Frequency of Low Clouds in Taiwan Retrieved from MODIS Data and Its Relation to Cloud Forest Occurrence

Remote Sensing

Boris Thies²  Alexander Groos²  Martin Schulz²  Ching-Feng Li⁴  Shih-Chieh Chang³  Jörg Bendix²  Randolph Wynne¹ 

[1] Faculty of Geography, Philipps-Universität Marburg, Deutschhausstrasse 12, 35032 Marburg, Germany;;Faculty of Geography, Philipps-Universität Marburg, Deutschhausstrasse 12, 35032 Marburg, Germany; E-Mails:;Department of Natural Resources and Environmental Studies, National Dong Hwa University, 974 Hualien, Taiwan; E-Mail:;Department of Botany and Zoology, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic; E-Mail:

关键词: Taiwan;    tropical montane cloud forest;    satellite;    MODIS;    vegetation survey;   

DOI  :  10.3390/rs71012986

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.