Minimal detectable flux estimator

Purpose

This app calculates the detection limit of static chamber-based soil greenhouse gas flux measurements. There are two "minimal detectable flux" (MDF) estimates that have different purposes

• non-linear: Allowing zero-fluxes to be estimated by the non-linear HMR regression will lead to high uncertainties and hence a high MDF. This value should be used to restrict the MDL for the dynamic kappa.max selection method in the gasfluxes package (see methods)

• robust-linear: Use this option to always apply the robust-linear flux estimate of the gasfluxes function. This lower MDF is useful to describe a GHG measurement system in a publication. It represents a low estimate of the accuary of your flux measurements.

Try out the Soil GHG Flux shiny tool or check Hueppi et al. 2018 on PLOSone for more details.

Method

The gasfluxes package is used to calculate the fluxes chosing HMR if available but otherwise applying linear regression. The detection limit of the chamber based greenhouse gas flux measurement is defined as 95 % confidence intervall according to Parkin et al. 2011. The calculation is also described in the help text of the selectfluxes function.

Background concentrations

• N₂O: 330 ppb
• CO₂: 400'000 ppb
• CH₄: 1'800 ppb

insert all GC.sd values in ppb!

SAE interactive data shiny server

Find this app on our SAE server

Issues and suggestions can be contributed on GitHub.

Feedback and questions please send to [email protected]