Nicholas Deutscher edited subsection_Instrumentation_Wollongong_has_been__.tex  about 7 years ago

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\subsection{Instrumentation}  Wollongong has been a long-standing contributor to the Infrared Working Group (IRWG) of the Network for Detection of Atmospheric Composition Change (NDACC), making mid infrared (MIR) measurements from 1996 to 2008 with a Bomem DA8 spectrometer. Since 2007 this instrumentation was accompanied and then replaced by a Bruker IFS125HR of sufficient standard to perform measurements in the near infrared (NIR) for the Total Carbon Column Observing Network (TCCON). The Bruker became the sole instrument in May 2008, and from this point onwards was operated in a configuration appropriate to TCCON standards. The FTS is equipped with four detectors: a room temperature silicon diode (Si) and a room temperature Indium Gallium Arsenide (InGaAs) operating in the NIR, and cryogenically cooled Indium Antimonide (InSb) and Mercury Cadmium Telluride (MCT) detectors operating in the MIR. The measurements made in the NIR are the subject of this paper. The timeseries from the 20 year history of measurements in the MIR at Wollongong is the subject of two forthcoming articles (Paton-Walsh, Jones??).  For the NIR measurements, the instrument follows standard TCCON configuration \cite{Washenfelder_2006,Wunch_2011}. An updated Bruker solar tracker with 80mm mirrors is used. Pressure sensors... other MET instrumentation. The automation is run by in house developed software "`Oscar"', which communicates with OPUS via DDE interface under Windows. Oscar monitors a number of environmental parameters via a Davis weather station, including external temperature, pressure, humidity, wind speed and direction, solar radiation, rainrate and leaf wetness. These parameters are used to decide when to open the environmental protection cover (see Figure xx). Measurements are then taken when the solar intensity is sufficient to instigate active tracking; that is, when the tracker diode signals cause the tracker to move from the calculated sun position (TPS - Tracker Position Sun) to the tracker position (TTM - Tracker Tracking Mode).  Aerosol optical depth has been measured since 2009 using Middleton Solar SP02 Sunphotometers mounted on an active  altitude - azimuth tracker as used by the Bureau of Meteorology \cite{Mitchell:2003kd}. The sunphotometers have