Measuring the vertical albedo profile of a subarctic boreal forest canopy

Riihelä, Aku; Manninen, Terhikki

doi:10.14214/sf.228

Cited by 8 publications

(3 citation statements)

References 29 publications

(28 reference statements)

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“…). Utilization and redistribution of sunlight caused absorption, reflection, and scattering of the forest canopy, which could result in different light environments on the forest floor (Riihelä and Manninen ). In the subtropical forests of China, both light intensity and quality differ significantly between the forest floor and the open field (Jiang ); 30–60% of sunlight can be detected in forests of intermediate age (Qin et al.…”

Section: Introductionmentioning

confidence: 99%

Effects of light intensity on litter decomposition in a subtropical region

Yang

et al. 2017

Ecosphere

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Abstract. Sunlight, as a main driver of terrestrial ecosystem process, not only runs the synthesis, but also the decomposition. In nature, soil surface might be exposed to different light intensities, but the decomposition as affected by light intensity remains unknown. A shading experiment was conducted to simulate the effects of different light intensities on decomposition of foliar litter in a subtropical region of western China. Over two-year incubation, foliar litter mass lost 54.46-100% depending on tree species and light intensities, and 37.21-80.58% of mass losses occurred in rainy seasons. Light intensity gave strong effects on litter mass loss, but the effects varied with tree species and season. Shading treatments promoted the litter decomposition in the dry seasons, but inhibited the decomposition in the rainy seasons. Light intensity, tree species, and their interactions are the main factors regulating litter decomposition in subtropical regions.

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Section: Introductionmentioning

confidence: 99%

Effects of light intensity on litter decomposition in a subtropical region

Yang

et al. 2017

Ecosphere

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“…MISR can provide multi-directional observations, but with less coverage [7]. Locally, surface albedo is often measured using mast-based or portable albedometers, and airborne measurements [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Land Surface Albedos Computed from BRF Measurements with a Study of Conversion Formulae

et al. 2010

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Land surface hemispherical albedos of several targets have been resolved using the bidirectional reflectance factor (BRF) library of the Finnish Geodetic Institute (FGI). The library contains BRF data measured by FGI during the years [2003][2004][2005][2006][2007][2008][2009]. Surface albedos are calculated using selected BRF datasets from the library. Polynomial interpolation and extrapolation have been used in computations. Several broadband conversion formulae generally used for satellite based surface albedo retrieval have been tested. The albedos were typically found to monotonically increase with increasing zenith angle of the Sun. The surface albedo variance was significant even within each target category / surface type. In general, the albedo estimates derived using diverse broadband conversion formulas and estimates obtained by direct integration of the measured spectra were in line.

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“…Cescatti et al 2012) and for observing long-term (Kirschbaum et al 2011) or seasonal (Hollinger et al 2010) trends in albedo. Albedo measurements using movable masts outside the maintained flux measuring sites are rare (but see Riihelä and Manninen 2008). Some studies have also used aircraft-mounted pyranometer measurements to obtain albedos of locally typical land cover types (Ben-Gai et al 1998).…”

Section: Methods For Estimating Albedomentioning

confidence: 99%

Boreal forest albedo and its spatial and temporal variation

Kuusinen¹

2014

Diss. For.

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Surface albedo refers to the fraction of shortwave solar irradiance that is reflected by a surface. Accurate characterisation of the albedo of various land cover types is required for evaluating the energy exchange between the Earth's surface and the atmosphere. The optical and structural properties of a surface determine its albedo. Boreal forest albedo can vary due to factors such as tree species composition, forest structure, understorey vegetation composition, and seasonal changes in vegetation and snow cover. The aim of this study was to characterise typical albedos of Finnish forests dominated by different tree species, evaluate the seasonal variation in forest albedo, and to estimate the effects of structural forest variables and understorey composition on forest albedo or spectral reflectance. To achieve these aims, forest albedo was measured in-situ using pyranometers, estimated from satellite data and calculated using a forest albedo model. Unmixing methods were used to estimate forest albedo from coarse spatial resolution MODIS albedo retrievals and understorey spectral reflectance from Landsat observations. Mature or middle aged pine, spruce and broadleaved deciduous (mainly birch) forests had distinctly different albedos in both summer and winter. Coniferous forest albedo was lower and showed less seasonal variation than albedo in open areas or broadleaved deciduous forests. Albedo of pine was somewhat higher than that of spruce. Snow cover on the ground and canopy increased forest albedo. Young stands with an assumedly high proportion of deciduous species in the under-and overstorey were characterised by a higher albedo than the mature coniferous forests. The high albedo at early succession rapidly decreased as the forest matured. The forest floor was typically covered by green understorey vegetation with rather low albedo, which decreased the influence of a changing canopy cover or leaf area index (LAI) on forest albedo. The spectral reflectances of the understorey varied with site fertility and forest age.

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Measuring the vertical albedo profile of a subarctic boreal forest canopy

Cited by 8 publications

References 29 publications

Effects of light intensity on litter decomposition in a subtropical region

Effects of light intensity on litter decomposition in a subtropical region

Land Surface Albedos Computed from BRF Measurements with a Study of Conversion Formulae

Boreal forest albedo and its spatial and temporal variation

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