Interannual variability of tropospheric moisture and temperature and relationships to ENSO using COSMIC-1 GNSS-RO retrievals

Upper-tropospheric q anomalies expand from the tropics into the midlatitude lower stratosphere, and the T vertical structure is consistent with a moist adiabatic response. C1 results are compared with NCAR's Whole Atmosphere Community Climate Model (WACCM), forced by observed sea surface temperatures, to evaluate model behavior in an idealized setting. WACCM ENSO variations in q and T generally show consistent behavior with C1 with somewhat smaller magnitudes.

Case studies are conducted for major ENSO events during the study period. The spatial variability of q is closely aligned with outgoing longwave radiation (OLR) anomalies. For example, midtropospheric q increases over 100% and OLR decreases over 50 W m(-2) over the central Pacific during the 2015/16 El Nino, and substantial regional q and T anomalies are observed throughout the tropics and midlatitudes for each event.