Correlation for Flow Forecasts

Here you can compare the forecast correlation for the headwater point, Williamsburg, and the downstream point, Newport. Remember that the blue plots show just the behavior with respect to correlation of the top 20% of flows. Remember that we want positive correlation, with 1.00 being a perfect correlation between forecasts and observations.

Correlation Coefficient (CC) of Ensemble Mean Forecast Per Lead Time Interval for a Headwater and a Downstream Point in the Juniata River Basin

Question

What can you say about the top 20% of flows at these locations? (Choose all that apply.)

The correct answers are a and b.

Both the headwater and downstream points show decreasing correlation with lead time between the forecasts and observation. This occurs more rapidly with the headwater point from 0 through 84 hours, and especially in the 48-84 hour period. The correlation at all lead times is worse for the headwater point.