Comparison of HIRLAM data with Sodankylä soundings – tools and results Evgeny Atlaskin Russina State Hydrometeorological University Saint-Petersburg

HIRLAM data  Vertical scale is determined by parameters A and B that are given for additional model levels  P k±1/2 = A k±1/2 + B k±1/2 P s  and for main model levels  P k = A k + B k P s

Sounding data  12 hour measurements at different heights: -temperature -relative humidity -wind speed -some synoptic masurements  Vertical scale is not fixed, i.e. there are no constant levels

Comparison of temperature and dew point temperature  Sounding data are calculated at the HIRLAM model levels determined by the same expression as for HIRLAM  P k±1/2 = A k±1/2 + B k±1/2 P s_obs P s_obs is an observational surface pressure  Linear interpolation of (dew point) temperature with respect to logarithmic pressure is applied for those levels

Determination of sounding temperatures at main model levels  Method of trapezes is applied - case when one or more sounding points are inside a model layer

- case of absence of souding points within the model layer

Ground based comparisons  Mast data available for comparison: Temperature Radiation fluxes Sensible heat flux Latent heatflux Momentum flux

Conclusions  Tools for comparisons of HIRLAM data with soundings are prepared and are available to use in boundary layer  Temperature time series at Sodankylä mast (surface 3m, 32m) could be plotted for comparison with HIRLAM T2m  Flux measurements are also prepared in appropriate format for further usage