摘要
When Typhoon Toraji(2001)reached the Bohai Gulf during 1-2 August 2001,a heavy rainfall event occurred over Shandong province in China along the gulf.The Advanced Research version of the Weather Research and Forecast(WRF-ARW)model was used to explore possible effects of environmental factors,including effects of moisture transportation,upper-level trough interaction with potential vorticity anomalies,tropical cyclone(TC)remnant circulation,and TC boundary-layer process on the re-intensification of Typhoon Toraji,which re-entered the Bohai Gulf after having made a landfall.The National Centers for Environmental Prediction(NCEP)global final(FNL)analysis provided both the initial and lateral boundary conditions for the WRF-ARW model.The model was initialized at 1200 UTC on 31 July and integrated until 1200 UTC on 3 August 2001,during which Toraji remnant experienced the extratropical transition and re-intensification.Five numerical experiments were performed in this study,including one control and four sensitivity experiments.In the control experiment,the simulated typhoon had a track and intensity change similar to those observed.The results from three sensitivity experiments showed that the moisture transfer by a southwesterly lower-level jet,a low vortex to the northeast of China,and the presence of Typhoon Toraji all played important roles in simulated heavy rainfall over Shandong and remnant re-intensification over the sea,which are consistent with the observation.One of the tests illustrated that the local boundary layer forcing played a secondary role in the TC intensity change over the sea.
When Typhoon Toraji （2001） reached the Bohai Gulf during 1-2 August 2001, a heavy rainfall event occurred over Shandong province in China along the gulf. The Advanced Research version of the Weather Research and Forecast （WRF-ARW） model was used to explore possible effects of environmental factors, including effects of moisture transportation, upper-level trough interaction with potential vorticity anomalies, tropical cyclone （TC） remnant circulation, and TC boundary-layer process on the re-intensification of Typhoon Toraji, which re-entered the Bohai Gulf after having made a landfall. The National Centers for Environmental Prediction （NCEP） global final （FNL） analysis provided both the initial and lateral boundary conditions for the WRF-ARW model. The model was initialized at 1200 UTC on 31 July and integrated until 1200 UTC on 3 August 2001, during which Toraji remnant experienced the extratropical transition and re-intensification. Five numerical experiments were performed in this study, including one control and four sensitivity experiments. In the control experiment, the simulated typhoon had a track and intensity change similar to those observed. The results from three sensitivity experiments showed that the moisture transfer by a southwesterly lower-level jet, a low vortex to the northeast of China, and the presence of Typhoon Toraji all played important roles in simulated heavy rainfall over Shandong and remnant re-intensification over the sea, which are consistent with the observation. One of the tests illustrated that the local boundary layer forcing played a secondary role in the TC intensity change over the sea.
基金
National Basic Research Program of China(973 Program)(2009CB421500)
Natural Science Foundation of China(40875039,40730948,40921160381)
Projects for Public Welfare(Meteorology)of China (GYHY201006008)
