This repository has data for the estimation of dissolved organic carbon and colored dissolved organic carbon in the 6 Great Arctic Rivers. The data has been derived from the arcticgreatrivers.org repository for use in the USGS LOADEST model https://water.usgs.gov/software/loadest/ to predict river mass load as a function of measured discharge. The *_discharge.dat files contain the river discharge data from arcticgreatrivers.org and each *.tar directory with the river's name contain the output file from the LOADEST model with 100 model runs each for each parameter defined below. The netcdf file ArcticRivers_CarbonTrends.nc contains all of the LOADEST model prediction ensembles and mean/total seasonal values used in the trend analysis. DOC=Dissolved organic carbon (mg/L) CDOC=Colored dissolved organic carbon (mg/L) S1=CDOM absorption spectral slope between 275-295 nm (1/nm) S2=CDOM absorption spectral slope between 350-400 nm (1/nm) a300 = CDOM absorption at 300 nm (1/m) There is also a file River_CDOM_PUB.mat that is a MATLAB data structure with the data used to construct the LOADEST model input files. Dr. J. Blake Clark should be contacted at bclark@umbc.edu with any specific questions.