G5.09

G5.09    A readily accessible online tool to perform radiative transfer calculations to transfer reference measurements of ECVs including their uncertainty estimates into the space measurement space is missing to enable characterisation of satellite measurements.

Gap detailed description

The GAIA-CLIM User Survey highlighted the need to have an online radiative transfer capability available in the planned Virtual Observatory to allow the transfer of reference measurements into the measurement space of satellite instruments. The impact of not comparing in measurement space is the need for uncertainty estimates for one or several retrieved geophysical parameters, which is usually more complex compared to assessing the uncertainty of a measured satellite count or radiance. This is because the forward calculation from the geophysical profile is unique, whereas the inverse calculation is non-unique in that several distinct geophysical profiles can be satisfied by a single radiative measurement.

Activities within GAIA-CLIM related to this gap

Gap remedy(s)

Implement a forward radiative transfer capability into the Virtual Observatory.

Remedy #1

Specific remedy proposed

Remedy for Gap4.01 (Lack of traceable uncertainty estimates for NWP and reanalysis fields & equivalent TOA radiances – relating to temperature) proposes the development of the GRUAN processor that is able to simulate measurements for many satellite instruments operating in the infrared and microwave spectral ranges consistent with GRUAN profile measures and their uncertainties. Here, it is proposed to integrate the GRUAN processor into the Virtual Observatory and make it online accessible to create simulated measurements for any satellite instrument for which co-locations with the GRUAN reference measurements exist in the Virtual Observatory database.

Measurable outcome of success

Online radiative transfer capability available as part of the Virtual Observatory.

Achievable outcomes

Technological viability: High

Indicative cost estimate: Low (<1 million)

Relevance

Implementing the proposed remedy would help to satisfy a clear user need expressed in the GAIA-CLIM User Survey.

Timebound

The remedy proposed here is part of deliverables of GAIA-CLIM WP5 due for delivery (D5.4) in month 30.

Gap risks to non-resolution