1.Key Laboratory of Meteorological Disaster of Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC), Nanjing University of Information Science and Technology;2.China Meteorological Administration Training Centre
In this study, the influence of the diurnal cycle of solar radiation on the development of the Tibetan plateau vortex (TPV) was examined by using WRF-ARW model. The results showed that the solar shortwave radiation has a significant effect on the occurrence and development of TPV. The control run (CTL; with diurnal cycle of solar shortwave radiation) well reproduced the development process of the TPV. In the experiment with turning off the shortwave radiation (All_night), the TPV developed much faster at the early stage, whereas in the daytime experiment (All_day), the shortwave radiation greatly suppressed the development of TPV. The diagnostic analysis indicated that the longwave radiation cooling steepened the tropospheric lapse rate and thus weakened the atmospheric static stability; Additionally, the decreases in temperature increased the relative humidity at night, which was conducive to potential instability in the lower troposphere and thus promoted the formation and development of TPV, Conversely, solar shortwave radiation warmed the upper troposphere and strengthened the static stability, which inhibited the development of convection. The convergence at lower layer is stronger at night than day, which is beneficial to the enhancement of the ascending motion and the formation of the TPV; The unbalance term indicated that, with the center of the TPV corresponding to the positive area of the unbalanced term and the outer edge of the TPV with the negative area of the unbalanced term. Numerical results showed that the development of TPV bears many similarities to tropical cyclogenesis in terms of dynamics and thermodynamics. The above conclusions are consistent with previous studies on the effect of solar radiation on strong convection.