NASA / E&O Project Meeting

April 23, 2013George Cooper

What I’ve Been Working On Lately

• Vectorized algorithms for faster computation• Working out a bug in the script, but the first

layers should be done once I’ve fixed it• Researching potentially useful indices of

extreme events/climate to deliver

DeriveIt Script

• Spans time-series layers and produces summary layers of:– Cumulative biovariables: Degree days, frost-free

days, evapotranspiration– Extreme events: Longest period of

rainfall/temperature over a threshold, severity of the longest dry season, most extreme temperatures

Moving Forward

• Once I have produced the layers, I want to:– Validate estimated features– Add more equations for extreme value calculation– Incorporate remote sensing information on cloud

cover and vapor pressure to correct evapotranspiration / degree-days as needed

Layer Validation

• Is there any data available that I can compare to assess the error in estimated features like degree-days or evapotranspiration?

• The strategy is to produce layers with the most biologically relevant thresholds (extremes given year-to-year variation, freezing temps, developmental temps) but are there any other categories of events to look at?

Extreme Value Modeling

• In addition to reporting extreme events themselves, would it be valuable to add functionality to compute statistical measures for extreme values:– If so, which methods might be most deliverable?• GEV distributional parameters• Poisson process parameters of sufficiently rare and

large events?