Laboratory for
Climatology and Remote Sensing

Abstract:

Land-use and land-cover changes (LULCC) affect local climate. Human-induced deforestation is a common phenomenon of LULCC. This also holds true for the biodiversity hotspot in the Andes of Ecuador. This study assesses the possibility to project LULCC to future time steps with a focus on deforestation in the San Francisco valley in South Ecuador. A business-as-usual scenario based on two Landsat scenes from 1987 and 2001 was created to project LULCC until 2006. The uncertainty assessment indicated the difficulty of projecting human impact on the ecosystem since circumstances of LULCC in the study area cannot be assumed to stay invariant. The projection performs better than a naive model relying on slope as its suitability factor.

Abstract:

The relationship between satellite-derived low cloud frequency and the occurrence of tropical montane cloud forest (TMCF) in Taiwan was investigated. From daily MODIS cloud mask products between 2003 and 2012 the low cloud class was extracted and mean low cloud frequency was calculated for Taiwan. This low cloud frequency map was blended with an existing plot-based vegetation classification for Taiwan to analyze the relationship between low cloud frequency and TMCF occurrence. Receiver operating characteristics curves and the area under the ROC curve (AUC) were used to analyze if a relationship exists. No relationship was found for all four TMCF types taken together (AUC = 0.61) and for the dominant TMCF type, Quercus montane evergreen broad-leaved cloud forest (AUC = 0.5). Strong relationships were found for the two spatially-restricted TMCF types, Fagus montane deciduous broad-leaved cloud forest (AUC = 0.91) and Pasania-Elaeocarpus montane evergreen broad-leaved forest (AUC = 0.84), as well as for the second dominant type Chamaecyparis montane mixed cloud forest (AUC = 0.74). The results show that low cloud frequency thresholds might be associated with specific cloud forest types in Taiwan. Further studies should incorporate information about cloud base height, cloud density, and cloud immersion time as well as satellite-based cloud frequency information with a higher temporal resolution. Combination with satellite-based land cover classifications for Taiwan would allow quasi-continuous observation of TMCF changes. Such knowledge would be the precondition for effective protective actions concerning this exceptional but threatened ecosystem.