Relation between Seasonally Detrended Shortwave Infrared Reflectance Data and Land Surface Moisture in Semi-Arid Sahel

Jørgen L. Olsen, Pietro Ceccato, Simon Richard Proud, Rasmus Fensholt, Manuela Grippa, Eric Mougin, Jonas Ardö, Inge Sandholt

Research output: Contribution to journalJournal articleResearchpeer-review


In the Sudano-Sahelian areas of Africa droughts can have serious impacts on natural resources, and therefore land surface moisture is an important factor. Insufficient conventional sites for monitoring land surface moisture make the use of Earth Observation data for this purpose a key issue. In this study we explored the potential of using reflectance data in the Red, Near Infrared (NIR), and Shortwave Infrared (SWIR) spectral regions for detecting short term variations in land surface moisture in the Sahel, by analyzing data from three test sites and observations from the geostationary Meteosat Second Generation (MSG) satellite. We focused on responses in surface reflectance to soil-and surface moisture for bare soil and early to mid-growing season. A method for implementing detrended time series of the Shortwave Infrared Water Stress Index (SIWSI) is examined for detecting variations in vegetation moisture status, and is compared to detrended time series of the Normalized Difference Vegetation Index (NDVI). It was found that when plant available water is low, the SIWSI anomalies increase over time, while the NDVI anomalies decrease over time, but less systematically. Therefore SIWSI may carry important complementary information to NDVI in terms of vegetation water status, and can provide this information with the unique combination of temporal and spatial resolution from optical geostationary observations over Sahel. However, the relation between SIWSI anomalies and periods of water stress were not found to be sufficiently robust to be used for water stress detection.
Original languageEnglish
JournalRemote Sensing
Issue number6
Pages (from-to)2898-2927
Publication statusPublished - 2013
Externally publishedYes


  • Soil moisture
  • Vegetation
  • Water stress
  • Earth observation
  • NDVI
  • Sahel
  • Drought


Dive into the research topics of 'Relation between Seasonally Detrended Shortwave Infrared Reflectance Data and Land Surface Moisture in Semi-Arid Sahel'. Together they form a unique fingerprint.

Cite this