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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #343072

Research Project: Precipitation and Irrigation Management to Optimize Profits from Crop Production

Location: Soil and Water Management Research

Title: Exceedance probability of the standardized precipitation-evapotranspiration index in the Texas High Plains

item Moorhead, Jerry
item Marek, Gary
item Gowda, Prasanna
item MAREK, THOMAS - Texas Agrilife Research
item PORTER, DANA - Texas Agrilife Research
item SINGH, VIJAY - Texas A&M University
item Brauer, David

Submitted to: Agricultural Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2017
Publication Date: 8/18/2017
Citation: Moorhead, J.E., Marek, G.W., Gowda, P., Marek, T.H., Porter, D.O., Singh, V.P., Brauer, D.K. 2017. Exceedance probability of the standardized precipitation-evapotranspiration index in the Texas High Plains. Agricultural Sciences. 8(8):783-800. doi:10.4236/as.2017.88058.

Interpretive Summary: Drought conditions are common in areas such as the Texas High Plains and can cause large losses in the agricultural industry. To try to prepare and minimize drought impacts, it is beneficial to understand how likely certain levels of drought can be. Drought likelihood can also be used for water planning and assessing different future scenarios. Scientists from ARS (Bushland, Texas)El Reno, OK and Texas A&M AgriLife Research and Extension Service) calculated the likelihood of drought conditions throughout the Texas High Plains, based on the exceedance probability of the Standardized Precipitation-Evapotranspiration Index, and found that drought conditions are very likely throughout the summer months. Maps were created for the exceedance probabilities and they showed a trend where drought conditions decreased from West to East, possible in response to rainfall increasing from West to East. These data can provide useful information for managing water in this region.

Technical Abstract: Drought is a common occurrence in many arid and semi-arid regions that can have large negative impacts on water resources and agricultural production. Since agricultural drought is affected by both water supply and demand (precipitation and evapotranspiration), it is beneficial to include both in agricultural drought monitoring. The Standardized Precipitation-Evapotranspiration Index (SPEI) was found to be a suitable drought index for monitoring agricultural drought. In this study, the SPEI calculated from agro-meteorological weather stations was used to determine exceedance probabilities at five levels in the Texas High Plains. In addition, the kriging method was used to interpolate between the stations to generate spatial maps for the exceedance probabilities. No significant differences were found between stations, indicating any station should be suitable to represent the Texas High Plains. Results showed drought conditions occurred at all five probability levels during the summer growing season for this region. The interpolated maps showed a trend where minor differences in the SPEI values were associated with the West-East precipitation gradient. However, there was no trend associated with the North-South air temperature gradient. A risk analysis showed that the SPEI probability values can provide policy and decision makers with additional information for better water management in the Texas High Plains.