Global River Flow Regimes and Implications on River CO2 Emission Dynamics
Abstract
Flow regime depicts temporal variability (timing, magnitude, duration, frequency and rate of change) of river flows and is a key factor shaping the physical habitats and ecological processes in streams and rivers. Flow regime varies across space in accordance with river size and geographic variation in climate, geology, topography and land uses. In an ongoing effort aimed at improving the estimate of CO2 emission from global streams and rivers, we classified and regionalized global river flow regimes using global monthly mean discharge of ~3 million flowlines derived from a global, 35-year daily discharge model. The global river flow regime regionalization, combined with basin wetness conditions, provides a new framework for spatial organization of the global drainage basins. From these flow regimes we can estimate monthly variability of river surface area, gas transfer velocity and CO2 concentration, the key three pillars in surface water CO2 evasion estimates. While wetness conditions dictate basin drainage density (or total stream length), flow regime controls expansion/contraction of the river network (and therefore variability of the total surface area on a monthly basis) and variability of gas transfer velocity on a monthly scale within the same flow regime classification. The global river flow regime classification further differentiates timing (month in a year) of river flows and provides a framework for exploring interactions between river flows and key biogeochemical processes/factors controlling CO2 production and transfers to streams and rivers. For example, the global river flow regime framework differentiates areas dominated by winter versus summer flows, and flows associated with regional growing seasons (spring) and/or snowmelts. This has the potential for facilitating a better understanding of how related biogeochemical processes/factors (e.g., temperature, vegetation productivity and snowmelt events) interact with hydrology to control CO2 concentration and gas emission from streams and rivers.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B13L2466L
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0469 Nitrogen cycling;
- BIOGEOSCIENCES;
- 0490 Trace gases;
- BIOGEOSCIENCES