[geeks] Global warming, was Mr Bill?

[Lionel Peterson]

   Dr. Pasken,

   You said "Even the more complex problem of forecasting on very small
   scales (300 meter resolution) is working in slightly better than real
   time."

   Could you explain what you mean by "slightly better than real time"?

   I don't doubt what you say, I can't figure out what you mean - as I
   look at it, that means that if you wanted to predict what the weather
   was going to be like in a certain neighborhood tomorrow at say 3:00 PM
   local time, it would take until almost 3:00 PM local time to figure it
   out, giving you a "prediction" of what the weather was going to be
   like, say, an hour or two before it happens?

   Again, I'm confused by the statement, not questioning it.

   Thanks,

   Lionel
   Sep 20, 2008 11:17:18 PM, geeks at sunhelp.org wrote:

     As a meteorologist specializing in numerical weather prediction
     models I
     can assure you that not only do climate models exist, but they work
     very
     well. Even the more complex problem of forecasting on very small
     scales
     (300 meter resolution) is working in slightly better than real
     time.
     Current generation microscale models are undergoing field
     verification
     tests. There are several DOE/DOD/DHS sponsored micro scale
     observing
     networks that are being used to verify the numerical forecasts from
     meso/micro scale forecast models. There are alot of reasons why
     this
     is important. Think of the problem of a gas/particulate whose
     dispersion
     and chemical composition is dependent of the temperature, humidity
     and winds.
     In this case not only do I need to worry about the meteorology, but
     the
     transport, diffusion, dispersion and deposition as well. Current
     generation meso/micro scale models can accurately predict the
     meteorology
     and dispersion/transport processes in better than real time.
     Although
     climate prediction is complex, it doesn't need to be concerned with
     things
     like turbulence around buildings which is ill-posed mathematically
     (the
     turbulence closure problem).
     Most climate models don't start with "smoothed values" rather they
     start
     with the observed conditions at specified time in the past. The
     typical
     initial conditions for a short run (75 years) of a climate model is
     January 1, 1950. The model is run forward for 50 years and then
     compared
     against conditions on January 1, 2000. Another simple alternative
     is to
     take current observed conditions and run the model backwards to a a
     point
     in the past and compare model "forecast" conditions against
     observed
     conditions.
     There are two reasons why supercomputers and now Beowulf clusters
     exist.
     One is bomb testing and the other is weather/climate prediction.
     _______________________________________________
     GEEKS: http://www.sunhelp.org/mailman/listinfo/geeks