Abstract
A sensitivity study of regional climate simulations over East Asia to three convective parameterization schemes (CPSs), the Grell, Kain-Fritsch, and Anthes-Kuo schemes, was conducted using a regional climate model, SNURCM with a 60 km horizontal resolution. Nesting experiments with a 20 km horizontal resolution were also performed in order to investigate the sensitivity of CPSs to horizontal resolution. In all runs with 60 km horizontal resolution, seasonal mean precipitation, low-and upper-level wind, and temporal and spatial variation of monsoon fronts over East Asia were simulated with a certain difference between CPSs. With higher horizontal resolution, all the schemes were likely to increase slightly the total precipitation amount and the precipitation intensity due to the increase of convective rain, but differences in the spatial distribution of precipitation between CPSs were relatively small. There were prominent differences in vertical profiles of wind, temperature, water vapor, and atmospheric hydrometeors amongst CPSs, although the vertical structures of those in GR and KF runs were similar to each other. Sensitivities of the vertical structure of most atmospheric variables to horizontal resolution were relatively smaller than they were to CPSs except for cloud water. Surface energy fluxes, in particular incoming solar radiation and latent heat between CPSs were different to each other because of differences in the vertical structure of atmospheric hydrometeors. Diurnal variation of precipitation was also sensitive to not only CPSs but also horizontal resolution. In this study, the AK scheme reproduced the East Asian Summer precipitation properly because of intrinsic triggering assumptions and the spectral nudging technique. The GR scheme was on the whole suitable to simulate the general features of East Asian summer monsoon in 1998 such as heavy precipitation, atmospheric vertical structure, and temporal evolution of the East Asian Summer monsoon. The KF scheme had the worst statistics in precipitation simulation due to large convective precipitation portion. Consequently, the AK and GR schemes simulated more reasonably the 1998 summer flood over East Asia which was affected by anomalous large-scale conditions.
Highlights
Since the successful inception of regional climate by Dickinson et al (1989) and Giorgi (1990), much effort has been devoted to the development, evaluation, and application of regional climate models (RCMs)
The objectives of this paper are to compare the results between different convective parameterization schemes (CPSs) in the regional climate simulations, in particular focusing on reproduction of the heavy precipitation occurring over East Asia during the 1998 summer, and to investigate the sensitivity of summer monsoon precipitation to cumulus parameterization and horizontal resolution in the simulations
The increase of total precipitation in the 20 km resolution runs was due to the increase in convective precipitation with higher horizontal resolution, while non-convective precipitation in the 20 km resolution runs decreased in the GR scheme and the AK scheme, and was unchanged in the KF scheme compared to that in the 60 km resolution runs
Summary
Since the successful inception of regional climate by Dickinson et al (1989) and Giorgi (1990), much effort has been devoted to the development, evaluation, and application of regional climate models (RCMs). In spite of enormous efforts to develop and improve RCMs, there still remain several debatable issues in RCM studies such as spin-up of precipitation, uncertainty of large-scale forcing data, parameterization of physical process, choice of model domain and its spatial resolution, and lateral boundary condition technique (Leung et al 2003). One physical process which has a pronounced influence on simulated results is cumulus convection. Since the typical range of horizontal resolution in regional climate modeling remains about 10~60 km, most RCMs have used an explicit moisture scheme and a convective cumulus parameterization scheme (CPS). Using different convective parameterization schemes (CPSs) can induce dissimilar results in regional climate simulation, since each CPS includes assumptions and parameters based on an individual formalism. The adequate selection of CPSs can be important in regional climate modeling
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
