Latent heat

About: Latent heat is a research topic. Over the lifetime, 13503 publications have been published within this topic receiving 302811 citations.

Surface Energy and Radiation Balance Systems: General Description and Improvements

Abstract: Surface evaluation of sensible and latent heat flux densities and the components of the radiation balance were desired for various vegetative surfaces during the ASCOT84 experiment to compare with modeled results and to relate these values to drainage winds. Five battery operated data systems equipped with sensors to determine the above values were operated for 105 station days during the ASCOT84 experiment. The Bowen ratio energy balance technique was used to partition the available energy into the sensible and latent heat flux densities. A description of the sensors and battery operated equipment used to collect and process the data is presented. In addition, improvements and modifications made since the 1984 experiments are given. Details of calculations of soil heat flow at the surface and an alternate method to calculate sensible and latent heat flux densities are provided.

Paleoaltimetry incorporating atmospheric physics and botanical estimates of paleoclimate

Abstract: We present a method for deducing paleoaltitudes that incorporates basic physical principles of atmospheric science and inferences of paleoclimates from plant leaf physiognomy. We exploit the average west-to-east flow of the atmosphere at mid-latitudes and a thermodynamically conserved variable in the atmosphere—moist static energy (the combined internal, latent heat, and gravitational potential energy of moist air)—to develop a method that relies on a parameter that varies with height in the atmosphere in a predictable fashion. Because the surface distribution of moist static energy is constrained by atmospheric dynamics and thermodynamics, the combined internal and latent heat energies, also known as the moist enthalpy, should only vary with altitude provided we know the distribution of moist static energy. Thus, we avoid having to make assumptions about the mean annual temperature lapse rate, which varies spatially and temporally owing to unpredictable variations in atmospheric water vapor. To estimate a paleoaltitude, therefore, we require (1) a priori knowledge of the spatial distribution of moist static energy for the paleoclimate and (2) the ability to estimate paleoenthalpy for two isochronous locations: one at sea level, the other at some unknown elevation. To achieve this, we investigated the spatial distribution of moist static energy for the present-day climate of North America to estimate the deviations in moist static energy from zonal invariance. In parallel, we quantified the relation between moist enthalpy and plant leaf physiognomy of modern forests. Assuming that such deviations from zonal invariance and such relationships between physiognomy and enthalpy apply to ancient climates and fossil leaves, these investigations yield an uncertainty estimate of ±910 m in the paleoaltitude difference between two isochronous fossil assemblage locations.

Soil and Canopy Energy Balances of a Row Crop at Partial Cover

Abstract: When crops are grown in a row configuration, heat and mass transfer within the soil-canopy system influence the energy and water balance of the crop. Field experiments were conducted near Lubbock, TX, to examine the energy balance of the soil and canopy separately, in cotton (Gossypium hirsutum L.) under a variety of aerial to obtain the field energy balance, including total latent heat flux (LE). Latent heat flux from the crop canopy (LE c ) was determined from sap flow measurements of transpiration. Latent heat flux from the soil (LE s ) was computed as the difference between LE and LE c (...)