| 一次东移西南涡对初始扰动的伴随敏感性试验 |
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| 作者姓名： | WANG Zhi GAO Kun |
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| 作者单位： | Department of Earth Science，Zhejiang University，Hangzhou 310028，Department of Earth Science，Zhejiang University，Hangzhou 310028 |
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| 基金项目： | This work was supported by the National Basic Research and Development，国家自然科学基金 |
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| 摘 要： | 初始条件能否包含有足够的中尺度信息对西南涡的模拟至关重要,采用中尺度模式MM5对我国长江流域一次东移西南涡进行模拟试验,并结合一个伴随模式MAMS对这次西南涡进行敏感性试验,分析预报变量对初始条件的敏感性分布,根据敏感性分析结果对初始条件追加一个适当的扰动进行模拟对比,结果表明:追加扰动后的初始条件较成功地模拟出了本次西南涡的形成和移动情况,而原来的试验模拟的低涡与实况相比要落后十几小时;伴随模式MAMS较好地模拟出了本次西南涡的敏感性场分布,本次西南涡对西风扰动的大敏感性区域主要位于400hPa以下的西南地区,对南风扰动的大敏感性区域主要位于500hPa以下的西南地区,对温度扰动的大敏感性区域则主要位于500hPa与900hPa之间的西南地区;追加的风场扰动在中低层的西南地区表现为一个气旋性环流,在这个气旋性环流的西南方存在另一个反气旋性环流;在此基础上增加初始场水汽扰动则在一定程度上加强了模拟低涡的强度和移动速度。
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| 关 键 词： | 西南涡 中尺度模拟 伴随模式 敏感性试验 |
| 收稿时间： | 26 January 2007 |
Sensitivity Experiments of an Eastward-Moving Southwest Vortex to Initial Perturbations |
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| WANG Zhi,GAO Kun.Sensitivity Experiments of an Eastward-Moving Southwest Vortex to Initial Perturbations[J].Advances in Atmospheric Sciences,2003,20(4):638-649. |
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| Authors: | WANG Zhi and GAO Kun |
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| Institution: | Department of Earth Science, Zhejiang University, Hangzhou 310028,Department of Earth Science, Zhejiang University, Hangzhou 310028 |
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| Abstract: | Whether the initial conditious contain pronounced mesoscale signals is important to the simulation ofthe southwest vortex. An eastward-moving southwest vortex is simulated using the PSU/NCAR MM5. Amodest degree of success is achieved, but the most serious failure is that the formation and displacement ofthe simulated vortex in its early phase are about fourteen hours later than the observed vortex. Consideringthe relatively sparse data on the mesoscale vortex and in an attempt to understaud the cause of the forecastfailure, an adjoint model is used to examine the sensitivity of the southwest vortex to perturbations of initialconditions. The adjoint sensitivity indicates how small perturbations of model variables at the initial timein the model domain can influence the vortex. A large sensitivity for zonal wind is located under 400 hPa, alarge sensitivity for meridional wind is located under 500 hPa, a large sensitivity for temperature is locatedbetween 500 and 900 hPa, and almost all of the large sensitivity areas are located in the southwesternarea. Based on the adjoint sensitivity results, perturbations are added to initial conditions to improvethe simulation of the southwest vortex. The results show that the initial conditions with perturbatiouscan successfully simulate the formation and displacement of the vortex; the wind perturbations added tothe initial conditions appear to be a cyclone circulation under the middle level of the atmosphere in thesouthwestern area with an anticyclone circulation to its southwest; a water vapor perturbation added toinitial conditions can strengthen the vortex and the speed of its displacement. |
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| Keywords: | southwest vortex mesoscale numerical simulation adjoint model sensitivity experiment |
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