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[IDV #TSE-918145]: About the data calculation of IDV 2.9

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: [IDV #TSE-918145]: About the data calculation of IDV 2.9
  • Date: Mon, 28 Jun 2010 16:40:57 -0600
> Full Name: Takehiro SUGIYAMA
> Email Address: address@hidden
> Organization: National Institute for Agro-Environmental Sciences
> Package Version:
> Operating System:
> Hardware:
> Description of problem: I have questions about data calculation of IDV 2.9.
> 
> I am trying to convert point data to grid data using IDV 2.9.
> 
> In "Dashboard" window, there is a "Grid Parameters" tab in "Field selector" 
> tab window. Using default setting, "Use Default" check box is already turned 
> on.
> 
> I would like to know the calculation process or grid parameters in "Use 
> dafault" or "automatic" mode, but I cannot find them.
> 
> I only find description in manual shown below;
> 
> > Automatic - grid spacing will be calculated from the observation density.
> > (IDV manual chap 5.6.2)
> 
> So, there are two questions I want to ask.
> 
> 1. How is the grid parameter calculated by IDV, when "Use Default" box is 
> checked or spacing "Automatic" is selected ?

The IDV calculates the gridded fields using the Barnes Objective Analysis, and 
the grid spacing is calculated from the density of the obs.
> 
> 2. How can I see the grid parameter or calculated formula by IDV, when using 
> "Use Default" or "Automatic" ?

The formula of the Barnes Obj Analysis can be found in many text book or 
articles, the following references are listed in the IDV user guide:

# Barnes, S.L., 1994a: Applications of the Barnes objective analysis scheme 
Part I: Effects of undersampling, wave position, and station randomness. J. 
Atmos. Oceanic Technol. 11, 1433-1448.

# Barnes, S.L., 1994b: Applications of the Barnes objective analysis scheme 
Part II: Improving derivative estimates. J. Atmos. Oceanic Technol. 11, 
1449-1458.

# Barnes, S.L., 1994c: Applications of the Barnes objective analysis scheme 
Part III: Tuning for minimum error. J. Atmos. Oceanic Technol. 11, 1459-1479. 

Yuan
> 
> 


Ticket Details
===================
Ticket ID: TSE-918145
Department: Support IDV
Priority: Normal
Status: Closed