The Pico Balloon Archive 

Information about Pico Balloons and the Pico Balloon Archive

This website serves as the repository for the Pico Balloon Archive (PBA), designed to store, visualize, and ensure the quality of pico balloon data for the advancement of atmospheric science research.

Pico balloons are ultra-lightweight, party-sized, super pressure balloons that can float at altitudes between 9 to 15 km AMSL. Globally, they are launched by students, enthusiasts, and scientists, and can stay afloat for extended periods ranging from months to years after being launched. This data set encompasses pico balloons that have traversed all seven continents, accumulating hundreds of hours of flight data. As such, it stands as the most extensive spatial data set for super pressure balloons to date!

This website severs as the front end to the current data set. The 'Data Archive' tab features a chart outlining the available data sets, complete with quicklook plots for various flights and options to download flight data files. The 'Synopsis' tab includes a summary of all collected data. Additional details about the data sets can be found further down the page. The raw data and quicklook files can also be found at a AWS server at: https://data.picoballoonarchive.org/data/

Telemetry System

Pico balloons typically carry a radio transmitter that weights less than 50 grams that is solar powered. This allows for continuous daytime location tracking. Pico balloons frequently use amateur radio protocols, including APRS (Automatic Packet Reporting System) and WSPR (Weak Signal Propagation Reporter), to transmit telemetry information, encompassing GPS coordinates, altitude, temperature, and other relevant data. Both APRS and WSPR rely on amateur radio infrastructure to receive, decode, and upload balloon telemetry to publicly accessible websites like aprs.fi and wsprnet.org.

Pico balloons utilizing APRS can typically transmit a broader range of telemetry data due to the higher frequency radio band, which accommodates more information. However, a drawback is that APRS receiving frequencies often require line-of-sight, rendering balloons inaudible when they are over remote areas. In contrast, Pico balloons using WSPR can transmit signals over great distances, thanks to ionospheric signal propagation. The drawback is that the amount of data a balloon can transmit is limited, and it is frequently of lower resolution (see info farther below about quantifying errors).

Once uploaded to aprs.fi or wsprnet.org, the data can be downloaded or visualized on alternative platforms like SondeHub Amateur. The PBA aggregates information from both aprs.fi and SondeHub Amateur, standardizing it into a unified format. A diagram illustrating this process can be found further below.

Data collection process for the Global Pico Balloon Dataset.

Data collection process for the Global Pico Balloon Dataset. 

PBA Naming Format and FIle Structure

In the PBA, the file structure for a pico balloon flight is organized by its callsign, transmitter type, and launch date (year-month-day). An example of this naming convention is provided below.

Within a PBA-formatted file, the first 13 lines consist of header information and data column labels with respective units. These headers encapsulate a summary of the flight, similar to what is displayed in the 'Archive' tab table. Flight details include the callsign, date range, initial latitude and longitude coordinates, time spent airborne, total number of data points, and latitude range. Additionally, the headers feature labels for any supplementary telemetry that the trackers may provide. A 'Calculated Number of Circumnavigations' metric is also included, which tallies the instances where the balloon crosses its starting longitude. However, this value may not always be accurate, as balloons can occasionally reverse direction, which does not constitute a full circumnavigation. An example file is given below showing the first few lines. 

All pico balloon flights in the GPBD come standard with GPS location and altitude, UTC time stamp in format year-month-day hour-minute-second, wind speed, wind direction, wind speed error, and wind direction error. If balloon has another sensors (pressure, temperature, etc...) it will show up in the telemetry columns. For WSPR pico balloon data, the size of the 6-digit WSPR grid squares varies with latitude. For instance, at a latitude of 45 degrees, a WSPR grid square measures roughly 4.6 kilometers in height and 1.6 kilometers across. The balloon's reported position corresponds to the latitude and longitude at the center of this grid square. Therefore, a error calculation of wind speed and direction calculation must be done. 

Example file for a PBA formatted pico balloon flight.

Example file for a PBA formatted pico balloon flight. 

Archive and Synopsis Tab

To facilitate easier access to data, the 'Archive' section displays a chart summarizing the flights contained within the PBA. This table enables users to download pico balloon flight data in .txt format and also offers quicklook visualizations of the data. 

The chart bears strong resemblance to the list of headers within each data file. Utilizing this table, users can identify pico balloons operating within specific latitude or time domains, or locate flights that are currently airborne. An example snippet of the table is list below. Data files can also be found at data.picoballoonarchive.org/data/processed/ 

Example table from on the 'Archive' tab. Parts of the table are labeled.

Example table from on the 'Archive' tab. Parts of the table are labeled.

A quicklook visualization for each flight is produced using a specialized Python plotting script. These plots display a global map indicating balloon locations, wind speeds, U and V components, float altitudes, and latitude. U and V are plotted as a histogram while other variables  are vs. time. Additionally, a textual summary is provided in the top right corner of the graphical representation. To view one, a user can click on the 'Quicklook' tab in the  Archive Table. Wind speed vs. time are plotted by day average scatter points and a 1 day rolling average. This is also done in the altitude vs. time plot.  Using the 'Synopsis' tab, all pico balloon data can be viewed using latitude bins and global maps. These plots are updated daily. In addition, a map showing the location of the "In Progress" flights is shown. 


Current Publications using the PBA

McKinney, Todd, et al. "Methodology, Deployment, and Performance of Pico Balloons in Antarctica." Journal of Atmospheric and Oceanic Technology 40.10 (2023): 1277-1290. 

McKinney, Todd, et al. "Insights on polar day Antarctica radio propagation using amateur radio beacons on circumnavigating balloons." Atmosphere 14.7 (2023): 1118. 

McKinney, Todd, et al. "Around the World They Go: Circumnavigating Balloon Satellites!." Bulletin of the American Meteorological Society 104.1 (2023): E192-E207.