Cloud cover statistics and their use in the planning of remote sensing missions

Greaves, J. R.; Sherr, Paul E.; Glaser, Arnold H.

doi:10.1016/s0034-4257(70)80010-4

Cited by 9 publications

(1 citation statement)

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“…In fact, the presence of clouds either completely blocks or to some degree attenuates both incoming and outgoing radiation. Therefore, nearly all Earth-orientated observations from space are cloud sensitive to some degree (Greaves et al 1970). Clouds are still one of the less-understood components in the Earth-atmosphere system, and the measurement of their radiative properties remains a challenge (Pfister et al 2003).…”

Section: Introductionmentioning

confidence: 99%

How sensitive is the CWSI to changes in solar radiation?

Agam

Cohen

Alchanatis

et al. 2013

International Journal of Remote Sensing

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Cloud cover drastically and instantaneously reduces net radiation and available energy. Appearance of clouds will therefore alter the surface energy balance and elicit response of plant canopy temperature (T C ). The attenuated shortwave radiation and altered T C during the presence of clouds may subsequently affect the crop water stress index (CWSI). Therefore, to correctly interpret T C measurements, the effect of clouds must be understood. The objective of this work was to study the effect of abrupt changes in solar radiation due to varying cloudy conditions on T C and CWSI for olive trees. Results from two separate experiments are presented, both comparing different levels of water status of Barnea olive trees. The first experiment was conducted in a commercial orchard where five irrigation levels were applied. Thermal images were acquired simultaneously with stomatal resistance measurements on a day with clear skies. The second experiment was conducted on single trees planted in lysimeters. Irrigation was withheld for five of 15 trees for 6 days until they were severely stressed. Thereafter, irrigation was resumed to levels higher than the transpiration rates. Throughout the stress and recovery periods, water status measurements were conducted daily between 12:00 and 14:00 on all trees. On the day of maximum stress, thermal images of well-watered and stressed trees were acquired every minute throughout a time sequence during which large fluctuations in radiation due to cloud cover were observed. The most pronounced result of this study was the greater response of stressed, compared to well-watered, trees to abrupt changes in radiation intensity. When solar radiation was high, the CWSI of stressed trees reached 0.8, while the CWSI of well-watered trees was near 0. When solar radiation dropped due to clouds, the CWSI of the stressed trees decreased to ∼0.3, while that of well-watered trees continued to fluctuate around 0. This finding implies that application of thermal imagery for water status detection would require very high radiometric resolution and constant reference measurements. For routine monitoring in commercial olive orchards, this could be facilitated by strategic maintenance of a few well-watered trees.

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Section: Introductionmentioning

confidence: 99%

How sensitive is the CWSI to changes in solar radiation?

Agam

Cohen

Alchanatis

et al. 2013

International Journal of Remote Sensing

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Qualitative interpretation of remotely sensored data as a key to mapping vegetation patterns in the Western Sudan

Oduolowu

1977

GeoJournal

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Data capabilities of satellites remote sensor systems are briefly discussed. Monthly remotely sensored data of NIMBUS 3 meteorological satellite over parts of the Sudan, West of Lake Chad in Africa, using the HRIR -High Resolution Infra Red Radiometer (sensing between 0.7-1.3 u wavelength) are used to study the monthly shifts in the vegetation boundaries for this area. These shifts are shown to be caused by changes in soil moisture content which is controlled by the prevailing meteorological conditions in the area during the months.

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Towards earth resources satellites: The american erts and skylab programs

Steiner

1971

Photogrammetria

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Cloud cover statistics and their use in the planning of remote sensing missions

Cited by 9 publications

References 0 publications

How sensitive is the CWSI to changes in solar radiation?

How sensitive is the CWSI to changes in solar radiation?

Qualitative interpretation of remotely sensored data as a key to mapping vegetation patterns in the Western Sudan

Towards earth resources satellites: The american erts and skylab programs

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