Remedy 1: Adoption of an international approach to implement recommendations for addressing existing gaps in MWR operational products for climate monitoring utilization

Primary gap remedy type: 
TRL 5-7
Secondary gap remedy type: 
Proposed remedy description: 

In order to close this overarching MWR gap, specific work plans should be developed to all the four aspects mentioned above: calibration and instrument characterization, retrieval method, radiative transfer and absorption model uncertainty, quality control. This may be best achieved via a collective set of actions which would be best achieved as a single project but could also be achieved via smaller distinct units of work as follows:

Calibration and instrument characterization

The currently available practices for MWR calibration and instrument characterization shall be reviewed. From these, the best practices should be defined and reported, and the documentation shall be made available to operators and users. Close collaboration with MWR manufacturers is desirable. The starting point is the outcome of the Microwave Radiometers Working Group (WG3) of the EU COST Action TOPROF, ended in October 2017. TOPROF WG3 produced a report on recommendations for operation and calibration of MWR within a network (Pospichal et al., 2016).

Retrieval method

The different types and flavours of retrieval methods currently exploited shall be reviewed and reported. A common retrieval method is recommended for MWR belonging to a network. The recommended retrieval method must produce explicitly and transparently the time-dependent estimated uncertainty of each atmospheric retrievals. A software package for a common retrieval method shall be developed and maintained. The starting point is the outcome of the TOPROF WG3 (Cimini et al. 2017b).

Radiative transfer and absorption model uncertainty

Modifications of absorption models are continuously proposed within the open literature based on laboratory data and MWR field observations. To estimate the total uncertainties affecting the MWR retrievals, the following activities are needed: (i) a review of the state-of-the-art and the associated uncertainty of MW absorption models; (ii) propagation of absorption model uncertainties through radiative transfer and inverse operator. Activities in this direction have started within GAIA-CLIM and shall eventually lead to a review paper (Cimini et al. 2017a).

Quality control

MWR quality control (QC) procedures shall be harmonized and automated to the maximum extent possible. A common network-wide data processing would be recommendable for the network products. Activities in this direction have started within TOPROF WG3, actively interacting with manufacturers for proposing ways for QC automation. Results of these activities shall be transferred as recommendations to users and manufacturers.

Activities contributing to the solution of the above issues have started within the COST action TOPROF and GAIA-CLIM. These two projects are ending in October 2017 and February 2018, respectively. Currently no plan is set for following up on these activities with research-oriented projects. The members of the TOPROF core group have submitted a proposal to the Policy and Finance Advisory Committee of EIG EUMETNET (grouping 31 European Meteorological Services) for including MWR into the next phase of their E-PROFILE project. If accepted, part of the above tasks may be accomplished in that framework, specially those concerning calibration and instrument characterization, and quality control. The next phase of E-PROFILE is scheduled for 2019-2023.


Once the above issues are addressed, traceable MWR observations and retrievals will be available together with the estimate of the time-dependent uncertainty uniformly across the network. The remedies above will foster:

  • The application of standardized calibration and uncertainty characterization procedures by MWR manufacturers and users;
  • The use of a common network-suitable retrieval method. This will harmonise the MWR network products. Product harmonization leads also to more solid characterization of uncertainties;
  • The consideration of MW forward model uncertainties in MWR retrievals, as quantifying the MW absorption model uncertainties will provide a common reference for MWR retrieval methods;
  • The application of improved QC procedures by MWR manufacturers and users. Better QC leads to more solid characterization of MWR retrieval uncertainties, as it reduces the impact of suspicious data and faulty calibration.
Measurable outcome of success: 

The measurable outcome of success for the above specific remedies are the following:

  • The number of MWR sites, users, and manufacturers adopting the proposed calibration and uncertainty characterization procedures;
  • The number of MWR users and manufacturers considering the rigorous estimates of MW forward model uncertainties in their MWR retrievals;
  • The number of MWR sites (i.e. network nodes) providing retrievals and associated uncertainty produced with the recommended uniform retrieval method;
  • The number of MWR sites, users, and manufacturers adopting the proposed QC procedures.
Expected viability for the outcome of success: 
  • Medium
Scale of work: 
  • Consortium
Time bound to remedy: 
  • Less than 5 years
Indicative cost estimate (investment): 
  • Medium cost (< 5 million)
Indicative cost estimate (exploitation): 
  • Yes
Potential actors: 
  • EU H2020 funding
  • Copernicus funding
  • National Meteorological Services
  • Academia, individual research institutes
  • SMEs/industry