## 2 Materials and Methods
### Satellite Data  
A summary of satellite-based datasets used in this study is shown in Table 2. We utilized two set of satellite-based SIF records. (1) The first dataset was obtained from Global Ozone Monitoring Experiment-2 onboard EUMETSAT's MetOp-A as well as MetOp-B platform (indicated as GOME-2A and GOME-2B, respectively, in this study). SIF is the retrieval of the far-red chlorophyll fluorescence peaking at 740 nm, based on a simplified radiative transfer model in the company of a principal component analysis [44]. Monthly global coverage of SIF data based on GOME-2A at 0.5\({}^{\circ}\) spatial resolution (Level 3, Version 28) from February 2007 to March 2019 was obtained from NASA Goddard Space Flight Centre (Available online: [[https://avdc.gsfc.nasa.gov/](https://avdc.gsfc.nasa.gov/)]([https://avdc.gsfc.nasa.gov/](https://avdc.gsfc.nasa.gov/)) (accessed on 10 May 2020)). Given the degradation of the GOME-2A instrument during its lifetime, SIF observed from GOME-2B was also downloaded, which spans from March 2013 to March 2019. The daily orbital data (Level 2, Version 28) was also used to aggregate 16-day interval records for higher temporal-resolution analysis. (2) We used a newly released SIF dataset based on TROPOMI onboard the Sentinel-5 Precursor satellite. A data-driven method was employed to retrieve the SIF signal using spectral measurements ranging from 743 nm to 758 nm [26]. Daily corrected ungirded TROPOMI SIF data at a 0.05\({}^{\circ}\) spatial resolution (2018-2019) was  
Figure 1: (**a**) Land cover map based on national Dynamic Land Cover Dataset. (**b**) Spatial pattern of rapidity index. (**c**) The locations of study area over Australian continent (image source: Google Earth). Black triangles refer to five flux tower sites. available at (Available online: [[ftp://fluo.gps.caltech.edu/data/tropomi/](ftp://fluo.gps.caltech.edu/data/tropomi/)]([ftp://fluo.gps.caltech.edu/data/tropomi/](ftp://fluo.gps.caltech.edu/data/tropomi/)) (accessed on 1 December 2020)). The daily orbital TROPOMI SIF were likewise aggregated to monthly and 16-day series by mean value, consistent with temporal resolution of GOME-2 SIF records. We used Moderate Resolution Imaging Spectroradiometer (MODIS on board Aqua, Collection 6) MYD13C1 (0.05\({}^{\circ}\), 16-day) and MYD13C2 (0.05\({}^{\circ}\), monthly) Vegetation Indices products from January 2007 to June 2019 downloaded from NASA Earth Observation data (Available online: [[https://search.earthdata.nasa.gov/search](https://search.earthdata.nasa.gov/search)]([https://search.earthdata.nasa.gov/search](https://search.earthdata.nasa.gov/search)) (accessed on 1 August 2020)). EVI is an optimized version of vegetation indices that effectively reduces soil background influences and is widely used as a proxy of canopy greenness [45; 46; 47]. The equation (1) of EVI is:  
\[EVI=2.5\frac{\rho_{NIR}-\rho_{red}}{\rho_{NIR}+6\rho_{red}-7.5\rho_{blue}+1} \tag{1}\]  
where \(\rho_{blue}\), \(\rho_{red}\), \(\rho_{NIR}\) are reflectance in the blue, red, and near infrared bands, respectively. To reduce noise and uncertainties, only best quality data remained in this study through removing pixels of which quality control flag of the first 2 bits neither 00 nor 01, and pixel-wise EVI time series data was smoothed using the Savitzky-Golay filter. To contrast with satellite-observed greenness and fluorescence, data-driven gross primary productivity (FluxSat_GPP, version 1.1, 2007-2019) derived primarily from MODIS reflectance product was used as the spatial reference of vegetation activity, obtained from NASA Goddard Space Flight Centre (Available online: [[https://avdc.gsfc.nasa.gov/](https://avdc.gsfc.nasa.gov/)]([https://avdc.gsfc.nasa.gov/](https://avdc.gsfc.nasa.gov/)) (accessed on 5 August 2020)). This is a monthly dataset with 0.5\({}^{\circ}\) spatial resolution, calibrated by a set of the FLUXNET 2015 eddy covariance data [48].