Description: Das Projekt "AURORa - Investigation of the Radar Backscatter of Rain Impinging on the Ocean Surface" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Meereskunde (IfM) durchgeführt. Over land, observations of rain rates are more or less operational. To obtain information about precipitation at the coastal zones, weather radars are used. However, over the oceans, especially away from the main shipping routes, no direct precipitation measurements are performed. In these regions, satellite data can provide information about precipitation events. Satellites deploying passive and active microwave sensors can operate independently of cloud cover and time of day. Passive microwave sensors give crude estimates of rain rates over large areas but cannot resolve small-scale rain events of short duration as are often observed in the tropics, for example. Active microwave sensors with high resolutions, such as synthetic aperture radars can provide more reliable information. Though the effect of rain on the atmosphere is a very topical area of research, the radar backscattering mechanisms at the water surface during rain events combined with wind are still not well understood. The purpose of this project is to investigate the radar backscattering from the water surface in the presence of rain and wind in order to interpret satellite radar data produced by active microwave sensors. Furthermore, the results should be embedded into models of the radar backscattering from the water surface to allow for estimating rain rates by using satellite data. Research topics: Rain impinging on a water surfaces generates splash products including crowns, cavities, stalks and secondary drops, which do not propagate, and ring waves and subsurface turbulence. We are investigating this phenomena at the wind-wave tank of the University of Hamburg. The tank is fitted with an artificial rain simulator of 2.3 m2 area mounted 4.5 m over the water surface. Rain drops of 2.1 and 2.9 mm in diameter with rain rates up to 100 mm/h have been produced. Wind with speeds 10 m/s and monomolecular slicks act on the water surface. The influence of the rain on the water surface is measured with a resistance type wire gauge, a two dimensional laser slope gauge and an coherent 9.8 GHz (x band) continuous wave scatterometer operating at VV-, HH- and HV-polarization. The influence of rain below the water surface is measured with colored raindrops which are observed with a video camera to investigate the turbulent motion and the depth of the mixed layer. At the North Sea Port of Buesum in Germany, a scatterometer operating at all polarizations and five frequencies will be mounted during summer of this year. The radar backscatter of the sea surface during rain events will be measured in combination with meteorological observations. With help of these measurements, existing radar backscatter models of the water surface will be improved for the presence of rain events. To validate the improved models, ERS-2 SAR-images will be compared with weather radar data.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Bewölkung ? Windgeschwindigkeit ? Mikrowellen ? Hamburg ? Kalibrierung ? Laser ? Radar ? Resistenz ? Satellitendaten ? Sensor ? Wind ? Brunnen ? Bundesrepublik Deutschland ? Main ? Regen ? Fällungsreaktion ? Meereskunde ? Satellit ? Sommer ? Tauchbad ? Wirkung ? Ackerrandstreifen ? Unterboden ? Tankbehälter ? Meeresoberfläche ? Klimaforschung ? Bodenart ? Bodenbelastung ? Bodenluft ? Daten ? Oberflächengewässer ? Regen ? Tropengebiet ? Wirkungsforschung ? Meeresgewässer ? Küstenregion ? Verwitterung ? Verbreitungsgebiet ? Höhle ? Modellierung ? Untergrund ? Messung ? Schifffahrt ? Nordsee ? Niederschlag ? Atmosphäre ? Turbulenz ? Wasseroberfläche ? Wasserstand ? Wetter ? Gebiet ? Hang ? Fläche ? Forschung ? SAR [Radar] ? Ablagerung ? Raum ? Beispiel ? vergleichen ? Hilf ? Gegenwart ? Mechanismen ? Räume ? gebraucht ? kurz ? Schicht ? Sicherungsanordnung ? oberirdisch ? unter ? Mischung ? unterirdisch ? Untergrund [Boden] ? Bemessung ? Oberfläche ? Armatur ? Pegel ? Untersuchung ? Betrachtung ? Vorgang ? Zweckbestimmung ? angepasst ? bestehend ? Projekt ? Dauer ? bewerten ? Ergebnis ?
Region: Hamburg
Bounding box: 9.99302° .. 9.99302° x 53.55073° .. 53.55073°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 1998-09-01 - 2000-08-31
Accessed 1 times.