# Evaluation of Water and Carbon Estimation Models in the Caatinga Biome Based on Remote Sensing
## 4 Conclusions  
The energy, water, and carbon fluxes for the Caatinga biome obtained are key to addressing current environmental issues that face this important region. Our results show, among others, the greater availability of energy to carry out physical processes in the area with the greatest amount of vegetation (DC), with higher values for them compared to the  
Figure 7: Statistical analysis (Standard Deviation-SD, Maximum-max, and median) of GPP for the state of Paraiba in 2013 derived from the product MOD17A2H. sparse Caatinga (SC). We also found that rainfall is a key factor in the Caatinga's ability to capture carbon and highlight the need for further studies on the effects of climate change on this biome. The ET also presented higher values when compared to the SC, which indicates that degradation tends to reduce the evapotranspiration process since the removed vegetation will imply less water vapor transferred to the atmosphere. The influence of water availability on gross primary productivity (GPP) for the regions with preserved Caatinga and regions with degraded Caatinga under study was also found to be evident. These differences were better observed through the estimates via MOD17A2H, which presented a better correlation with the observed data. However, these results were less accurate in comparison to the field measurements than the model proposed in this work (modeled GPP). Rainfall is a key factor in Caatinga's capacity to capture CO\({}_{2}\). The greatest differences between the dense and sparse areas occur during higher/lower water availability, depending on the season. We believe that the results found here will help to design new studies focusing on the role of current climate change and its effect on contrasting Caatinga areas, based, for example, on whether they are more or less capable of releasing water and absorbing carbon given their level of degradation. This study can also bring benefits to the Caatinga region by helping to further establish priority areas for conservation and agriculture in the surrounding areas. Summarizing, this study highlights the importance of preserving the Caatinga biome for its ecological and societal benefits. The results suggest that areas with greater vegetation (DC) have higher availability of energy and water, as well as greater carbon capture capacity. On the other hand, the degradation of the Caatinga biome leads to reduced evapotranspiration and carbon capture. This highlights the need for more sustainable resource management practices. These findings can help prioritize areas for the conservation and sustainable development in the Caatinga region. Moreover, they can serve for the development of priority policies reports, for example, in order to show the involved stakeholders what paths should be considered in order to contribute to the preservation of this important ecosystem. Conceptualization, M.L.d.O., C.A.C.d.S. and F.A.C.S. ; methodology, M.L.d.O., C.A.C.d.S. and F.A.C.S. ; software, M.L.d.O. and F.A.C.S. ; validation, M.L.d.O. and F.A.C.S. ; formal analysis, M.L.d.O. and F.A.C.S. ; investigation, M.L.d.O., C.A.C.d.S. and F.A.C.S. ; resources, C.A.C.d.S. ; data curation, M.L.d.O. and F.A.C.S. ; writing--original draft preparation, M.L.d.O., C.A.C.d.S., F.A.C.S., G.d.O., C.A.G.S., U.A.B., J.E.d.B.L.C. and R.M.d.S. ; writing--review and editing, M.L.d.O., C.A.C.d.S., F.A.C.S., G.d.O., C.A.G.S., U.A.B., J.E.d.B.L.C. and R.M.d.S. ; visualization, M.L.d.O., C.A.C.d.S., F.A.C.S., G.d.O., C.A.G.S., U.A.B., J.E.d.B.L.C. and R.M.d.S. ; supervision, C.A.C.d.S. ; project administration, C.A.C.d.S. ; funding acquisition, C.A.C.d.S. All authors have read and agreed to the published version of the manuscript. Fundacao de Apoio a Pesquisa do Estado da Paraiba (Edital N\({}^{\mathrm{o}}\) 09/2021 Demanda Universal), Chamada Interna Produtividade em Pesquisa PROPESQ/PRPG/UFPB (Edital N\({}^{\mathrm{o}}\) 04/2021), and the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) (Process No. 304493/2019-8).