Standard Values for the Solar Constant and its Spectral Components

Thekaekara, M. P.; Drummond, A. J.

doi:10.1038/physci229006a0

Cited by 123 publications

(35 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We found that wCS larvae are capable of directionbased avoidance across a 2,500-fold change in light intensity (0.04-100 W/m 2 , an ecologically relevant range) (Fig. 6B) (8,16,(21)(22)(23). The BO is strictly required for this behavior at both low and high intensities.…”

Section: Significancementioning

confidence: 90%

Sensorimotor structure of Drosophila larva phototaxis

Kane

Gershow

Afonso

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

119

216

View full text Add to dashboard Cite

The avoidance of light by fly larvae is a classic paradigm for sensorimotor behavior. Here, we use behavioral assays and video microscopy to quantify the sensorimotor structure of phototaxis using the Drosophila larva. Larval locomotion is composed of sequences of runs (periods of forward movement) that are interrupted by abrupt turns, during which the larva pauses and sweeps its head back and forth, probing local light information to determine the direction of the successive run. All phototactic responses are mediated by the same set of sensorimotor transformations that require temporal processing of sensory inputs. Through functional imaging and genetic inactivation of specific neurons downstream of the sensory periphery, we have begun to map these sensorimotor circuits into the larval central brain. We find that specific sensorimotor pathways that govern distinct light-evoked responses begin to segregate at the first relay after the photosensory neurons.N avigating organisms must extract spatial information about their surroundings to orient and move toward preferred environments. Phototaxis of fly larvae has long been a paradigm for understanding the mechanisms of animal orientation behavior (1). The study of phototaxis in the Drosophila larva provides an opportunity to investigate the circuits for orientation behavior from sensory input to motor output in a small nervous system. First, however, the sensorimotor structure of responses to illumination must be defined by studying larval behavior in controlled environments.The tropism theory of Jacques Loeb states that bilateral body plans allow animals to extract spatial information through the sensation of external forces acting asymmetrically on symmetric body halves. The navigation of fly larvae away from incident light rays was interpreted as a direct demonstration of tropism. However, temporal comparisons performed by moving animals, also known as klinotaxis, also can encode spatial information (2). Like most fly larvae, Drosophila larvae are negatively phototactic during most of their development (3-9). To navigate away from light, the Drosophila larva uses two sets of photosensors, the Rhodopsin-expressing Bolwig's organs (BO) that mediate phototaxis at low light levels and the non-Rhodopsin-expressing class IV multidendritic (md) neurons that respond to intense light levels comparable to direct sunlight (10). Here, we sought to resolve the sensorimotor structure of larval phototaxis to understand how these photosensitive structures extract and use information about ambient light conditions to control motor behavior.We developed a tracking assay and illumination system that allowed us to quantify the movements of individual animals in defined spatiotemporal illumination patterns at both low and high light intensities. We uncovered a set of sensorimotor relationships that allow the larva to navigate away from light based on temporal processing of sensory inputs. Even the capacity to navigate away from directed illumination is mediated by temporal process...

show abstract

Section: Significancementioning

confidence: 90%

Sensorimotor structure of Drosophila larva phototaxis

Kane

Gershow

Afonso

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

119

216

View full text Add to dashboard Cite

show abstract

“…The incoming solar irradiance at TOA is computed for the spectral interval 0.2-10.0 µm, based on the spectral profile of Thekaekara and Drummond (1971), using a solar constant S o =1367 W m −2 (e.g. Willson, 1997) corrected for the Earth's elliptical orbit.…”

Section: The Radiative Transfer Modelmentioning

confidence: 99%

The direct effect of aerosols on solar radiation based on satellite observations, reanalysis datasets, and spectral aerosol optical properties from Global Aerosol Data Set (GADS)

et al. 2007

View full text Add to dashboard Cite

Abstract.A global estimate of the seasonal direct radiative effect (DRE) of natural plus anthropogenic aerosols on solar radiation under all-sky conditions is obtained by combining satellite measurements and reanalysis data with a spectral radiative transfer model and spectral aerosol optical properties taken from the Global Aerosol Data Set (GADS). The estimates are obtained with detailed spectral model computations separating the ultraviolet (UV), visible and near-infrared wavelengths. The global distribution of spectral aerosol optical properties was taken from GADS whereas data for clouds, water vapour, ozone, carbon dioxide, methane and surface albedo were taken from various satellite and reanalysis datasets. Using these aerosol properties and other related variables, we generate climatological (for the 12-year period 1984-1995) monthly mean aerosol DREs. The global annual mean DRE on the outgoing SW radiation at the top of atmosphere (TOA, F TOA ) is −1.62 W m −2 (with a range of −15 to 10 W m −2 , negative values corresponding to planetary cooling), the effect on the atmospheric absorption of SW radiation ( F atmab ) is 1.6 W m −2 (values up to 35 W m −2 , corresponding to atmospheric warming), and the effect on the surface downward and absorbed SW radiation ( F surf , and F surfnet , respectively) is −3.93 and −3.22 W m −2 (values up to −45 and −35 W m −2 , respectively, corresponding to surface cooling). According to our results, aerosols decrease/increase the planCorrespondence to: N. Hatzianastassiou (nhatzian@cc.uoi.gr) etary albedo by −3 to 13% at the local scale, whereas on planetary scale the result is an increase of 1.5%. Aerosols can warm locally the atmosphere by up to 0.98 K day −1 , whereas they can cool the Earth's surface by up to −2.9 K day −1 . Both these effects, which can significantly modify atmospheric dynamics and the hydrological cycle, can produce significant planetary cooling on a regional scale, although planetary warming can arise over highly reflecting surfaces. The aerosol DRE at the Earth's surface compared to TOA can be up to 15 times larger at the local scale. The largest aerosol DRE takes place in the northern hemisphere both at the surface and the atmosphere, arising mainly at ultraviolet and visible wavelengths.

show abstract

“…The sensitivity curves (product of filter transmittance and photocathode quantum efficiency for sensors A-C) are shown in Figure 1 with Thekaekara (1970), Neckel (1968, 1970), Makarova andKharitonov (1969), andTousey (1963) The wavelength selectivity of a sensor is produced by using a suitable radiation resistant optical filter (Heath and Sacher, 1966) Measurements of the solar irradiance at 12 discrete wavelengths from 2550-3400A with a 10A band pass are being made with a tandem Ebert-Fastie type double monochromator on Nimbus 4 (BUV experiment). In the latter experiment the monochromator views a solar illuminated diffuser plate.…”

mentioning

confidence: 99%

Space observations of the variability of solar irradiance in the near and far ultraviolet

Heath

1973

J. Geophys. Res.

View full text Add to dashboard Cite

Satellite observations of UV solar irradiance in selected wavelength bands between 1200 and 3000 A have been made continuously by photometers consisting of broad band sensors operated on Nimbus 3 and 4, which were launched in April 1969 and April 1970, respectively. In addition, on Nimbus 4, spectrophotometer measurements of solar irradiance have been made with a dispersive instrument at 12 selected wavelengths from 2550 to 3400 A with a 10‐A band pass. Variations of solar irradiance associated with the solar rotational period have been observed since the launch of Nimbus 3. These variations are apparently associated with two source regions separated by about 180° in solar longitude. The change in irradiance with solar rotation was found to increase with decreasing wavelengths. Different types of observed variations in UV solar irradiance can be classified in accordance with characteristic times; in order of increasing periods, they are (1) flare‐associated enhancements, (2) 27‐day variations due to solar rotation, (3) a possible biennial effect, and (4) long‐term variations associated with the 11‐year solar cycle.

show abstract

Standard Values for the Solar Constant and its Spectral Components

Cited by 123 publications

References 10 publications

Sensorimotor structure of Drosophila larva phototaxis

Sensorimotor structure of Drosophila larva phototaxis

The direct effect of aerosols on solar radiation based on satellite observations, reanalysis datasets, and spectral aerosol optical properties from Global Aerosol Data Set (GADS)

Space observations of the variability of solar irradiance in the near and far ultraviolet

Contact Info

Product

Resources

About