PBL Profiling Capabilities from the HiPPO Instrument Concept

A new instrument concept for profiling temperature and water vapor at high vertical resolution in the troposphere and planetary boundary layer (PBL) has been studied. This concept, dubbed HiPPO, is based on crosslink radio occultation (RO) between two low Earth orbiters operating in multiple frequencies between 8-35 GHz. It preserves the many advantages of GNSS-RO while providing a more accurate temperature and water vapor retrievals. To assess the accuracy of this technique and derive instrument requirements, high-fidelity end-to-end simulations are performed under a wide range of PBL conditions and measurement noise. We present the latest simulation results, along with estimates of transmit power and antenna gains needed to achieve the desired accuracy and resolution of temperature and water vapor in the PBL.