Comparison is Key to Validating Aircraft Measurement Datasets
Comparing large datasets from coordinated aircraft flights provides critical information about the data for researchers.
The Science
As more studies focus on how atmospheric properties in the Amazon basin change in space and over time, obtaining quality-controlled measurements is essential. However, the challenges of airborne operations, especially with multiple aircraft collecting data in the same area, makes direct comparison studies fundamental, but rare. A field campaign led by the Atmospheric Radiation Measurement program used two different aircraft equipped with similar instruments to collect data in the same region. Researchers then compared these data and observed good agreement between the two aircraft measurements for a relatively broad range of atmospheric-related variables measured in a challenging lower troposphere environment.
The Impact
This study provides other researchers with an approach to designing coordinated flights that allows them to make meaningful comparisons between the measurements of two aircraft. The comparisons and related uncertainty estimations quantify current measurement limits, which provides guidance to modelers for realistically determining input value and evaluating the variation between measurements and model output. This work quantifies the uncertainty ranges of the data collected from the different platforms, providing a foundation for evaluating further modeling and validating remote sensing.
Summary
Researchers compared in situ measurements made by well-characterized instruments installed on two research aircraft (the G1 and HALO) during the GoAmazon 2014/5 and ACRIDICON (Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems)-CHUVA (Cloud Processes of the Main Precipitation Systems in Brazil) campaigns. Similar instruments mounted on the G1 and HALO collected vertical profiles of atmospheric state parameters, aerosol particles, trace gases, clouds, and atmospheric radiation properties. Researchers found that the studied measurements from the two aircraft agreed within predicted measurement uncertainties. The comparisons and related uncertainty estimations quantify current measurement limits, which provide guidance for realistically quantifying the model input values and evaluating variations between measurements and model output. The comparison identified the main factors contributing to the uncertainties in measurements from two research aircraft. Three of the primary sources that contributed to the variations between the two aircraft are temporal and spatial variations, differences in the inlet characterization, and limitations of the instruments themselves.
The Atmospheric Radiation Measurment Aerial Facility operated the G1 aircraft.
PNNL Contact
Fan Mei, Pacific Northwest National Laboratory, Fan.Mei@pnnl.gov
Funding
This research was supported by the U.S. Department of Energy’s Atmospheric Radiation Measurement program.
Published: January 19, 2021
Mei, F., Wang, J., Comstock, J. M., Weigel, R., Krämer, M., Mahnke, C., Shilling, J. E., Schneider, J., Schulz, C., Long, C. N., Wendisch, M., Machado, L. A. T., Schmid, B., Krisna, T., Pekour, M., Hubbe, J., Giez, A., Weinzierl, B., Zoeger, M., Pöhlker, M. L., Schlager, H., Cecchini, M. A., Andreae, M. O., Martin, S. T., de Sá, S. S., Fan, J., Tomlinson, J., Springston, S., Pöschl, U., Artaxo, P., Pöhlker, C., Klimach, T., Minikin, A., Afchine, A., and Borrmann, S. “Comparison of aircraft measurements during GoAmazon2014/5 and ACRIDICON-CHUVA”, Atmos. Meas. Tech., 13, 661–684, (2020). [DOI: https://doi.org/10.5194/amt-13-661-2020].