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研究笔记 · Research Note

Walker/Hadley Circulation Response Under Global Warming @ PKU

Zhenyu He · Jobs Stroustrup 阅读约 5 分钟

Walker/Hadley Circulation Response Under Global Warming @ PKU

基本信息

  • 时间: 2019.10 — 2020.05 (~7 months, 本科大二秋季到大二末)
  • 角色: 本科研究 (Ji Nie 组 first project — 本科生科研 onboarding)
  • 组织: 北京大学物理学院大气与海洋科学系
  • 指导教师: Ji-Nie-聂绩 (primary PI)
  • 地点: 北京 / Tianhe-II NSCC-GZ (早期 (undergraduate Tianhe-II account) account)
  • 资助: PKU 本科生科研训练项目 (Zhenyu 在 4 advisor candidate 中 selected Ji Nie climate dynamics direction 之后 onboarding)

核心问题

全球变暖 (不同 CO₂ level: Picontrol vs Abrupt2xCO₂ vs Abrupt4xCO₂) 下 Walker Cell 与 Hadley Cell 强度变化 + 两者对热带地区 total mass flux change 的 contribution 分解。

🌟 Signature Contribution: Earliest Multi-Method Comparison (Walker strength 3 metric 并列对比)

2019-11-04 first long report (the impact on the strength of tropical circulations 2.pptx, 43 slides) — Zhenyu 大二 Ji Nie 组会 first long PPT report, 详见 。

Walker strength 量化 method comparison (3 methods 并列对比):

  1. Velocity potential @ 200 hPa peak (Tanaka et al. 2004 method)
  2. Integral (vertical velocity + zonal wind 综合, 选 longitude-height domain 120E-60W × 925-150 hPa, 3 latitudinal zones) ⭐ — 后被 Walker paper v6 §3.1 Walker 强度 metric inherit 的早期 source
  3. Precipitation + 850 hPa wind velocity vector

5 篇 papers 对比表 (Walker 增强 vs 减弱 trend contradiction):

  • Tanaka et al. 2004 (velocity potential decomposition method)
  • Strengthening of Walker Circulation under Global Warming in an Aqua-Planet (MRI Japan, 3 cumulus parameterization YS/AS/KF parallel)
  • CMIP5 projected 减弱 papers
  • NCEP/NCAR obs records
  • Holton 2004 An Introduction to Dynamic Meteorology 教材 reference

每个 paper 给出 advantage + defect review (“the measuring method adopted by the author contradicts to some other scholars’ results, the author doesn’t explain Table 2 in detail”) — multi-method critical comparison alongside paper review capability 在大二 11 月 first long report 已成形, 这是 Multi-Method-Comparison-Spine root evidence (比 PhD Phase 4.5 SWTG failed cancellation 早 6 年, 比 Walker paper v6 ω-vs-u 早 1.5 年, 比 Caltech DSCOVR 7-method regularization comparison 早 2 年)。

2020-09 全员大组会 Walker metric source-of-truth evidence

聂绩202009刚开学不久的全员大组会_我的报告 Abrupt4xCo2 vs Picontrol.pptx (16 slides, 大三秋季 Ji Nie 组全员大组会):

  • All data averaged on 140th-150th year
  • Hadley strength = max mass-streamfunction: Picontrol 7.9097e+10 (600 hPa, 13.66°N) / 2xCO₂ 8.807e+10 (12.7°N) / 4xCO₂ 8.4451e+10 (10.84°N, peak shifts equatorward)
  • Walker strength = ω@500mb WEP-EEP diff (WEP 10N-10S × 100E-150E, EEP 10N-10S × 180-100W): Picontrol 0.0913 / 2xCO₂ 0.0587 / 4xCO₂ 0.0909 (monotonic non-trend) ⭐

→ 此 metric 定义 与 Walker paper v6 §3.1 完全 identical, 比 paper v6 (2021-10-22) 早 1 年 7 个月 articulated。Walker paper metric 不是 paper drafting 阶段才决定的, 而是 Phase 0 reading + ENSO 文献 review 阶段已 settle — 大三秋季 research taste 的 early locked-in。

关键成就

  1. 3-method Walker strength 并列对比 (velocity potential / integral / precip+850hPa wind) in 2019-11-04 43-slide report — multi-method discipline earliest evidence
  2. Contribution decomposition to total tropical mass flux change — Walker vs Hadley 分别定量化
  3. Cross-reading breadth: 跨 monsoon (6 papers, two undergraduate co-leaders) + Boundary Layer (8 papers: Lindzen-Nigam / Matsuno 1966 / Gill 1980 / Betts 1989 / Chiang 2001 / West Indian / Back 2009 MLM / Entrainment-Rayleigh-Friction) + Walker/Hadley/ENSO 文献 = ~30+ papers 跨 2 个月
  4. Tianhe-II HPC onboarding: a junior labmate (师弟) .bashrc inheritance → Zhenyu .bashrc → (undergraduate Tianhe-II account) (early Ji Nie lab account) — 同 lab HPC inheritance trail, Fortran 95 教材 + Tianhe-II V1.1 / V1.4.1 / CESM1_on_Tianhe2 共 5 manuals 全部 familiar
  5. First CAM5 aqua-planet 实验 (2020-04 → 2020-05, data_summary_big_picture.pptx 22 slides + data_summary_contrast.pptx 11 slides): 大二春季 first model 实验 + first self-observation comparison, slide 22 observation “热带辐合带那里，相比之前，是由 0-8°S 变成 0-5°S，只是变窄一些，但是仍然是偏南方”
  6. 2020-09-27 Zhenyu first appearance in Hu group (hzy_Hu's group meeting 20200927.pptx 28 slides) — 题目 “Hadley 环流和 Walker 环流的相关性: 1. ENSO 条件下 (文献总结) + 2. 变暖条件下 (在研究中)”; 早 PKU-Walker-Circulation-Research 项目 2021-04-01 mid-term 7 个月

与 Walker/width 项目的 continuity (2020-11 transition)

此 project 是 PKU-Walker-Circulation-Research (2020.11 — 2021.10) 的直接 prequel:

  • Walker paper v6 §3.1 metric = 本 project 2020-09 全员大组会 metric 完全 identical
  • Walker paper v6 §2 cite Merlis 2013 + Ceppi/Hwang 2013 = 本 project 2020-11 跑 cam3 reference paper folder 中 PDF
  • Walker paper v6 ω-vs-u 流函数 methodology + multi-method comparison = 本 project 2019-11-04 43-slide first long report 中 3 method comparison 的 capability spine
  • 2020-11 从 cam6 ((undergraduate Tianhe-II account) account, 14-slide cam6水球运行.pptx) → cam3 ((undergraduate Tianhe-II account) Walker account) transition, 连 Tianhe account 都继承
  • Moment 1 of Independent Judgment narrative (held until 2026-06-10) spine — 4-advisor evaluation ([four PKU faculty across quantitative-biology / optics / quantum-materials / climate]), Zhenyu 大二春季 selected Ji Nie climate direction (与 18 岁 critical reflection on academic credit system 一致, 见 Evidence Preservation Discipline (private companion) 概念 parallel)

使用的技能

相关页面

  • PKU-Undergraduate-Research — 本科研究 umbrella page
  • PKU-Walker-Circulation-Research — successor project (2020.11 — 2021.10 继续 Ji Nie 组), paper v6 metric 源于此 project
  • Ji-Nie-聂绩 — Walker/Hadley 项目 PI
  • — 2019-11-04 43-slide first long report source page
  • Multi-Method-Comparison-Spine — 3-method Walker strength 并列对比 root evidence
  • Independent Judgment narrative (held until 2026-06-10) — Moment 1 (4-advisor evaluation)
  • 2019 critical reflection note (private) — 大二春季 critical reflection on Chinese academic credit system

来源

  • research_wiki/projects/early_exploration/overview.md (285 行, 18-month prequel phase 完整 capture)
  • research_wiki/resume_angles/independent_judgment.md §Extended: First Long Report 2 Months After Choice