An Assessment of Design of Observation Network over the Tibetan Plateau Based on Observing System Simulation Experiments (OSSE)

An Observing System Simulation Experiment (OSSE) was conducted to test the rationality and regional representation of the layout of the upper-air observation system over the Tibetan Plateau and neighboring areas and to consider the actual significance of observation stations. The simulations were validated primarily by comparing results from corresponding experiments wherein simulated observations were assimilated into the initial fields or not. The results showed that there were significant differences in prediction for the different layouts. The layout with both existing and planned observation stations was better than the ones with only existing or only planned stations in terms of forecast accuracy, especially around the areas with new observations added. Specifically, for winds, there were large improvements in Xinjiang, Qinghai, Gansu Corridor, Tibet, Yunnan and mid-west and northeast Sichuan. For temperature and relative humidity, the most significant improvement was in Tibet, southwest and east Qinghai, mid-east Sichuan, and mid-north Yunnan. For heights, the major improvements were in Xinjiang, Qinghai, east Tibet, mid-west Sichuan and Yunnan. The results also validated the layout of the observations and indicated the necessity to add planned observations over the Tibetan Plateau and neighboring areas.