What are 'Calibration Data'?

Continuous Monitoring Program 'calibration data' vs 15min increment 'continuous measurements'

Continuous Measurements:
Water quality meters or sondes are deployed in-situ and autonomously measure and record water quality parameters such as water temperature, specific conductance, salinity, dissolved oxygen, pH, turbidity, and chlorophyll in 15-min increments. These data are referred to as the 'continuous measurements' or '15-min increment' data, and are available for download or viewing in chart form on our Continuous Monitoring Data and Charts page.

Calibration Data:
Every two weeks, the water quality meters need to be exchanged for cleaning and calibration. During this time additional measurements are recorded by the scientists switching out the meters. In addition to recording water quality data (water temperature, specific conductance, salinity, dissolved oxygen, pH, etc) which are used for calibration comparisons and data quality assurance between the meters, they also measure secchi depth, photosynthetic active radiation (PAR)/light attenuation, and take samples for measurement of Total Suspended Solids (TSS), chlorophyll a and pheophytin a. Additionally, at some stations, samples are also taken for the measurement of VSS, PC, PIP, TDN, TDP, NH4,TN, TP, PO4, NO2, NO23. These data are referred to as the 'calibration data' and are submitted to the Environmental Protection Agency's Chesapeake Bay Program and are available for download from the CBP DataHub, or using the handy links on our Continuous Monitoring Station Information Table.

Our Data Types Overview Table summarizes this information as well.