Land cover and its transformation in the backward trajectory footprint region of the Amazon Tall Tower Observatory

Abstract

<p><strong>Abstract.</strong> The Amazon rain forest experiences the combined pressures from man-made deforestation and progressing climate change, causing severe and potentially disruptive perturbations of the ecosystem's integrity and stability. To intensify research on critical aspects of Amazonian biosphere-atmosphere exchange, the Amazon Tall Tower Observatory (ATTO) has been established in the central Amazon Basin. Here we present a multi-year analysis of backward trajectories to derive an effective footprint region of the observatory, which spans large parts of the particularly vulnerable eastern basin. Further, we characterize geospatial properties of the footprint regions, such as climatic conditions, distribution of ecoregions, land cover categories, deforestation dynamics, agricultural expansion, fire regimes, infrastructural development, protected areas, as well as future deforestation scenarios. This study is meant to be a resource and reference work, helping to embed the ATTO observations into the larger context of man-made transformations of Amazonia. We conclude that the chances to observe an unperturbed rain forest-atmosphere exchange will likely decrease in the future, whereas the atmospheric signals from man-made and climate change-related forest perturbations will likewise increase in frequency and intensity.</p>

Surprising chiral composition changes over the Amazon rainforest with height, time and season

“…Air is usually transported from the East sector (NE~20%, ENE~27%, E~33%, ESE~19%, Supplementary Fig. 1), covering a footprint of continental area of~1.5 × 10 6 Km 2 , whereby 54% is considered untouched 11 . Meteorological conditions vary through the year according to the position of the inter-tropical convergence zone (ITCZ), with a cooler rainy season (February-May) and a hotter drier season (June-October) 10 .…”

“…The ATTO tower is surrounded by pristine rainforest (see Fig. 1), which extends over 500 km upwind of the site 10,11 . Each day biogenic volatile organic compounds emitted at ground level are transported through vertical turbulent mixing up to the tower´s summit at 325 m over timescales of circa 20-40 min by day 12 .…”

Microclimatic and ecophysiological conditions experienced by epiphytic bryophytes in an Amazonian rain forest

“…Long-term climate data have shown that the winds during the wet season predominantly originated from north and north-eastern directions, while during the dry season south-and south-easterly winds prevailed (Pöhlker et al, 2018). In contrast to that, the bryophytes at 18 m height showed a clear response to precipitation events.…”

“…150 km northeast of Manaus, Brazil. The average annual rainfall is 2 540 mm year -1 (de Ribeiro, 1984), reaching its monthly maximum of ~ 335 mm in the wet (February to May) and its minimum of ~ 47 mm in the dry season (August to November) (Pöhlker et al, 2018).…”

Amazonian biogenic volatile organic compounds under global change

“…80% of global terpenoid emissions and 50% of other BVOC emissions (Guenther et al., 2012). With half of the global tropical forests, Amazonia is the largest remaining pristine continental area (Andreae et al., 2015; Pöhlker et al., 2019). Amazonia stores 50% of tropical‐forest carbon, plays a vital role in the global cycles of energy, water and carbon, and has the largest biodiversity in the world (Levine et al., 2016; Malhi et al., 2008; Swift et al., 1998; ter Steege et al., 2013).…”