Evaporation and surface temperature

[1] This review surveys the basic theories, observational methods, satellite algorithms, and land surface models for terrestrial evapotranspiration, E (or λE, i.e., latent heat flux), including a long-term variability and trends perspective. The basic theories used to estimate E are the Monin-Obukhov similarity theory (MOST), the Bowen ratio method, and the Penman-Monteith equation. The latter two theoretical expressions combine MOST with surface energy balance. Estimates of E can differ substantially between these three approaches because of their use of different input data. Surface and satellite-based measurement systems can provide accurate estimates of diurnal, daily, and annual variability of E. But their estimation of longer time variability is largely not established. A reasonable estimate of E as a global mean can be obtained from a surface water budget method, but its regional distribution is still rather uncertain. Current land surface models provide widely different ratios of the transpiration by vegetation to total E. This source of uncertainty therefore limits the capability of models to provide the sensitivities of E to precipitation deficits and land cover change.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2011RG000373

A review of global terrestrial evapotranspiration: observation, modeling, climatology, and climatic variability

A Review of Global Terrestrial Evapotranspiration: Observation, Modeling, Climatology, and Climatic Variability

SEBAL-based sensible and latent heat fluxes in the irrigated Gediz Basin, Turkey

Publisher Summary The purpose of this chapter is to assess the possibility of obtaining general relationships between the CO2 flux over canopies (F) and absorbed PPFD (Q). In particular, it emphasizes on determining whether the relationship for a closed canopy is linear, consistent with the Monteith model, or curvilinear, consistent with the results of many mechanistic canopy models. Both general relationships and relationships for different vegetation classes are sought. Some methodology-related differences are also investigated, including comparison between micrometeorological and enclosure methods, the effect of taking into account respiration rate, and the effect of integrating measurements in time. For this, statistics are used on similar data sets, that is, except for the variable under study, all environmental conditions are similar, and the data are obtained on the same site, with the same measuring technique, by the same scientific team, and statistics on grouped data sets, that is, all the data sets on closed canopies satisfying the conditions described in the data analysis section are grouped by vegetation class or method of measurement or representation.

CO2 fluxes over plant canopies and solar radiation: a review

We present a complete study of geodesic motion in G\"odel's universe, using the method of the effective potential. A clear physical picture of free motion and its stability in this universe emerges. A large class of geodesics have finite intervals in which the particle moves back in time ($\frac{\mathrm{dt}}{\mathrm{ds}}l0$) without violation of causality. G\"odel's geometry produces the important property of confinement for a large class of geodesics. We use this property to discuss the construction of a gravitational container. This structure is highly stable, since there is no singularity in its interior, and is independent of the energy of the particles contained in it.

Geodesic motion and confinement in Gödel's universe

We define curves on a Riemannian manifold as integrals of generalized Jacobi fields. We show that the force term that deviates the trajectory from the geodesic motion can be constructed as a functional of the metric tensor. These curves can be interpreted as particles (observers) coupled nonminimally with gravitation that can provide a class of residual observers for the inevitable singularity—as shown in the text.

M. Novello

Papers

Geodesic motion and confinement in Gödel's universe

On Jacobi fields

Erratum: Geodesic motion and confinement in Gödel's universe

Spherically symmetric neutrino radiating stars

Eigenvalue treatment of cosmological models