Overview of observations from the RADAGAST experiment in Niamey, Niger: Meteorology and thermodynamic variables
An overview is presented of the meteorological and thermodynamic data obtained during the RADAGAST experiment in Niamey, Niger, in 2006. RADAGAST (Radiative Atmospheric Divergence using ARM Mobile Facility, GERB data and AMMA STations), combined data from the Atmospheric Radiation Measurement (ARM) Program Mobile Facility (AMF) at Niamey airport with broadband satellite data from the Geostationary Earth Radiation Budget (GERB) instrument on Meteosat-8. The experiment was conducted in collaboration with the African Monsoon Multidisciplinary Analysis (AMMA) project. The focus in this paper is on the variations through the year of key surface and atmospheric variables. The seasonal advance and retreat of the InterTropical Front (ITF) and the seasonal changes in near-surface variables and precipitation in 2006 are discussed and contrasted with the behavior in 2005 and with long-term averages. Observations from the AMF at Niamey airport are used to document the evolution of near-surface variables and of the atmosphere above the site. There are large seasonal changes in these variables, from the arid and dusty conditions typical of the dry season to the much moister and more cloudy wet season accompanying the arrival and intensification of the West African monsoon. Back trajectories show the origin of the air sampled at Niamey and profiles for selected case studies from rawinsondes and from a MicroPulse Lidar at the AMF site reveal details of typical atmospheric structures. Radiative fluxes and divergences are discussed in the second part of this overview and the subsequent papers in this special section explore other aspects of the measurements and of the associated modeling.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 946654
- Report Number(s):
- PNNL-SA-61852; KP1701000; TRN: US200903%%448
- Journal Information:
- Journal of Geophysical Research. D. (Atmospheres), 113(D00E01), Vol. 113
- Country of Publication:
- United States
- Language:
- English
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