No Correlation Between Precipitation Amounts (Rain Gauge) and Brightness Temperature (GOES-16 ABI, Band 13)

The Advanced Baseline Imager (ABI) is the main instrument on GOES-16. It represents a historic improvement over past GOES instruments. The previous generation of GOES gathered information using five spectral bands. The ABI uses 16. The research in this project used Band 13 data. Band 13 measures energy at 10.3 microns. The energy at this wavelength can give information about cloud top temperature (Brightness Temperature - BT) and cloud particle size. Clouds have a correlation to precipitation, so the research team decided to check Band 13 data against amounts of precipitation.

Over a span of 30 days, 21 precipitation measurements were taken using a metric rain gauge, positioned in the school courtyard. The GLOBE program precipitation protocol was followed. ABI Band 13 data was retrieved from the RAMMB Slider, Colorado State University. The team reached out to two scientists. Dr. Tim Schmit, CIMSS, NOAA and Dr. Dan Lindsey, NOAA were great mentors.

About 3⁄4 of the way through the research window, the team realized there was a flaw in the experimental design. The rain gauge was emptied around solar noon every day and on a Monday after the weekend. Brightness Temperature was recorded at the same time. But, the actual rain event might have happened anytime within the 24- or 72-hour period. The team turned to Dr. Lindsey and it was suggested that instead of looking at amounts of precipitation, it would better to check BT as the rain was occurring.

This required the team to go back and use NWS archived precipitation data for Medford to get the approximate times when rain occurred. This information was then checked against Band 13 data. There seemed to be a correlation. A recommendation to future CSEPers is to redo the research by checking BT as the rain is occurring.