Arctic Urbanization:
Effects of human activity and global warming on the
vegetation productivity around 28 cities detected
from satellites over 2000-2014
Igor Esau and Victoria Miles
Nansen Environmental and Remote Sensing Centre and Bjerknes Centre for Climate Research, Bergen, Norway
* Supported by the International Belmont Forum project:
Anthropogenic Heat Islands in the Arctic: Windows to the Future of the Regional Climates, Ecosystems, and Societies
Arctic vegetation in vicinity of urban settlements experiences significant stress from
both the human activity and global warming. Our study reveals significant and
divergent changes in vegetation productivity in Northern West Siberia and around
its 28 major cities. The statistical analysis is based on the MODIS NDVI (0.25 km)
and LST (1 km) products over 2000-2014.
Results. The obtained NDVI maps show widespread but rather fragmented greening
of northern biomes. Contrary, the southern “taiga” forest show browning (the
decay of productivity). We found statistically significant but still rather local impact
of the regional industrial development on the long-term trends of apparent
vegetation productivity. Moreover, the disturbed vegetation cover becomes
generally more productive.
Fig. 1. The mean NDVImax
LST 0C
High : -26,4582
Low : -29,0648
Fig. 2. The significant (p <0.01) linear trends in NDVImax
Fig. 4. The spatio-temporal and correlation analysis of NDVImax
at the city core and 8 surrounding buffer zones for 4 selected
cities (see Fig. 3). Triangles show the years with max and min
NDVImax; the squares – 2 and 3 RMS intervals; the vertical
black lines – trends over 15 yrs (black dots) and 13 yrs (white
dots). Corr. Are given between city and the buffer zones.
urban, bare
low
moderate to low
moderate to high
higly negative
slightly positive
high
slightly negative
higly positive
negative
positive
near zero
Fig. 3. The detailed maps for 4 different cities situated in four bioclimatic zones:
tundra (Tazovskiy); forest-tundra (Nadym); Northern taiga (Noyabrsk); and
southern taiga (Megion). The leftmost column shows the LANDSAT visual image.
The 2nd col. – the mean wintertime urban heat island using LST MODIS data. The
3rd col. – the mean NDVImax around the city. The 4th col. – the NDVImax trends;
and the 5th col. – the statistically significant (p <0.01) NDVImax trends. Square side
is 20 km. Blue ellipses help to collocate the patterns.
Fig. 5. Relative NDVImax
differences and changes
in the city core and the
natural vegetation (40km ring). Size of the
circles shows the city
population; colors show
the bioclimatic zones:
tundra (blue); foresttundra (cyan); northern
taiga
(green);
and
southern taiga (red).