JIFRESSE Summer Internship Program (JSIP) Research Reports

 Project 3: Characterization of the Tropical Precipitation-Moisture Relationship with Observations from GNSS Radio Occultation Data


Intern Student: Yi-Hung Kuo  

Mentors: J. David Neelin,  F. Joseph Turk,  Manuel de la Torre Juarez,  Chi Ao   

Collaborator: Ramon Padullés


This study examines the precipitation-buoyancy relationships using the entraining plume calculations. The results derived from radio occultation (RO) retrievals are compared with reanalysis. The RO retrievals are found to be useful for estimating the environment conditional instability, with suitable care. The RO-derived precipitation-buoyancy relationships are generally consistent with those in reanalysis, thus serve as an observational validation of prior work based on reanalysis. The sensitivity of the estimated buoyancy to entrainment is tested, and the importance of the lower free-tropospheric temperature and moisture is reaffirmed. The consistency of results obtained here directly from RO moisture with those obtained from reanalysis is significant, because the model used in the reanalysis, while in some ways helpful in enforcing self-consistency on the temperature and moisture profiles, could be suspected of influencing these profiles with its own entrainment assumptions.


The estimated buoyancy profile from RO and its dependence on the tropospheric moisture exhibit contrast over land and ocean, as seen in radiosondes, confirming the RO retrievals can be useful for studying regional differences. However, there seem to be negative buoyancy biases in the RO data in the lower free-troposphere/boundary layer, which requires further investigation to clarify. The near-surface temperature biases in the RO retrievals noted here suggest a novel constraint for the retrieval procedure.

project 3 figures