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Thursday, December 23, 2010

Final Deluge of 2010

Just before we trundle off for the holiday season, it is worth noting that the Los Angeles area has just suffered unprecedented rainfall in the past couple of days. More than 20 inches of precipitation (No, that is not a typo!) in the mountains surrounding the LA basin, while more than 6 inches (half the "normal" annual rainfall) fell in the basin itself. The media are broadcasting hourly reports of houses slumping into ravines, sinkholes opening in the streets, and flash-flood channels filled with water, debris and automobiles. In summary, the last few years have shown record precipitation events of a severity unknown in modern times, WORLDWIDE.

We also note that the surface temperature of the waters of the Gulf of Mexico are over one degree Fahrenheit higher than average sea surface temperatures (SST) just a few decades ago. For every 1-degree rise in SST, moisture content of the overlying atmosphere goes up 7-8 percent. This translates into a 4-5 percent increase in subsequent precipitation. Doesn't seem like much, does it? Until you consider that precipitation on the land doesn't come down uniformly across the year, but has to be wedged into the time available in each of the seasons described here in our previous post (that ecliptic thingy).

In a nutshell, global warming increases global precipitation, and the amplitude (severity) of meteorological events such as rainfall, windstorms, tornadoes and other gradient-reducing phenomena. Will this affect our runoff patterns in trout country? Could it not?  Go Figure!

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