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Abstract
Based on the Lagrangian change equation of vertical vorticity deduced from the equation of threedimensional
Ertel potential vorticity (PVe), the development and movement of vortex are investigated from
the view of potential vorticity and diabatic heating (PV–Q). It is demonstrated that the asymmetric distribution
in the vortex of the non-uniform diabatic heating in both vertical and horizontal can lead to the
vortex’s development and movement. The theoretical results are used to analyze the development and movement
of a Tibetan Plateau (TP) vortex (TPV), which appeared over the TP, then slid down and moved
eastward in late July 2008, resulting in heavy rainfall in Sichuan Province and along the middle and lower
reaches of the Yangtze River. The relative contributions to the vertical vorticity development of the TPV
are decomposed into three parts: the diabatic heating, the change in horizontal component of PVe (defined
as PV2), and the change in static stability θz. The results show that in most cases, diabatic heating plays
a leading role, followed by the change in PV2, while the change of θz usually has a negative impact in a
stable atmosphere when the atmosphere becomes more stable, and has a positive contribution when the
atmosphere approaches neutral stratification. The intensification of the TPV from 0600 to 1200 UTC 22
July 2008 is mainly due to the diabatic heating associated with the precipitation on the eastern side of the
TPV when it uplifted on the up-slope of the northeastern edge of the Sichuan basin. The vertical gradient of
diabatic heating makes positive (negative) PVe generation below (above) the maximum of diabatic heating;
the positive PVe generation not only intensifies the low-level vortex but also enhances the vertical extent
of the vortex as it uplifts. The change in PVe due to the horizontal gradient of diabatic heating depends
on the vertical shear of horizontal wind that passes through the center of diabatic heating. The horizontal
gradient of diabatic heating makes positive (negative) PVe generation on the right (left) side of the vertical
shear of horizontal wind. The positive PVe generation on the right side of the vertical shear of horizontal
wind not only intensifies the local vertical vorticity but also affects direction of movement of the TPV. These
diagnostic results are in good agreement with the theoretic results developed from the PV–Q view.
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Citation
ZHENG Yongjun, WU Guoxiong, LIU Yimin. 2013: Dynamical and Thermal Problems in Vortex Development and Movement. Part I: A PV–Q View. Journal of Meteorological Research, 27(1): 1-14. DOI: 10.1007/s13351-013-0101-3
ZHENG Yongjun, WU Guoxiong, LIU Yimin. 2013: Dynamical and Thermal Problems in Vortex Development and Movement. Part I: A PV–Q View. Journal of Meteorological Research, 27(1): 1-14. DOI: 10.1007/s13351-013-0101-3
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ZHENG Yongjun, WU Guoxiong, LIU Yimin. 2013: Dynamical and Thermal Problems in Vortex Development and Movement. Part I: A PV–Q View. Journal of Meteorological Research, 27(1): 1-14. DOI: 10.1007/s13351-013-0101-3
ZHENG Yongjun, WU Guoxiong, LIU Yimin. 2013: Dynamical and Thermal Problems in Vortex Development and Movement. Part I: A PV–Q View. Journal of Meteorological Research, 27(1): 1-14. DOI: 10.1007/s13351-013-0101-3
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