International geosphere‐biosphere programme/international global atmospheric chemistry SAFARI‐92 field experiment: Background and overview

Abstract

The International Geosphere‐Biosphere Programme/International Global Atmospheric Chemistry (IGBP/IGAC) Southern Africa Fire‐Atmosphere Research Initiative (SAFARI‐92) field experiment was conducted in the 1992 dry season in southern Africa. The objective of the experiment was a comprehensive investigation of the role of vegetation fires, particularly savanna fires, in atmospheric chemistry, climate, and ecology. During SAFARI‐92 experimental fires were conducted in Kruger National Park, South Africa, and at some sites in Zambia, in order to study fire behavior and trace gas and aerosol emissions. Regional studies on atmospheric chemistry and meteorology showed that vegetation fires account for a substantial amount of photochemical oxidants and haze over the subcontinent, and that the export of smoke‐laden air masses contributed strongly to the ozone burden of the remote atmosphere in the southern tropical Atlantic region. The relationships between fire, soil moisture status, and soil trace gas emissions were investigated for several climatically and chemically important gases. Remote sensing studies showed that advanced very high resolution radiometer/local area coverage (AVHRR/LAC) imagery was valuable for fire monitoring in the region and in combination with biomass models could be used for the estimation of pyrogenic emissions.

A model analysis of the tropical South Atlantic Ocean tropospheric ozone maximum: The interaction of transport and chemistry

“…The basic flow field features a surface anticyclone anchored off the African coast near 30øS which produces southeast trade winds from the west coast of Africa to the Intertropical Convergence Zone (ITCZ) north of the equator, and this divergent anticyclonic outflow is supported by significant regional subsidence [Krishnamufti et al, 1993]. In addition, work done by Kidson [1975] showed that this region undergoes a Walker-type circulation with rising motion over the continents of South America and Africa, convergent flow were published Lindesay et al, 1996]. The findings indicated that a complex mix of meteorology and photochemistry produces the SAO maximum.…”

Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

“…In the beginning of the 1990s, the experiments of these individual groups were followed by a number of large international biomass burning experiments in various ecosystems throughout the world. These included the Southern Africa Fire-Atmosphere Research Initiative (SAFARI 92 and SAFARI 2000) in southern Africa (Lindesay et al, 1996;Swap et al, 2002), Dynamique et Chimie Atmosphérique en Forêt Equatoriale-Fire of Savannas (DECAFE-FOS) in West Africa (Lacaux et al, 1995), Transport and Atmospheric Chemistry Near the Equator-Atlantic (Trace-A) over Brazil, southern Africa, and the South Atlantic (Fishman et al, 1996), Fire Research Campaign Asia-North (FireS-CAN) in central Siberia (FIRESCAN Science Team, 1996), and Smoke, Clouds, and Radiation-Brazil (SCAR-B) in Brazil (Kaufman et al, 1998).…”

Study of ozone formation and transatlantic transport from biomass burning emissions over West Africa during the airborne Tropospheric Ozone Campaigns TROPOZ I and TROPOZ II

“…As mentioned previously, detailed investigations of phenomena occurring in southern Africa have been performed within the frame of SAFARI 92 (September-October 1992): "regional studies of atmospheric chemistry and meteorology show that vegetation fires account for a substantial amount of photochemical oxidants and haze over the subcontinent, and that the export of smoke-laden air masses has contributed strongly to the ozone burden of the remote atmosphere in the southern tropical Atlantic region" [Lindesay et al, 1996 [1990,1991] do not detect any significant ozone formation in the troposphere from the northern African tropics during the burning season (December-February) although important biomass-burning emissions are known to occur in these regions. Various explanations can be proposed to explain such a phenomenon: (1) interference in the satellite picture method from copious amounts of lower tropospheric aerosols [Fishman et al, 1996a] or from the presence of cloud coverage, (2) compensation between ozone-laden and ozonedepleted air layers in the case of a contrasted vertical structure of the atmosphere, (3) a better view by satellites of ozone densities in the upper troposphere than in the lower, and (4) much lower 03 formation from biomass-burning emissions in the northern regions.…”