East-Southeast Asia is currently one of the fastest urbanizing regions in the world, with countries such as China climbing from 20 to 50% urbanized in just a few decades. By 2050, these countries are projected to add 1 billion people, with 90% of that growth occurring in cities. This population shift parallels an equally astounding amount of built-up land expansion. However, spatially-and temporallydetailed information on regional-scale changes in urban land or population distribution do not exist; previous efforts have been either sample-based, focused on one country, or drawn conclusions from datasets with substantial temporal/spatial mismatch and variability in urban definitions. Using consistent methodology, satellite imagery and census data for >1000 agglomerations in the East-Southeast Asian region, we show that urban land increased >22% between 2000 and 2010 (from 155 000 to 189 000 km 2 ), an amount equivalent to the area of Taiwan, while urban populations climbed >31% (from 738 to 969 million). Although urban land expanded at unprecedented rates, urban populations grew more rapidly, resulting in increasing densities for the majority of urban agglomerations, including those in both more developed (Japan, South Korea) and industrializing nations (China, Vietnam, Indonesia). This result contrasts previous sample-based studies, which conclude that cities are universally declining in density. The patterns and rates of change uncovered by these datasets provide a unique record of the massive urban transition currently underway in East-Southeast Asia that is impacting local-regional climate, pollution levels, water quality/availability, arable land, as well as the livelihoods and vulnerability of populations in the region.
Abstract. The increasing availability of high-quality remote sensing data and advanced
technologies has spurred land cover mapping to characterize land change from
local to global scales. However, most land change datasets either span
multiple decades at a local scale or cover limited time over a larger
geographic extent. Here, we present a new land cover and land surface change
dataset created by the Land Change Monitoring, Assessment, and Projection
(LCMAP) program over the conterminous United States (CONUS). The LCMAP land
cover change dataset consists of annual land cover and land cover change
products over the period 1985–2017 at a 30 m resolution using Landsat and
other ancillary data via the Continuous Change Detection and Classification (CCDC) algorithm. In this paper, we describe our novel approach to implement
the CCDC algorithm to produce the LCMAP product suite composed of five land
cover products and five products related to land surface change. The LCMAP land cover
products were validated using a collection of ∼25 000
reference samples collected independently across CONUS. The overall
agreement for all years of the LCMAP primary land cover product reached
82.5 %. The LCMAP products are produced through the LCMAP Information
Warehouse and Data Store (IW+DS) and shared Mesos cluster systems that can
process, store, and deliver all datasets for public access. To our
knowledge, this is the first set of published 30 m annual land change
datasets that include land cover, land cover change, and spectral change
spanning from the 1980s to the present for the United States. The LCMAP
product suite provides useful information for land resource management and
facilitates studies to improve the understanding of terrestrial ecosystems
and the complex dynamics of the Earth system. The LCMAP system could be
implemented to produce global land change products in the future. The LCMAP
products introduced in this paper are freely available at
https://doi.org/10.5066/P9W1TO6E (LCMAP, 2021).
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