Atmospheric analysis

Drawing with dimensions of diffuser BAT 5
The diffuser’s distance to fibre distance is matched to the fibre’s N.A. There is a slight slope in the diffuser’s surface to drain the water through a drainage hole. An 'o'-ring gives additional protection against rain.
The diffuser can be made in almost any size.

DCE,Q?

Previous meaurements show indications that the transmission of teflon might change after cleaning the diffuser with alcohol. The next graph shows the signal before and after cleaning the diffuser with alcohol.
This graph shows that there are no significant changes in signal after cleaning with alcohol.

The position of the diffuser's entrance aperture needs to be known for accurate calibration. Because the diffuser has a hemispherical shape the effective entrance aperture is not exactly located at the front surface.
Experiments with the lamp at 1.5 m and 0.5 m show that according to the inverse square law the location of the effective entrance aperture is 1.4 mm (±1mm) behind the front surface of the diffuser.
Info, questions and remarks, contact:
Richard McKenzie [ [email protected] ]

While in use it is best to clean the diffuser on a daily base with a piece of dry cotton. This to wipe of any dirt, dust, snow etc. If the diffuser for some reason gets really dirty it is recommendable to clean it with water and soap or alcohol. Dust inside the diffuser can be removed with a cotton bud.
Info, questions and remarks, contact:
Richard McKenzie [ [email protected] ]

There is a wide range of instruments at Lauder, which are listed on this page.

DCE,Q?

NIWA uses Trimble RTK GPS surveying equipment to undertake precise topographic and bathymetric surveys. These surveys are used to measure beach stability, river bed erosion and deposition, and to make digital terrain models of rivers for 2-dimensional hydrodynamic modelling. 

Mass of Seawater = w(sw) [kg]
Volume of Manometer = Vman [cm3]
Manometer Temperature = T [°C]
Manometer Pressure = Pfinal [Pa]
Pressure transducer zero = Po [Pa]
Universal Gas Constant = R = 8.314 J K-1 mol-1
Virial Co-efficient B(CO2) [cm3 mol-1] B = 1636.75+(12.0408*(T+273.16))-(0.0327957*(T+273.16)2)+(0.0000316528*(T+273.16)3)
Vm(CO2 at manometer T and P) [m3] – calculate iteratively, initial Vm = 0.22264 =R*(T+273.16)/((Pfinal - Po))*(1+(B*0.000001/Vm))
CT

Alice is an instrument package for measuring bottom-boundary-layer processes in estuaries and the ocean. It consists of a self-ballasted tripod upon which is mounted a "core" sensor package for measuring boundary-layer currents, turbulence and waves. Alice is principally rigged for sediment-transport studies (with optical and acoustic backscatter sensors, sediment traps and a pump sampler) but has also been used extensively in studies of boundary-layer mechanics, animal–flow–sediment interactions, wave dynamics and nutrient/gas fluxes.

BEVIS has been developed for rapid, cost-effective seafloor habitat surveys. Sled-borne cameras are monitored and controlled from the surface, affording investigation at depths where using divers to collect video data or macrobenthic cores would be impractical or impossible. 

Our Computerised Research Echo Sounder Technology (CREST) is a highly adaptable approach to fisheries and other acoustic data acquisition.