frost forecasting for lettuce fields in yuma, arizona
DESCRIPTION
Frost Forecasting for Lettuce Fields in Yuma, Arizona. Nick Dawson Soil, Water, and Environmental Sciences Department Advisor: Dr. Paul Brown. Outline. Background Model description Test cases Experimental m odel Results Future work. Why Do We Care?. > 90% winter production - PowerPoint PPT PresentationTRANSCRIPT
Frost Forecasting for Lettuce Fields in Yuma, Arizona
Nick DawsonSoil, Water, and Environmental Sciences DepartmentAdvisor: Dr. Paul Brown
Outline
Background Model description Test cases Experimental model Results Future work
Why Do We Care?
> 90% winter production 450 million dollars Consumer prices
1000% price hike
Weather Research and Forecasting Model
WRF 1.8 km resolution 27 hour forecasts
5am – 8am Winter 2010/11
~4 C too warm
Resolution Comparison
Case Study Days for Trials
5 case study days Above freezing/humid Above/dry Below/humid Below/dry Cold advective
5 weather station sites
Default Land Use Classification
Urban (Yuma)
Forest
Crop Fields
Default
Revised
Trial Setup
Trial #
Adjustment
1LAI min= 1.56; LAI max = 5.68 min = 0.01; max = 0.1
2
Input file soil changes: Sand changed to loamy sand, sandy loam to clay loam. Table file changes: minimum SMC = 0.36
3Trial 2 + Top two soil layers SMC = 0.36 for all crop/pasture land, VF = 85% (all changes made to input files)
4 Trial 2 + VF = 85% (input file changes)
Input Files Look-up Tables VF = vegetation fraction SMC = soil moisture content
Trial ResultsTrial Change
1 Table
2 Soil Change
3SMC = 0.36
and VF = 80%
4 VF = 80%
Experimental Model 60% VF 0.32 SMC Updated Land Use
Results
Coldest 15-minute Temperature Scatter Plots
1 December 2011 – 15 January 2012
Statistic Control Model Experimental ModelRMSE 2.95 1.79MAE 2.51 2.35Bias 2.39 -0.42
Results in Action 7am temperatures GFS and NAM 51 hr forecast movie
http://ag.arizona.edu/azmet/LIF.htm
Future Work
Post forecast products Bi-weekly VF updates Lettuce leaf temperature forecast
Review
Big/important business Identified model issues Improved ~ 3 degrees Celsius
Frost Forecasting for Lettuce Fields In Yuma, Arizona Questions? Selected references:
Deardorff, J. W., 1978. Efficient Prediction of Ground Surface Temperature and Moisture, With Inclusion of a Layer of Vegetation. J. Geo Research, 83, 1889-1903.
Ek, M. B., K. E. Mitchell, Y. Lin, E. Rogers, P. Grunmann, V. Koren, G. Gayno, and J. D. Tarpley, 2003. Implementation of Noah land surface model advances in the National centers for Environmental Prediction operational mesoscale Eta model. J. Geophys. Res., 108, 22 PP, doi:10.1029/2002JD003296.
Hogue, T.S., L. Bastidas, H Gupta, S. Sorooshian, K. Mitchell, W. Emmerich, 2005. Evaluation and Transferability of the Noah Land Surface Mode in Semiarid Environments. J. Hydrometeor, 6, 68-84.
Prabhakaran, T., G. Hoogenboom, S. G. Gopalakrishnan, 2008. Evaluation of WRF for frost warning and consequences of cold air pooling. J. Compute. Electron. Agric., 64, 234-347.
Wilks, D. S., 2006. Statistical methods in the atmospheric sciences. Burlington, MA [etc.]: Academic Press.