Abstract:Modifications of human land use and climate change are known to be a threat for the health and proper functioning of tropical wetlands. They interfere with the seasonal flood pulse, which is seen as the most important driver for biodiversity and directly controls evaporation. In order to investigate the impact of local and upstream changes on wetlands, a regional assessment of evaporation is crucial but challenging in such often remote and poorly gauged ecosystems. Evaporation is the major water balance component of these wetlands and links the flood pulse with the ecosystem. It can therefore be seen as a proxy for their functioning. In the last decades, information from space became an important data source to assess remote wetland areas. Here, we developed a new approach to quantify regional evaporation driven by inundation dynamics as its dominant control. We used three water and vegetation indices (mNDWI (modified Normalized Difference Water Index), NDVI (Normalized Difference Vegetation Index), and EVI (Enhanced Vegetation Index)) from MODIS (Moderate Resolution Imaging Spectroradiometer) surface reflectance products to assess regional inundation dynamics between the dry and wet seasons. Two years of continual in situ water level measurements at different locations in our study area, the OPEN ACCESS Remote Sens. 2015, 7
9770Pantanal wetland of South America, provided the reference to evaluate our method. With process-based modeling that used the inundation dynamics to determine the water available for evaporation, we were able to estimate actual evaporation (AET) on a regional scale. Relating AET to changes in discharge due to upstream flow modifications and on local precipitation over the last 13 years, we found that the Pantanal is more vulnerable to alternated inundation dynamics than to changes in local precipitation. We concluded that coupling ground-and space-based information in this remote wetland area is a valuable first step to investigate the status of the Pantanal ecosystem.
Moderate resolution imaging spectroradiometer (MODIS) time series (TS) have been widely applied for flood monitoring in large tropical wetlands. However, little systematic work is available on the influence of pixel quality, vegetation cover, and the annual hydroclimatic cycle on classification performance. In this study, this issue is examined based on a six-year, 250 m res-
Análise da complexidade do saldo de radiação em uma floresta sazonalmente inundada no norte do pantanalAnalysis of the complexity of net radiation in a seasonal flooded forest in the northern Pantanal
AbstractThe ecosystem net radiation has a complex variation, and represents the energy available for physical and biological processes that occur between the vegetated surface and atmosphere. Therefore, the objective of this study was to analyze the complexity of net radiation measured above the canopy of a seasonal flooded forest in the northern Pantanal from the perspective of complexity theory. The attractors were seasonal reconstructed by the estimation of the exponents correlation dimension (D 2(wet) = 1,73±0,05 and D 2(dry) = 1,36±0,18), embedded dimension (m = 7), rate of recurrence (RR (wet) = 0,144±0,004 and RR (dry) = 0,169±0,002) and determinism (DET (wet) = 0,896±0,013 and DET (dry) = 0,973±0,015) data sets analyzed. The results showed the existence of strange attractors of low fractal dimension, and sensitive to the seasonality of radiation balance.
Among the categories of conservation units, the Natural Monument (MoNa) presents a high challenge because it is established areas. MoNa Morro de Santo Antônio is the only one in the state of Mato Grosso and degree of preservation is unknown. Thus, the objective of this work was to evaluate the use and occupation of the soil after the creation of MoNa Morro de Santo Antônio in the state of Mato Grosso and its influence on biophysical parameters from remote sensing techniques. For this, images of the surface reflectance obtained by Landsat 5 and 8 were used. The vegetation classification in the MoNa Morro de Santo Antônio was supervised. The estimated biophysical parameters were the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and the Normalized Difference Moisture Index (NDMI). The results presented in this work show that after the creation of MoNa Morro de Santo Antônio the native Cerrado class increased by 3.38%, the Undergrowth vegetation increased by 5.59% and the Forest dense class increased from 2.21% between 2006 and 2015. The Undergrowth vegetation class had a greater predominance. All indexes were lower in 2006 and higher in 2015. The results of this study are preliminary, but indicate that the creation of MoNa Morro de Santo Antônio in Mato Grosso influenced the preservation of its vegetation.
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