During the search for AF447, France's BEA commissioned a working group (The Drift Group) to evaluate all the methods of backtracking wreckage floating on the surface.
This did not produce sufficient accuracy for a viable search and actually seems to have delayed the location of the wreckage.
The Drift Group report can be found here:
http://www.bea.aero/en/enquetes/flig...oup.report.pdf
There was one useful jewel in the report, but it didn't fit the group think concept and so was ignored. Appendix 7 of the report contained an anomalous "pollution spot" detected by the Cosmo-skymed synthetic aperture radar satellite. The shape of the spot was unusual and it was very close to the LKP.
MH370 was likely flown to fuel exhaustion however there would still be some fuel retained in the tanks which would have spread out on the surface and changed its radar reflectivity slightly. Jet fuel would evaporate fairly quickly with the rate likely dependent on temperature and surface turbulence and wind velocity. In the case of AF447, the slick was predicted to evaporate within 30 hours. MH370 would undoubtedly be a shorter period.
There is some chance of a detectable slick. The Cosmo Skymed is a small constellation of satellites designed to revisit areas relatively quickly, and there may be a fair chance of detection of a fuel slick from the crash of MH370.
Here is a link to the Cosmo Skymed information and tasking site:
https://directory.eoportal.org/web/e...s/cosmo-skymed
To improve the odds of detection it would really be useful to narrow down the area of interest by finding actual floating wreckage and backtracking it using whatever means possible.
The collected data from the Cosmo skymed satellites appears to be stored in bulk and is extracted as needed based on tasking requests.