Remedy 1: Use of Observing System Simulation Experiments (OSSEs)

Primary gap remedy type: 
Proposed remedy description: 

This remedy concerns Observing System Simulation Experiments (OSSEs), such as those performed with the OSSSMOSE system by Verhoelst et al. (2015) on total ozone column comparisons. These are based on a quantification of the atmospheric field and its variability (c.f. gap G3.01), e.g. in the shape of reanalysis fields, and on a detailed description of the sampling and smoothing properties of the instruments that are being compared (c.f. gap G3.04). The aim is to calculate the error due to spatiotemporal mismatch for each comparison pair, and to derive the mismatch uncertainties from these, so that they can be added to the measurement uncertainties to derive the full uncertainty budget.

The technological and organizational challenges are mostly related to the underlying gaps G3.01 and G3.04.  When these are properly addressed, the calculation of the full uncertainty budget of a comparison exercise requires only a low investment in time and resources. Integrating this into an operational validation context does constitute an additional challenge requiring dedicated effort and funding.


This remedy addresses directly the gap. 

Measurable outcome of success: 

At a high level, success is achieved when validation (and other comparison) results are published including a full uncertainty budget decomposition, taking into account spatiotemporal mismatch uncertainties. Or when they include a convincing demonstration that mismatch uncertainties are well below the measurement uncertainties and are negligible. 

At a lower level, success is achieved if the OSSE allows one to close the uncertainty budget, i.e. the measured differences (or their statistics) are compatible with the sum of all uncertainty sources. Note that this requires reliable measurement uncertainties as well. 

Expected viability for the outcome of success: 
  • High
Scale of work: 
  • Single institution
  • Consortium
Time bound to remedy: 
  • Less than 3 years
Indicative cost estimate (investment): 
  • Medium cost (< 5 million)
Indicative cost estimate (exploitation): 
  • No
Potential actors: 
  • EU H2020 funding
  • Copernicus funding
  • National funding agencies
  • National Meteorological Services
  • ESA, EUMETSAT or other space agency
  • Academia, individual research institutes