Relationship among the surface albedo, spectral reflectance of canopy, and evaporative fraction at grassland and paddy field

Higuchi, Atsushi; Kondoh, Akihiko; Kishi, Satoshi

doi:10.1016/s0273-1177(99)01113-8

Cited by 8 publications

(4 citation statements)

References 3 publications

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“…The surface albedo (α s = UPAR/DPAR) was found to be ∼0.065 at the station during the field campaign. This value is in agreement with the measurements of Higuchi et al [2000] who report values of surface albedo in the wavelength range of 490–900 nm ranging from ∼0.06–0.1 for a grassland in Japan on November 1997.…”

Section: Experimental Methodssupporting

confidence: 92%

Direct aerosol radiative forcing in the Yangtze delta region of China: Observation and model estimation

Bergin

Greenwald

et al. 2003

J. Geophys. Res.

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[1] The Yangtze delta region of China is a key agricultural area that experiences relatively high aerosol loadings . In order to characterize the aerosol radiative properties and estimate direct aerosol radiative forcing in this region, measurements of the multiwavelength aerosol optical depth, t l , light scattering coefficient, s sp , and absorption coefficient, s ap , as well as the downward photosynthetically active radiation (400-700 nm), DPAR, were conducted during November 1999 in Linan, China. The direct aerosol radiative forcing for photosynthetically active radiation (PAR) and total solar radiation (0.2-4.0 mm, TSR) at both the surface and top of atmosphere (TOA) are estimated based on the measurements using two radiative transfer models. The model estimates indicate that the mean cloud-free instantaneous direct aerosol radiative forcing efficiency (for solar zenith angle < 70°) at the surface for PAR is À73.5 W m À2 , which is in agreement with the value of À74.4 W m À2 derived directly from the measurements of DPAR and 500 nm aerosol optical depth (t 500 ). On the basis of the measured mean t 500 of 0.61, and the estimated cloud optical depth and cloud coverage of 5.0 and 50%, respectively, the 24-hr mean direct aerosol radiative forcing at the surface for PAR is estimated to be approximately À11.2 W m À2 . This suggests that the amount of PAR reaching the surface over the Yangtze delta region is reduced by $16% as a result of the direct radiative effect of aerosols. The model results also indicate that the cloud-free 24-hr average direct aerosol radiative forcing efficiency at the TOA for TSR is À30.4 W m À2 . When the presence of clouds is considered, the mean direct aerosol radiative forcing at the TOA for TSR is estimated to be approximately À12.1 W m À2 . This value is roughly an order of magnitude greater than the estimated global mean aerosol radiative forcing of À0.3 to À1.0 W m À2 suggested by the Intergovernmental Panel on Climate Change [1996]. Overall, this study indicates that aerosols have a substantial impact on the amount of radiation reaching the surface as well as the radiation balance at the TOA in the Yangtze delta region.

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Section: Experimental Methodssupporting

confidence: 92%

Direct aerosol radiative forcing in the Yangtze delta region of China: Observation and model estimation

Bergin

Greenwald

et al. 2003

J. Geophys. Res.

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“…Since it is well known that EF is related to water availability provided by rainfall, particularly in the natural vegetation of semi-arid environments, vegetation growth and land cover [29,35,38,64], we used the RFE, SPOT-VGT NDVI and GlobCover classes to assess the consistency of EF estimation. In particular, average and relative standard deviation (RSD) maps of EF are computed from the 448 8-day EF maps and analyzed for the major land cover classes of the study area, thanks to GlobCover map.…”

Section: Evaluation Of the Estimated Efmentioning

confidence: 99%

Evaporative Fraction as an Indicator of Moisture Condition and Water Stress Status in Semi-Arid Rangeland Ecosystems

et al. 2014

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Rangeland monitoring services require the capability to investigate vegetation condition and to assess biomass production, especially in areas where local livelihood depends on rangeland status. Remote sensing solutions are strongly recommended, where the systematic acquisition of field data is not feasible and does not guarantee properly describing the spatio-temporal dynamics of wide areas. Recent research on semi-arid rangelands has focused its attention on the evaporative fraction (EF), a key factor to estimate evapotranspiration (ET) in the energy balance (EB) algorithm. EF is strongly linked to the vegetation water status, and works conducted on eddy covariance towers used this parameter to increase the performances of satellite-based biomass estimation. In this work, a method to estimate EF from MODIS products, originally developed for evapotranspiration estimation, is tested and evaluated. Results show that the EF estimation from low spatial resolution over wide semi-arid area is feasible. Estimated EF resulted in being well correlated to field ET measurements, and the spatial patterns of EF maps are in agreement with the well-known climatic and landscape Sahelian features. The preliminary test on rangeland biomass production shows that satellite-retrieved EF as a water availability factor significantly increased the capacity of a remote sensing operational product to detect the variability of the field biomass measurements.

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“…Evaporative fraction (EF), which is defined as the ratio of latent heat flux to the available energy, plays an important role in interpreting the components of surface available energy, and improving the accuracy of field evapotranspiration (ET) estimation based on an energy balance algorithm [19][20][21][22]. It has been shown to vary in different behaviors and characteristics in response to the vegetation coverage [23], rainfall events [24], successions of wet and dry periods [25], vapor pressure deficit, and vegetation photosynthesis activity [26]. EF has been examined over several different vegetation land surfaces, such as grassland [27], rangeland [21], Vineyard [28], banana crop [29], and wheat and corn land [30].…”

Section: Introductionmentioning

confidence: 99%

“…For rainfed rice fields in eastern India, EF was found to be 79-82% in different cultivars and seasons, with a gentle broad peak from the maximum tillering stage to the heading stage [35]. Higuchi et al [26] found that the value of EF in flooded rice fields was always close to one, due to the fact that soil is flooding in rice fields or the soil moisture is almost saturated. The variations of surface energy balance components and EF in the rice ecosystem are different from those in upland crops due to the flooding or saturated soil moisture conditions [34,36,37].…”

Section: Introductionmentioning

confidence: 99%

Surface Energy Partitioning and Evaporative Fraction in a Water-Saving Irrigated Rice Field

Liu

Sung-Bum

et al. 2019

Atmosphere

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Surface energy distribution in paddy fields and the ratio of latent heat flux (LE) to available energy, termed as the evaporative fraction (EF), are essential for an understanding of water and energy processes. They are expected to vary in different ways in response to changes in the soil moisture condition under water-saving irrigation practice. In this study, the diurnal and seasonal variations in energy distribution were examined based on the data measured by the eddy covariance system and corrected with enforcing energy balance closure by the EF method in water-saving irrigated rice paddies in 2015 and 2016. Soil heat flux (G) values were similar in magnitude to sensible heat flux (Hs) values, with both accounting for approximately 5% of the energy input. Both magnitudes of G and Hs were significantly lower than that of LE. Generally, EF in water-saving irrigated rice paddies was larger than that of other ecosystems, and varied within a narrow range from 0.7 to 1.0. Diurnally, EF decreased till noon and then increased slowly in the afternoon till sunset. It was found be less varied between 10:00 and 14:00. Seasonally, the alternative drying-wetting soil water conditions in water-saving irrigated rice paddies resulted in a change in the variation of the EF. The LE flux is the largest component of available energy, with EF being mostly higher than 0.9. EF, increasing consistently till the tillering stage, remaining high from the late tillering to milk stage, and then following a declining trend. The maximum EF (approaching 1.0) was found in the milk stage. The results of EF in water-saving irrigated rice paddies will be helpful for estimating daily or long temporal scale evapotranspiration (ET) by the EF method based on satellite-derived ET.

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Relationship among the surface albedo, spectral reflectance of canopy, and evaporative fraction at grassland and paddy field

Cited by 8 publications

References 3 publications

Direct aerosol radiative forcing in the Yangtze delta region of China: Observation and model estimation

Direct aerosol radiative forcing in the Yangtze delta region of China: Observation and model estimation

Evaporative Fraction as an Indicator of Moisture Condition and Water Stress Status in Semi-Arid Rangeland Ecosystems

Surface Energy Partitioning and Evaporative Fraction in a Water-Saving Irrigated Rice Field

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