Modeling the Error of Estimated River Discharge in the Eurasian Pan-Arctic
Abstract
Recent work by Peterson et al. (2002) has shown increases in the river discharge to the Arctic Ocean of the six largest Eurasian Rivers to be 7% (2.0 +/- 0.7 km3/year) from 1936 to 1999. As with most measures of the natural environment this increase represents the trend of a highly variable time series containing annual, seasonal, and daily cycles. Accurate estimates of the error associated with these time and space aggregated annual series have not been well characterized. We seek here to define the expected error surrounding the time series of annual river discharge in the pan-Arctic region. Using standard hydrometric data along with information on the i) frequency and precision of measurements, ii) characteristics of river channel capacity, and iii) method of discharge computation, we develop a model of error for river discharge. We focus on the random error in the daily river discharge of the major down-stream gauges of the pan-Arctic drainage system. A simplified method to define possible errors in the average discharge data has been developed to estimate the reliability of monthly and yearly data over the long-term period of observation (up to 64 years). Results to date have shown that the accuracy of daily discharge estimates for the large Eurasian rivers is highly variable throughout any given year. Maximum errors, exceeding 40% for some rivers take place during ice and backwater conditions when the stage-discharge rating curves cannot be applied. The annual discharge over the long-term is more accurate with 3-10% error. This error range for annual data holds even for more recent periods, such as for the last 15 years, when the actual number of discharge measurements declined significantly. With this error model we have found the estimated error for river discharge in the six largest Eurasian watersheds can be reduced by up to 50% to 2.0 +/- 0.4 km3/year over the previous estimates
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2004
- Bibcode:
- 2004AGUSM.H43A..01S
- Keywords:
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- 1848 Networks;
- 1860 Runoff and streamflow;
- 1894 Instruments and techniques