A pair of new moisture-dynamic diagnostic parameters for heavy rain location

作者：Yuan, Kai; Zhu, Zhiwei^*; Li, Ming

来源：Meteorology and Atmospheric Physics, 2018, 130(3): 325-331.

DOI：10.1007/s00703-017-0522-0

• POTENTIAL VORTICITY

In this study, the regional persistent heavy rain process occurred in the middle and lower reaches of the Yangtze River valley from 30 June 2016 to 7 July 2016 is analyzed. We find that the pure dynamic parameters [e.g., vorticity (V) and divergence (D)] and two-dimensional moisture-dynamic parameters [e.g., moist vorticity (MV), moist divergence (MD)] have difficulty in capturing the rainfall location during such a critical process. Given the poor performance of these traditional parameters, a pair of new parameters [namely, one-dimensional moist vorticity (ODMV) and one-dimensional moist divergence (ODMD)] based on low-level jet is proposed for diagnosing heavy rain location. The results show that (1) ODMV and ODMD have better relations with rain belt in terms of spatial distribution. Precipitation occurs in positive (negative) region of ODMV (ODMD), and heavy rainfall accurately locates in the positive (negative) center of ODMV (ODMD); (2) ODMV and ODMD also have good correlation with the precipitation in terms of temporal variation (significant at the 99% confidence level). When ODMV (ODMD) is in strong positive (negative) phase, precipitation is large, and vice versa; (3) the threat score of ODMV and ODMD for the areal-mean rainfall is improved by 119% and 16%, respectively, compared to V/D and MV/MD. It is anticipated that the proposed new parameters would facilitate the skills of diagnosing and forecasting the heavy rainfall.

• 出版日期2018-6
• 单位南京信息工程大学