====== Precipitation correction ======

Rain gauges cause turbulence that tends to reduce the amount of precipitation collected. Therefore station data need to be corrected. Deficiencies of 10 % or rain and up to 50 % of snow can occur. The correction factor $K$ accounts for these losses.

==== Unshielded gage ====

$K_{usg} = 100*exp^{(-4.605+0.062*v_a^{0.58})}$

where

$v_a$ = wind speed in [m/s]

At zero wind speed the effect is negligible and can amount to about 80% at high speeds. For snow the effect is much stronger. The estimation equation reads:

$K_{usgs} = 100*exp^{(-4.606+0.157*v_a^{1.28})}$