Recent FEWS NET research

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Recent FEWS NET research

• Cropped Area
• Improved Rainfall Estimates
• Climate Change Analyses

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TM to Hi-Res Comparison
High Resolution imagery used to classify dots
spaced at 500m intervals, and represent truth
Field photos provided by USDA give a ground-view
of landscape
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Quickbird with classification
TM with classification
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Mathematical Comparison

• TM tends to systematically overestimate cropped
  area
• Assessing the relationship between TM cropped
  area and true cropped area reveals an
  approximately linear relationship
• R2 0.62
• For our tested locations cropped area is 20.1
  /- 1.9

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Improved RFE Estimates (IRE)
ARC Means Slope Elevation Climate Normals
Enhanced Monthly Mean Fields
regression
RFE s
Multiplication
Unbiased Rainfall Estimates
IDW
Improved Rainfall Estimates (IRE)
Station Data
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Mean Fields Comparison

• R0.8 at 0.1
• Bias0.01 mm

N73 n19
MAM
Much better mean fields than the CHARM
Driven by GPCP
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Western Kenya Temporal Error Validation
Monthly March, April and May Observations

Driven by GPCP
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SPI Regression Maps

• Compare 1979-2005 IRE SPI values
• 2 predictors
• Southwest Indian Ocean Precip
• Indian Ocean Dipole

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850 MAM winds
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Concerning Trends