Birgit Gerasch

Regional products for the Baltic Sea using MERIS data

For many questions of the coastal zone management the knowledge on the biological and ecological state of coastal waters is of high importance. Due to the complexity of this water type, characterized by different classes of water constituents, a sophisticated methodology needs to be applied for quantitative remote sensing. Within the MAPP‐Project (MERIS Applications and Regional Products Project) a specific remote sensing interpretation algorithm was developed for the regional assessment of water constituents in the Baltic Sea. This is a part of the ESA Cat‐1 proposal ID 1413 GEMEL‐3 (“Generation of MERIS Level‐3 products for European multidisciplinary regional applications”). The operational implementation in a MERIS‐value‐adding system allows a near real‐time estimation of chlorophyll sediment and gelbstoff concentrations on a regular basis. The algorithm, based on a principal component inversion (PCI) technique and the model will be introduced. The applicability of the model will be demonstrated on a couple of comparisons of MERIS reflectances and in‐situ measurements. The potential of the model shall be demonstrated on available MERIS data.

The hyperspectral sensor DESIS on MUSES: Processing and applications

The hyperspectral instrument DLR Earth Sensing Imaging Spectrometer (DESIS) will be developed and integrated in the Multi-User-System for Earth Sensing (MUSES) platform installed on the International Space Station (ISS). The DESIS instrument will be launched to the ISS mid of 2017 and installed in one of the four slots of the MUSES platform. The MUSES / DESIS system will be commanded and operated by the publically traded company Teledyne Brown Engineering (TBE), which initiated the program. TBE provides the MUSES platform and the German Aerospace Center (DLR) develops DESIS and establishes a Ground Segment for processing, archiving, delivering and calibrating the data used for scientific and humanitarian applications. Harmonized products will be generated by the Ground Segment established at Teledyne. This article describes the processing ground segment and the foreseen data validation activities. Finally comments regarding the data policy and foreseen scientific uses are given.

Resume of seven-year MOS in-orbit calibration: events, effects, and explanations

The in-orbit calibration of the Modular Optoelectronic Scanner MOS on the Indian Remote Sensing Satellite IRS-P3 has delivered the actual radiometric recalibration coefficients with sufficient accuracy for most of the 18 spectral channels in the VIS/NIR spectral range during the 7 years mission time. This has been the basis for the thematic interpretation of the MOS data. The three different and independent in-orbit calibration methods: lamp calibration, sun calibration and ground target based (vicarious) calibration as well as different possibilities of dark signal determination and the extensive knowledge of instrument performance data and instrument characteristics from the lab measurements have enabled us to overcome all failures and difficulties of the instrument which occurred in orbit. The failure of the lamp and sun calibration equipment in September 2000 has been overcome by using the vicarious calibration and dark signal measurements at the earth night side at new moon. The failure of the thermo-electric cooling of the detectors in November 2002 could be overcome only by the knowledge of the temperature dependence of the spectral responsivity of the different spectral channels and its dark signals. Thus we are able to continue the determination of the time trend of the recalibration coefficients in spite of these problems. In the paper we will give a resume of the most important events concerning the in-orbit calibration during the mission time, try to find explanations for some effects and present the results of determining the recalibration coefficients and the accuracy reached under the concrete environmental and instrumental conditions in orbit.

Remote sensing of atmospheric properties with the modular optical scanner (MOS)

Satellite remote sensing of atmospheric properties is important for investigation of atmospheric pollution and also for remote sensing of the underlying surface, where an atmospheric correction is needed. For the proof of new methodological concepts the multispectral imaging spectrometer MOS was developed in the DLR Institute of Space Sensor Technology and launched on the Indian satellite IRS- P3. It has 13 bands in the VIS/NIR region with 10nm bandwidth. MOS successfully provides data for more than 2 years over European and Northern African coasts. The paper will introduce a standard atmospheric correction scheme for MOS data over water regions using measurements in the near IR form 685 nm to 1000 nm. This method is based on a 2- channel correction, estimating the aerosol optical depth and the Angstrom coefficient for the spectral behavior of the optical thickness. After extrapolation of the visible region the atmospheric correction is applied. Examples will be shown from the Baltic and North Sea regions. The obtained result will be compared and discussed with available in situ measurements taken simultaneously with MOS overflights. Lastly, this algorithm is applied to an observation of forest fire smoke over Malaysia.