Impacts of Neighboring Buildings on the Cold Island Effect of Central Parks: A Case Study of Beijing, China

Urban parks have been considered as an effective measure to mitigate the urban heat island (UHI) effects. Many studies have investigated the impacts of shape, size and interior components on the cold island effect (CIE) of parks, while little attention has been given to the impact of neighboring buildings. Thus, taking twenty-two parks in Beijing as samples, this study investigated the impacts of the neighboring building on the CIE of central parks. The results showed that the average land surface temperature (LST) of parks are 30.98 °C in summer and −1.10 °C in winter. Parks have a strong CIE in summer, and average cold island footprint (CIF) and LST difference are 0.15 km2 and 2.01 °C higher than that in winter. The components of the building in the CIF of parks are dominated by middle-rise building (MRB), followed by low-rise building (LRB), and high-rise building (HRB) is the least dominant. The percentage of landscape (PLAND) and landscape shape index (LSI) of MRB, and perimeter area fractal dimension (PAFRAC) of LRB are significantly related to CIF in summer and winter. This study could extend scientific understanding of the impacts of neighboring buildings on the CIE of central parks, and could guide urban planners in mitigating the UHI effects through the rational allocation of buildings.

Numerical Simulation on Oasis Effect over Northwestern China

The characteristics of air temperature, circulation and energy budget of Jinta Oasis are simulated by WRF model, which is the weather research and forecast model of NCAR. The results show that the WRF model has good quality in simulating the diurnal characteristics of surface layer temperature, wind fields, net radiation, sensible heat flux and latent flux. In addition, the model initial fields were also modified by observations of soil temperature and moisture in order to improve the simulations in this study due to important roles of the soil moisture and temperature playing in affecting the cold island effect, the wet island effect properties and surface energy budget balance over the oasis in arid area. Then, the microclimate characteristics and local thermal circulation generated by inhomogeneous underlying surface over Jinta Oasis are analyzed.