Biophysical parameters and L-band polarimetry synthetic aperture radar observation data were taken for 59 test sites in Tomakomai national forest, which is located in the northern part of Japan. Correlations between the derived σ 0 HH , σ 0 HV , and σ 0 VV and the biophysical parameters are investigated and yield the following results. 1) The above-ground biomass-σ 0 curves saturate above 50 tons/ha for σ 0 VV , 100 tons/ha for σ 0 HH , and over 100 tons/ha for σ 0 HV when all forest species are included in the curves. 2) The σ 0 HH -above-ground biomass curve for one forest species indicates a higher saturation level than that for the other forest species. Dependence on the forest species was absent for VV polarization and low for HV polarization.3) A simple three-component scattering model indicates that volume scattering accounts for 80%-90% when the above-ground biomass exceeds 50 tons/ha. The surface-scattering components are up to ∼20% for young stands, and the volume-scattering components are down to 70%. The origin of the dependency among the forest species was examined for the σ 0 HH -above-ground biomass. It is concluded that a possible cause of the dependency is the different characteristics of the stands rather than forest species.Index Terms-Forestry, synthetic aperture radar (SAR).

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a b s t r a c tBecause of the lack of time-series spatial data on urban components, urban expansion in developing countries has usually been studied using a pixel-based approach, despite the coarse spatial resolution associated with this technique. To understand the residential-scale processes involved in urban expansion, we developed feature-oriented GIS data extracted from very high spatial resolution satellite images (IKONOS for 2000 and Quickbird for 2006 and 2008). We selected a fringe area of Ulaanbaatar, the capital municipality of Mongolia, as a case study. Residential plots in this area have developed in an unplanned manner owing to the poor execution of land reform policy. This study facilitated the residential-scale delineation of the significantly expanding area occupied by private land plots in time series. It also permitted the identification of geographical factors driving the expansion. Using a logistic regression model, we found that such expansion is related to social infrastructure rather than to natural landforms. In particular, new plots of private land tended to be built near pre-existing plots and in proximity to roads and water kiosks (which provide essential drinking water for residents). These findings and the probability map predicted by the model have implications for urban planners and decision makers.

We report long‐term continuous phenological and sky images taken by time‐lapse cameras through the Phenological Eyes Network (http://www.pheno-eye.org. Accessed 29 May 2018) in various ecosystems from the Arctic to the tropics. Phenological images are useful in recording the year‐to‐year variability in the timing of flowering, leaf‐flush, leaf‐coloring, and leaf‐fall and detecting the characteristics of phenological patterns and timing sensitivity among species and ecosystems. They can also help interpret variations in carbon, water, and heat cycling in terrestrial ecosystems, and be used to obtain ground‐truth data for the validation of satellite‐observed products. Sky images are useful in continuously recording atmospheric conditions and obtaining ground‐truth data for the validation of cloud contamination and atmospheric noise present in satellite remote‐sensing data. We have taken sky, forest canopy, forest floor, and shoot images of a range of tree species and landscapes, using time‐lapse cameras installed on forest floors, towers, and rooftops. In total, 84 time‐lapse cameras at 29 sites have taken 8 million images since 1999. Our images provide (1) long‐term, continuous detailed records of plant phenology that are more quantitative than in situ visual phenological observations of index trees; (2) basic information to explain the responsiveness, vulnerability, and resilience of ecosystem canopies and their functions and services to changes in climate; and (3) ground‐truthing for the validation of satellite remote‐sensing observations.

Abstract:To analyse the long-term water balance of the Yellow River basin, a new hydrological model was developed and applied to the source area of the basin. The analysis involved 41 years of daily observation data from 16 meteorological stations. The model is composed of the following three sub-models: a heat balance model, a runoff formation model and a river-routing network model. To understand the heat and water balances more precisely, the original model was modified as follows. First, the land surface was classified into five types (bare, grassland, forest, irrigation area and water surface) using a high-resolution land-use map. Potential evaporation was then calculated using land-surface temperatures estimated by the heat balance model. The maximum evapotranspiration of each land surface was calculated from potential evaporation using functions of the leaf area index (LAI). Finally, actual evapotranspiration was estimated by regulating the maximum evapotranspiration using functions of soil moisture content. The river discharge estimated by the model agreed well with the observed data in most years. However, relatively large errors, which may have been caused by the overestimation of surface flow, appeared in some summer periods. The rapid decrease of river discharge in recent years in the source area of the Yellow River basin depended primarily on the decrease in precipitation. Furthermore, the results suggested that the long-term water balance in the source area of the Yellow River basin is influenced by land-use changes.