Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 27, 1998
Publication Date: N/A
Interpretive Summary: Management of grazing- and range-lands are dependent on weather and climate conditions. Management alternatives can be planned by considering long range climate forecasts with lead time of up to a year in advance. The benefit of these general forecasts for grazinglands management purposes can be increased by complementary precipitation characteristics at monthly and daily time scales. This study demonstrates that precipitation characteristics at monthly and daily time scales in the El Reno region have systematic differences between wet and dry years. These systematic trends could be exploited in conjunction with long lead climate forecasts to optimize grazinglands productivity through pro-active management strategies. Management examples include erosion and flood control; stocking rates and forage supply estimation; and fertilizer, plant diseases and insect pest management which are dependent on moisture and air temperature variations.
Technical Abstract: General precipitation anomalies and trends can be forecasted with some accuracy up to a year in advance. The benefits of these general forecasts for grazinglands management can be increased by complementary precipitation characteristics at monthly and daily time scales. The existence and possible quantification of systematic trends and distinguishing characteristics in precipitation at smaller time scales between wet and dry years from past records is demonstrated in this study for central Oklahoma. Variability of monthly precipitation peaks and daily precipitation characteristics are quantified, and the annual precipitation distribution is analyzed. The increased (decreased) precipitation during wet (dry) years is shown to disproportionally impact the summer and fall months. Precipitation amount on rainy days appear to be the main cause for this summer-fall trend, whereas changes in number of rainy days do not show any particular seasonal trend. The relevance of precipitation characteristics and differences between wet (dry) years and the complementary use of this information with long lead forecasts is exemplified for a few grazinglands management situations.