Characteristics Analysis Of Land-Atmosphere Energy Transfer And Turbulence Over Urban And Suburban Underlying Surfaces In Nanjing Winter

With the rapid development and expansion of city, the physical characteristics(such as surface albedo, roughness and so on)and property of the urban underlying surfaceare undergoing substantially changes,which significantly impact the atmosphere and environment of urban, including both the energy budget and the turbulent characteristic which was rare on heterogenous boundary laye, especially Comparison at the urban with suburban sites due to complexities of urban environment and lack of instrument. And It maybe can provide some useful clues for heterogenous boundary layer meteorological study.Concrete surface, with typical characteristics of urban surface, accounts for much in all kinds of anthropogenic surfaces in urban regions. The thermodynamic characteristics of concrete are quite different from those of natural surfaces, which is a key factor of local weather and climate change.The radiation, turbulence flux, fluctuation wind velocity data observed using the eddy correlation method at the urban and suburban sites in Nanjing in 17 february - 2 March 2006 are used in this paper to analyze the characteristics of the radiation and heat budget over urban and suburban different underlying surfaces, and the changes of each component, as well as the differences of urban and suburban. The results show: (1) the diurnal variation patterns of various radiation components accorded with the generally observed patterns, and the urban and suburban difference of net short and long wave radiation, and net radiation varied with different weather conditions, with a largest difference in Sun-shining days, a least difference in snowing days, and a medium, representative difference in cloudy days. Among various radiation components, the net short wave radiation dominated the ground surface radiation budget. (2) Characteristics of the heat budget change over the urban and suburban different underlyingsurfaces were significantly different. The Bowen ratio (Q_h/Q_e)in the observation period was7.8(about equivalent to that in desert/arid areas) in the urban area, but only 1.8 in the suburban area. (3) The surface net radiation, sensible heat and latent heat fluxes over the urban and suburban areas showed large differences, especially, the latent heat fluxes showed a largest difference.The variance similarities of wind velocity (u, v and w), air temperature and air humidity at the urban and suburban sites in Nanjing are analyzed with the data observed in 17 february - 2 March 2006 by using the eddy correlation method, and the verification of applicability of Similarity theory compared urban with suburb,In addition, with the results for the other sites about the variance simlarity be compared,The results show: (1) At non-neutral stratification , the relationship between wind velocity (u, v and w) normalized standard deviation and stability is conform to power 1/3 , especially the relationship betweenσw/u_* and z/L ,but not so good in horizontal direction, particularly in stable stratification data dots disperse greatly; (2) The relationship between normalized standard deviation of temperature and stability with difference over differenr underlying surface, especially under stable condition.