Modeling global scale Sediment Flux, a new component in the spa8ally distributed Framework for Aqua8c Modeling of Earth System (FrAMES) Sagy Cohen, Albert J. Ke4ner and James P.M. Syvitski Community Surface Dynamics Modeling System (CSDMS), InsDtute of ArcDc and Alpine Research (INSTAAR), University of Colorado, Boulder, USA Sagy.Cohen@Colorado.edu Introduc8on The Framework for AquaDc Modeling of Earth System (FrAMES) is a spaDally and temporally explicit mulD‐scale (local through global) hydrological/biogeochemical modeling scheme (Wollheim et al., 2008). FrAMES is an ongoing interdisciplinary project, modeling varying aspects of river flux response to changing environmental condiDons. Here we present a new component within this framework, a spaDally explicit sediment flux model. Methodology We expend the BQART sediment flux model from point (river outlet) to distributed (pixel) scale by integraDng it into the WBM plus conDnental hydrology model (an integral part of the FrAMES scheme). The BQART model An analyDcal model describing the empirical relaDonship between basin geomorphology, climatology, geology, human characterisDcs and long‐ term sediment flux (Syvitski and Milliman, 2007; Fig. 1): (Eq. 1) where 0.02 [‐] long‐term Average Suspended Sediment load [kg/s] long‐term Average Discharge [m 3 /s] contribuDng Area [km 2 ] maximum Relief [km] .. long‐term average Temperature [ 0 C] (Eq. 2) I = 1+0.09A g (Ag is percentage of Ice Cover) L– Lithology Factor T E –Sediment Trapping by reservoirs E h –Anthropogenic Factor: f(Pop. density, GNP) Daily suspended Sediment load (Q s ) is predicted with the Psi model (Morehead et al., 2003; Fig. 1): (Eq. 3) where Q ‐ Daily Discharge [m 3 /s] C – yearly random variable with mean (C m ) and StdDev deviation (s): (Eq. 4) (Eq. 5) Q s = wBQ 0.31 A 0.5 RT w − Q s − Q − A − R − T − B = IL (1 − T E ) E h Q s = ψ Q s Q Q       C σ (ψ ) = 0.763(0.99995) Q C m = 1.4 − (0.025T ) + (0.00013R ) + 0.145ln(Q s ) s = 0.17 + (0.0000183Q) The BQART/WBM model WBM plus is a spaDally explicit model describing varying components of the global hydrological cycle (Wisser et al., 2010). BQART was integrated as a new component in the WBM plus pladorm to allow spaDally explicit calculaDons of sediment flux at a global scale (the BQART/WBM model). As BQART is a basin‐outlet model, BQART/WBM consider each pixel as a local outlet of its upstream contribuDng area. The BQART/WBM model has two phases. The first phase generate the long‐term average temperature and discharge values (illustrated in the ‘Preprocess’ frame in Fig. 1) needed for calculaDng Average long term Sediment Flux (Q s ; Eq. 1). The second phase calculate the Daily Sediment Flux (Q s ) values with the Psi model (Eq. 3). BQART/WBM make use the Daily Discharge (Q) and Reservoirs Capacity (to determine T E ; Eq. 2) modules of WBM plus (Fig. 1). B Long‐term average Discharge (Q̅) Long‐term average Temp. (T: ) ContribuDng Area (A) Max. Relief (R) Daily Temperature (T) WBM plus model Ice Cover (I) Lithology (L) Sediment Trapping (T E ) PopulaDon Density GNP Anthropogenic Factor (E h ) BQART Ψ C Psi model Q s = ψ Q s Q Q       C Q s = wBQ 0.31 A 0.5 RT B = IL(1 − T E ) E h Reservoirs Capacity Daily Discharge (Q) Input layer to the model Intermediate layer calculated by the model Long‐term average Sediment Load (Q s ) Daily Sediment Load (Q s ) Output layer Parameter connecDon with daily update Parameter connecDon which are constant in Dme Preprocess & daily updates Legend References: Syvitski, J.P.M. and Milliman, J.D., 2007, Geology, geography and humans ba4le for dominance over the delivery of sediment to the coastal ocean. J. Geology 115: 1‐19. Morehead, M.D., Syvitski, J.P.M., Hu4on, E.W.H., and Peckham, S.D. 2003. Modeling the temporal variability in the flux of sediment from ungauged river basins. Global and Planetary Change, 39, 95‐110. Wisser, D., B. M. Fekete, C. J. Vörösmarty, and A. H. Schumann (2010): ReconstrucDng 20th century global hydrography: a contribuDon to the Global Terrestrial Network‐ Hydrology (GTN‐H), Hydrology and Earth System Science, 14,1‐24. Wollheim, W.M., C.J. Vörösmarty, A.F. Bouwman, P. Green, J.A. Harrison, M. Meybeck, B.J. Peterson, S.P. Seitzinger, and J.P. Syvitski 2008. A spaDally distributed framework for aquaDc modeling of the Earth system (FrAMES). Global Biogeochemical Cycles 22, GB2026, doi:10.1029/2007GB002963. Acknowledgments This research is funded by NASA, through the Interdisciplinary Research in Earth Science Program, NNH062DA001N‐IDS Results The BQART/WBM model is sDll in development and yet to be fully validated. We present two yearly‐averaged (1976 and 2000) global‐scale sediment flux maps from a daily 49 years test‐run (1960‐2009 at 30 minute spaDal resoluDon). Some notable differences between the two maps: ‐ Higher sediment flux in Africa’s major rivers (Nile and Zaire/Congo) in 1976; ‐ Higher sediment flux in Northern Asia (Ob River) in 2000; ‐ Higher sediment flux in the Middle‐East (Tigris‐Euphrates system) in 1976; ‐ Higher sediment flux at the lower Colorado River in 1976; 1976 2000 Applica8ons and future development Distributed sediment flux predicDons are useful for a wide array of scienDfic and engineering applicaDons (e.g. carbon cycle predicDons and infrastructure design). The BQART/WBM model will soon be applied with higher spaDal resoluDon and will be used to test scenarios of future environmental changes (e.g. climate, land‐use). In the next couple of years we intend to further develop the model by adding a bedload sediment transport component and introduce more physically‐based equaDons to be4er account for the spaDo‐ temporal variability of the sediment transport processes. Figure 1. Flowchart of the sediment flux module in the BQART/WBM model.3 Figure 2. Two yearly‐averaged sediment flux (kg/s) maps (30 minutes spaRal resoluRon) from a daily Rme‐step 49 years test run of BQART/WBM. Top map is for the year 1976 and the boXom map for the year 2000.