Index Geophysics

Impact of a Diagnostic Pressure Equation Constraint on Tornadic Supercell Thunderstorm Forecasts Initialized Using 3DVAR Radar Data Assimilation

A diagnostic pressure equation constraint has been incorporated into a storm-scale three-dimensional variational (3DVAR) data assimilation system. This diagnostic pressure equation constraint (DPEC) is aimed to improve dynamic consistency among different model variables so as to produce better data assimilation results and improve the subsequent forecasts. Ge et al. (2012) described the development of DPEC and testing of it with idealized experiments. DPEC was also applied to a real supercell case, but only radial velocity was assimilated. In this paper, DPEC is further applied to two real tornadic supercell thunderstorm cases, where both radial velocity and radar reflectivity data are assimilated. The impact of DPEC on radar data assimilation is examined mainly based on the storm forecasts. It is found that the experiments using DPEC generally predict higher low-level vertical vorticity than the experiments not using DPEC near the time of observed tornadoes. Therefore, it is concluded that the use of DPEC improves the forecast of mesocyclone rotation within supercell thunderstorms. The experiments using different weighting coefficients generate similar results. This suggests that DPEC is not very sensitive to the weighting coefficients.

Guoqing Ge

Jidong Gao

Ming Xue

Meteorology. Climatology

QC851-999

Hindawi Limited

2013-01-01T00:00:00Z

article

1687-9309

1687-9317

10.1155/2013/947874

https://doaj.org/article/bc4820cf8be3457498476d0c1be9320a

Advances in Meteorology, Vol 2013 (2013)

EN

http://dx.doi.org/10.1155/2013/947874

https://doaj.org/toc/1687-9309

https://doaj.org/toc/1687-9317

Journal Licence: CC BY