Quarterly Update: February 2021

DAWG charter

As discussed during the PIs/co-chairs meeting on 11 December, we have added a ‘do no harm’-type statement to the DAWG charter. We phrased this statement in terms of preserving the speed, functionality and usability of the software from release to release.

The updated charter is available here, and the new statement is shown in bold.

FITACF 3.0 White Paper

A white paper on FITACF 3.0 is now available on the DAWG website. This paper provides an overview of the FITACF method in general, and a description of the differences between FITACF 2.5 and FITACF 3.0. A second paper providing comparisons between the two fitting algorithms is in preparation.

Pasha Ponomarenko and Emma Bland are also preparing a manuscript on factors that affect the SuperDARN background noise estimation. Through this work we have been able to understand why the ACF selection (qflg=1) behaves so differently for the two fitting algorithms for some radars, especially in relation to:

Pasha has also written software to filter out these types of echoes from the fitted data. DAWG will begin testing this code soon.

FITACF file format: elevation angle fields for FITACF3.0

The elevation angle fields in FITACF-format files are used slightly differently in FITACF2.5 and FITACF3.0:

FITACF2.5 (documented here)

FITACF3.0 (documented here)

FITACF3.0’s use of the elv_high and elv_low fields to store other information is misleading. We suggest that two new fields, elv_fitted and elv_error, be added to the fitacf file format to capture the different output in FITACF3.0:

Field FITACF2.5 FITACF3.0 Notes
elv Elevation angle calculated from the fitted phase Elevation angle calculated from the lag zero phase The elevation angle that is recommended for scientific use
elv_fitted   Elevation angle calculated from the fitted phase The same as elv in FITACF2.5
elv_low Lower estimate of the elevation angle   Often meaningless due to phase flipping.
elv_high Upper estimate of the elevation angle   (see above)
elv_error   Least square elevation angle error Replaces elv_low/elv_high

The above suggestion would not change the FITACF2.5 output. We will only implement this change with PI approval, since it potentially impacts the scientific interpretation of the data. Alternative suggestions are also most welcome. We have not yet investigated the practicality of implementing this change in the RST; we would like PI feedback first.

Removing version numbers from RST directories

We are planning to remove the version numbers from the directory structure in RST. For example, all of these directories would be renamed from [binary name].[version] to just [binary name] (e.g. make_fit.1.19 will become make_fit). The reasons for this change are:

This does not apply to RST libraries where two parallel versions are maintained for scientific reasons, e.g. fitacf2.5/fitacf3.0, aacgm/aacgm_v2, elevation/elevation_v2.

Please contact the DAWG chairs by 31 March 2021 if you have any concerns about this change.

Software releases

RST

RST4.5 was released on 13 January. Please see the Zenodo site for a description of the new release and to download the software.

pyDARN

pyDARN 2.0 is out for testing and planned to be release mid February. The following changes to pyDARN are as follows: