Dr. Alain DABAS
Meteo-France, Centre National de Recherches Meteorologiques
Toulouse, France.
Dedicated to the documentation of the west-African monsoon
offset, the Special Observation Period (SOP) 2a1 of AMMA took
place from July 1 to July 15, 2006. During this period, two
airborne lidars were operated from the Niamey airport, Niger. One
was the Doppler wind lidar WIND, the other one the water vapor
lidar LEANDRE II. Both were flown on Falcon 20 aircrafts (German
F20 of DLR for WIND, French F20 of SAFIRE for LEANDRE II), one of
them (DLR) was additionally equipped with a drop-sonde system.
Several missions involved coordinated flights aimed at
documenting the monsoon flow. Flying at about 20000 feet above
the ground, the two lidars were operated simultaneously along a
straight, return tracks starting from Niamey (13°29’N, 2°10’E)
and extending to 20°N, 7°E to the North-East. The Inter-Tropical
Discontinuity was flown several times and documented with an
unprecedented wealth of details. Data show in particular the
lifting of Saharian dust at the northern tip of the monsoon and
the vertical layering of the aerosol content above the monsoon flow.
The WIND lidar was also operated on the 30th of June while the
German Falcon made its way from Munich in Germany to Niamey via
Djerba (Tunisia). The wind profiles measured by the system
document the troposheric dynamics along a North-South cross
section extending from ∼35°N to ∼15°N. All the major, expected
wind circulations – low-level monsoon flow, African easterly jet…
- are clearly visible. The measurements compare rather well with
analyses from the European Center for Medium range Weather
Forecast, but significant departures appear, related in
particular to the orographic perturbations brought by the Hoggar
mountain.
The presentation will start with a short presentation of the
lidar systems. The observation data will be shown, discussed, and
compared to model analyses.
Friday July 6 at 2pm in FL2-1022.
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