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- Title
Examination of Vorticity and Divergence on a Rotating Turbulent Convection Model of Jupiter's Polar Vortices.
- Authors
Cai, Tao
- Abstract
The correlation between divergence and vorticity has traditionally served as a signature of convection in rotating fluids. While this correlation has been observed in the JIRAM brightness temperature data for Jupiter's polar vortices, it is notably absent in the JIRAM images. This discrepancy presents a new challenge in determining whether this correlation can serve as a reliable signature of convection in rapidly rotating atmospheres. In this study, we analyzed data from a three‐dimensional simulation of Jupiter's polar vortices using a deep convection model. Our findings confirm the theoretical prediction of a negative correlation between divergence and vorticity in the northern hemisphere. Interestingly, this correlation is weaker within the cyclones compared to outside them. The skewness of upflows and downflows plays an important role in this negative correlation. We also observed that the correlation varies with height, being strongest near the interface and decaying away from it. The correlation diminishes when the resolution is reduced. Furthermore, our findings suggest that the geostrophic approximation may not be suitable for the Jovian atmosphere, particularly in the stable layer. Both tilting and stretching effects contribute to the material derivative of vorticity, with the tilting effect dominating in the unstable layer and the stretching effect prevailing in the stable layer. This suggests a transfer of vorticity from the convectively unstable layer to the stable layer. Consistent with observations, we also noted an upscale energy transfer from smaller to larger scales. Plain Language Summary: Jupiter has fascinating polar vortices on its poles. But how do they form, how deep are they, and how do they survive? Answering these questions will not only enhance our understanding of Jupiter's weather patterns but also provide insights into the climatic conditions on our own planet, Earth. In this study, we employ a deep convection model to elucidate the formation of these vortices. By analyzing the simulation data, we can ascertain whether the observed data at the top of the atmosphere bear signatures from deep within. Divergence, which quantifies the tendency of fluid to accumulate or disperse at a point, and vorticity, which measures the tendency of fluid to swirl around a point, are key parameters in our analysis. The correlation between these two parameters can serve as a signature of convection. Indeed, our simulation identifies this signature. However, its strength varies with the depth of the atmosphere and the resolution of the measurement. Furthermore, our findings suggest that the spin of the polar vortices at the top of the atmosphere is likely maintained by the transfer of vorticity from the deeper layers of the atmosphere. Key Points: Deep convection model shows that the divergence and vorticity are correlated in the polar vortices of JupiterThe correlation varies with the depth of the atmosphere and the resolution of the measurementThe polar vortices at the top of atmosphere are likely sustained by the transfer of vorticity from deeper layers
- Subjects
POLAR vortex; VORTEX motion; ATMOSPHERE of Jupiter; JUPITER (Planet); ROTATING fluid; CYCLOGENESIS; ATMOSPHERE
- Publication
Journal of Geophysical Research. Planets, 2024, Vol 129, Issue 5, p1
- ISSN
2169-9097
- Publication type
Article
- DOI
10.1029/2023JE008281