All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 236 49 9
PDF Downloads 102 64 3

Atmospheric Water Vapor Transport in NCEP–NCAR Reanalyses: Comparison with River Discharge in the Central United States

William J. Gutowski Jr.
Search for other papers by William J. Gutowski Jr. in
Current site
Google Scholar
PubMed
Close
,
Yibin Chen
Search for other papers by Yibin Chen in
Current site
Google Scholar
PubMed
Close
, and
Zekai Ötles
Search for other papers by Zekai Ötles in
Current site
Google Scholar
PubMed
Close
Full access

The authors extract the water transport produced by the National Centers for Environmental Prediction reanalysis for a 10-yr period, 1984–93, and compare its convergence into two river basins with an independent dataset, river discharge (streamflow). Analysis focuses on two basins in the United States, the Upper Mississippi and the Ohio–Tennessee Basins, where the relatively high density of routine upper-air observations might be expected to give the reanalysis its closest rendition of the actual water transport. Over periods of several years, water input by the atmosphere should match water output from these basins in streamflow. However, in both basins an imbalance between the two with biases with respect to streamflow approaching 40% is found. The accuracy attributed to river discharge measurements averaged over several years and the apparent lack of significant multiyear storage in the basins lead us to conclude that the bias is largely an inaccuracy in the atmospheric transport. Temporal variability of atmospheric input and streamflow output shows somewhat better correspondence, with statistically significant correlations occurring for both basins on interannual and several-day timescales. The overall behavior suggests that the temporal variability of water transport depicted by the reanalysis can be used to gain insight into the actual variability of atmospheric transport, at least for well-observed regions such as the United States.

*Iowa Agriculture and Home Economics Journal Paper No. 17131.

+Department of Agronomy, Iowa State University, Ames, Iowa.

#Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa.

Corresponding author address: Dr. William J. Gutowski Jr., Dept. of Geological and Atmospheric Sciences, Dept. of Agronomy, 3021 Agronomy, Iowa State University, Ames, IA 50011. E-mail: gutowski@iastate.edu

The authors extract the water transport produced by the National Centers for Environmental Prediction reanalysis for a 10-yr period, 1984–93, and compare its convergence into two river basins with an independent dataset, river discharge (streamflow). Analysis focuses on two basins in the United States, the Upper Mississippi and the Ohio–Tennessee Basins, where the relatively high density of routine upper-air observations might be expected to give the reanalysis its closest rendition of the actual water transport. Over periods of several years, water input by the atmosphere should match water output from these basins in streamflow. However, in both basins an imbalance between the two with biases with respect to streamflow approaching 40% is found. The accuracy attributed to river discharge measurements averaged over several years and the apparent lack of significant multiyear storage in the basins lead us to conclude that the bias is largely an inaccuracy in the atmospheric transport. Temporal variability of atmospheric input and streamflow output shows somewhat better correspondence, with statistically significant correlations occurring for both basins on interannual and several-day timescales. The overall behavior suggests that the temporal variability of water transport depicted by the reanalysis can be used to gain insight into the actual variability of atmospheric transport, at least for well-observed regions such as the United States.

*Iowa Agriculture and Home Economics Journal Paper No. 17131.

+Department of Agronomy, Iowa State University, Ames, Iowa.

#Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa.

Corresponding author address: Dr. William J. Gutowski Jr., Dept. of Geological and Atmospheric Sciences, Dept. of Agronomy, 3021 Agronomy, Iowa State University, Ames, IA 50011. E-mail: gutowski@iastate.edu
Save