Dec 4, 2013

When rainfall doesn't matter

The swamp received its first dry season rain ...

But does it matter?

This chart shows the 7-day running daily rain total from Big Cypress Nat'l Preserve from January 2013 to present (solid blue).  The dotted line shows the long-term mean 7-day rain total and the solid line the median.  The median more than the mean does a nice job of showing exactly when the wet season starts and ends (because unlike the mean it is not skewed by a few large readings).  Background coding shows the calendar duration of the wet and dry seasons.  We are officially entering our low ET season when any rain counts double thanks to the absence of water being lost to the sky.

In fact it counts double!

The reason for that is that the water cycle has now entered into -- from December through early February -- what I like to call "low evapotranspiration (ET)" season. With loss of water to the sky at a minimum (thanks to the cooler air), a little winter rain can go a long way.

Or in the lack of rain water levels only recede slowly.

That's the corollary.

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