(1965). (4) 411 where, G, is the ground heat flux, it is possible (Monteith,
(1986). 1.84 2.06 216 2.47 Table 3. Predicted daily total transpiration (mm) by the PenMan-Monteith
(1988). A four-laver model for the heat budget of homogeneous land surfaces'.
(1988). A four-layer model for the heat budget of homogeneous land surfaces.
(1987). A Langrangian analysis of scalar transfer in vegetation Canopies.
(1987). A number of studies have emerged during the last decade questioning the validity of K-theory for within canopy transfer (e.g. Finnigan and Raupach,
(1986). A simple biosphere model (SiB) for use within general circulation models.
(1989). A simple parametrization of land surface processes for meteorological models.
(1982). Aerodynamic roughness of a plant canopy: a numerical experiment.
(1991). Agricultural and Forest Meteorology 54: in press. 41
(1990). Amazon deforestation and climate change.
(1989). An investigation of mesoscale flows induced by vegetation inhomogeneities using an evapotranspiration model calibrated against HAPEX-MOBILHY data.
Analysis of turbulence profiles for several plant canopies led Raupach (1989b) to suggest that in the absence of measurements, the profiles of the vertical velocity variance and the Lagrangian time scale may be approximated from (z)
(1989). Applying Langrangian fluid mechanics to infer scalar source distributions from concentration profiles in plant canopies.
(1988). Average rainfall intensities as measured in the Reserva Ducke are 5.15 mm hr.' (Lloyd et al.,
(1988). Boundary Layer Meterology : submitted. 41
(1989). Calibrating the Simple Biosphere Model for Amazonian tropical forest using held and remote sensing data. Part I: Average calibration with field data.
(1985). Charactcristia of tilt soil and crop
(1987). Characteristics of measurement period, sitc and crop. Thc values of d and 7.0 for bare soil is basal on Olcc
(1986). Climate of Niamey', ICRISAT Sahclian Center, Progress Report I.
(1991). Derivation of the aerodynamic roughness parameters for a Sahelian savannah site using the eddy correlation technique': Submitted to Boundary-Layer Macorol.
(1989). Effects of implementing the Simple Biosphere model in a General Circulation Model.
(1991). Estimates of sensible heat flux from observations of temperature fluctuations. Boundary Layer Meterology : submitted. 110 '
(1981). Evaporation and surface temperature.
(1988). Evaporation from Amazonian rainforest. Proceedings of the Royal Society of London series 8,
(1986). Frequency rcsponse corrcctlottN tot eddy cotrelation systems'.
(1983). Global atmospheric circulation statistics,
(1988). HAPEX-MOBILHY: first results from the special observing period'.
(1982). Influence of land surface evaporation on the Earth's climate.
(1988). is the friction velocity. The boundary layer resistances are calculated according to Choudhury and Monteith
(1948). It is proposed to take the current GCM land surface models one step further and introduce the combination equation of Penman
(1991). Lagrangian and K-theory approaches in modelling evaporation from sparse canopies.
(1990). Measurements of evaporation from fallow sahelian savanna at the start of the dry season. Quarterly Journal of the Royal Meteorological Society : Accepted for publication.
(1991). Measurements of evaporation from fallow Sahelian savannah at the start of the dry season'.
(1988). Measurements of heat flux were made with thc Institute of Hydrology Mk 2 Hydra eddy correlation device (Shuttleworth et at,
(1948). Natural evaporation from open water, bare soil and grass.
(1990). Outline of a new GCM land surface parameterization, the MITRE model. Unpublished internal note, ID Institute of Hydrology,
(1986). predicted source density profiles of latent heat are shown lor three different times on 13
(1973). Principles of environmental physics,
(1975). proposed a mechanism whereby the higher albedo 110 ol bare soil could paxluce an atmospheric feedback process which resulted in lower rainlall. General Circulation Models (GCMs) have modelled Ihis ellect (see ROwntree,
(1988). Recently a number of models have been described
(1991). Regional roughness 40 of an area of degraded forest in the Sahel. to be submitted to Boundary Layer Meteorology.
(1991). Regional roughness of an arca of degraded forest in the Sahel'. In preparation.
(1973). remains fixed at d+zo, calculated according to the relations of Monteith
(1990). Renar d
(1989). Results of GCM deforestation experiments LW refers to Me results of Lean and Warrilow
(1986). Review of General Circulation Models as a basis for predicting the effects of vegetation change on climate.
(1989). Schematic diagram of the land surface scheme as used in UKMO GCM and in the original version of the SCM (Redrawn from Warrilow and Buckley,
(1990). Sensitivity of a single column model to tropical rainforest parameterizations.
(1990). shows the predicted frequency distribution of rainfall with time of day at Reserve Ducke Manaus, compared with observations reported by Lloyd
(1971). Statistical Fluid Mechanics
(1948). The concept of K-theory has been extensively used in physically based evaporation models (Penman,
(1985). The current generation of land surface models in GCM's
(1982). The energy balance of the earth's surface a practical approach'.
(1990). the fields of meteorology, hydrology and agriculture. As the most simple-model for evaporation from sparse canopies a modified Penman-Monteith equation suggested by Wallace et al
(1989). The impact of land surface processes on the moisture budget of a climate model.
(1988). The measurements were made between 28 September and 10
(1991). The parameterisation of rainfall interception in GCMs. to be submitted to the Journal of Applied Meteorology.
(1990). The Quarterly
(1972). The results substantiate Tillman's
(1990). the Royal Society of London series
(1984). The sensitivity of numerically simulated climates to land surface boundary conditions.
(1990). The theoretical relationship between foliage temperature and canopy resistance in sparse crops.
(1990). The third K-theory model usecl in this paper is the updated version of the Shuuleworth and Wallace model as described by Shuttleworth and Gurney
(1986). They include a canopy which distinguishes them from the Met Office scheme (Warrilow et al,
(1985). This model is different from both the Shuttleworth and Wallace
(1988). Typical canopy storage capacities for forest are about 1 mm, for the tropical rainforest, Lloyd
(1990). vali le derived tor this fallow bushland site by Lloyd
(1981). When the canopy cover is incomplete, the big leaf approach tends to be less appropriate as the exposed soil becomes a significant additional source of heat and water vapour.
(1981). where G is the soil heat flux). Introducing A , the rate of change of the saturated vapour pressure with temperature yields two equations, similair to the Penman-Monteith equation (Monteith,
(1971). where k is von Kármán's constant and g is the acceleration due to gravity. Equation (5) covers the whole of the unstable region and Equation (6) applies in thc limiting case of free convection. Tillman, basing his analksis on work by Wvngaard ci a/.
(1988). with II e Thom and Oliver aerodynainic Ruction and the data from the Sadore aqrnineteorological station. The curve is the resinl cif Wing Equation (8) to the data trout 6
(1984). XE1 (15) This is the same flux variable as described by Chen