Understanding and Measuring Earth’s Energy Budget: From Fourier, Humboldt, and Tyndall to CERES and Beyond

Abstract

This historical perspective on the determination of Earth's energy fluxes, beginning with the classical description of climate, outlines the establishment of the basic physics of the Earth climate system in the nineteenth century. After recalling the early twentieth century ground-based attempts to determine the Earth's energy budget, I review the growing contributions of observations from space to quantifying these exchanges. In particular, space observations have shown that variations of solar luminosity have been extremely small (of order 0.1%) over past decades and probably past centuries and that they play practically no role in present-day climate variations or variations that may be expected in coming decades. Overall geographical structure, diurnal and seasonal cycles, and some of the interannual and interdecadal variations of Earth's energy exchanges with the Sun and space are now quite well determined, but much remains to be done regarding, on the one hand, fluxes at the surface and, on the other hand, variations of clouds. Improvements are essential if scientific assessment of anthropogenic climate change risk is to keep up with the changes themselves.Keywords Earth's energy flows Á Satellite observations Á Historical background Historical PerspectiveThe Earth's energy budget is at the heart of physical climatology, and the principles of this science have been well established for over a century and a half, well before the development of any understanding of the physical structure of the Sun and stars, the nature of the physical processes accounting for their luminosities, and indeed the details of the transfer of radiation in the atmospheres of stars and planets. Only celestial mechanics is an older science.

On Uncertainty in Global Terrestrial Evapotranspiration Estimates from Choice of Input Forcing Datasets*

“…It hints at the possibility of creating a long-term, calibrated ET dataset from heterogeneous sources, though this work would require finer-resolution analysis of both regional and seasonal trends in evapotranspiration. But as our results demonstrate, remotely sensed estimates of surface net radiation are still fraught with uncertainties (Kandel 2012), a limitation that must be overcome if we hope to have reliable estimates of global terrestrial evapotranspiration. Recent work by Pan et al (2012) shows the promise of fusing data from multiple sources to produce highquality, long-term records of ET over land.…”

Radiation budget biases in AMIP5 models over the East Asian monsoon region

“…A great deal of effort has been devoted to both measuring and understanding the Earth's RB [ Kandel , ]. The marked increases in number of satellites and improvements in remote sensing techniques have also resulted in great increase in RB measurements from space.…”

Reconciling Estimates of Ocean Heating and Earth’s Radiation Budget

“…[14]), systematic monitoring of the radiative components only began in the late 1970s with Nimbus-7 [15]. As an illustration of successive satellite missions to monitor ERB, we show the continuous 31-year record of tropical outgoing LW radiation between 1979 and 2010 published by Loeb et al [2] (Fig.…”