Validation of GOME (ERS-2) NO2 vertical column data with ground-based measurements at Issyk-Kul (Kyrgyzstan)

Here we present the results of comparison between operational NO₂ vertical column data by Global Ozone Monitoring Experiment (GOME) onboard ERS-2 satellite and ground-based measurements at Issyk-Kul station in Kyrgyzstan, northern Tien Shan. The data of GOME, taken for the period of 1996–2002, was found to be reasonably close to the results of ground-based sunrise measurements. The latter were adjusted to the time of GOME overpass nearby noon, providing direct comparison between satellite and ground-based data. According to the results, there is 0.6 × 10¹⁵ mol/cm² (18%) overestimation of NO₂ vertical column by GOME, compared to our ground-based data.     

Choice of flight conditions and modes of engine operation for its diagnostics

We consider a method for diagnostics of the engine flow passage technical status of a maneuverable aircraft operating in a wide range of altitudes and speeds; the behavior of measured parameter deviations from throttle characteristics and calculated characteristics of the flow passage units from their initial values is used for diagnostics. We present the methods for determining these deviations as well as flight conditions and engine operation modes at which diagnostics is made possible.     

Evaluation of the influence of a measurable parameter error on precision of determining αΣ and Tg* by regression models

We present the regression models for determining the total excess air ratio α_Σ and gas temperature T _g ^* upstream of the high-pressure turbine formed on the basis of the engine parameter values that are regularly measured. The sensitivity of the regression models presented to the sensor and instrumentation precision is studied. The errors of measuring and calculating α_Σ and T _g ^* in different altitude-speed engine operation conditions are shown.