Moving to GOES-16: a new generation of GOES AMVs

GOES-16 is the first of the third generation of GOES satellites and in December 2017 replaced GOES- 13 as the primary satellite in the GOES-East position. GOES-16 carries the Advanced Baseline Imager (ABI) instrument from which Atmospheric Motion Vectors (AMVs) can be derived. ABI is a more advanced instrument than its predecessor on GOES-13. A new AMV derivation method has also been developed which employs a nested tracking method to calculate the initial vector and uses an optimal estimation approach for the height assignment. The combination of new instrument and algorithm has led to a significant increase in the number of AMVs and changes in the characteristics of the data.

A quality assessment using first guess departure statistics showed that after appropriate quality control measures GOES-16 was able to achieve Root Mean Square Vector Difference (RMSVD) values that were generally similar to GOES-13/-15 and better than Meteosat-10 in the overlap region. The speed bias was more mixed with larger negative biases at low pressures and larger biases particularly in the tropics. Early test data where the GOES-16 algorithm had been modified and applied to GOES-13/-15 data presented different speed bias patterns with generally more positive/less negative speed biases. Our analysis therefore suggests that the characteristics of the new ABI instrument contribute at least as much to the different data quality as the change in the derivation algorithm. This assumes that similar settings are used as far as possible for the derivation algorithm across both generations of satellite.

With more conservative spatial blacklisting employed, the GOES-16 data were tested in assimilation experiments. Forecast impacts were generally neutral but encouragingly, small reductions in the vector wind error (verified against own analysis) were seen at short range forecasts at low levels and in the southern hemisphere. Changes to the fit of independent observations to the model background were also mostly neutral with indications of positive benefit in some humidity sensitive microwave sounding channels. Operational monitoring of GOES-16 AMVs at ECMWF started on 17th April 2018 while active assimilation began on 22nd May 2018.