Friday, July 8, 2011

Rain Event



As the old Arab saying goes "All sunshine makes a desert", so it is that I post a recent rain event here in our valley. We received 2.28 inches of rain Tuesday morning. This event was recorded by our Decagon Echo data logger and connected instruments. *see image.

The bar graph shows the rainfall amounts with 1.4 plus inches of rain falling between midnight and 1 am. Capacitance soil moisture sensors responded to the moisture from the rain event. First the top foot (red line) responded. Then the second foot (yellow) and even the deep soil moisture sensor (green line) at 36 inch depth increased. This field is in alfalfa and irrigated by center pivot irrigation system. Due to high water demand (ETo) and limited water supply, it is difficult to refill the soil profile this time of the year to the deep sensor. But it was accomplished by the precipitation that night. Note green line appears at about 4 am after the water had infiltrated to the depth.

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