The IMERG version 6 for monthly rain data for the upper reaches of the Ruaha River which proved to correlate well with the occurrence of zero flow at Mtera, stopped being produced in September 2021.
The IMERG version 7 rainfall data are now available. The total precipitation for November and December of the rainy season preceding the zero flow at Mtera is now selected for the prediction in 2024. With the IMERG rain data available in April adequate time is available to alert the authority well in advance. The formula for prediction of 1st day of zero flow is:
DoY 1st zero flow =0.294*(total rain in November and December mm) + 161
For details on the IMERG data, visit NASA’s Global Precipitation Measurements project website