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Monthly pCO2, gas transfer velocity and CO2 efflux rate in global streams and rivers (the GRADES river networks)

Citation

Liu, Shaoda (2021), Monthly pCO2, gas transfer velocity and CO2 efflux rate in global streams and rivers (the GRADES river networks), Dryad, Dataset, https://doi.org/10.5061/dryad.d7wm37pz9

Abstract

The datasets contain monthly partial pressure of dissolved CO2 (pCO2, µatm), gas transfer velocity (k, m d-1), and CO2 efflux rate (g C m-2 d-1) estimates for global streams and rivers in both comma separated values (csv) and GeoTIFF formats. These datasets served as the base for monthly CO2 emission estimates for global streams and rivers and can be used to support regional terrestrial carbon balances. Original vector-version of products is based on the Global Reach–level A priori Discharge Estimates for SWOT or GRADES river networks, which have ~ 3 million individual reaches of global streams and rivers. The GeoTIFF version has a spatial resolution of approximately 0.0083º (1 km). The datasets also contain direct CO2 measurements compiled from the literature (Supplementary Data 1).

Usage Notes

TheGlobal Reach–level A priori Discharge Estimates for SWOT or GRADES river networks and associated river-reach slope and length estimates can be found at http://hydrology.princeton.edu/data/mpan/MERIT_Basins/. The GRADES daily discharge estimates can be found at http://hydrology.princeton.edu/data/mpan/GRADES/. Monthly river widths can be estimated utilizing the GRADES annual and monthly mean discharge, and downstream and at-a-station hydraulic geometry developed for each of the wetness conditions. Length, width and surface area are aggregaged to 78 cross-region basins based on hydrology and flow regime for stream order extrapolation (to an end width of 0.3 m). Total surface area of a basin is the sum of the surface area represented by the GRADES river networks and the extrapolated area. Both the GRADES and the extrapolated surface areas are corrected for loss due to temporal drying up and ice coverages.

CO2 flux is the product of dissolved CO2 concentration (converted from pCO2 according to Henry's Law), gas transfer velocity (k) and stream/river surface area. CO2 flux can be calculated for each river reach of the GRADES river networks and each stream order for the extrapolated area. Total CO2 emission from streams and rivers in a basin is the sum of CO2 emission from the GRADES river reaches and extrapolated river surface area, taking into account both losses from both ephemeral streams and ice covered periods. Relevant codes are available at https:///github.com/lsdeel/globalRiverCO2emission.

Funding

National Aeronautics and Space Administration, Award: NNX17AI74G