What are Aircraft Instruments?

Aircraft pilots cannot just look out of the window and know where they and what is going on around them. They instead rely on instruments. Instruments essentially concern measurement. Common aircraft measurements include fuel consumption, direction, position, speed, and altitude.

Aircraft instruments are basically grouped in two ways: 1) work performance; and, 2) operating principles. Instruments that measure work performance include vertical speed, altimeter, and airspeed. The basic principles of engine operation concern the relationships between the temperature, volume, and pressure of gases. Instruments that measure operating principles, therefore, include those that measure such interactions.

What are Atmospheric Aerosols?

Aerosols are minuscule, suspended particles in the atmosphere. They drastically influence climate. They impact radiative transfer by absorbing sunlight, by scattering, by altering clouds’ lifetime, amount, and microphysical structure. When they are big enough, we can see them scatter about and absorb sunlight.

How Can Aircraft Instruments be used for Characterization of Aerosol Optical Properties?

For experts to study atmospheric aerosols’ effect on climate, they need to understand their optical properties. Aircrafts have been productive in characterizing the atmospheric aerosol optical properties.

Vertical distributions of aerosol optical properties based on Avionic Instruments over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients (ssc), absorption coefficients (sab), Angström exponent (a), single scattering albedo (?), backscattering ratio (ßsc), aerosol mass scattering proficiency (Qsc) and aerosol surface scattering proficiency (Qsc') were obtained. The mean statistical values of ssc were 77.45 Mm- 1 (at 450 nm), 50.72 Mm- 1 (at 550 nm), and 32.02 Mm- 1 (at 700 nm). The mean value of sab was 7.62 Mm- 1 (at 550 nm). The mean values of a, ßsc and ? were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters (ED) of aerosols were less than 0.8 µm. The vertical profiles of ssc,, a, ßsc, Qsc and Qsc' showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both a and ßsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of ssc, a, ßsc, Qsc, Qsc', sab and ? at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of Aircraft Sensor Systems masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.