Impact of Lost Russian RAOBs on Numerical Weather Prediction Skill

From the spring of 1995 to the present the number of radiosonde reports from the former USSR dropped by about 41 % from 196 to 80 per day. In March 2000, the World Meteorological Organization's Commission for Basic Systems organized an Expert Team to use routine verification statistics in an attempt to determine if the loss of the Russian RAOBS had a noticeable impact on the NWP forecasts produced by the main operational centers. Results of the WMO study suggest that the signal, if any, will be difficult to detect. This paper reviews the studies conducted to examine the impact on NWP of the loss of the Russian RAOBs.