¶ Broadband Radiometer Station (BRS)
¶ Instrument Description
The Broadband Radiometer Station (BRS) is a suite of instruments that measure down-welling radiation in both visible and infrared wavelengths.. It is very similar to the SIRS instrument. It measures the three primary measurements: Hemispheric, Diffuse and Direct in the visible. Currently, there is not a lot of information on the ARM website about the BRS.
* For more information see the BRS Instrument web page
¶ Additional Information
Please see Radiation Information for more information on the radiation processes and variables.
¶ Expected Operations
¶ Metrics
As you can see from the figures below, the data does trip flags during both clear and cloudy conditions. The data normally trips flags overnight when the incoming shortwave radiation is 0. Instrument noise and the accuracy of the instrument/data collector cause the values to become negative overnight.
Clear Conditions
Cloudy Conditions
¶ RS QC Bit Overview
The tests and bit numbers can vary between variables. Below is a list of many of the QC Tests specific for the rain instrument.
QC Bits
- Comparison Tests with SIRS - Checks to see if the same measurements are off by more than a specified amount.
- Persistence Test - Flags if the variable does not change for more than 1 hour
¶ Plots
Weekly plots of the following are also available.
¶ Expected Operations
¶ Shortwave
- The first plot shows the direct shortwave, downwelling diffuse shortwave, downwelling hemispheric shortwave, and the derived downwelling hemispheric shortwave radiations. Please see Radiation Information for more information on radiative processes and variables.
- The second plot shows the difference and ratio between the measured and derived downwelling hemispheric shortwave radiation. The difference can sometimes be as high as 50 W/m^2. The Ratio should be between 1 and 1.2 for the most part. A ratio of 1 would indicate that there is no difference between the 2.
¶ Longwave
The longwave radiations shows the downwelling longwave shaded hemispheric radiation. Also plotted are estimates of what the longwave radiation should be based on the surface conditions at the local met station. There are 2 different clear sky estimates and one overcast estimate. For more information, please see the papers indicated on the plot.
¶ Battery Volt
This plot shows the data logger voltage and temperature. Normally, they show inverse patterns of each other.
¶ Comparison Plots
The comparison plot for the BRS is a 4-panel plot showing different variable comparisons with the SIRS instrument. Each panel has the BRS and SIRS data plotted on the left Y-Axis and the difference between the two on the right Y-Axis. The difference for each variable will be different. There may be some larger spikes in the data, but if the difference is consistently large (>100) then it may warrant ad DQPR.
¶ Site-Specific Information
The BRS is currently located at SGP.
¶ Known Issues
¶ Known Issues
Issues that may not require mention in DQA's can be documented here.
¶ Past Problems
Past problems that DO need to be mentioned in DQA's and potentially DQPR's:
short_direct_normal values drop out
Description: The short_direct_normal values have dropped out and are set to missing value indicator. Multiple other instruments at the site are showing similar issues around the same time. A lightning strike appeared to be the cause of the issues.
Solution: Various components of the BRS were changed out since it was due for calibrations.
down_long_netir is flatlined
Description: The down_long_netir variable is flatlined. Please see DQPR 2882 for details.
Solution: None at the moment.
