Vertical distribution and radiative effects of mineral dust and biomass burning aerosol over West Africa during DABEX

Journal Article · Fri Sep 12 04:00:00 EDT 2008 · Journal of Geophysical Research. D. (Atmospheres), 113:Art. No. D00C12

DOI:https://doi.org/10.1029/2008JD009848· OSTI ID:985030

Johnson, Ben; Heese, B; McFarlane, Sally A; Chazette, P; Jones, A; Bellouin, N

This paper presents measurements of the vertical distribution of aerosol extinction coefficient over West Africa, during the Dust and Biomass burning aerosol Experiment (DABEX) / African Monsoon Multidisciplinary Analysis dry season Special Observing period zero (AMMA-SOP0). In situ aircraft measurements from the UK FAAM aircraft are compared with two ground based lidars (POLIS and ARM MPL) and an airborne lidar on an ultra-light aircraft. In general mineral dust was observed at low altitudes (up to 2km) and a mixture of biomass burning aerosol and dust was observed at altitudes of 2-5km. The study exposes difficulties associated with spatial and temporal variability when inter-comparing aircraft and ground measurements. Averaging over many profiles provided a better means of assessing consistent errors and biases associated with in situ sampling instruments and retrievals of lidar ratios. Shortwave radiative transfer calculations and a 3-year simulation with the HadGEM2-A climate model show that the radiative effect of biomass burning aerosol is somewhat sensitive to the vertical distribution of aerosol. Results show a 15% increase in absorption of solar radiation by elevated biomass burning aerosol when the observed low-level dust layer is included as part of the background atmospheric state in the model. This illustrates that the radiative forcing of anthropogenic absorbing aerosol is sensitive to the treatment of other aerosol species and that care is needed in simulating natural aerosols assumed to exist in the pre-industrial, or natural state of the atmosphere.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 985030
• Report Number(s): PNNL-SA-58843; KP1205010
• Journal Information: Journal of Geophysical Research. D. (Atmospheres), 113:Art. No. D00C12, Journal Name: Journal of Geophysical Research. D. (Atmospheres), 113:Art. No. D00C12 Vol. 113; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
ABSORPTION
AEROSOLS
AFRICA
AIRCRAFT
BIOMASS
CLIMATE MODELS
DISTRIBUTION
DUSTS
MIXTURES
MONSOONS
OPTICAL RADAR
RADIANT HEAT TRANSFER
SAMPLING
SEASONS
SIMULATION
SOLAR RADIATION