Abstract
This paper presents a multiple linear regression model developed for
describing global river export of sediments (suspended solids, TSS) to
coastal seas, and approaches for estimating organic carbon, nitrogen,
and phosphorous transported as particulate matter (POC, PN, and PP)
associated with sediments. The model, with river-basin spatial scale and
a 1-year temporal scale, is based on five factors with a significant
influence on TSS yields (the extent of marginal grassland and wetland
rice, Fournier precipitation, Fournier slope, and lithology), and
accounts for sediment trapping in reservoirs. The model generates
predictions within a factor of 4 for 80% of the 124 rivers in the data
set. It is a robust model which was cross-validated by using training
and validation sets of data, and validated against independent data. In
addition, Monte Carlo simulations were used to deal with uncertainties
in the model coefficients for the five model factors. The global river
export of TSS calculated thus is 19 Pg yr-1 with a 95%
confidence interval of 11-27 Pg yr-1 when accounting for
sediment trapping in regulated rivers. Associated POC, PN, and PP export
is 197 Tg yr-1 (as C), 30 Tg yr-1 (N), and 9 Tg
yr-1 (P), respectively. The global sediment trapping included
in these estimates is 13%. Most particulate nutrients are transported by
rivers to the Pacific (˜37% of global particulate nutrient
export), Atlantic (28-29%), and Indian (˜20%) oceans, and the
major source regions are Asia (˜50% of global particulate nutrient
export), South America (˜20%), and Africa (12%).
Original language | English |
---|---|
Article number | GB4S05 |
Number of pages | 17 |
Journal | Global Biogeochemical Cycles |
Volume | 19 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Dec 2005 |
Keywords
- Atmospheric Composition and Structure: Geochemical cycles (1030)
- Biogeosciences: Modeling
- Biogeosciences: Nutrients and nutrient cycling (4845
- 4850)
- Global Change: Earth system modeling (1225)
- carbon
- coastal ocean
- nitrogen
- particulate
- phosphorous
- river basin
- river export
- sediment
- suspended solids