Testing gridded NWS 1-day observed precipitation analysis in a daily irrigation scheduler
- 1 Southeast Agricultural Research Center, Kansas State University, Parsons, USA
- 2 USDA Agricultural Research Service, Grazinglands Research Laboratory, El Reno, USA
- 3 Biological Systems Engineering, University of Nebraska, Lincoln, USA
- 4 USDA Agricultural Research Service, Crop Production Systems Research Unit, Stoneville, USA
- 5 USDA Agricultural Research Service, New England Plant, Soil and Water Research Laboratory, University of Maine, Orono, USA
- 6 Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi, USA
Abstract
One of the inputs required by daily decision support tools for scheduling irrigation is the amount of water supplied by rainfall. In-field measurements of daily precipitation are expensive or laborious, while measurements from gauges within a few kilometers are frequently not representative due to the high spatiotemporal variability of precipitation. Online radarbased precipitation analyses from NOAA’s National Weather Service (NWS) have obvious potential to provide the needed data, but are known to have varying degrees of accuracy with location and conditions. The NWS precipitation analysis is computed on a 4 km × 4 km grid, so differences should also be expected between the product and individual gauge measurements under each grid cell. In order to test the utility of the NWS precipitation analysis in a daily irrigation scheduler, daily data were gathered in July 2012 from 18 weather stations under 2 NWS precapitation analysis grid cells across instru-mented research and production fields in the Mississippi Delta. Differences between individual station measurements and the NWS precipitation analysis are examined, and root-zone daily soil water deficits computed using both station data and the NWS precipitation analysis. Sub-grid spatial variability between gauge locations, and differences in precipitation between gauges and the gridded NWS analysis, are found to be similar to those reported elsewhere. Dif ferences between time series of soil water deficit computed using the two different precipitation data sources are noted, but prove to be of limited impact on the decision to irrigate or not to irrigate. It is also noted that profile-filling rainfalls limit the impact of accumulating error, resetting the modeled soil water to “full”. Given the Delta-local practice of irrigating to replace full evapotranspirational water used, use of the NWS daily precipitation analysis data as input for a daily irrigation scheduler is judged not only accepta ble, but also preferable to other sources of daily pre cipitation data.
- Evett, S., Carman, D. and Bucks, D. (2003) Expansion of irrigation in the mid-south United States: Water allocation and research issues. Proceedings of the 2nd International Conference on Irrigation and Drainage, Water for a Sustainable World—Limited Supplies and Expanding Demand, Phoenix, 12-15 May 2003, pp. 247-260.
- Powers, S. (2007) Agricultural water use in the Mississippi Delta. http://www.ymd.org/pdfs/wateruse/Agricultural%20Water%20Use%20Presentation.pdf
- Bennett, D. (2002) Balancing demands for water. Delta Farm Press, Clarksdale. http://deltafarmpress.com/news/farming_balancing_demands_water/index.html
- Soil and Water Conservation Society (2003) Conservation implications of climate change: Soil erosion and runoff from croplands. Soil and Water Conservation Society, Ankeny.
- National Agricultural Statistics Service (2007) Census of agriculture. http://www.nass.usda.gov
- Sassenrath, G.F., Schmidt, A.M., Schneider, J.M., Tagert, M.L., Corbitt, J.Q., van Riessen, H., Crumpton, J., Rice, B., Thornton, R., Prabhu, R., Pote, J. and Wax, C. (2013) Development of the Mississippi irrigation scheduling tool —MIST. ASABE Annual International Meeting, Kansas City, 21-23 July 2013, Paper No. 131619807
- Bronner, I. (2005) Irrigation scheduling: The water balance approach. Colorado State University Extension.
- Sassenrath, G.F., Pringle, H.C., Fisher, D.K., Samson, S., Schmidt, A.M. and Shrestha, B. (2010) Development of irrigation scheduling tools for the humid, high-rainfall environment of the Lower Mississippi Delta. 5th National Decennial Irrigation Proceedings, Phoenix, 5-8 December 2010, Paper Number: IFF10-9797.
- Sassenrath, G.F., Schneider, J.M., Schmidt, A.M. and Silva, A.M. (2012) Quality assurance of weather parameters for determining daily evapotranspiration in the humid growing environment of the Mid-South. Mississippi Academy of Science, 57, 178-192.
- Schmidt, A.M., Sassenrath, G.F., Crumpton, J., Corbitt, J.Q., Rice, B., van Riessen, H., Thornton, R., Prabhu, R., Pote, J., Wax, C. and Tagert, M.L. (2013) Development and delivery of educational tools for irrigation water management and on-farm implementation of the Mississippi Irrigation Scheduling Tool (MIST). ASABE Annual International Meeting, Kansas City, 21-23 July 2013, Paper No. 131620243.
- NOAA National Weather Service (2013) About the NWS precip analysis. http://water.weather.gov/precip/about.php