Convection Initiation in Climate Models Using the Heated Condensation Framework: A Review
This chapter presents a review of the Heated Condensation Framework (HCF) theory and applications. The HCF offers an alternative approach to methods of parameterizing convection based on parcel theory. Formulated to take into account the role of atmospheric mixing within the boundary layer, the HCF uses profiles of temperature and humidity to quantify how conditioned the atmosphere is to moist free convection. The initiation of convection is evaluated based on both the availability of large-scale convective instability and local surface heating. Therefore, the HCF can be applied as a trigger function for convective parameterizations. When compared to conventional convective trigger criteria, the HCF triggers returns less false positives, and when implemented into the CFSv2 model, the HCF trigger improves the representation of the Indian monsoon and tropical cyclone intensity. From a climate perspective, applying the HCF trigger to the Community Earth System Model reduces convective overactivity in the model and improves the frequency of intense precipitation events. The use of the HCF as a convective trigger is still under active investigation, and strategies for including the effects of remote dynamical forcings and model sub-grid triggering are being explored.
KeywordsConvective trigger function CFSv2 CESM Convection initiation Convective inhibition
This study was primarily supported by the National Monsoon Mission, Ministry of Earth Sciences, Government of India. Additional support comes from NSF (AGS-1338427), NOAA (NA14OAR4310160 and NA15NWS4680018), and NASA (NNX14AM19G). The radiosonde data were collected as part of DYNAMO, which was sponsored by NSF, NOAA, ONR, DOE, NASA, JAMSTEC, [Indian and Australian funding agencies]. The involvement of the NSF-sponsored National Center for Atmospheric Research (NCAR) Earth Observing Laboratory (EOL) is acknowledged. The data are archived at the DYNAMO Data Archive Center maintained by NCAR EOL.
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