Design and development of a rotating shadowband radiometer solar radiation/daylight network

Michalsky, Joseph; Perez, Richard; Stewart, Ronald E.; LeBaron, B.A.; Harrison, L.

doi:10.1016/0038-092x(88)90060-6

Cited by 41 publications

(16 citation statements)

References 5 publications

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“…Diffuse PAR was measured at Sherman Island with a custom‐designed rotating shadow band radiometer. As the shadow band rotates around the photodiode in the radiometer, measurements of global (i.e., direct and diffuse) and diffuse light are recorded when the sensor is fully shaded and covered [ Michalsky et al , ]. At the remaining sites, diffuse PAR was measured with a model BF2, BF3, or BF5 sensor (Delta‐T Devices, Ltd., Cambridge, UK).…”

Section: Methodsmentioning

confidence: 99%

Using satellite‐derived optical thickness to assess the influence of clouds on terrestrial carbon uptake

et al. 2016

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Clouds scatter direct solar radiation, generating diffuse radiation and altering the ratio of direct to diffuse light. If diffuse light increases plant canopy CO2 uptake, clouds may indirectly influence climate by altering the terrestrial carbon cycle. However, past research primarily uses proxies or qualitative categories of clouds to connect the effect of diffuse light on CO2 uptake to sky conditions. We mechanistically link and quantify effects of cloud optical thickness (τc) to surface light and plant canopy CO2 uptake by comparing satellite retrievals of τc to ground‐based measurements of diffuse and total photosynthetically active radiation (PAR; 400–700 nm) and gross primary production (GPP) in forests and croplands. Overall, total PAR decreased with τc, while diffuse PAR increased until an average τc of 6.8 and decreased with larger τc. When diffuse PAR increased with τc, 7–24% of variation in diffuse PAR was explained by τc. Light‐use efficiency (LUE) in this range increased 0.001–0.002 per unit increase in τc. Although τc explained 10–20% of the variation in LUE, there was no significant relationship between τc and GPP (p > 0.05) when diffuse PAR increased. We conclude that diffuse PAR increases under a narrow range of optically thin clouds and the dominant effect of clouds is to reduce total plant‐available PAR. This decrease in total PAR offsets the increase in LUE under increasing diffuse PAR, providing evidence that changes within this range of low cloud optical thickness are unlikely to alter the magnitude of terrestrial CO2 fluxes.

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Section: Methodsmentioning

confidence: 99%

Using satellite‐derived optical thickness to assess the influence of clouds on terrestrial carbon uptake

et al. 2016

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“…The USDA Ultraviolet Radiation Monitoring Program [ Bigelow et al , 1998] (available at http://uvb.nrel.colostate.edu/UVB/home_page.html) was developed primarily for the monitoring of spectral and broadband UV‐B and UV‐A, especially in rural areas, to determine their effect on agriculture. The primary instrument used is the YES MFRSR [ Michalsky et al , 1988; Harrison et al , 1994]. These instruments are capable of measuring both the diffuse and global components of the incoming irradiance.…”

Section: Instrumentation and Network Protocolsmentioning

confidence: 99%

Field comparison of network Sun photometers

McArthur¹,

Halliwell²,

Niebergall³

et al. 2003

J. Geophys. Res.

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[1] Measurements of aerosol optical depth have become more numerous since the mid1990s with the onset of commercially available, high-quality, low-maintenance automatic instrumentation. The development of several networks for aerosol measurements, and the next day availability of preliminary data for some, have further enhanced interest in the products this type of measurement can provide. With several networks operating globally and others operating either regionally or continentally within North America the comparability of the data emanating from the various archive centers is an important issue. The Bratt's Lake Observatory operates four separate types of Sun photometers in conjunction with three different networks: Aerosols in Canada, Global Atmosphere Watch, and the U.S. Department of Agriculture UV-B Monitoring Program. Data collected during the summer of 2001, following the protocols established by the networks and the Meteorological Service of Canada, were analyzed to determine the comparability among these networks. As the instruments and conversion algorithms are similar to other networks from around the globe, it is believed that the results of this comparison can be transferred, at least in part, to other operational networks. The results of the 3-month study indicate that the data obtained from the networks that operate direct-pointing instruments are very comparable, being within ±0.01 of an optical depth for instantaneous measurements during cloud-free line-of-sight conditions. Over the length of the comparison the root mean square difference of aerosol optical depth at 500 nm between the direct sun-pointing instruments was 0.0069. The rotating shadowband instruments did not perform as well. These results indicate that the data from well-maintained networks of direct sun-pointing photometers can provide data of the quality necessary to compare stations from across the globe.

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“…On the other hand, the rotating shadowband pyranometer (Michalsky et al, 1988;Little, 2005;Michalsky et al, 2009) has a motorized partial ring which rotates through a latitude tilted axis from sunrise to sunset (see Fig. 2)) to block beam irradiance.…”

Section: Measuring Diffuse Solar Irradiancementioning

confidence: 99%

New device for the simultaneous measurement of diffuse solar irradiance on several azimuth and tilting angles

et al. 2015

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A device is proposed for the measurement of diffuse solar irradiance on tilted surfaces pointing-to as well as fixed on the equatorial direction. Most commercial devices are not designed for this purpose. Here, we present a specific design for a system based on a single multi-lobe shadow-ring that allows us to measure diffuse irradiance with several tilted pyranometers -from 60 to 90 degrees from the horizontal plane -and on different azimuth angles. This first prototype allows us to measure in the four cardinal directions. The ring is designed to minimize the covered celestial dome observed by each sensor. Moreover, the complete device needs a very small installation area and its simplicity means it is inexpensive and easy to operate. The measurements have subsequently to be corrected with a geometrical correction factor that takes into account the portion of the sky vault blocked by the shadow-ring. These measurements are essential for estimating solar potential on tilted surfaces -such as building façades -and for improving current anisotropic solar models, among many other applications.

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Design and development of a rotating shadowband radiometer solar radiation/daylight network

Cited by 41 publications

References 5 publications

Using satellite‐derived optical thickness to assess the influence of clouds on terrestrial carbon uptake

Using satellite‐derived optical thickness to assess the influence of clouds on terrestrial carbon uptake

Field comparison of network Sun photometers

New device for the simultaneous measurement of diffuse solar irradiance on several azimuth and tilting angles

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