Yuyang Cui, Yaxue Zhao and Xuecao Li
Abstract
As urbanization processes are no longer characterized by simple linear expansion but
exhibit leaping, edge-sparse, and discontinuous features, spatiotemporally continuous
impervious surface coverage data are needed to better characterize urbanization processes.
This study utilized GAIA impervious surface binary data and employed spatiotemporal
aggregation methods to convert thirty years of 30 m resolution data into 1 km resolution
spatiotemporal impervious surface coverage data, constructing a long-term time series
annual impervious surface coverage dataset for the Beijing–Tianjin–Hebei region. Based on
this dataset, we analyzed urban expansion processes and landscape pattern indices in the
Beijing–Tianjin–Hebei region, exploring the spatiotemporal response relationships of ecological environment changes. Results revealed that the impervious surface area increased
dramatically from 7579.3 km2
in 1985 to 37,484.0 km2
in 2020, representing a year-on-year
growth of 88.5%. Urban expansion rates showed two distinct peaks: 800 km2/year around
1990 and approximately 1700 km2/year during 2010–2015. In high-density urbanized areas
with impervious surfaces, the average forest area significantly increased from approximately 2500 km2
to 7000 km2 during 1985–2005 before rapidly declining, grassland patch
fragmentation intensified, while in low-density areas, grassland area showed fluctuating
decline with poor ecosystem stability. Furthermore, by incorporating natural and social
factors such as Fractional Vegetation Coverage (FVC), Habitat Quality Index (HQI), Land
Surface Temperature (LST), slope, and population density, we assessed the vulnerability
of urbanization development in the Beijing–Tianjin–Hebei region. Results showed that
high vulnerability areas (EVI > 0.5) in the Beijing–Tianjin core region continue to expand,
while the proportion of low vulnerability areas (EVI < 0.25) in the northern mountainous
regions decreased by 4.2% in 2020 compared to 2005. This study provides scientific support
for the sustainable development of the Beijing–Tianjin–Hebei urban agglomeration, suggesting location-specific and differentiated regulation of urbanization processes to reduce
ecological risks.
Long-Term_Time_Series_Estimati.pdf