Eddy fluxes of CO2, water vapor, and sensible heat over a deciduous forest

Abstract

Fluxes of CO,, latent heat and sensible heat were measured above a fully-leafed deciduous forest in eastern Tennessee with the eddy correlation technique. These are among the first reported observations over such a surface. The influences of solar radiation, vapor pressure deficit and the aerodynamic and canopy resistances on these mass and energy exchanges are examined. Following a concept introduced by McNaughton and Jarvis (1983). examination of our data suggest that the water vapor exchange of a deciduous forest is not as strongly coupled with net radiation as is that of agricultural crops. The degree of decoupling is smaller than in the case of a coniferous forest. This difference may be attributable in part to the greater aerodynamic resistance to water vapor transfer in a deciduous forest. It appears that the concept of decoupling may be extended to the CO, exchange of a deciduous forest as well.

Temporal dynamics of soil water balance components in a karst range in southeastern Spain: estimation of potential recharge

“…Evapotranspiration was measured by an eddy covariance system (Anderson et al, 1984;Verma et al, 1986). The eddy covariance system measured the (Contreras, 2006).…”

Turbulence structure in a deciduous forest

“…This site is situated on a ridge in moderately sloping terrain. A topographic map of the site is presented in Verma et al (1986). The vegetation at the site consists of an uneven-aged, mixed species stand of predominantly oak and hickory trees (Quercus and Carp spp.).…”

A more accurate scheme for calculating Earth’s skin temperature

“…At the site, the daytime aerodynamic and canopy resistances in the summer are about 37 and 60 s m -1 , respectively (Wilson et al 2002). Following the method of Wilson et al (2002), r a is derived from the sum of the resistance to momentum transport and an excess resistance for scalar fluxes (Verma et al 1986) and r c is determined according to the PenmanMonteith approximation to the big leaf equations (Jarvis and McNaughton 1986;Shuttleworth et al 1984). It can be seen that at this site, typical value for winter nighttime qG 0 * /qT 0 * (qG 0 /qT 0 ) was about 1.8 (29.04 W m -2 K -1 ), and that of summer day was about 4.4 (70.93 W m -2 K -1 ), of which the annual mean was 2.86 (46 W m -2 K -1 ) with the median value at 2.64 (42 W m -2 K -1 ), when T 0 during wintertime (November-January) was usually \273 K. Table 6 shows the bias, RMSE and normalized RMSE of skin temperature, and the bias, RMSE and normalized RMSE for surface ground heat of Case 7 simulated by ''A74'', ''D78'', ''op(0,0,0)'', ''op(1,0,0)'', ''op(1,1,0)'', ''op(2,1,0)'', ''echam'', ''ecmwf'', ''ecmwf ?…”