Abstract
Observations of radio waves in the Extremely Low Frequency and Very Low
Frequency band (ELF/VLF, 0.3-30 kHz) have a host of geophysical uses,
including lightning detection and characterization, D-region ionosphere
remote sensing, detection of solar flares and geomagnetic storms,
gravity waves, gamma-ray burst detection, observations of whistlers,
chorus and hiss, to infer wave-particle interactions in the
magnetosphere, plasmaspheric state. It’s been looked at for earthquake
forecasting and also has commercial uses like submarine communications
and subterranean prospecting. For many years ELF/VLF data have been
collected at various locations and by various groups around the world
for a variety of scientific purposes, but most of this data is not
available publicly. We introduce the World Archive of Low-frequency Data
and Observations (WALDO), a repository of ELF/VLF data from recordings
taken over the past two decades by Stanford University and subsequently
by Georgia Tech and University of Colorado Denver. The locations of the
recordings are all around the world, including Alaska, Antarctica,
Australia, and many low and mid latitude stations. Some sites were more
consistent than others but there’s a lot of untapped value in this
dataset. Funding for these recordings came from many years of funding
from NSF, NASA, DoD, and others, on various basic science projects, and
we feel a responsibility to make sure the datasets are now preserved. We
are in the process of transferring many 100s of TBs of data and sharing
every raw bit for anyone to download and analyze. This includes both
“broadband” data that includes the entire spectrum from 500 Hz – 50
kHz, and “narrowband” data corresponding to amplitudes and phases of
specific transmitting beacons. We are also including automatically
generated summary plots, and a host of basic analysis tools to allow
anyone to download and analyze the data. We will announce and present
WALDO, update its status and timeline for full deployment, and detail
some of the uses of ELF/VLF data, with the goal of enabling its use by
anyone interested. We will not be finished by the Fall meeting (ripping
80,000 DVDs can take a while) but whatever we finished will be public
and hopefully we will be far along by then. Finally, we will have the
answer to the age-old question…”Where’s WALDO?”