Conductivity/Salinity: Conductivity is a key parameter for in-situ determination of salinity, density and speed of sound. The Aanderaa Conductivity Sensors are based on an inductive principle which provides stable measurement without electrodes. The sensors are 132 point calibrated and automatically switch between lower, below 10 psu, and higher salinities at which different methods to calculate salinity are used. Experiences from factory re-calibrations reveal that these sensor have a minimal drift in the field, less than 0.008 mS/cm-year. For field verification of the sensor functioning a multi-resistor loop is used.
Oxygen Optodes: Most chemical and biological processes are influenced by changes in dissolved oxygen. Consequently oxygen is a prime parameter to measure in aquatic studies. Aanderaa revolutionised natural water oxygen measurements with the introduction of oxygen optodes in 2002. The proven long-term stability (years) and reliability of these sensors have opened new possibilities in coastal and open ocean water monitoring, which are described in more than 150 scientific publications The latest developments include new ultra stable and trace foils. The opcodes are forty-point calibrated with an absolute accuracy better than ±2 % over the whole range of oxygen concentrations and temperatures. Different sensor versions are rated from 100 to 12 000 m depth.
Pressure/Wave/Tide: In 2006 a new series of compact Pressure/Wave/Tide sensors based on silicon sensing elements using a piezoresistive measuring principle were introduced. These sensors are 20 point calibrated and have demonstrated excellent accuracy (0.01 %), resolution (0.1 mm) and stability (drift less than 0.01 % per year). Also they consume little energy, can handle shock and are able to withstand 50% overpressure without damage and the need for recalibration. These sensor have outperformed quartz pressure sensors in several studies and are selected in application ranging from coastal wave measurements to mm movements of the seafloor in seismic areas and in off-shore oil and gas applications.
Turbidity: Turbidity is a proxy for water suspended mineralogenic particles like sand, silt and clay. The combination of turbidity measurements with acoustic backscatter from Doppler Current Profiling sensor is useful and gives high resolution information on the origins and distribution of Particles in the water column.
Currents: Aanderaa offers Acoustic Doppler Current Profiler (ADCP) and Single Point instruments and Stand alone sensors that are used in a wide range of applications, from surface buoys to the deepest trenches, to measure currents, waves and particles.
Waves: At Aanderaa we have focused on three different methods for spot measurements of waves including:
Integration of sensors from other manufacturers: For parameters that we do not offer we integrate sensors from other manufacturers to our systems including EXO units from YSI for shallow water applications with sensors for e.g. pH, Algae, CDOM, ORP/Redox, Blue green algae, Salinity, Temperature, Oxygen and with a wiper for anti-fouling. For deeper waters we integrate sensors from other manufacturers.