For the period 03Z August 21 to 16Z August 22, the IMERG real time system experienced an outage of CPC 4-km IR data. Despite the outage, IMERG EARLY and LATE products continued to be produced but users should be aware that the quality of these products during this period may be suspect and should be used judiciously. Furthermore, the products for the first few hours after the outage are less than optimal due to IMERG restart but should be acceptable for most users.
(1) The precipitation propagation vectors for the period slowly degraded after 03Z August 21 due to the missing CPC 4-km even-odd IR files. Mechanisms are in place to extrapolate motion vectors into the future in case of brief IR outages but will degrade quickly if the outage is beyond a few hours.
(2) As IR precipitation estimates were unavailable for the outage period, microwave estimates propagated beyond ±90 minutes were used as is. Normally, IR precipitation is weighted in the final precipitation products outside the ±90 minute window (precipitationCal and precipitationUncal).