Variogram analysis

[SimonHarper1]

Hi,

I have some questions relating to kriging that I???m hoping you might help me with??

I want to redesign my groundwater level monitoring network using the kriging standard error as the criterion for optimising my design.  There are many journal articles to help guide me in my work.  However few comment on the assumptions and limitations behind the methods used.  My questions relate to variogram analysis and defining an appropriate spatial structure for my redesign.

Groundwater levels in Hawke???s Bay fluctuate seasonally and possess a long-term decline, therefore the spatial structure or variogram model must change accordingly.  As such, how can I produce a valid variogram model for my redesign if the model parameters are not static? (I.e. change with time). Is this just part of the limitation of the method? Or is there another way to combat the temporal component of the data?

Kind regards,

Simon

[EricKrause]

We do not have spatio-temporal kriging in ArcGIS, so you won't be able to model the temporal correlation directly in the kriging.

However, we have the Densify Sampling Network tool that suggests new locations of monitoring stations based on (among other things) kriging standard errors.  The tool also can take an optional weight raster where you can weight certain locations higher than others.  Though I don't have any specific recommendations about how you would do it, you may want to try to model this weight raster based on temporal trends in the data.