[TRNSYS-users] meteo data files

[Ruut Brandsma]

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 at engr.wisc.edu
[mailto:trnsys-users-admin at engr.wisc.edu]On Behalf Of Werner Keilholz
Sent: donderdag, december 02, 2004 13:01
To: trnsys-users at 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/



-- 


  /    \____ Werner Keilholz, Software Development Group Leader
  \____/     CSTB Sophia Antipolis, SAIL
  /    \____ s-mail: BP 209, 06904 SOPHIA ANTIPOLIS,  F R A N C E
  \____/     phone: +33 (0)4 93 95 67 00 -- fax: +33 (0)4 93 95 67 33
  /    \____ Mailto:werner at cstb.fr -- ASPAM=antispamwpk42
  \____/     http://evl.cstb.fr/english/team/WK/werner.htm

  *** 7èmes Journées TRNSYS francophones ***
  http://software.cstb.fr/events/trnsys7/journees_trnsys7.htm


_______________________________________________
TRNSYS-users mailing list
TRNSYS-users at engr.wisc.edu
https://www.cae.wisc.edu/mailman/listinfo/trnsys-users