Reply to Comment by Chang on “Anticyclonic Suppression of the North Pacific Transient Eddy Activity in Midwinter”

Satoru Okajima*, Hisashi Nakamura, Yohai Kaspi

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review

1 Citation (Scopus)

Abstract

Chang (2024, https://doi.org/10.1029/2024gl110011) challenged the methodology proposed recently by Okajima et al. for evaluating cyclonic and anticyclonic contributions to Eulerian eddy statistics and atmospheric energetics based on the local flow curvature. He argued that using the local wind curvature to separate energetic contributions from cyclones and anticyclones is not physically meaningful. Here we argue that his claims are based on an unrealistic assumption of monopolar relative vorticity in an entire storm-track domain and a meridionally uniform zonal background flow atypical to midlatitudes. We also demonstrate that the error in attributing eddy statistics to cyclones and anticyclones is significantly smaller than his estimation. Rather, we further demonstrate that the curvature-based methodology effectively eliminates the shear influence to identify cyclonic and anticyclonic regions, which is dismissed in his argument. We conclude that the curvature-based methodology is beneficial in evaluating distinct cyclonic and anticyclonic contributions to atmospheric energetics in realistic conditions.

Original languageEnglish
Article numbere2024GL111599
Number of pages6
JournalGeophysical Research Letters
Volume51
Issue number20
DOIs
Publication statusPublished - 28 Oct 2024

Funding

The authors are grateful to the two anonymous reviewers for their sound criticism and valuable comments. We thank E. K. Chang for raising those aspects that have not been explicitly discussed in our earlier works. This study is supported in part by the Japan Society for the Promotion of Science through Grants-in-Aid for Scientific Research 22H01292 and 22K14097, by the Japan Science and Technology Agency through COI-NEXT (JPMJPF2013), and by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) through the Arctic Challenge for Sustainability II (ArCS-II; JPMXD1420318865).

All Science Journal Classification (ASJC) codes

  • Geophysics
  • General Earth and Planetary Sciences

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