SUMMARY
In this report ion on the probabi ty of (extreme) dry or wet pe
Netherlands Meteorological
in the @ The Royal
t i tute often d
for this information, because it is needed for the solution of
several hydrological and to
vater management and vater supply.
It is cult to an objec parameter for
In this report the indication of is called " or "we
we chosen RR, open water evaporation E and
o
the potential ipitation RR-E po t' where E pot is the pot,nt
distributions for
these three frequency
ods in the ng-season
- 1 six selected stations.
These have been pre d from time series of years (1
1-1975)
of mon amounts of RR, the main station De Bilt 1 cessed ..The evapotranspiration
.. Moreover, for $) have been
pro-has been estimated w,ith the method of Penman (1948): f"E o ' where
is computed 'cal cula t ions
f is a crop- and constant, and
with the well-known (1948).
of E t and thus of the
po prec tat ion surplus RR-E pot
are carried out only for grass with a height of 10 em. Ex-perience shows that then under the climatological conditions in the Netherlands f about
0,8
in the growing-season.In Chapter 2 the theoretical of the quanti
E and
pot is zed that the
on method used for the deter on of E is rather pot
crude. However, it has the E pot can be
estimated from mete ons only, and
of these An publ
records are lable can be d ..
earlier by the KNMI in its mon and by (1 ). On dete
remarks have to be made:
*) In fact these are not exac
10 a month, the second the month. The period days"
of used here was weather reviews
two important
odst but the first
, and the remainder of 8, 9 t 10 or 11
