Eigenbrodt GmbH & Co. KG products

Precipitation measurement over the global oceans onboard moving ships is a notoriously difficult task. Gauge based systems are prone to large undercatch errors due to fluctuating high wind speeds and flow distortion. While the errors are large for rainfall, the estimation of snowfall and mixed-phase precipitation is impossible. In addition to the precipitation accumulation, precise information about the particle size distributions for rain and snow are required for various tasks, e.g. calibrating spaceborne radars or to improve understanding of the microphysical properties of precipitation. Thus, systematic high quality oceanic in situ precipitation measurements are requested on an international science level and are essential for improved understanding and validation of hydrological processes in satellite, re-analysis and model data.

ONES 250 (OFS) is a sensor for visibility with a good cost-performance ration with a main application in traffic purposes. Using so called backscatter technique it measures the amount of water particles i.e. fog in the air that limit the visibility. The design allows the operation in various locations and applications. The validity and the stability has been - so far - resulting in satisfied customers.

The ship rain gauge is designed to measure rain fall on moving ships or buoys. The high relative flow velocities on a cruising vessel may carry the rain almost horizontally over the ship. By measuring the amount of water that is collected by a vertical surface, a correction for the wind effect is possible. Evidently the local relative wind speed at the monitoring site of the instrument is to be measured simultaneously. Rain is collected at the horizontal orifice and at the vertical collector. There are five vertical T-bars at the circumference of the vertical collector that hinders rain water to wander around the cylinder and to be blown off in lee.

Collection of precipitation for analyzing organic components as well a mercury in the precipitation, the choice of the best fitting contact material like sample funnels is very important. In these cases PTFE and DURAN-glass, in some cases also stainless steel are preferable to HD-polyethylene. Collecting precipitation for acidifying components HD-PE is seen as the appropriate contact material to the sample. Eigenbrodt has developed a complete series of collection funnels to fit the collector the application.

Collection of precipitation for analysing inorganic components like acidifying components in the precipitation, the choice of the best fitting contact material like sample bottles and funnels is very important. In these cases HD-PE and silicone are preferable. For all types of instruments funnels and sample bottles are available in HD-polyethelene. The separating system components for type “D”, “T” and “S” are made out of HD-PE and silicone.

The precipitation collectors NSA 181/NSA 181K and UNS 130 can optionally be equipped with a tipping bucket system. For Eigenbrodt precipitation monitors NMO 191 the tipping bucket is standard.

Precipitation contains a high amount of organic, inorganic and suspended substances. It is believed to be the major atmospheric purification process and has a high contribution to the trace element cycle in the atmosphere. The PRECIPITATION SAMPLER NSA 181 is equipped with a cover lid for a wet only application. This lid is opened only during deposition. So now it is possible to catch the wet precipitation only. This characteristic is in contrast to bulk samplers, which collect both the wet deposition and the dry deposits (e.g. dust).

Continuous measurements of pH and conductivity yield instantaneous values for the amount of dissolved trace substances as well as the acidity. The synchronous measurement of the two parameters allows quality control of the results and a good estimate of the amount of free acid in the precipitation. Acidity and amounts of trace substances obtained by precipitation correspond closely to the temporal development of the precipitation event. Therefore the concurrent measurement of amount and intensity of precipitation gives insight into the physics of the removal processes. Further analysis of precipitation is possible through the separation of material flowing through the measurement block and material collected in the optional sample bottle.

All types of Eigenbrodt fog sampler feature the same principle of collection: Fog water is collected with a sampler operating on the impactor principle (see figure). The air is sucked at a rate of rd. 125 m³/h through a twin nozzle behind. Droplets are been excellerated. They slash onto a specially designed deposition body, where the water is captured and flows down into a collection body. 

The NILU particulate fallout collector and the NILU precipitation collector have been developed to collect representative samples of dry and wet atmospheric particulate fallout for subsequent analysis.