Coherent scatter modes

As coherent scatter radar, Jicamarca is sensitive to 3-m atmospheric and ionsopheric irregularities. Moreover, in the ionosphere these irregularities have to be aligned with the magnetic field. From atmospheric irregularities working mainly in the MST (Mesosphere, Stratosphere and Troposphere) mode, the radar gets measurements of the 3D neutral wind velocity, i.e., zonal (u), meridional (v) and vertical (w).

In this mode the radars can measure vertical and horizontal plasma drift velocities via the echo Doppler shifts (radial velocity) and/or interferometry (giving velocities transverse to the beam direction) from irregularities in the E and F regions. From these one can determine the electric fields (from V = E x B/B2) and sometimes wind velocities.

The recent imaging studies of the irregularities in the equatorial electrojet by Dr. David Hysell, using 6 receivers (15 different baselines aligned in the east-west direction) is impressive. To appreciate the power of this work watch at some of the “movies” on the web by visiting and clicking on “ftp” at the bottom of the page to get a list of available mpeg movie files (image0424c is a recomended one.)  In some cases individual “blobs” are clearly seen moving horizontally and vertically and  there is a radar Doppler information (color coding) for each blob as well. Other examples show shear, with blobs at one altitude moving east and those at another altitude moving west.

In the table below, we summarize the main coherent scatter modes currently available. Click on  the Modes to get more details on the technique and some results.

Coherent scatter modes

Modes Range (km) Vz Vx ρ u v w
Interferometry 95-1500 [1 [        
Imaging 95-1500 [1 [   [2    
MST 4-853 [1     [ [ [
Oblique Wide East–West 4 ~105 [     [2    
Oblique Narrow-Wide 4 95-120 [     [6    
Bistatic 95-115     [2.5      
1 from 150-km echoes only during the daytime
2 In progress
3 25-65 km Stratospheric gap. Mesosphere only daytime.
4 Wider longitudinal coverage
5 Nighttime to be tested
6 Height profiles