Impacts of TY “Haitang” (0505) on a Torrential Rain in Henan Province, China

To investigate the possible mechanism of the torrential rain in Henan province, China, during 21-23 July, 2005, numerical experiments were designed by using WRF model. Several sensitivity experiments with/without Typhoon “Haitang” (0505) are conducted to understand the role of TC in this server event. It is found that the TC plays an important role in moisture transfer. Meanwhile, the topography effect is investigated by removing the adjacent mountain. In this set of experiments, the TaihangMountain is removed or different topography gravity wave drag coefficientsare tested. Based on the simulations above, the moisture potential vorticity (MPV), moisturehelicity are used to reveal the thermodynamical and dynamical conditions associated with this torrential rainfall. It is found that the interactions of TC circulation and topography play a curial role in triggering the heavy rainfall.