The data this page describes are here.
Each data file consists of the output over each of the three Cloudnet sites for one run of the model. The model is run every six hours, so there are four files per day, and each run produces forecasts every three hours from T+0 to T+48. In addition to the variables at the nearest gridpoint to each site, the variables from the eight nearest gridpoints are also reported, in the form of a 3×3 grid. The filenames are of the form cloudnet.YYYYMMDDHH, where YYYYMMDD is the date and HH is the forecast time. They are zipped up into monthly archives with names of the form HIRLAM_YYYYMM.zip.
The format is summarized here (this makes sense on examination of an actual data file):
HIRLAM [analysis time of forecast]
-------------
| 1 | 2 | 3 | Layout
------------- of
| 4 | 5 | 6 |
------------- the
| 7 | 8 | 9 | area
-------------
For forecast period 00 03 06 09 12 15 18 21 24 27 30 33 36 39 42 45
Forecast [forecast period]
CHIBOLTON [latitude longitude]
single level data
6 105 0 Geopotential of the surface m2/s2
83 105 0 Roughness length of surface m
1 105 0 Pressure at surface Pa
1 103 0 Pressure at mean sea level Pa
11 105 0 Skin temperature of surface K
11 105 2 2 meter temperature K
31 105 10 Wind direction at 10 meter degree w.r.t. true N
32 105 10 Wind speed at 10 meter m/s
51 105 2 Specific humidity at 2 meter g/g
17 105 2 Dew point temperature at 2 m K
62 105 0 Large scale precipitation kg/m2
63 105 0 Convective precipitation kg/m2
71 105 0 Cloud cover 0 .. 1
multilevel data
For level 31 .. 1
11 Pressure Pa temperature K
For level 31 .. 1
31 Pressure Pa wind direction degree w.r.t. true N
For level 31 .. 1
32 Pressure Pa wind speed m/s
For level 31 .. 1
39 Pressure Pa vertical velocity Pa/s
For level 31 .. 1
51 Pressure Pa specific humidity g/g
For level 31 .. 1
76 Pressure Pa cloud water g/g
PALAISEAU [latitude longitude]
[idem]
CABAUW [latitude longitude]
[idem]
The 9-squre indicates the correspondence between column number and
sub-area; column 5 always corresponds with the subarea in which the
given lat/lon coordinates fall.
The multilevel data need a pressure coordinate, because the height of
the coordinate surface varies with ground level (so called eta
coordinates).
Note also: