Supplement of Hydrol. Earth Syst. Sci., 23, 2841–2862, 2019 https://doi.org/10.5194/hess-23-2841-2019-supplement © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Supplement of Multi-decadal hydrologic change and variability in the Amazon River basin: understanding terrestrial water storage variations and drought characteristics Suyog Chaudhari et al. Correspondence to: Yadu Pokhrel (
[email protected]) The copyright of individual parts of the supplement might differ from the CC BY 4.0 License.
1 LHF Model and Setup Figure S1 – Stores and fluxes included in LEAF-Hydro-Flood (LHF) model along with its overall structure and inputs. This flowchart is modified after Miguez-Macho and Fan, (2012).
2 Validation of Simulated streamflow with Observations Figure S2 show the locations of the streamflow gauge stations for which the data was acquired from Agência Nacional de Águas (ANA) in Brazil (http:// hidroweb.ana.gov.br). Selection of stations are made with respect to the length of the data available, with minimum data gaps, and their location in the basin. Figure S3 compares the simulated streamflow with observed streamflow acquired from ANA at 12 main stations in the Amazon 5 River basin (locations are indicated in Figure S2). Seasonal dynamics for both simulated and observed streamflow for each streamflow station are also shown in the right panel of each subplot. Trend and the comparison statistics are indicated in each subplot. Note that the y-axis values are expressed exponentially. Figure S4 compares the observed and simulated streamflow with climatology removed at 12 main streamflow stations. Shaded areas indicate the seasonal minimums and maximums for both observed and simulated streamflow values. The model 10 successfully captures the transitions from the climatological mean compared to observed transitions. Maximum and minimum monthly variations are also well apprehended by the model. Although the model operates adeptly in varying geographical regions, the uncertainties carried from the forcing input are evident from the comparison with observed values. Given that none of the model parameters are calibrated or altered, it can be concluded that the interannual and climatological biases found in the model results are directly carried over from the forcing input (see section 3.2). 15
3 Figure S2 – Spatial distribution of simulated streamflow from LHF at the original ~2 km model grids. Markers indicate the locations of the stream gauge stations we use to validate the simulated streamflow from LHF. Highlighted and indexed markers are the gauge stations for which a timeseries comparisons are shown in Supplementary Figure S2. Red line shows the extend of Amazon River basin including the Tocantins region. 5
4 Figure S3 – Comparison of observed streamflow (black) obtained from ANA Brazil and simulated streamflow (red) from LHF at 12 main gauge stations. Seasonal cycle for each station is also shown in the right panel of each subplot. The locations of the streamflow gauge stations are indicated in Figure S1. 5
5 Figure S4 – Comparison of observed streamflow (black) and simulated streamflow (red) with climatology removed at 12 main gauge stations along with the mean seasonal cycle. The shaded area represents the seasonal minimum and maximum observed (black) and simulated (red) streamflow. 5
6 Trends in Forcing Precipitation and Temperature Figure S5 displays temporal trends in the input precipitation and temperature from WFDEI dataset, we use to drive the LHF model. Grids with significant trend at 99% level are highlighted with markers. Figure S5 – Temporal trend in precipitation and temperature obtained from WFDEI forcing dataset for the simulation period (i.e. 5 1980-2015). Markers indicate significant trends at 99% level.
7 Comparison of Simulated TWS anomalies with GRACE Figure S6 presents temporal trends in input precipitation form WFDEI during the GRACE period, i.e. 2002-2015. The trends are calculated for anomalies at 0.5ox 0.5o resolution. The uncertainty with decreasing precipitation trend evident over the Andes is carried over to the model results causing slight discrepancies between simulated TWS and GRACE anomalies. All the trends are expressed in cm/year. 5 Figure S7 presents the comparison of GRACE and simulated TWS anomalies with climatology removed for 2002-2015 period along with their seasonal minimums and maximums. This result contributes a crucial insight in the ongoing heated discussion regarding the mismatch between GRACE and model TWS trends (Scanlon et al., 2018; Sun et al., 2019). Note only the mean of GRACE mascon products from JPL and GFZ centres is used in this comparison. 10 Figure S6 – Temporal trend in precipitation obtained from WFDEI forcing dataset for the model-GRACE overlap period (i.e. 2002- 2015). Note that the entire model-GRACE overlap period was split in two timeframes for further analysis (see Section 4.3).
8 Figure S7 – Comparison of GRACE and simulated TWS anomalies with climatology removed for Amazon and its sub-basins. Shaded areas in the right panel of each subplot indicate the seasonal mean of GRACE (red) and TWS from LHF (black). Temporal trends in GRACE and simulated TWS anomalies are also indicated in each subplot. 5
