As far as I know MeteoNorm version 5.0 still works with hourly
generated data based on measured monthly data.
A quote from the MeteoNorm v5.0 manual:
----------- BEGIN OF QUOTE -----------
What is Meteonorm?
METEONORM is a comprehensive climatological database for solar energy
applications:
- a meteorological database containing comprehensive climatological
data for solar engineering applications at every location of the globe.
- a computer program for climatological calculations.
- a data source for engineering design programs in the passive,
active and photovoltaic application of solar energy with comprehensive
data interfaces.
a standardization tool permitting developers and users of engineering
design programs access to a comprehensive, uniform data basis.
meteorological reference for environmental research, agriculture,
forestry and anyone else interested in meteorology and solar energy.
What is it based on?
METEONORM's orderly facade conceals not only numerous databases from
all parts of the world but also a large number of computational models
developed in international research programs.
METEONORM is primarily a method for the calculation of solar radiation
on arbitrarily orientated surfaces at any desired location. The method
is based on databases and algorithms coupled according to a
predetermined scheme. It commences with the user specifying a
particular location for which meteorological data are required, and
terminates with the delivery of data of the desired structure and in
the required format.
Depending on user requirements, the calculation procedure employs
between one and four computation models):
The table shows the sequence in which the computational models are
coupled in generating hourly radiation data on an arbitrarily
orientated surface at a site for which no measurements are available.
------- BEGIN TABLE ---------
Interpolation with monthly average value model Gh, Ta:
Space dependent interpolation of horizontal radiation and temperature
based on weather data taking altitude, topography, region, etc. into
account
Hourly value generator Gh, Ta:
Stochastic generation of time dependent global horizontal radiation
and temperature data having a quasi-natural distribution and an
average monthly value equal to the average value over 10 years
Radiation resolution Gh ® Dh, Bn:
Resolution of global radiation into diffuse and direct components
Radiation on inclined surface with skyline effect, hourly value model Gk:
Calculation of hemispherical radiation on arbitrarily orientated
surfaces taking the reduction due to skyline profile into account
------- END TABLE ---------
In addition to the monthly values, METEONORM provides maximum
radiation values under clear sky conditions. For Switzerland,
standardized data (design reference years) for building simulation
purposes are available for a number of locations.
Which data for what problem?
Depending on his/her specific requirements, the user must choose the
most suitable method from among the numerous procedures available in
METEONORM. To provide the user with the best possible service, a whole
series of dependent parameters in addition to the measured data are
available. In choosing the data, the quality and relevance of the
basis data sets must be considered. The following criteria should be
applied:
Measured and interpolated monthly values are of similar precision.
Although measured data reflect the specific characteristics of a local
site, they are always subject to measurement errors, and these tend to
be compensated by the interpolation process. Interpolated data should
therefore be used at sites with no weather station in the vicinity
(approx. 20 km distance).
Dependent parameters such as diffuse radiation, celestial radiation,
dew point temperature, etc., which are determined from calculated as
opposed to measured data, are subject to greater inaccuracy owing to
error propagation.
Design reference year - DRY - data (for Switzerland only) should
preferably be used in situations for which they were generated and
tested, i.e. for building simulations. This is because, like generated
data, they are produced from original data via a data transformation
procedure.
What has changed since the last edition?
The new version 5.0 includes much more data and many additional features:
First of all the climatological mean values of approx. 4'500 Stations
all around the world were added. These mainly contain monthly values
of air temperature, wind speed, humidity, precipitation and days with
rain. In version 5.0 about 7'000 stations are directly accessible.
Use of satellite pictures for radiation measurements for areas with
low density of radiation network.
Inclusion of current data (monthly means) for control of systems. The
current data are accessible by internet.
Automatic calculation of high horizons. In Switzerland high horizons
can be calculated automatically based on a digital terrain model.
Adaptation of the algorithms to the latest results found in the
European Union Information Society Technology research project SODA
and addition of more parameters (driving rain, UV).
Enhanced temperature generation based on measured distributions. Mean
minimum design temperatures (1 and 4 day minimum temperatures) now
included (e.g. output format sia 380/1).
The new edition includes 4 new output formats for TRY/WUFI (German
test reference years, WUFI import format), Spectral (UVA/B and
erythemal radiation), Meteo Matrix (TISO) and PVS.
The on-line-help has been enhanced.
The polar regions were added. METEONORM can now really covers the
whole world.
The monthly radiation model - a relict of 1992 METEONORM Version 1.0 -
was removed.
How precise is METEONORM?
Owing to the comprehensive framework chosen for the present edition,
certain inconsistencies could not be avoided. However, it is always
possible to establish which data basis and algorithms were used.
Differences between the various data bases and algorithms may be
summarized as follows:
Quality of basis data: The radiation data was subjected to
extensive tests. The error in interpolating the monthly radiation
values was 15%, and for temperature 1.3°C.
Climatic variations: The METEONORM radiation data base is based on
10-year measurement periods, the other parameters mainly on 1961-90
means. Comparisons with longer term measurements show that the
discrepancy in average total radiation due to choice of time period is
less than 2% for all weather stations.
Computational models: The models used in METEONORM are designed to
calculate radiation on inclined surfaces and additional parameters.
One or more models are used depending on data basis. If the results
are to be passed on for further processing, the data basis and models
used should be specified to ensure that the results are correctly
interpreted.
In general, the hourly model tends to overestimate slightly the total
radiation on inclined surfaces by 1%. The discrepancy compared to
measured values is ±6% for individual months and ±3% for yearly sums.
It is important for users of METEONORM to be aware that the data basis
and computational models only approximate the real situation.
Notwithstanding this, the variation in measured total radiation
between one year and another is greater than the inaccuracy in the
models. ----------- END OF QUOTE -----------
Regards, Ruut Brandsma
-----Original Message-----
From: trnsys-users-admin@engr.wisc.edu
[mailto:trnsys-users-admin@engr.wisc.edu]On Behalf Of Werner Keilholz
Sent: donderdag, december 02, 2004 13:01
To: trnsys-users@engr.wisc.edu
Subject: Re: [TRNSYS-users] meteo data files
Hi Isabelle,
The data is based on hourly data.
In the present version, most of the data is taken from the GEBA
(Global Energy
Balance Archive), from the World Meteorological Organization (WMO/OMM)
Climato-logical Normals 1961-1990 and from the Swiss database compiled
by MeteoSwiss.
Interpolations are made for certain variables which are not available
at a given site.
If you install the additional French weather data distributed by CSTB
(in \Trnsys16\Weather\Meteonorm\Europe\France)
you will find a readme.htm file which explains which parameters are
measured
for each site.
You find details about meteonorm at
http://software.cstb.fr/soft/present.asp?langue=us&m=lpr&context=Meteonorm
Werner
Isabelle BRUYERE wrote:
Hi everybody,
Can anyone tell me how the meteo files available for Europe in TRNSYS
16 were built ? I've read in the documentation that
"All files were generated using default options in Meteonorm
V5.0.13". Does that mean that data sets of hourly values were built
using mean daily values ? Or is it derived from real hourly mesures
for many years (like the US-TMY2 data) ?
Thanks a lot already.
Best regards,
Isabelle Bruyère
*Isabelle Bruyère
*Université Catholique de Louvain Place du
Levant, 1 à 1348 Louvain-la-Neuve
Unité d'architecture - Architecture et Climat Tél : 010/47
21 38 - Fax : 010/47 21 50
http://www-climat.arch.ucl.ac.be/