%0 Journal Article
%T The Predictability of a Squall Line in South China on 23 April 2007<br>
%A WU Duochang
%A MENG Zhiyong
%A YAN Dachun
%A <br>
%J 大气科学进展
%D 2013
%I 
%X This study investigated the predictability of a squall line associated with a quasi-stationary front on 23 April 2007 in South China through deterministic and probabilistic forecasts. Our results show that the squall-line simulation was very sensitive to model error from horizontal resolution and uncertainties in physical parameterization schemes. At least a 10-km grid size was necessary to decently capture this squall line. The simulated squall line with a grid size of 4.5 km was most sensitive to long-wave radiation parameterization schemes relative to other physical schemes such as microphysics and planetary boundary layer. For a grid size from 20 to 5 km, a cumulus parameterization scheme degraded the squall-line simulation (relative to turning it off), with a more severe degradation to grid size <10 km than >10 km. The sensitivity of the squall-line simulation to initial error was investigated through ensemble forecast. The performance of the ensemble simulation of the squall line was very sensitive to the initial error. Approximately 15% of the ensemble members decently captured the evolution of the squall line, 25% failed, and 60% dislocated the squall line. Using different combinations of physical parameterization schemes for different members can improve the probabilistic forecast. The lead time of this case was only a few hours. Error growth was clearly associated with moist convection development. A linear improvement in the performance of the squall line simulation was observed when the initial error was decreased gradually, with the largest contribution from initial moisture field.
%K squall line
%K predictability
%K South China
%K ensemble
%K moisture<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=28A2F569B2458C17&jid=5434AFBF6CB6E7E8D67733B541F211C7&aid=11696725A3704AB6E287FF1856F0B243&yid=FF7AA908D58E97FA&vid=340AC2BF8E7AB4FD&iid=0B39A22176CE99FB&sid=5CB576B96D187F64&eid=51F9E747BA1ACB45&journal_id=0256-1530&journal_name=大气科学进展&referenced_num=0&reference_num=40