Abstract: The rapid urbanization and global climate change have brought many urban environmental problems, in which the urban heat island effects and urban flooding are two 
serious ones. Green roof provides a potential solution for these issues by vegetating the current barren roof surfaces, and has particular significances for cities with extreme 
shortage of green spaces. Many previous studies analyzed the microclimatic and hydrological impacts of a singletype and smallsize experimental green roof under one 
particular weather condition. This study aims to evaluate and compare the effectiveness of five typical types of green roofs, with different scales, plant species and soil 
depths over different weather conditions. The five experimental green roofs, namely grass, bare soil, vegetable land, smallsize and largesize sky gardens, were installed on 
five office buildings in an industrial park of Nanjing city. Firstly, the daily dynamics of air temperature (10 cm and 150 cm above the roof surface) differences between the  green roofs and the control roof were studied. Secondly, two of the five roofs, representing the extensive and intensive roof greening respectively, were selected for stormwater  runoff analysis under four rainfall conditions. The results indicate that on a typical sunny summer day, green roofs can reduce the air temperature up to 5.3℃ and 2.5℃ at 10  cm and 150 cm heights above the roof surface, respectively. On cloudy and rainy days, some green roofs can even elevate the air temperature. The largesize sky garden has the  greatest air temperature reduction ability, and other four types of roofs cooling abilities can be ordered as: grass > smallsize sky garden > bare soil > vegetable land. The  stormwater runoff control abilities of the roofs are most related to plant and soil configuration and rainfall types. The sky garden can reduce runoff by 50.8%, 78%, 100% and  100% of the extremely heavy, heavy, middle and light rainfall events, respectively. The equivalent values for the extensive green roof were 24.3%，58.6%，98.2% and100%,  respectively. These findings can shed light on greenroof design and management for cities in similar climate zones as Nanjing. 
Key words：Green roof; urban heat island effects; urban flooding; microclimate amelioration; stromwater runoff reduction