dominated area was concentrated in the urban center area, social sensitivity dominated area was mainly located in urban edge area, heat island stress dominated area was mainly bare land and part of industry zone, and land vulnerability dominated area was located in sparse vegetation cultivated land far from the urban areas. This study can provide insight into cool   island  demand and spatial pattern optimization of greenspace and water.

Key words: urban heat island effect, cool island demand, spatial pattern, spatial autocorrelation, Fujian Delta urban agglomeration.