Trends and Step Changes in U.S. Streamflow Data
Abstract
The study presented here focuses on the changes/trends in U.S. streamflow from 639 unimpaired stations for the period 1951 - 2002. This is particularly relevant since the issue of climate change is of interest to many and studies have also indicated an abrupt change in climate around the year 1976/77. Trends in U.S. streamflow were evaluated using three statistical tests: Spearman's Rho, Mann-Kendall, and Linear Regression. Step changes in the streamflow data were evaluated using the Rank Sum and Student t test. The multiple tests provide robust results in which areas of the U.S. have experienced significant changes in streamflow data. Different quantities of streamflow were evaluated including seasonal and annual data, and changes in the timing of peak runoff. In addition, the changes in droughts and floods were evaluated based on the number of stations experiencing conditions < 25th percentile or > 75th percentile in any given year. Results indicate that the Upper Mississippi River basin has an increasing trend in streamflow quantity. For the Pacific Northwest and some stations in Florida, the streamflow quantity is decreasing.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFM.H21A1324P
- Keywords:
-
- 1807 Climate impacts;
- 1860 Streamflow