During the last year we completed the testing and deployment of our first run of Continuous Light Absorption Photometer (CLAP) instruments. As you know, we made these instruments because the existing commercially-available, multi-wavelength instruments for measuring aerosol light absorption (e.g., PSAP) were inadequate in many respects. One of the primary issues we had was the loss of data from the PSAP instrument when its single sample filter became overloaded and station personnel were not available to change it. The CLAP was designed with 8 sample spots with an automatic spot advance feature so that it can sample much longer (e.g., over weekends) without the data loss.
By manufacturing the CLAPs ourselves, we were able to incorporate improvements into the design, including miniaturization, instrument control options, and data interface and output options. The quality control of these units is superior to the PSAPs because of manufacturing consistency and careful pre-deployment testing. The instrumental noise level of each unit is measured (and improved if necessary) and the flow sensors are calibrated before the units are deployed. The spectral output of the LEDs in each unit are measured and documented using a spectrophotometer, and the light sources are optimized for maximum photon count rates. As with the PSAP, the CLAP instruments are fully supported by our CPD software, so the raw CLAP data are ingested, transferred to NOAA, and processed automatically.
At our NOAA monitoring stations, the goal is to run a CLAP alongside a PSAP for an extended period of time (typically one year or longer) to try to understand the relationship between the two sets of light absorption measurements. When we are satisfied that we understand the relationship, we will remove the PSAP from the aerosol system. At non-NOAA stations, the decision to remove PSAPs is left up to the Principal Investigator. We expect to offer software support for the PSAP for the foreseeable future in case some stations prefer to continue their PSAP measurements.
It was our long term goal to transfer this technology to the private sector, and we are happy to announce that Brechtel Manufacturing, Inc. (BMI) of Hayward, California has decided to accept our offer and to manufacture and provide service for the CLAP instruments. The new instrument sold by BMI will be known as Continuous Light Absorption Photometer Model 2900. Inquiries on the price, availability, and service (i.e., cleaning, repair and calibration) of these instruments should go directly to BMI.