Characteristics of carbon dioxide, thermo-hydrological fluxes and atmospheric turbulence structure over Gobi Desert

Based on the turbulence data obtained from an atmospheric boundary layer station located in Gobi Desert in northwest China during the summer of 2006, the carbon dioxide fluxes, latent heat fluxes and sensible heat fluxes were investigated. The results showed that the carbon dioxide flux was transferred down to land surface in daytime but conversely at night, and the mean value of carbon dioxide flux was -0. 199 mg . m(-2) . s(-1), which indicated that the Gobi Desert was a carbon sink in summer. Since the value of the moisture content of the surface layer over the Gobi Desert was small, the specific humidity is almost passively controlled by horizontal moisture fluxes and its diurnal variation was unobvious. On the other hand, the statistical characteristic of the turbulent transport of temperature was in accordance with Monin-Obukhov Similarity theory. The normalized spectra of temperature were similar with that of the CO2 concentration (c). The normalized cospectra of u-wind component (u) and carbon dioxide (c) were similar with that of u and the potential temperature (theta). The normalized cospectra of the vertical wind component (w) and carbon dioxide (c) were similar with that of w and theta. The transport of humidity and CO2 depended on horizontal fluxes.