English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Forest overstory and understory layers differ in carbonand water cycle regimes and phenology, as well as ecosystem functions. Separateretrievals of leaf area index (LAI) for these two layers would help toimprove modeling forest biogeochemical cycles, evaluating forest ecosystemfunctions and also remote sensing of forest canopies by inversion of canopyreflectance models. In this paper, overstory and understory LAI values wereestimated separately for global needleleaf and deciduous broadleaf forestsby fusing MISR and MODIS observations. Monthly forest understory LAI wasretrieved from the forest understory reflectivity estimated using MISR data.After correcting for the background contribution using monthly mean forestunderstory reflectivities, the forest overstory LAI was estimated from MODISobservations. The results demonstrate that the largest extent of forestunderstory vegetation is present in the boreal forest zones at northernlatitudes. Significant seasonal variations occur for understory vegetationin these zones with LAI values up to 2–3 from June to August. The meanproportion of understory LAI to total LAI is greater than 30 %. Higherunderstory LAI values are found in needleleaf forests (with a mean value of1.06 for evergreen needleleaf forests and 1.04 for deciduous needleleafforests) than in deciduous broadleaf forests (0.96) due to the more clumpedfoliage and easier penetration of light to the forest floor in needleleafforests. Spatially and seasonally variable forest understory reflectivityhelps to account for the effects of the forest background on LAI retrievalwhile compared with constant forest background. The retrieved forestoverstory and understory LAI values were compared with an existing datasetfor larch forests in eastern Siberia (40–75° N,45–180° E). The retrieved overstory and understory LAIis close to that of the existing dataset, with an absolute error of 0.02(0.06), relative error of 1.3 % (14.3 %) and RMSE of 0.93 (0.29) foroverstory (understory). The comparisons between our results and fieldmeasurements in eight forest sites show that the <i>R</i><sup>2</sup> values are 0.52 and 0.62,and the RMSEs are 1.36 and 0.62 for overstory and understory LAI,respectively

Separating overstory and understory leaf area indices for global needleleaf and deciduous broadleaf forests by fusion of MODIS and MISR data