摘要
An evaluation of the urban park vegetation was conducted by integrating airborne multispectral scanning system ( MSS ) thermal band data with meteorological. MSS data acquired in the morning and afternoon were utilized to assess the radiant energy budget of different ground cover types and its relationship with the surface types. The spatial distribution of surface temperature ( Ts ) and surface albedo ( A ) varied between different surfaces. However, the spatial variability of net radiation ( Rn ) was reduced by negative feedback of A Ts relationship. The Normalized Difference Vegetation Index ( NDVI ) had a negative correlation with Ts but positively correlated to Rn of the different surface types. Thermal response number ( TRN ), which expresses the dissipative behavior of radiant energy, correctly characterized each ground cover type according to the validated surface property. Forested and lawn covered sites had the highest TRN values consistent with their tendency to resist microclimatic change. The approach shows that by utilizing the MSS thermal signatures, we can relate the microenvironment processes to the biophysical character of each site offering an opportunity to diagnose site specific problems. The approach is proposed as a direct and easily adaptable method for monitoring the urban green park areas and for making objective decisions about their management.
An evaluation of the urban park vegetation was conducted by integrating airborne multispectral scanning system ( MSS ) thermal band data with meteorological. MSS data acquired in the morning and afternoon were utilized to assess the radiant energy budget of different ground cover types and its relationship with the surface types. The spatial distribution of surface temperature ( Ts ) and surface albedo ( A ) varied between different surfaces. However, the spatial variability of net radiation ( Rn ) was reduced by negative feedback of A Ts relationship. The Normalized Difference Vegetation Index ( NDVI ) had a negative correlation with Ts but positively correlated to Rn of the different surface types. Thermal response number ( TRN ), which expresses the dissipative behavior of radiant energy, correctly characterized each ground cover type according to the validated surface property. Forested and lawn covered sites had the highest TRN values consistent with their tendency to resist microclimatic change. The approach shows that by utilizing the MSS thermal signatures, we can relate the microenvironment processes to the biophysical character of each site offering an opportunity to diagnose site specific problems. The approach is proposed as a direct and easily adaptable method for monitoring the urban green park areas and for making objective decisions about their management.
