New paper on modelling the Arctic taiga-tundra ecotone

New paper on modelling the Arctic taiga-tundra ecotone

m

November 28, 2019

We tried to go one step further to quantify northern latitude vegetation trends. This paper on modelling the arctic taiga-tundra ecotone using ALOS PALSAR and optical #earthobservation data was published two months ago.

Find the paper here: https://doi.org/10.1016/j.jag.2019.05.008

Abstract:

The taiga-tundra ecotone (TTE) extends over 13.400 km around the northern hemisphere and marks the transition
zone between taiga and tundra. Since this area is vulnerable to climate change, human activities and
natural disturbances such as wildfires, monitoring of this region is extremely important. Dealing with the
characterization of this transition zone, very few studies are available on a global scale. Existing approaches lack
the thorough characterization of the ecotone as they capture just a part of the complex transition zone.
The objective of this research is to develop a monitoring concept for detecting the taiga-tundra interface for a
designated study area in northern Siberia. We used optical and SAR remote sensing data products from 2007 to
2010, whereby the spatial resolution of all datasets were unified to 1 km. Earth Observation data and products
from ALOS PALSAR, MODIS, AMSR-E were utilized in addition to digital elevation model data and the Percent
Tree Cover product. Using random forest variable importance measure, most relevant statistics were selected and
used for different model setups. The final random forest model setup included statistics of land surface temperature
(LST), albedo, NDVI, EVI, Vegetation Continuous Fields (VCF), PALSAR HV-Polarization and LAI. Snow
water equivalent (SWE) statistics had to be excluded for compensating artifacts.
Since sharp distinctions between forest and tundra do not occur in nature, class probability values were
computed. This allowed the unique allocation per class for each grid cell. The model setup showed high performance
values, which were cross validated, with accuracies of 95.6% (±1.5%). The model result was validated
using high resolution Google Earth imagery, where an overall map accuracy of 93% (Kappa 0.89) was
achieved. The assessment of the input data products revealed that statistics of LST, SWE and albedo were most
important.
Compared to existing circumpolar products the advantage of this approach is the derivation of continuous
probability values for the taiga-tundra transition zone instead of sharp borders between the biogeographic
classes. The model provides the basis for a monitoring effort aiming at detecting changes over time. This would
help to understand the dynamics of ecosystem changes with respect to influencing factors.

you may also like:

EORC and EAGLE summer BBQ

EORC and EAGLE summer BBQ

We’re happy to announce that our summer BBQ is happening again on Thursday, July 24th at 4pm! Alongside good food and a relaxed atmosphere, we’re also hosting a series of short talks highlighting exciting topics in Earth Observation and environmental science: “The...

🗺 Exploring Map Visualizations

🗺 Exploring Map Visualizations

Within our EAGLE courses our students have to learn a wide variety of skills - beside the fundamental earth observation theory and practice also skills like map creation is part of the curriculum. One of our students Ronja Seitz has created three visualizations guides...

Successful Completion of UNIversInternational Certificate

Successful Completion of UNIversInternational Certificate

In line with its internationalization strategy, the University of Würzburg supports administrative staff in their task of advising and supporting international students, guests, and academics. To this end, it has launched the "UNIversInternational" certificate...

The “Geolingual Studies” team visited the DLR EOC

The “Geolingual Studies” team visited the DLR EOC

The "Geolingual Studies" team of the University Würzburg visited the DLR-EOC on 3 and 4 July 2025. Geolingual Studies is an innovative area of research and teaching which takes a decisively applied linguistic approach and combines methodologies from linguistics,...

Course on Object-based image analysis

Course on Object-based image analysis

Dr. Michael Wurm from the German Aerospace Center (DLR) gave a class about Object-based image analysis (OBIA) using the eCognition Software for the EAGLE students. The course gives an insight into the theoretical basis of OBIA and using different datasets and tasks...