Tuesday, April 07, 2015

1938 atmospheric river that caused the Los Angeles flood of 1938

At least one person asked why I used a reanalysis that does not assimilate satellite water vapor data to study an atmospheric river (AR) event.

That's a good question because the NOAA/CIRES Twentieth Century Global Reanalysis Version 2c (20thCR V2c) only ingests three things: surface pressure, sea ice coverage and sea surface temperature. The rest of the analysis is generated by the physical models of NOAA's Global Forecast System (GFS).

The short answer is that 20thCR V2c extends all the way back to 1851, which means you can compare storm intensity between storms, including events that occurred before the modern satellite era.

E.g. how does the AR event of 2004-2005 compare with one responsible for the Los Angeles flood of 1938, that felled thousands of buildings?  Let's take a look.
Global animation of PWV from 20thCR V2c for 1938-02-27-00 UTC through 1938-03-03-18 UTC.
Click here to read the rest.

I am happy to announce the NCAR Research Data Archive Blog.  My fellow data whisperers and I will blog about weather and climate data analysis. This is part of my omnimedia strategy, which will include YouTube tutorial videos for performing your own data mashups. Stop by and visit!

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