The Observing System Simulation Experiments (OSSEs) have been conducted at National Centers for Environmental Prediction for the past 10 years using a T213 Nature Run (NR) produced by ECMWF. Now the OSSE effort has been expanded internationally and a Joint OSSE formed which will share a common Nature Run. This paper includes miscellaneous results from OSSEs with the T213 Nature Run, which will help to design the new OSSE using the new Joint OSSE NR.

One of the subjects is designing the best use of solar power, which is not enough to operate a DWL with a 100% duty cycle. Adapted targeted DWL experiments were conducted. In these experiments low level scan lidar, which represents coherent lidar, is combined with an upper level lidar, direct detection lidar, or non scan lidar (ADM Aeolus). The strategies for effective targeting and combined effects are discussed.

The balance between data density and model resolution is investigated using globally uniformly distributed observations. The results showed that the number of vertical resolution levels is very essential for a high resolution data set. The results showed that without a sufficient number of vertical levels, a high density of observations could be damaging to the forecast skill.

Simulation of radiances is a challenging task for OSSEs. In the Joint OSSE, we are planning to use CRTM to simulate and assimilate radiance data. Various approaches for simulating AIRS data are presented as an example of simulating radiances.

These results will be used to design the Joint OSSEs using the new higher resolution Joint OSSE Nature Runs: a 13 month long, three hourly dump at T511 resolution with 91 levels and an hourly dump at T799 resolution.