Light detectors sensitive to wavelength ranges 240–400nm and beyond 610nm (which we refer to, for simplicity, as the UV and Red bands) on board UniversitetskyTatiana-2 satellite have detected transient flashes in the atmosphere of duration 1–128ms. Measured ratio of the number of Red photons to the number of UV photons indicates that source of transient radiation is at high atmosphere altitude (>50km). Distribution of events with various photon numbers Qa in the atmosphere found to be different for “luminous” events Q_a = 10²³ – 10²⁶ (with exponent of differential distribution –2.2) and for “faint” events Q_a = 10²¹ – 10²³ (with exponent
0.97). Luminous event parameters (atmosphere altitude, energy released to radiation, and temporal profiles) are similar to observed elsewhere parameters of transient luminous events (TLE) of elves, sprites, halo, and gigantic blue jets types. Global map of luminous events demonstrates concentration to equatorial zones (latitudes 30ºN to 30ºS) above continents. Faint events (with number of photons Q_a = 10²⁰ – 5·10²¹) are distributed more uniformly over latitudes and longitudes. Phenomenon of series of transients registered every minute along satellite orbit (from 3 to 16 transients in one series) was observed. Most TLE-type events belonged to series. Single transients are in average fainter than serial ones. Some transients belonging to series occurs far away of thunderstorm regions. Origin of faint single transients is not clear; several hypothetical models of their production are discussed.