HIRLAM AT KNMI

Toon Moene

Below you find an overview of the operational setup of HIRLAM at KNMI.

Operational compute power

SGI Origin 2000 with 8 180 Mhz R10000 processors, 512 Mbyte of main memory, 1 Mbyte of cache.

Operational HIRLAM: 0.5 x 0.5 degrees

A 48 hour forecast is made every 6 hours on the area indicated below. The analysis cycle is 3 hours. The cut-off time for observations is 2 hours.

Hirlam 2.7.15 code base.
Eulerian advection.
Kuo/cond convection/condensation scheme

Dynamics time step: 3 minutes.
Physics time step: 12 minutes.

Grid: 164 x 130 x 31. South pole at 15 W, 30 S.
Nested in 1.5 x 1.5 ECMWF boundaries, on a rotated grid oriented the same as Hirlam grid.
Resources needed:

Analysis: 150 seconds

Surface obs: 3000
Aireps: 700
Satobs: 200
Temps: 130
Pilots: 10

Forecast: 2400 seconds

The large extent of this area to the east and south is due to requests from the Dutch public television, who wanted to show the whole Mediterranean area with their weather presentations.

High resolution HIRLAM: 0.1 x 0.1 degrees

A 12 hour forecast is made every 3 hours on the area indicated below. The analysis cycle is 3 hours. The cut-off time for observations is 1 hour. This run is pre-operational, in the sense that the output isn't used for any operational purposes, but weather maps and meteograms are available (via KNMI's intranet) for the duty meteorologist (and others).

Hirlam 4.3.4 code base.
Semi-Lagrangian advection.
Straco convection/condensation scheme

Dynamics time step: 3 minutes.
Physics time step: 3 minutes.

Grid: 164 x 150 x 40. South pole at 0 W, 35 S.
Nested in 0.5 x 0.5 operational HIRLAM boundaries.
Resources needed:

Analysis: 450 seconds

Surface obs: 1000
Aireps: 400
Satobs: <10
Temps: 25
Pilots: <3

Forecast: 2500 seconds

However, at a time step of 3 minutes for a 0.1 degree resolution, there is clearly a problem with vertical diffusion, as exemplified by the wind speed and direction "spikes" in this meteogram.

Some verification results

Here are some verification scores for the period 23rd of February till 14th of March 1999 for the operational run, a pre-operational run of HIRLAM 4.3.4 and the pre-operational 0.1x0.1 run.