The NAMMA Upstream Sounding Network over West Africa:

1
The NAMMA Upstream Sounding Network over West
Africa What worked and didnt workand was it
worth the effort? How can these observations help
NAMMA studies? Michael W. Douglas1, Javier
Murillo2, Jose Galvez3, John Mejia3, and Raquel
Orozco3 1NOAA/NSSL, 2OU/CIMMS, and 3OU/School of
Meteorology
Successes
Summary

• Pilot balloon observations from Mauritanian sites
  should be useful for describing dust outbreaks
  and wave passages at higher latitudes (16-20
  N).
• Two Mali sites, making twice-daily soundings at
  06Z and 18Z, functioned for about 50 days.
• Guinean radiosonde site (Conakry) provided some
  overlap with NAMMA aircraft observational phase.

Between July 10 and August 10, 2006 four
individuals from NSSL and CIMMS/Univ. of Oklahoma
(together with one volunteer) worked in four West
African countries (Mali, Senegal, Mauritania, and
Guinea) to improve the sounding network for
NAMMA. The objective was to rehabilitate the
existing pilot balloon stations and ensure their
functioning for NAMMA. To this end three
sounding sites were visited in Mali, 4 in
Senegal, one in Guinea, and two in Mauritania.
One additional site in Guinea (Kankan) was
reactivated for NAMMA but was not visited, and a
radiosonde station in Conakry (Guinea) was also
reactivated with supplies from another NAMMA
project. In addition to replacing defective
theodolites where needed with our reconditioned
theodolites, we provided training to each station
in the use of software to correct errors and
automatically calculate the winds on a personal
computer. We also showed how to transmit the
data via email where Internet existed. Most
observers had extensive experience making pilot
balloon observations, but the poor quality of
their theodolites often limited the duration of
the observations. The enhanced NAMMA sites
provided additional soundings, some in real time
for NAMMA aircraft operations in Sal.
Unfortunately, a number of the sites that we
visited and left in operating conditions
apparently did not make any observations, or
fewer than expected, despite the availability of
supplies or personnel. Some of the problems
encountered were not entirely technical in
nature.
Fig. 1 In all, 385 pilot balloon observations
have been received to date. This was
considerably short of our expectations.
AUGUST
SEPTEMBER
Left Time-height sections of the wind from pilot
balloon observations at Nouadhibou, Mauritania.
This site provided the most complete data overall
of any pibal site during NAMMA.
NOUADHIBOU
Failures
Fig. 2. The NAMMA radiosonde and pilot balloon
network, showing which sites made observations
and those that apparently did not.

• Gas supplies were unreliable throughout the
  region, complicating station operations only
  partial solutions to these problems were fouond
  during NAMMA.
• Protocol problems and gas supply issues prevented
  any observations being made from Senegal, despite
  a major effort there to arrange for the operation
  of four pilot balloon stations.
• One Mali site was discovered to be abandoned, but
  only after a lengthy visit to the site.

Establishing stations
Our group traveled to Dakar, Senegal on July 10th
to determine the current status of the sounding
network, establish the Senegalese component
first, and then travel to the surrounding
countries. Because of the mis-shipment of
materials to Senegal, travel to the other
countries in the region was delayed. After
visiting Mali and splitting to visit the widely
separated sites at Mopti and Kayes, the team
returned to Senegal. Splitting again in early
August, one group traveled to Guinea and the
other to Mauritania. In addition, permission to
establish the observations and travel to the
stations within Senegal (4 sites, including
Dakar) was also delayed due to some protocol
mistakes. Although all Senegalese sites were
visited by August 8th and procedures seemingly
worked out (the observers had been trained and
theodolites replaced) no observations seemingly
were made at any of the sites.
In maps above, note the value of the pilot
balloon data in confirming the radiosonde winds.
Bamako and Nouakchott pibal winds not plotted.
Conclusions
Acknowledgements

• Observations will provide modest help in
  improving upstream continuity of tropical waves
  existing Africa during NAMMA.
• Our NAMMA effort provides a reality-check for any
  future activity related to studies of easterly
  waves over Africa. We found that the current
  pilot balloon station network is mostly abandoned
  and poorly functioning in may countries in the
  region. There are many reasons for this. Much
  longer lead times are needed for any land-based
  future activity - a minimum of 1 year (instead
  of the 3 months available during NAMMA). Finally,
  the basic infrastructure and personnel problems
  in West African Meteorological Services must be
  dealt with to realistically expect routine
  monitoring from enhanced sounding network on this
  region.

Funding for this work has been provided by the
Atmospheric Dynamics section of NASA. The
logistical support of the NAMMA community is
gratefully acknowledged.