Satellite observations from microwave sounding instruments and radio occultation technology have contributed significantly to the reductions of global forecast errors. Assimilation of Advanced technology Microwave Sounder (ATMS) antenna temperature data resulted in the largest positive impacts on both global and regional forecasts.  This is attributed to well-designed calibration system, well-characterized instrument performance in both prelaunch and post-launch periods, data-stream structure and robust quality control in data assimilation system. However, the data from microwave humidity sounder (MHS) onboard other NOAA/EUMETSAT satellites are separated from Advanced Microwave Sounding Unit (AMSU) data and thus the MHS data quality control of clouds-affected radiances is relying on high-frequency data. In NWP system, many of cloud-affected radiance can pass the quality control and are assimilated as clear sky radiances and clear-sky data are mistakenly as clouds-affected radiances, and are then rejected.  In addition to this data-stream issue, both MHS and Suomi NPP ATMS show an along-track striping and the radiance with striping has larger NEDT. In using the microwave sounding data for climate trend studies, the data from each mission must be cross-calibrated to a standard instrument or a reference. Such a reference is now developed through RO-simulated radiances at microwave temperature sounders. After MSU and AMSU data are cross-calibrated, the climate trends still differ among various groups. It is believed that the analysis methodology can also affect the MSU/AMSU temperature trend. In assimilating RO bending angle data in NWP models, the current GPS RO data stream is lack of quality-control information. The QC using only NWP O-B rejects many good data and passes many bad data. Indeed, the bad data are those with large spectrum width (LSW) in its bending angle power spectrum.  It is recommended that the bending angle LSW is required in RO data stream.