With the CAPE 2015 project, we wanted to compare the temperatures that the Citation II research aircraft recorded to temperatures recorded by local weather balloon launches and COAMPS model soundings. Our hypothesis was that the aircraft, balloon, and model soundings would agree more at higher altitudes.

comparesounding

Two python scripts were used to calculate the temperature differences: comparesoundingMCR.py and comparesoundingCOAMPS.py. Both of these scripts are located in $ADPAA_DIR/src/scripts_python .

comparesoundingMCR.py compares the aircraft temperatures to the MCR radiosonde balloon temperatures. The differences are calculated by finding where the aircraft altitude is closest to the balloon altitude and subtracting the balloon temps from the aircraft temps. The temperature differences, along with some other aircraft and balloon data, are written to a NASA-formatted ASCII file.

This script generates an output file called MCR_<date of aircraft flight>_comp.txt.

comparesoundingCOAMPS.py compares the aircraft temperatures to the COAMPS model sounding temperatures. The differences are calculated by finding where the aircraft altitude is closest to the model sounding altitude and subtracting the model temps from the aircraft temps. The temperature differences, along with some other aircraft and COAMPS model data, are written to a NASA-formatted ASCII file.

This script generates an output file called COAMPS_<date of aircraft flight>_comp.txt.

cplot2

cplot2 was used to plot the output files generated from the two comparesounding scripts. The temperature differences were plotted on the y-axis and the aircraft altitudes were plotted on the x-axis.

This is the plot of the sounding comparisons for July 30 between the aircraft and the radiosonde balloon soundings.

Unfortunately, we did not see a pattern between altitude and how well the temperatures agreed. Here are the averaged results.

This table shows the average differences between the aircraft and the COAMPS model sounding, along with the differences between the aircraft and the MCR radiosonde balloon soundings. These differences were calculated by subtracting the model temperatures from the aircraft temperatures and by subtracting the balloon temperatures from the aircraft temperatures. As this table shows, the aircraft was recording slightly lower than both the COAMPS model and the balloons.

Our hypothesis that the temperatures would agree more at higher altitudes was not correct. The pattern we were hoping to observe was not present. The differences between the aircraft, balloons, and model soundings are within the range of random error. This error could be attributed to differences in location and in cloud/out of cloud differences.