Diurnal and Seasonal Variations in Carbon Dioxide Exchange in a Primary Forest on Amazonia – Brazil
Gross Primary Productivity, Net Ecosystem Exchange, Evapotranspiration
Carbon exchanges in forest areas, either by Net Ecosystem Exchange (NEE) or by gross primary productivity (GPP) have an important role in understanding biosphere-atmosphere interactions and terrestrial ecosystems, while estimating water use efficiency ( WUE) provides an understanding of the trade-off between carbon gain and water loss by ecosystems, so understanding their dynamics and controlling factors in these environments is essential to understand the possible responses of ecosystems to climate change that the planet is going through. It is particularly important to have these estimates and patterns well defined in areas such as the Amazon, given the increasing rates of degradation and deforestation in the region in recent years. Using flow measurement tower data in the Caxiuanã-PA flona, climate data, CO2 exchange and WUE data were estimated. It is intended to compare the GPP data with the product MOD17A2 (GPPMOD17) for validation. The results so far show:
i) marked seasonality of climatic variables and energy flows, with evapotranspiration and air temperature at the site following the annual rate of solar radiation and precipitation; ii) in-phase and energy-dependent energy flows; iii) The site as a carbon sink, varying the intensity according to the site's annual water availability.