## Materials and Methods
### Eddy Covariance Climate and Carbon Flux Data  
Experimental data were collected in the period from January 2014 to December 2015 through an eddy covariance system installed in an 11 m height flux tower belonging to the Brazilian National Institute of the Semiarid (INSA) and integrating the National Observatory of Water and Carbon Dynamics in the Caatinga Biome (NOWCDCB) network. The analyzed variables were daily and monthly means of air temperature (Ta, \({}^{\circ}\)C), net ecosystem exchange (NEE, gC m\({}^{-2}\) day\({}^{-1}\)), gross primary production (GPP, gC m\({}^{-2}\) day\({}^{-1}\)), ecosystem respiration (Reco, gC m\({}^{-2}\) day\({}^{-1}\)), vapor pressure deficit (VPD, kPa), relative humidity (RH, %), rainfall (mm), latent heat flux (LE, in W m\({}^{-2}\)), sensible heat flux (H, in W m\({}^{-2}\))m and net radiation (Rn, in W m\({}^{-2}\)). High (10 Hz) and low frequency data (sampled every 5 s and stored as half-hour averages) were recorded. The high frequency  
Figure 1: Location of the Caatinga biome and topography map with Brazilian states division and the location of the micrometeorological tower installed in the ESEC-Serido, Brazil. data consist of measurements of CO\({}_{2}\) concentration and water vapor and the three components of wind speed (u_x, u_y, u_z), using an Integrated CO\({}_{2}\)/H\({}_{2}\)O Open-Path Gas Analyzer and 3D Sonic Anemometer (IRGASON, Campbell Scientific, Inc., Logan, UT, USA). Atmospheric pressure was measured using an Enhanced Barometer PTB110 (Vaisala Corporation, Helsinki, Finland) and air temperature by an HMP155A probe (Vaisala Corporation, Helsinki, Finland) of low frequency include net radiation (Rn), air temperature (Tair), and relative humidity (RH), in addition to precipitation. Rn measurements were performed using a net radiometer model CNR4 (Kipp and Zonen B. V., Delft, Netherlands Ta) and RH data were measured using a model HMP45C temperature and relative humidity probe (Vaisala Corporation, Helsinki, Finland). Net Ecosystem Exchange (hereafter referred as NEE) is the sum of the eddy CO\({}_{2}\) flux (FCO\({}_{2}\)), calculated as the covariance between the fluctuations of the vertical wind speed (w\({}^{\prime}\)) and the density of CO\({}_{2}\) (c\({}^{\prime}\)) and the rate of change of CO\({}_{2}\) stored in the air column below the EC measurements height (Sc). Since no concentration profile was installed at the site, we opted for the discrete approach, assuming that the CO\({}_{2}\) concentration inside the canopy can be estimated as an approximation [33]  
CO\({}_{2}\) concentrations in the form of Net Ecosystem Exchange (NEE) were partitioned into Gross Primary Production (GPP) and Ecosystem Respiration (Reco) which is equivalent to the sum of autotrophic and heterotrophic respiration, using a flux partitioning method based on night time as described by [PERSON] [34]. Thus, the GPP was estimated according to Equation (1):  
\[\text{GPP}=\text{NEE}-\text{Reco} \tag{1}\]  
in which Reco and GPP were calculated using the online tool provided by the Max Plank Institute (Max Planck Institute for Biogeochemistry--[[http://www.bgc-jena.mpg.de/~MDIwork/eddyproc/](http://www.bgc-jena.mpg.de/~MDIwork/eddyproc/)]([http://www.bgc-jena.mpg.de/~MDIwork/eddyproc/](http://www.bgc-jena.mpg.de/~MDIwork/eddyproc/)) accessed on 24 April 2022). The NEE was modeled based on daytime data using the common rectangular hyperbolic light response curve model [35]:  
\[\text{NEE}=(\alpha\cdot\beta\cdot\text{R}_{\text{g}})/(\alpha\cdot\text{R}_{ \text{g}}+\beta)+\gamma \tag{2}\]  
where \(\alpha\) (\(\mu\)mol C [\(\bar{\chi}\)] \({}^{-1}\)) is the light utilization efficiency and represents the initial slope of the light response curve, \(\beta\) (\(\mu\)mol C m\({}^{-2}\) s\({}^{-1}\)) is the maximum CO\({}_{2}\) absorption rate of the canopy at light saturation, \(\gamma\) (\(\mu\)mol C m\({}^{-2}\) s\({}^{-1}\)) is the ecosystem respiration, and R\({}_{\text{g}}\) (W m\({}^{-2}\)) is the global radiation.