JULIA Radar Homepage

The JULIA radar is located at the Jicamarca Radio Observatory near Lima, Peru. JULIA stands for Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere , a descriptive name for a system designed to observe equatorial plasma irregularities and neutral atmospheric waves for extended periods of time. JULIA is an independent PC-based data acquisition system that makes use of some of the exciter stages of the Jicamarca radar along with the main antenna array. In many ways, this system duplicates the function of the Jicamarca radar except that it does not use the main high-power transmitters, which are expensive and labor intensive to operate and maintain. It can therefore run unsupervised for long intervals. With its pair of 30 kW peak power pulsed transmitters driving a (290 m)^2 modular antenna array, JULIA is a formidable MST/coherent scatter radar. It is uniquely suited for studying the day-to-day and long-term variability of equatorial irregularities, which until now have only been investigated episodicly or in campaign mode.

A large quantity of ionospheric irregularity data have been collected as part of the CEDAR MISETA campaign in the fall of 1996. There is also a significant amount of data from the years following. These data include daytime observations of the electrojet and 150 km echoes and nighttime observations of equatorial spread F. Data can be accessed through this site in graphical format. Researchers interested in acquiring the data in numerical format may contact the atmospheric physics group at Cornell University.

The benefits of unattended operations can be appreciated by looking at some early morning spread F data. RTI and drift data for a radar plume observed until shortly before sunrise are shown here. These very remarkable observations probably would not have been made had human intervention in the experiments been necessary. It now appears that such early morning events are commonplace.


The data are divided by type, by region and by date. The time/height boxes are only needed for the averaging plots. Use the following form to view the data in GIF image format.

JULIA data time line

Here are several example plots from the different regions.

Example 150 km Region Plot
Example E Region Plot
Example F Region Plot

There are five possible plot types available which allow the user to examine the selected data in different ways. Signal to noise ratios are shown in conventional range-time-intensity (RTI) power map format. Horizontal and vertical drifts are shown with color coded speeds. Horizontal drifts are deduced by interferometry and positive values correspond to an eastward direction. On the vertical drift plots, upward vertical drifts are shown by positive values and represent Doppler phase speeds. If the OPTIONAL starting and ending times are entered, the plot only shows that time range. However, leaving the default "*"'s is usually the best choice! The last two plot types are the time-average plots and the height average plots. They show S/N ratios, horizontal drift speeds, and vertical drift speeds as three seperate plots. Each of the smaller plots are averaged over a specified region. The specified values must be times for the time-averaged plot and heights for the height-average plot. Example values are placed in the fields aleady. The three plots are presented in a single screen. Listed below are examples of the different plot types.

Example S/N Plot
Example Horizontal Velocity Plot
Example Vertical Velocity Plot
Example Time-Average Plot
Example Height-Average Plot


Set the region, year and date. Set the time (if necessary) and click the button corresponding to the plot type you would like to see. Leaving the default "*" will plot all available data for the chosen date and height region.


F region
E region
150km region



Plot Types:

Range-Time-Intensity Plot

Values greater than 24 represent the following morning.

Start time (hours LT):
End time (hours LT):

Horizontal Velocity Plot

Values greater than 24 represent the following morning.

Start time (hours LT):
End time (hours LT):

Vertical Velocity Plot

Values greater than 24 represent the following morning.

Start time (hours LT):
End time (hours LT):

Time-Average Plot

Values greater than 24 represent the following morning.

Start time (hours LT):
End time (hours LT):

Height-Average Plot

Start height (km):
End height (km):

Please consult the CEDAR database rules of the road before downloading.

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