Goal: characterize the winds available around the world.
First we need to construct our grid:
The horizontal, latitude-longitude grid ranges from +70 to -70 deg in latitude and from 0 to 357.5E deg in longitude, producing a grid that has dimensions of 57 x 144 points.
In matlab, this is:
[cells/degree northern_latitude_limit western_longitude_limit]
These data were produced from the “NCEP/NCAR Reanalysis”:http://www.esrl.noaa.gov/psd/data/reanalysis/reanalysis.shtml are available at six-hour intervals, from January 1, 1948 to the present, and it is this 6-hour data that was used as the basis for this work.
Spatially, the delivered data values are given at points in a three-dimensional, global system using a 2.5 x 2.5 deg grid of latitude-longitude and altitudes that are specified by atmospheric pressure.
Above each point in this grid, horizontal wind information is delivered at 4 pressure levels: 50 mb, 70 mb, 100 mb, and 150 mb. If we assume a standard day, this corresponds to: 67,726 60,504 53,083 44,647 feet. At each grid point and pressure altitude, the horizontal wind vectors have been sorted into 12 directional bins.
Cells per degree = 2.5 Degrees per cell = 0.4
– how linear is the wind change with altitude?
– where are winds high?