## 1 Introduction  
Sea surface temperature (SST), the essential geophysical variable that provides information about the ocean surface heat, is a key element in determining the earth's climate [1]. This fundamental oceanic variable substantially influences our planet's weather and climate patterns by regulating dynamic and biogeochemical processes linking the ocean with the atmosphere [2]. SST is used as a simple and sensible indicator to understand complex air-sea interactions and their implications on the earth's surface [3]. In conjunction with surface air temperatures, SST variations can create intensified extreme climate phenomena that trigger severe economic and agricultural losses [4]. Some regional SST anomalies control the photosynthetic assimilation of carbon in terrestrial ecosystems by altering heat and moisture fluxes through the atmospheric bridge [5, 6]. Climatic oscillations such as the El Nino Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Pacific DecadalOscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) affect global vegetation through teleconnections, establishing the relevance of oceanic contribution to the terrestrial ecosystem functioning [7; 8; 9]. Hence, a detailed study of the relationship between SST and terrestrial photosynthesis should be conducted to understand the vegetation response to ocean variability [10]. Solar-induced chlorophyll fluorescence (SIF) is an innovative measure of photosynthetic activity that offers a physiological proxy of vegetation gross primary productivity (GPP) [11; 12]. SIF serves as a better indicator of actual plant photosynthesis because of its direct mechanistic connection to the internal photosynthetic systems rather than an indicator of vegetation greenness as in traditionally used vegetation indices (VIs) [13; 14; 15]. SIF captures variations in vegetation's photosynthetic activity and thus reflects the plant's physiological state in real-time rather than waiting for its visible changes to come [16]. SIF retrievals trace the response of vegetation functioning to dynamic environments and help to understand, quantify and predict the corresponding anomalies in vegetation [17]. This radiation flux re-emitted by plants from chlorophyll molecules excited during photosynthesis in the red and far-red bands of the electromagnetic spectrum (650-850 nm) with peaks at 685 nm and 740 nm is a small portion of absorbed photosynthetically active radiation, which requires sensitive instruments of sub-nanometer spectral resolution and high signal-to-noise ratio to capture [18]. SIF goes one step ahead of the reflectance-based VIs as a surrogate measure of GPP [19] as it responds rapidly to changes in environmental factors, especially to stress [20]. Remote sensing of SIF from space using atmospheric spectrometers greatly improved tracking vegetation photosynthesis at various spatial and temporal scales [21]. It thus became widely useful in agricultural and forestry fields, such as drought/stress detection, phenology monitoring and crop yield/productivity estimations [22; 23; 24]. SSTs act as a significant external control of land climate [25], consequently regulating the spatio-temporal distribution of climate variables that directly affect the vegetation's photosynthetic activity through physiological processes [26]. The West Pacific Warm Pool exerts a robust but variable influence on net ecosystem productivity in both the northern (positive correlation) and southern (negative correlation) hemispheres through modification of precipitation and land surface temperature [27]. Coupled CCM3-IBIS model demonstrated correlations of vegetation net primary productivity (NPP) across South America with SST of the surrounding oceans and simulated changes in the NPP under the IPCC A2 warming scenario for the first half of the 21 st century [28].