Combination of sentinel-2 and palsar-2 for local climate zone classification: A case study of nanchang, China

Chaomin Chen, Hasi Bagan, Xuan Xie, Yune La, Yoshiki Yamagata

Research output: Contribution to journalArticlepeer-review

Abstract

Local climate zone (LCZ) maps have been used widely to study urban structures and urban heat islands. Because remote sensing data enable automated LCZ mapping on a large scale, there is a need to evaluate how well remote sensing resources can produce fine LCZ maps to assess urban thermal environments. In this study, we combined Sentinel-2 multispectral imagery and dual-polarized (HH + HV) PALSAR-2 data to generate LCZ maps of Nanchang, China using a random forest classifier and a grid-cell-based method. We then used the classifier to evaluate the importance scores of different input features (Sentinel-2 bands, PALSAR-2 channels, and textural features) for the classification model and their contribution to each LCZ class. Finally, we investigated the relationship between LCZs and land surface temperatures (LSTs) derived from summer nighttime ASTER thermal imagery by spatial statistical analysis. The highest classification accuracy was 89.96% when all features were used, which highlighted the potential of Sentinel-2 and dual-polarized PALSAR-2 data. The most important input feature was the short-wave infrared-2 band of Sentinel-2. The spectral reflectance was more important than polarimetric and textural features in LCZ classification. PALSAR-2 data were beneficial for several land cover LCZ types when Sentinel-2 and PALSAR-2 were combined. Summer nighttime LSTs in most LCZs differed significantly from each other. Results also demonstrated that grid-cell processing provided more homogeneous LCZ maps than the usual resampling methods. This study provided a promising reference to further improve LCZ classification and quantitative analysis of local climate.

Original languageEnglish
Article number1902
JournalRemote Sensing
Volume13
Issue number10
DOIs
Publication statusPublished - 2021 May 2
Externally publishedYes

Keywords

  • ASTER
  • Feature importance
  • Grid cells
  • Land surface temperature
  • Local climate zone
  • PALSAR-2
  • Random forest
  • Sentinel-2

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

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