EOL Facility: 
In-Situ Sensing Facility (ISF)
Maintenance Status: 
Used by these EOL facilities: 
Visualization and quality control of upsonde and dropsonde radiosonde soundings. Command line, batch and GUI based interfaces are available. For support questions, email eol-aspen(at)ucar.edu.


Operating System: 

ASPEN Versions

The changes that are visible to users are given below. The many changes that are made for software maintenance and obscure bug fixes are not listed here.

Find the most recent revision number here, and locate that in the Downloads area below.

Note that due to web site limitations, the revisions are not sorted correctly in the Downloads area.

Windows releases of 3.4.0 and above are currently not available on the website due to hosting size limitations. Windows releases are available here.


3.4.2 — Jul 24, 2019

  • Add a missing dependency to the Linux version

3.4.1 — Jul 3, 2019

  • Fixed bug where ignoring lat/lon wouldn't remove them from QC data

3.4.0 — May 20, 2019

  • Threshold RH values of up to 110% to 100% before removing invalid RH
  • Add wind error check, which removes wind speed and direction if error value for GPS winds is too high
  • Build Aspen on Windows 10 and OSX Mojave
  • Update Qt graphics library to version 5
  • Switch Aspen release numbering and AEV coding to semantic versioning
  • Set monotonic pressure check off by default in dropsonde config sets
  • Set buddy check wind speed threshold to 10m/s^2 in dropsonde config sets
  • Add ability to automatically correct early launch detects
  • Update attribute icons

33819 — Jan 2, 2019

  • Update netcdf output to comply with CF conventions
    • Exclude config set from global attributes when in no-qc or passthrough mode
    • Get rid of unused obsolete variables (range) and attributes (zebra_platform, history, field_type, bad_value_flag)
    • Move reference (aircraft or ground) observations from the -1 timestamp in data variables to their own variables in the obs dimension
    • Change time variable to be sec since launch and include launch_time and reference_time as scalar
    • Add featureType attribute to identify files as trajectory data
    • Add standard_name attribute to those variables that have a defined standard name
  • Add lat/lon XY plot
  • Add ability to set keep and ignore flags on raw lat/lon/alt data
  • Get rid of differences in TEMP output between operating systems
  • Fix coding extrapolated surface pressure level so it only appears below 850mb
  • Set extrapolated surface pressure level to take precedence over lowest thermo level when they are at the same time and pressure
  • Fixed crash when setting keep/ignore flags on winds with CRC errors
  • Fixed coding of minutes field of BUFR abbreviated header (originally released in V3.3-668)
  • Fixed bug in CSV input where blank reference observations would be coded as zeros
  • Added more kinds of parseable metadata to CSV input
  • Updated Windows build environment

33666 — June 25, 2018

  • Remove option to force dew point in TEMP messages to comply to a now-obsolete NHOP standard.
  • Fix bug where LST WND would be encoded rather than a surface observation for heights of less than 12.5m
  • Add warning message when there is no data from sonde prior to launch time
  • Fix bug in averaging winds for WL150 layer when sonde is not monotonically descending
  • Add option to parse launch time from comment line in AVAPS files when LAU line is missing or bad
  • Update behavior of ‘ignore launch RH’ checkbox to check/uncheck with ‘ignore launch temp’ checkbox

33652 — May 21, 2018

  • Added script to set library path when running commandline Aspen on OSX.
  • Flag and remove RH values of 0.1% due to dry bias correction.
  • Fixed bug so REL and SPG will always both appear in TEMP messages.
  • Added OB number to BUFR output.
  • Changed saturation vapor pressure equation to Hardy 1998.
  • Added QC to GPS lat/lon and altitude, using buddy check and filter check.

33543 — Nov 27, 2017

  • Fixed error in launching Aspen for Windows.

33541 — Nov 13, 2017

  • Fixes to decoding WMO messages.
  • Add max winds and tropopause levels to synoptic map and sounding database.
  • Set RH values > 100% to 100% rather than removing them.
  • Don't display dew point on skew-Ts for points with RH of 0.1%.

33461 — Sep 1, 2017

  • Fixed two bugs in the graphical interface that caused Aspen to crash.
  • Updated relative humidity thresholding to set values less than 0.1% to 0.1% (formerly the threshold was 0.2%).
  • Added a new configuration option for whether to follow US national practice for reporting dew point in WMO messages when temperature < -40 deg C or relative humidity < 20%.

33429 — Jul 28, 2017

  • Include temperature and relative humidity time constants for new NRD41 sondes

33419 — Jul 7, 2017

  • Fix WMO abbreviated header for upsondes in AspenQC and BatchAspen
  • When it is present, levels use observed lat/lon instead of extrapolated lat/lon
  • Update dry bias correction function to convert all RH values, then set RH values of less than 1% to 0.1% (rather than setting as missing all RH values <1% pre-conversion)
  • Many BUFR changes:
    • Reduce all BUFR output to one sample per second, by averaging all samples within each second
    • Merge levels data with QC data series, setting the appropriate vertical significance flags
    • Remove samples with no non-missing data
    • Set the local significance flag for the aircraft observation for dropsondes

33333 — Oct 13, 2016

  • Fix configuration handling of BUFR abbreviated header fields.

33329 — Sep 28, 2016

  • (Optionally) add the BUFR abbreviated header to the BUFR file.

aspenfixrh-1.1 — Sep 22, 2016

  • Minor update to build with python 2.6 on RHEL6.

33313 — Sep 16, 2016

  • Copy raw dz and geopotential to qc series so that QC passthrough is more logical.
  • When saving from the raw tab, include the raw geopotential altitude in the file.
  • Make the netcdf file output CF-1.6 compliant.

33304 — Sep 15, 2016

  • Consolidated the information (about) dialogs.
  • Fixed a synoptic map crash that was happening only on older MacBooks. OSX libspatialite was rolled back from version to 4.1.1 to version 4.3.0a. This also now matches the libspatialite versions on Linux and W7.

33297 — Sep 9, 2016

  • Fixed error in WMO section 5/6 coding of the surface thermo and surface winds. The error was introduced in version 33236.

  • Corrected several internal errors that led to application instability.

aspenfixrh-1.0 — Aug 24, 2016

  • First release of aspenfixrh, a python script to correct the temperature-dependent dry bias from certain Vaisala sonde sensor modules deployed in 2010 and later. It edits files in EOL, FRD, and AVAPS D-file format.

33270 — July 24, 2016

  • For OSX only: corrected missing library. Prior version 33265 was non-funtional.

33265 — July 14, 2016

  • Corrected the Aspen version number in the output files generated by the command line version of Aspen (Aspen-QC).
  • FIxed console output for W7 version of Aspen-QC.

33236 — May 27, 2016

  • Reworked the BatchAspen user interface.
  • Added levels database writing to BatchAspen.
  • Added the synoptic map display to BatchAspen.
  • Added BUFR output product generation.
  • Redesigned the dropsonde WL150 computation, to match the EditSonde procedure.
  • Dropsonde theoretical fall rate is now the default fall rate for time constant computations.
  • Added the Time-Dependent Dry Bias (TDDryBias) relative humidity correction for AVAPS dropsondes.
  • Important internal fixes leading to “valgrind” compliance.
  • Other usability improvements and bug fixes.

32179 — Aug 20, 2015

  • Adjustments to the buid environment. Sounding processing unchanged.

32172 — June18, 2015

  • Restore the Aspen-QC command line program to the OSX and W7 distributions.

32169 — June 15, 2015

  • Fixed the OSX distribution, which was crashing on startup.
  • Corrected the handling of input CLASS format files. The syntax checking is relaxed a bit, to support a small variation in the CLASS file header formatted, as generated by the NCAR DMG group.

32152 — May 28, 2015

  • Rework of the WL150 code in the 62626 group of the TEMPDROP message. Winds are interpolated if necessary to provide coverage over a full 150m layer.
  • Sensor ventilation rate is now taken from the theoretical fall rate rather than the observed fall rate. The old behavior is available via an option.
  • Options were reorganized onto more tabs.
  • Version scheme has been changed to VVCCC, where VV holds the release tag (VV:32 corresponds to release 3.2), and CCC represents the number of source commits on that tag.
  • EYE is no longer avaiable as an environment option for the 6262 group; use CENTER instead.

Note that on OSX Yosemite, due to a new Qt incompatibility, drag-and-drop is no longer avaiable. We are working on adding the file menu back to BatchAspen, but in the meantime BatchAspen is not functional on OSX Yosemite.


Derived from the HRD Editsonde program (1998). Initially developed for AFRES 53rd Hurricane Hunters real-time operations. Later expanded for general upsonde and dropsonde application.