About me

My research is motivated by the great potential Earth observation offers to explore and understand the ecosystems of our planet. I use hyperspectral and multispectral time series to quantify land cover, retrieve vegetation parameters, and monitor ecosystem changes and dynamics over time. My studies extend across diverse terrestrial ecosystems and address environmental challenges related to global change, including disturbance and recovery processes, as well as drought and wildfire impacts. A key component of my work is developing innovative and effective image processing workflows to address real-world application challenges.

I am currently working as a senior scientist at the Helmholtz Center Potsdam, GFZ German Research Center for Geosciences, and I am a guest researcher at the Earth Observation Lab, Humboldt-Universität zu Berlin. In these roles, I additionally coordinate the EnMAP PI Project and lead the EnFireMap Project.

Interests
  • Remote sensing of vegetation
  • Urban remote sensing
  • Imaging spectroscopy
  • Multispectral time series
  • Image processing workflows
Education

  • PhD in Remote Sensing, 2014

    Humboldt-Universität zu Berlin, Germany

  • Diplom (MSc) in Geography, 2009

    Humboldt-Universität zu Berlin, Germany

Research

Monitoring (semi-)natural ecosystems

Monitoring (semi-)natural ecosystems

Mapping and monitoring urban areas

Mapping and monitoring urban areas

Implementing image processing workflows

Implementing image processing workflows

Publications

Quickly discover relevant content by filtering publications.
Sabine Chabrillat, Saskia Foerster, Karl Segl, Alison Beamish, Maximilian Brell, Saeid Asadzadeh, Robert Milewski, Kathrin J. Ward, Arlena Brosinsky, Katrin Koch, Daniel Scheffler, Stephane Guillaso, Alexander Kokhanovsky, Sigrid Roessner, Luis Guanter, Hermann Kaufmann, Nicole Pinnel, Emiliano Carmona, Tobias Storch, Tobias Hank, Katja Berger, Mathias Wocher, Patrick Hostert, Sebastian van der Linden, Akpona Okujeni, Andreas Janz, Benjamin Jakimow, Astrid Bracher, Mariana A. Soppa, Leonardo M.A. Alvarado, Henning Buddenbaum, Birgit Heim, Uta Heiden, Jose Moreno, Cindy Ong, Niklas Bohn, Robert O. Green, Martin Bachmann, Raymond Kokaly, Martin Schodlok, Thomas H. Painter, Ferran Gascon, Fabrizia Buongiorno, Matti Mottus, Vittorio Ernesto Brando, Hannes Feilhauer, Matthias Betz, Simon Baur, Rupert Feckl, Anke Schickling, Vera Krieger, Michael Bock, Laura La Porta, Sebastian Fischer (2024). The EnMAP spaceborne imaging spectroscopy mission: Initial scientific results two years after launch. Remote Sensing of Environment.

Cite DOI URL

Franz Schug, Kira A. Pfoch, Vu-Dong Pham, Sebastian van der Linden, Akpona Okujeni, David Frantz, Volker C. Radeloff (2024). Land cover fraction mapping across global biomes with Landsat data, spatially generalized regression models and spectral-temporal metrics. Remote Sensing of Environment.

Cite DOI URL

Katja Kowalski, Cornelius Senf, Akpona Okujeni, Patrick Hostert (2024). Large-scale remote sensing analysis reveals an increasing coupling of grassland vitality to atmospheric water demand.. Global change biology.

Cite DOI

Vu-Dong Pham, Fabian Thiel, David Frantz, Akpona Okujeni, Franz Schug, Sebastian van der Linden (2024). Learning the variations in annual spectral-temporal metrics to enhance the transferability of regression models for land cover fraction monitoring. Remote Sensing of Environment.

Cite DOI URL

Akpona Okujeni, Katja Kowalski, Katarzyna Ewa Lewińska, Shawn Schneidereit, Patrick Hostert (2024). Multidecadal grassland fractional cover time series retrieval for Germany from the Landsat and Sentinel-2 archives. Remote Sensing of Environment.

Cite DOI URL

See all publications

Data

Berlin-Urban-Gradient

A ready-to-use imaging spectrometry dataset for multi-scale unmixing and classification analyses in urban environments.

Simulated EnMAP (BA)

This dataset comprises spring, summer and fall 2013 simulated hyperspectral EnMAP mosaics for the San Francisco Bay Area, USA.

Simulated EnMAP (LT)

This dataset comprises spring, summer and fall 2013 simulated hyperspectral EnMAP mosaics for the Lake Tahoe region, USA.

Simulated EnMAP (SB)

This dataset comprises spring, summer and fall 2013 simulated hyperspectral EnMAP mosaics for the Santa Barbara region, USA.

Building height map (GER)

This dataset features a map of building height predictions for entire Germany based on Sentinel-1A/B and Sentinel-2A/B time series.

Land cover map (GER)

This dataset features a map of built-up and infrastructure, woody and non-woody vegetation fraction predictions for Germany.

Land cover map (AUT)

This dataset features a map of built-up and infrastructure, woody and non-woody vegetation fraction predictions for Austria.

Software & Tutorials

Software - EnMAP-Box 3

A free and open source python plug-in for QGIS, designed to process and visualize remote sensing data.

Software - FORCE

Processing engine for medium-resolution EO image archives, enabeling Analysis Ready Data generation and large area/time series analyses.

Tutorial - Forest biomass

Learn how to estimate forest aboveground biomass using the regression workflow of the EnMAP-Box.

Tutorial - Urban mapping

Learn how to map urban class fractions using the regression-based unmixing workflow of the EnMAP-Box.

Contact