## 1 Introduction  
Tropical vegetation accounts for the majority (60%) of terrestrial gross primary productivity (GPP), the largest component of the carbon budget, e.g., [1; 2; 3; 4; 5]. Although tropical ecosystems play a critical role in the global carbon budget, our understanding of local and regional variability in gross primary production (GPP) is severely limited. These limitations arise due to the complexity of tropical ecosystems, as well as difficulties collecting and scaling data from systems such as eddy covariance flux instruments e.g., [3; 6; 7; 8; 9; 10]. Satellite-based measurements of solar-induced fluorescence (SIF) developed in recent years are providing a new tool to measure photosynthetic activity from local to global scales. SIF is a by-product of the photosynthetic process, thus is mechanistically coupled to vegetation functioning in contrast to optical reflectance-based vegetation indices (VIs), such as the normalized difference vegetation index, which is often used to model or predict productivity [9; 11; 12; 13; 14; 15; 16; 17]. SIF data from satellite platforms have been demonstrated to be related to plant photosynthetic functioning, have been shown to scale linearly with modelled and flux tower GPP, have empirical links with crop and deciduous forest GPP in temperate zones, and captured differences in relative productivity of different vegetative classes in temperate regions [11; 12; 14; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29]. Studies also suggest SIF is an earlier indicator of vegetation stress than other remote sensing vegetative health indices [20; 30; 31; 32; 33; 34; 35; 36; 37]. Global scale studies utilizing satellite-based SIF measurements and vegetation classes based on the International Geosphere Biosphere Programme (IGBP) classifications have shown significant vegetation class-specific SIF-GPP relationships, except for tropical evergreen broadleaf forest (EBF) [12; 15; 28; 29; 38; 39; 40; 41; 42]. [PERSON], [PERSON] [41], in particular, examined the vegetation class-specific SIF for eight vegetation classes for the entire globe (deciduous broadleaf forest (DBF), EBF, grasslands (GRA), savanna (SAV), evergreen needleleaf forest (ENF), open shrubland (OSH), crop (CRO) and mixed forests (MF)) and found significant differences in SIF among some classes at global scale as well as SIF-GPP relationships for all but EBF [42]. Thus, the SIF-GPP relationship remains elusive for tropical forests (EBF) and unexamined for other vegetation types, such as DBF, GRA, SAV in the tropical regions. There is a consensus in the literature that improving our understanding of regional photosynthetic activity in tropical regions is urgent and SIF has the potential for addressing the gaps in our knowledge by improving characterization of productivity of tropical vegetation types at multiple scales [12; 13; 21; 43; 44; 45], however, of the studies utilizing satellite-based SIF in South America, the focus has only been on Amazon evergreen broadleaf forest (EBF) e.g., [22]. Thus, other tropical vegetation and areas outside the Amazon are relatively unstudied. Tropical vegetation, including tropical forests, appear to have seasonal cycles, yet the magnitudes, timing, and seasonal variation in carbon fluxes, greenness, GPP, leaf area index (LAI), structural changes, for example, are more complex than those observed in more temperate regions [46; 47; 48; 49] due to the less pronounced cycles and the high degree of biodiversity in tropical regions [9; 35; 39; 40; 50; 51; 52; 53; 54]. Vegetation phenology influences spatiotemporal variability of ecosystem productivity and the measures of seasonality are related to fluxes in the carbon cycle, i.e., GPP responds to timing of seasons [9; 30; 55; 56; 57; 58; 59]. Understanding phenology of tropical vegetation, and tropical forests in particular, is critical to understanding the current functioning of tropical biomes and predict responses to a changing climate [2; 47; 60; 61; 62; 63].