Dear Maha,
I developed a tool that generates time series of daily weather that
exactly match a series of monthly targets, but with statistical
properties that are consistent with historic daily observations at a
given location. It is described in:
Hansen, J.W. and Ines, A.V.M., 2005. Stochastic disaggregation of
monthly rainfall data for crop simulation studies. Agric. For. Meteorol.
131:233 246.
It uses the same stochastic weather generator that I developed for the
WeatherMan software that is part of DSSAT 4.x (described in: Hansen,
J.W. and Mavromatis, T., 2001. Correcting low frequency variability bias
in stochastic weather generators. Agric. For. Meteorol. 109:297-310;
Mavromatis, T. and Hansen, J.W., 2001. Interannual variability
characteristics and simulated crop response of four stochastic weather
generators. Agric. For. Meteorol. 109:283-296; and Hansen, J.W., 1999.
Stochastic daily solar irradiance for biological modeling applications.
Agric. For. Meteorol. 94:53-63.). It uses the same parameter file that
WeatherMan produces and uses for its unconstrained weather generator,
but is constrained to reproduce a time series of monthly targets. This
of course assumes that you have sufficient historic daily data to
estimate the weather generator parameters.
I have not yet implemented a user-friendly GUI version. For my own
work, I developed a stand-alone command-line version of the parameter
estimation tool (extracted from what I developed for WeatherMan),
stand-alone weather disaggregation tools for DSSAT and APSIM weather
file formats, and a version that also deals with dewpoint and wind speed
to support variations of the Penman model of potential
evapotranspiration (used for the SARRA-H crop models). If you are
interested, let me know, and I can send files and instructions.
Regards,
Jim
On 12/30/2010 5:14 AM, Maha Lotfy Mohamed Elsayed wrote:
> All DSSAT group,
>
> I wish you a new year full of happiness, success, progress, and peace.
>
> I have two future weather scenarios but monthly based (from 2011 to 2082)
> for the location here under study. Could anyone help me on how to obtain
> the daily values?
>
> Thanks a lot in advance.
>
> Best regards,
>
> Maha
>
>
> --
> Maha ELSAYED
> PhD Student, DAAPV, Università di Padova
> Agripolis - viale dell'Università 16
> 35020 Legnaro (PD)
> Italy
> Mobile: +39 3896479117
> www.griffin.uga.edu/ageng/people_files/Elsayed.htm
> Skype ID: maha_lotfy
>
--
James W. Hansen, Ph.D.
Research Scientist - Agricultural Systems, CCAFS Theme 4 Leader
The International Research Institute for Climate and Society
The Earth Institute, Columbia University, Lamont Campus
61 Route 9W, Monell Building
Palisades, NY 10964-8000
USA
voice: +1-845-680-4410
fax: +1-845-680-4864
e-mail: [log in to unmask]
WWW: http://iri.columbia.edu/cgi-bin/staff?jhansen
Skype: j.w.hansen
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