New Methodology of Designation the Precise Aircraft Position Based on the RTK GPS Solution

The paper presents the results of research on improving the accuracy of aircraft positioning using RTK-OTF (Real Time Kinematic–On The Fly) technique in air navigation. The paper shows a new solution of aircraft positioning for the application of the differential RTK-OTF technique in air navigation. In particular, a new mathematical model is presented which makes it possible to determine the resultant position of an aircraft based on the solution for the method of least squares in a stochastic process. The developed method combines in the process of alignment of GPS (Global Positioning System) observations, three independent solutions of the aircraft position in OTF mode for geocentric coordinates XYZ of the aircraft. Measurement weights as a function of the vector length and the mean vector length error, respectively, were used in the calculations. The applied calculation method makes it possible to determine the resultant position of the aircraft with high accuracy: better than 0.039 m with using the measurement weight as a function of the vector length and better than 0.009 m with the measurement weight as a function of the mean error of the vector length, respectively. In relation to the classical RTK-OTF solution as a model of the arithmetic mean, the proposed method makes it possible to increase the accuracy of determination of the aircraft position by 45–46% using the measurement weight as a function of the vector length, and 86–88% using the measurement weight as a function of the mean error of the vector length, respectively. The obtained test results show that the developed method improves to significantly improve the accuracy of the RTK-OTF solution as a method for determining the reference position in air navigation.

Application of a Spatially Explicit Scaling Factor Method on CO2 Emissions From New York

<p>Assessing progress towards greenhouse gas mitigation targets in recent legislation requires reliable, precise methods for emissions quantification.  Top-down approaches can provide a complementary assessment to the bottom-up inventories typically used by cities.</p><p>In this work we have performed a series of 9 winter aircraft measurement flights downwind of New York City in 2018 – 2020.  We use dispersion modeling driven by publicly available meteorological products to calculate footprints relevant to the flight data.  To calculate modeled emissions, we combine these footprints with four CO<sub>2</sub> inventories (ODIAC, EDGAR, ACES, and Vulcan) using a spatially explicit scaling factor approach.  We show that we can isolate the emissions from two areas of interest, New York City and the New York-Newark urban area, by using the fraction of modeled enhancements originating in said areas of interest as weighting functions.  We then calculate a scaling factor that optimizes agreement with measurements for each flight.  Here we discuss this technique and the posterior emissions for both areas of interest as compared to inversion analyses for the same areas.  We also quantify the variability across the ensemble including multiple meteorological products, scaling factor calculation methods, and mixing parameterizations across all inventories and flight days.</p>

A Study on modification of Aircraft Platform for Air Quality Measurement in Korea

<p>The aircraft measurement for air quality is able to fly in three dimensions within the planetary boundary layer of inland and sea. In this study, the Beechcraft B1900D was modified to build a unique aircraft measurement platform for the measurement of particulate matter and gas. This aircraft has a maximum takeoff weight of 7,765kg and this aircraft is loaded with various air quality measurement equipment. The contents of aircraft modification are as follows. The installed contents for air quality measurement are aircraft aerosol inlets, trace gas inlets, discharge tubes, AIMMS-30, and pylon adapter. The power supply of the measurement equipment replaced the generating capacity of starter generators from 300A to 400A (at DC 28V). In addition, this aircraft was installed on the time synchronization and network system of measurement equipment (HR-ToF-AMS, PTR-ToF-MS, CIMS, etc). Currently, the air quality scientists in Korea have been investigating on long-range transport or local large point sources.</p>

The Horizontal Spectrum of Vertical Velocities near the Tropopause from Global to Gravity Wave Scales

Vertical motions are fundamental for atmospheric dynamics. Compared to horizontal motions, the horizontal spectrum of vertical velocity w is less well known. Here, w spectra are related to spectra of horizontal motions in the free atmosphere near the tropopause from global to gravity wave scales. At large scales, w is related to vertically averaged horizontal divergent motions by continuity. At small scales, the velocity energy spectra reach anisotropy as in stably stratified turbulence. Combining these limits approximates the w spectrum from global to small scales. The w spectrum is flat at large scales when the divergent spectrum shows a −2 slope, reaches a maximum at mesoscales after transition to −5/3 slopes, and then approaches a fraction of horizontal kinetic energy. The ratio of vertical kinetic energy to potential energy increases quadratically with wavenumber at large scales. It exceeds unity at small scales in stratified turbulence. Global and regional simulations and two recent aircraft measurement field campaigns support these relationships within 30% deviations. Energy exchange between horizontal and vertical motions may contribute to slope changes in the spectra. The model allows for checking measurement validity. Isotropy at large and small scales varies between the datasets. The fraction of divergent energy is 40%–70% in the measurements, with higher values in the stratosphere. Spectra above the tropopause are often steeper over mountains than over oceans, partly with two −5/3 subranges. A total of 80% of w variance near the tropopause occurs at scales between about 0.5 and 80 km.