An year in the life of a continent.
Sunday, December 11, 2011 1:05:37 AM
The grace satellite programme was initially designed to map out the gravity field of the planet. It came up with detailed information about the groundwater in the USA:
This isn't a picture, GRACE doesn't work like that. It is a composite of all the little aberrations in the distances between two orbiting satellites.
Don't ask me to try and explain that one, it's beyond the great Weatherlawyer to even imagine that.
The write up on EarthObservatory is to bne found here: http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=76575&src=nha
Drought in Texas reduced levels of water trapped in pores in the soil and in underground gaps in rock (aquifers) to the lowest observed in more than 63 years.
Deep reds are the most depleted, deep blues represent aquifers and soils that are nearly full. The maroon shading over eastern Texas, for example, shows that the ground has been this dry less than two percent of the time between 1948 and the present.
At the end of November 2011, groundwater supplies were extremely depleted in more than half of Texas, as well as parts of New Mexico, Louisiana, Alabama, and Georgia. The north-eastern states and the High Plains appear saturated.
“Even if we have a major rainfall event, most of the water runs off. It takes a longer period of sustained, greater-than-average precipitation to recharge aquifers significantly.”
The map is based on data from the twin satellites of the Gravity Recovery and Climate Experiment (GRACE), which detects small changes in Earth’s gravity field that are caused by the redistribution of water on and beneath the land surface.