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Solar constant
About: Solar constant is a research topic. Over the lifetime, 967 publications have been published within this topic receiving 29647 citations.
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TL;DR: In this article, a small, accurate, inexpensive instrument to integrate daily solar radiation flux density can be constructed using two or more silicon solar cells and a Curtis mercury integrator, with a maximum error of less than 200 watt hr m−2 over a 1-day period.
Abstract: A small, accurate, inexpensive instrument to integrate daily solar radiation flux density can be constructed using two or more silicon solar cells and a Curtis mercury integrator. Maximum error is less than 200 watt hr m−2 over a 1-day period, out of a possible total of 8000 watt hr m−2 on a clear day. Response is linear, temperature sensitivity is low, and cosine response does not cause serious error except at high latitude.
13 citations
TL;DR: In this article, the authors explain how and why Pouillet, Herschel and Forbes made the first estimates of the solar constant, estimates which would acquire new importance with the discovery of the laws of thermodynamics by the mid century.
Abstract: Summary Inspired by early-nineteenth-century discoveries about heat transfer, the French physicist Claude Pouillet measured the influx of solar radiation at the earth and, in 1838, asked what these observations revealed about the temperature of the sun and of space itself. At about the same time, the British natural philosophers John Herschel and J. D. Forbes made similar measurements in order to better understand the sun's influence on climate. This paper tells how and why Pouillet, Herschel and Forbes made the first estimates of the solar constant, estimates which would acquire new importance with the discovery of the laws of thermodynamics by the mid century.
13 citations
TL;DR: In this article, the authors estimate the local impact of a reduced solar constant on the projected GrIS surface mass balance (SMB) decrease and show that even in the case of a low-mitigation greenhouse gas emissions scenario (SSP585), the Greenland surface mass loss can be brought in line with the medium-mitigated emissions scenario by reducing the solar downward flux at the top of the atmosphere by ∼ ǫW/m 2 or ∼ ´1.5´
Abstract: . The Greenland Ice Sheet (GrIS) will be losing mass at an accelerating pace
throughout the 21st century, with a direct link between anthropogenic
greenhouse gas emissions and the magnitude of Greenland mass loss.
Currently, approximately 60 % of the mass loss contribution comes from
surface melt and subsequent meltwater runoff, while 40 % are due to ice
calving. In the ablation zone covered by bare ice in summer, most of the
surface melt energy is provided by absorbed shortwave fluxes, which could be
reduced by solar geoengineering measures. However, so far very little is
known about the potential impacts of an artificial reduction in the incoming
solar radiation on the GrIS surface energy budget and the subsequent change
in meltwater production. By forcing the regional climate model MAR with the
latest CMIP6 shared socioeconomic pathways (SSP) future emission scenarios
(SSP245, SSP585) and associated G6solar experiment from the CNRM-ESM2-1
Earth system model, we estimate the local impact of a reduced solar constant
on the projected GrIS surface mass balance (SMB) decrease. Overall, our
results show that even in the case of a low-mitigation greenhouse gas emissions
scenario (SSP585), the Greenland surface mass loss can be brought in line
with the medium-mitigation emissions scenario (SSP245) by reducing the solar
downward flux at the top of the atmosphere by ∼ 40 W/m 2 or
∼ 1.5 % (using the G6solar experiment). In addition to
reducing global warming in line with SSP245, G6solar also decreases the
efficiency of surface meltwater production over the Greenland ice sheet by
damping the well-known positive melt–albedo feedback. With respect to a MAR
simulation where the solar constant remains unchanged, decreasing the solar
constant according to G6solar in the MAR radiative scheme mitigates the
projected Greenland ice sheet surface melt increase by 6 %. However, only
more constraining geoengineering experiments than G6solar would allow us to
maintain a positive SMB until the end of this century without any reduction in
our greenhouse gas emissions.
13 citations
TL;DR: In this paper, the authors show that bright, contiguous active regions cause much of the observed variability in the full disc UV irradiances over time scales of solar rotation and active region evolution, but can account for only about half variability observed over the 11-year solar cycle.
13 citations
TL;DR: In this paper, the physics of the sun, the nature of the radiant energy emanating from its surface, spectral distribution, and the total quantity of that energy arriving just outside the earth's atmosphere are discussed.
Abstract: This chapter discusses the physics of the sun, the nature of the radiant energy emanating from its surface, spectral distribution, and the total quantity of that energy arriving just outside the earth's atmosphere. The sun is the star closest to the earth, and its radiant energy is practically the only source of energy that influences atmospheric motions and our climate. The sun is a completely gaseous body composed mainly of hydrogen. The spectral distribution of radiation arriving on the surface of the earth is indeed a function of its extraterrestrial distribution and the atmospheric constituents. The solar constant is the rate of total solar energy at all wavelengths incident on a unit area, exposed normally to rays of the sun at one astronomical unit. The temperature of the sun is calculated from two types of information: the solar constant and its spectral distribution. The chapter describes more recent values of the solar constant and its spectral distribution.
13 citations