About Time Zone & Scale factor

[Aruna Awale]

Dear Sir,

I am Aruna Awale from Alternative Energy Pomotion Centre, Kathmandu Nepal. I would like to inform you that we have 9 data loggers all together among which 5 data loggers are NRG 9300 SA and 4 are Symhonie data loggers and we are collecting wind data since 5 years. The earlier data logger installer did not have set time zone, latitude, longitude and elvation in data logger so we had adjusted it while processing by symphonie data retriver but in one site i had installed myself setting time zone, latitude, longitude and elevation. While setting i thought i had set the time zone as plus 6 but after six months when i collected data and try to process by data retriver, load heading i found that the time zone is minus 6. So i would like to ask a question if i correct it in site information editor and save the site while processing by data retriver software, will it work effectectively?

My second question is that since the earlier data were processed by setting the default value of scale factor and offset value as 0.765 and 0.35 respectively. But i came to know  from your website of FAQ portion that scale factor is same as slop. So in the context of Nepal where there is maximum variation in topography, will it reliable by setting the same scale factor everywhere?  i would like to study in detail so please suggest me for the reference so that i could get detail knowledge about it.

yours sincerely,

Aruna Awale

Data officer, AEPC

Kathmandu Nepal

[David Carlson]

Hello Aruna,

Thanks for your questions.  Making the change in the Site Information Editor will work.  Just be sure to re-import all of the raw data files after this change is made, so as to properly apply the timestamps.

Nepal has a lot of varied terrain for sure.  This will come into play after the measurement campaign, when determining the "roughness factor" of the site.  There is more information on this here: http://www.windpower.org/en/tour/wres/shear.htm 

For scale factor (slope) and offset for the #40 anemometers, no changes have to made for differing terrain types.  You should use either the consensus transfer function you mentioned above, or the specific calibration values for these anemometers.

 All the best,

Dave (NRG Tech Support)