| 摘要: |
| 通过NCEP再分析资料和Micaps实况资料对“尤特”发生发展以及登陆过程的水汽条件、螺旋度变化进行分析，发现：“尤特”在发生发展前期，西南急流和副高南侧偏东气流对“尤特”水汽输送作用相当，中后期“尤特”则主要以西南急流形成的南支水汽通道输送为主，水汽的源地主要来自南海.对于广西强降雨区，在“尤特”进入广西前，该区为一个水汽源，南边界水汽输出显著，而到了15～19日主要降雨发生时段，受南支水汽输送带的影响，广西强降雨区转为水汽汇，水汽输入以南边界为主.环境场水汽通量和水汽通量散度的变化对“尤特”强度的变化和移向有一定的指示作用，“尤特”在加强或减弱前，其中心水汽通量往往先加强或减弱，且在台风维持一定的强度时，“尤特”有趋向周边水汽大值中心移动的趋势.“尤特”水汽辐合主要位于低层，其强降雨区与850～950hPa水汽通量散度场、850hPa螺旋度相对大值区内有一定的对应关系，未来6h强降雨区多出现在低层强度强、垂直伸展高度高的水汽辐合区和螺旋度相对大值区内. |
| 关键词: 海洋气象学；热带气旋 “尤特” 水汽 螺旋度 |
| DOI： |
|
| 基金项目:中国气象局2014年预报员专项资助项目（CMAYBY2014-052） |
|
| Analysis of moisture and helicity of typhoon 1311 Utor |
| QIN Changliu,LI Huijin,ZHANG Dingding |
| (Laibin Municipal Burean of Meteorology， Laibin 546100，China) |
| Abstract: |
| The NCEP reanalysis and MIcaps data have been employed to study moisture and helicity of typhoon Utor. The results show that， at the early stage development of typhoon Utor， the transportation function of water vapor from the southwesterly jet stream and east flow on the southern of the sub-tropical high have the same effect， but the south water vapor transportation made by southwest jet stream become the main part of middle and late Utor， namely the vapor source is from the South China Sea. Before typhoon affect Guangxi， the main moisture source from the south boundary played leading role. However， during the sustained rainfall， influenced by the south water vapor transportation， the Guangxi heavy rainfall area became moisture sink， and the water vapor transportation is based on the south. The change of moisture flux and it's convergence can be indicatively significant to forecast when the heavy rain fall. The moisture fluxes of typhoon often intensify or weaken before the typhoon intensifies or weakens. When Utor remains suitable intensity， it has the trend moving to the center of high value water vapor. The moisture converges mainly at the low level of atmosphere， and the heavy rainfall has a good corresponding relationship with the moisture flux divergence field from 850hPa to 925hPa and the positive area of the helicity at 850hPa. The 6h heavy rainfall should mostly take place at the low level atmosphere where it has a high vertical stretching altitude and intensity． |
| Key words: marine meteorology typhoon Utor moisture helicity |
