The phase difference W F measured on the received echoes is proportional to the group path: 5) the vertical velocity measured by an incoherent scatter radar (ISR) is shown for comparison.Īs one of the standard operating modes, Digisondes measure the Precision Group Height (PGH) by transmitting 2 frequencies separated by D f. The DPS also measures the three components of the F region plasma velocity, Vvert, magnetic Vnorth and Veast (Fig. Spread F developed in the first night when the F layer peak height rose above 500 km.

3 shows strong spread on the 'overhead' echoes as well as an off-vertical patch of ionisation (light grey) with foF2 = 5.4 MHz, compared to 4.3 MHz for the overhead ionosphere.Ĭonverting the sequence of measured electron density profiles to plasma frequency contours 5 gives the diurnal variations of the E and F layers, as in Fig.4 for two days at Jicamarca, Peru. This information is compressed into a standard ionogram, and for routine archiving each echo amplitude is amended by Doppler, polarisation and incidence angle. Superimposed on the ionogram is the electron density profile.įor each range, the DPS measures a full complex spectrum with 2N Doppler lines (N = 1,2.7) for both O and X polarisation. The ARTIST-scaled3 traces are marked by the letters E and F. Small optically coded numbers represent the echo amplitudes: X polarisation in grey, O in black. 2) from El Arenosillo, Spain, illustrates the format applied for routine sounding: 100 kHz frequency steps, 128 x 5 km height increments.

The Digisondes measure all observables of the received signals at each of 128 or 256 ranges: Doppler spectrum (amplitude and phase), angles of arrival, and polarizations. Low weight (40 kg), low power (500W peak) and pulse-to-pulse software control of the transmission waveforms make the DPS very attractive for routine monitoring and research. Since the D256 has previously been described2,3 it suffices to present the main differences between the DPS and the D256 (Table 1). 1), including the Digisonde 256 (D256) and the Digisonde Portable Sounder (DPS). This paper shows results from selected stations of the Digisonde network (Fig. Today's advanced digital sounders1 are digital HF radars with real time analysis capabilities. Unlike any other ionosonde, these instruments routinely perform a variety of complementary operations in real time: automatic ionogram scaling, calculation of electron density profiles, high resolution Doppler and angle of arrival, plasma drift velocity, polarisation, and precision group height. The capabilities of modern ionospheric sounders are illustrated using results obtained with the Digisonde 256 and the Digisonde Portable Sounder.

University of Massachusetts Lowell, Center for Atmospheric Research 450 Aiken Street, Lowell, MA 01854, USA THE DIGISONDE NETWORK AND DATABASING Back to INAG Homepage

Dps velocity editing