Dr. Jörg Förster Profile

Dr. Jörg Förster

at WTD 71

SPIE Involvement:

Author

Publications (9)

Proceedings Article | 1 November 2012 Paper

Joint French-German radar measurements for the determination of the refractive index in the maritime boundary layer

Helmut Essen, Andreas Danklmayer, Jörg Förster, Mario Behn, Yvonick Hurtaud, Vincent Fabbro, Laurent Castanet

Proceedings Volume 8535, 853505 (2012) https://doi.org/10.1117/12.924793

KEYWORDS: Radar, Atmospheric propagation, Refractive index, Wave propagation, Radio propagation, Troposphere, Environmental sensing, Atmospheric modeling, Antennas, Weapons

Read Abstract +

Proceedings Article | 1 October 2009 Paper

Measurements of mixing layer height variability during the Ligurian air-sea interaction experiment (LASIE '07)

J. Förster

Proceedings Volume 7476, 747603 (2009) https://doi.org/10.1117/12.830384

KEYWORDS: Humidity, Sensors, Planets, LIDAR, Temperature metrology, Environmental sensing, Meteorology, Visibility, Atmospheric propagation, Aerosols

Read Abstract +

Air-sea interaction processes play a dominant role with respect to detection ranges of shipborne radar and infrared sensor systems. Especially in the littoral most often temperature and humidity gradients affect propagation paths and are the reason for abnormal phenomena such as ducting or mirage. Besides refractivity, spray and aerosols ejected from the sea surface can further degrade the quality of shipborne surveillance systems. Thus environmental effects might seriously hamper ship self defense. During the Ligurian Air-Sea Interaction Experiment (LASIE '07 - 16.06.-26.06.2007) the Federal Armed Forces Underwater Acoustics and Marine Geophysics Research Institute (FWG) carried out simultaneous in-situ measurements of meteorological and oceanographic parameters to study air-sea interaction processes with respect to littoral boundary layer variability. The characterization of the environment included both, in-situ measurements of atmospheric and sea surface parameters. Investigations were carried out on board RV PLANET, RV URANIA and at the ODAS-Italy1 buoy of the Italian National Council of Research (CNR). On board RV PLANET the sea surface and meteorological conditions were analyzed by two multi-sensor buoys, ship sensors and radiosondes. Emphasis was given to the vertical structure of the Marine Boundary Layer (MBL) and its variability. It was analyzed by a one lense lidar ceilometer CL31, a tethersonde system TT12 and radiosondes RS92 (Vaisala). The latter were launched every three hours. The TT12 consisted of three radiosondes, which could be adapted to separate altitudes of special interest. The experiment was characterized by changing meteorological conditions resulting in offshore and onshore blowing winds. In the first case the air temperature TAir was higher than the sea surface temperature TWater leading to a very stable surface layer. This situation was associated with a strong temperature inversion and a very clear atmosphere with a visibility of about 70 km. The second case (T_Air<T_Water) was dominated by convection processes and a pronounced aerosol production. Good correlation was found for the Mixing Layer Height (MLH) by the lidar ceilometer and the radio soundings.

SPIE Journal Paper | 1 January 2009

Retrieve the evaporation duct height by least-squares support vector machine algorithm

Remi Douvenot, Vincent Fabbro, Christophe Bourlier, Joseph Saillard, Hans-Helmut Fuchs, Helmut Essen, Joerg Foerster

JARS, Vol. 3, Issue 01, 033503, (January 2009) https://doi.org/10.1117/12.10.1117/1.3081546

KEYWORDS: Atmospheric propagation, Refractive index, Databases, Radar, Data modeling, Atmospheric modeling, Humidity, Reflectors, Wave propagation, Geophysics

Read Abstract +

Proceedings Article | 29 October 2007 Paper

Determination of evaporation duct heights by an inverse method

R. Douvenot, V. Fabbro, C. Bourlier, J. Saillard, H.-H. Fuchs, H. Essen, J. Förster

Proceedings Volume 6747, 67470Q (2007) https://doi.org/10.1117/12.727976

KEYWORDS: Atmospheric propagation, Databases, Refractive index, Radar, Radio propagation, Humidity, Reflectors, Data modeling, Target detection, Modeling

Read Abstract +

Proceedings Article | 11 October 2007 Paper

Millimeter-wave propagation over sea in tropical regions

H.-H. Fuchs, H. Essen, T. Brehm, J. Foerster

Proceedings Volume 6747, 674702 (2007) https://doi.org/10.1117/12.726358

KEYWORDS: Radar, Atmospheric propagation, Atmospheric modeling, Data modeling, Antennas, Reflectors, Oscillators, Signal attenuation, Climatology, Sensors

Read Abstract +

Proceedings Article | 28 September 2006 Paper

Measurements of refractive variability in the marine boundary layer in comparison with mesoscale meteorological model predictions

J. Förster, J. Riechen

Proceedings Volume 6364, 636402 (2006) https://doi.org/10.1117/12.690138

KEYWORDS: Radar, Humidity, Atmospheric propagation, Radio propagation, Meteorology, Atmospheric modeling, Sensors, Temperature metrology, Coastal modeling, Water

Read Abstract +

Proceedings Article | 11 November 2004 Paper

Simultaneous characterization of propagation within the marine boundary layer at X-, Ka- and W-band

Helmut Essen, Hans-Hellmuth Fuchs, Joerg Foerster

Proceedings Volume 5572, (2004) https://doi.org/10.1117/12.556813

KEYWORDS: Radar, Reflectors, Atmospheric propagation, Sensors, Environmental sensing, Data modeling, Oceanography, Coastal modeling, Sensor performance, Data acquisition

Read Abstract +

Proceedings Article | 11 November 2004 Paper

Refractivity variability of the marine boundary layer and its impact on electromagnetic wave propagation

Joerg Foerster, Joerg Riechen, Gregor Biegel, Hans-Hellmuth Fuchs, Helmut Essen

Proceedings Volume 5572, (2004) https://doi.org/10.1117/12.581279

KEYWORDS: Atmospheric propagation, Radar, Radio propagation, Humidity, Temperature metrology, Wave propagation, Antennas, Meteorology, Water, Data modeling

Read Abstract +

Radar propagation near the sea surface depends on meteorological conditions and sea surface roughness. Often strong gradients of humidity and temperature can be observed close to the air-water interface leading to abnormal propagation effects such as ducting. For shipborne radars operating at frequencies above L-band, the evaporation duct is the dominant propagation mechanism affecting the maximum detection range of horizon-search radars. Ducting can also increase sea clutter return within and beyond the normal horizon, and surface-based ducts can enhance land clutter return from extended ranges. During sea trials in the Skagerrak and the Baltic Sea in 2003 and 2004, FWG was responsible for environmental characterization of the boundary layer. In-situ measurements included recordings of atmospheric and sea surface parameters. Investigations with multi-sensor buoys and with radiosondes were performed on board the German research vessel PLANET respectively on FGS HELMSAND. The drift buoys developed by FWG provided unperturbed, time resolved information on air-sea interaction processes. In addition to meteorological parameters sea state, sea surface roughness, and sea surface temperature were measured. Refractivity profiles were determined based on data sets gathered by measurements of pressure, humidity and temperature from the sea surface up to 1 km altitude. Simultaneously to atmospheric measurements radar propagation investigations were performed by FGAN-FHR (Research Institute for High Frequency Physics and Radar Techniques). PLANET, FGS STOLLERGRUND were illuminated by a radar operating at X-, Ka- and W-band. The radar system was located at the land-based test site Hirtshals, Denmark during the trials in 2003 and at the land-based test site Surendorf, Germany during the experiment in 2004. Radar propagation characteristics at X-band were measured on board the ships with two omnidirectional antennas mounted in two different altitudes above sea surface. Results of refractivity variability in the marine boundary layer are presented in conjunction with radar propagation data and model outputs.

Proceedings Article | 20 March 2003 Paper

Evironmental characterization of the marine boundary layer for electromagnetic wave propagation

Thomas Scholz, Joerg Foerster

Proceedings Volume 4884, (2003) https://doi.org/10.1117/12.462638

KEYWORDS: Atmospheric propagation, Radio propagation, Wave propagation, Radar, Ocean optics, Sensors, Electromagnetic radiation, Temperature metrology, Humidity, Microwave radiation

Read Abstract +

Showing 5 of 9 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years