Preface

When seen from space, "Planet Earth" is a mix of clouds, with the majority (two thirds) of the total surface under ocean water with the remaining third of land forming what we call continents, with various degrees of increasing albedo from open water bodies, vegetation, bare soil, rocks, deserts, and snow/ice packs.

In a very short time (relative to Earth's age), the modern human civilization has conquered its neighboring space with probes, satellites, and vehicles carrying humans for exploration. From the range of observing platforms (airborne or space-borne) circumventing our inner atmosphere to its boundary, in low Earth orbit up to geostationary orbit, a large number of Earth observation sensors and satellites are monitoring the state of our home planet.

Monitoring of water and land objects enters a revolutionary age with the rise of ubiquitous remote sensing and public access. Earth monitoring satellites permit detailed, descriptive, quantitative, holistic, standardized, global evaluation of the state of the Earth skin in a manner that our actual Earthen civilization has never been able to before.

The water monitoring topics covered in this book include the remote sensing of open water bodies, wetlands and small lakes, snow depth and underwater seagrass, along with a variety of remote sensing techniques, platforms, and sensors.

The Earth monitoring topics include geomorphology, land cover in arid climate, and disaster assessment after a tsunami. Finally, advanced topics of remote sensing cover atmosphere analysis with GNSS signals, earthquake visual monitoring, and fundamental analyses of laser reflectometry in the atmosphere medium.

Remotely yours,

**Dr. Yann Chemin**  International Water Management Institute Sri Lanka

**Part 1** 

**Water Monitoring** 

**Part 1** 

**Water Monitoring** 

**1** 

*Germany* 

Mathias Bochow1,2 et al.\*

**On the Use of Airborne Imaging Spectroscopy** 

*2Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association* 

There is economical and ecological relevance for remote sensing applications of inland and coastal waters: The European Union Water Framework Directive (European Parliament and the Council of the European Union, 2000) for inland and coastal waters requires the EU member states to take actions in order to reach a good ecological status in inland and coastal waters by 2015. This involves characterization of the specific trophic state and the implementation of monitoring systems to verify the ecological status. Financial resources at the national and local level are insufficient to assess the water quality using conventional methods of regularly field and laboratory work only. While remote sensing cannot replace the assessment of all aquatic parameters in the field, it powerfully complements existing sampling programs and offers the

The delineation of surface water bodies is a prerequisite for any further remote sensing based analysis and even can by itself provide up-to-date information for water resource management, monitoring and modelling (Manavalan *et al.*, 1993). It is further important in the monitoring of seasonally changing water reservoirs (e.g., Alesheikh *et al.*, 2007) and of shortterm events like floods (Overton, 2005). Usually the detection and delineation of surface water bodies in optical remote sensing data is described as being an easy task. Since water absorbs most of the irradiation in the near-infrared (NIR) part of the electromagnetic spectrum water bodies appear very dark in NIR spectral bands and can be mapped by simply applying a maximum threshold on one of these bands (Swain & Davis, 1978: section 5-4). Many studies took advantage of this spectral behaviour of water and applied methods like single band density slicing (e.g., Work & Gilmer, 1976), spectral indices (McFeeters, 1996, Xu, 2006) or multispectral supervised classification (e.g., Frazier & Page, 2000, Lira, 2006). However, all of

Birgit Heim2, Theres Küster1, Christian Rogaß1, Inka Bartsch2, Karl Segl1, Sandra Reigber3,4 and

*1Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences, Germany 2Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association, Germany 3RapidEye AG, Germany* 

base to extrapolate the sampled parameter information in time and in space.

**1. Introduction** 

 \*

Hermann Kaufmann1

*4Technical University of Berlin, Germany* 

**Data for the Automatic Detection and** 

**Delineation of Surface Water Bodies** 

*1Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences* 
