Contents

Syllabus

2021/22 Semester; Credit: 3; Class Number: AtmSci7098

Instructor

Professor Yu-Chiao Liang (梁禹喬)
Contacting email: yuchiaoliang@ntu.edu.tw
Office phone: 02-3366-3907

Teaching Assistant

Ms Yi-Jhen Zeng (曾怡甄)
Contacting email: r10229015@ntu.edu.tw

Office Hours

By appointment

Location and Time

Online with Google Meet, Monday 1:20-3:10 pm and Thursday 11:20 am-12:10

Grading

  • Leading discussion:

    • IPCC AR6 WGI Report (group presentation 15%)

    • Assigned literature (group presentation 15%))

  • Sea-ice data illustration (individual homework assignment 10%)

  • Polar vortex and machine learning applications (individual homework assignment 10%)

  • Linear baroclinic model project (individual homework assignment 15%)

  • Final project (group presentation 30%)

  • Additional credit (5%)

Course Description

(in Chinese) 本課程探討極區的氣候變化。我們不僅介紹極區冰圈以及大氣圈過去幾十年的快速變化，包括海冰，永凍土，降雪，冰河，極地渦旋，也會介紹北極暖化增強現象的成因與影響，以及探討高緯度氣候變化與中低緯度大氣海洋環流的交互作用。我們會閱讀IPCC最新關於冰圈的特別報告以及最新的研究文獻，來幫助我們掌握極區最新的研究成果與發展趨勢，同時也會使用不同複雜度的大氣模式，來加深了解極區與中低緯度大氣環流交互作用背後的物理動力機制。

Rapid polar climate change in the past decades was the dominant signature of anthropogenic global warming. This course aims to understand the polar climate change and its interaction with regional and global atmospheric circulations. The first part gives an overview of the fast-changing polar cryosphere and atmosphere, including sea ice, permafrost, snow, glaciers, and stratospheric polar vortex. Students will read IPCC’s AR6 WG1 and Special Report on the Ocean and Cryosphere in a Changing Climate and present main conclusions. The second part discusses the two-way interactions of the polar climate change and lower-latitude (including mid-latitude and tropical) atmospheric and oceanic circulations at various spatial and temporal scales, with an emphasis on the cause and effect of Arctic Amplification. We will use a hierarchical modelling approach with different complexity in attempt to understand the potential atmospheric circulation changes in response to polar warming. The anticipated results will be compared to the observations and the state-of-the-art global climate model simulations, for example CMIP5/6 and Polar Amplification Model Intercomparison Project.

Course Objectives

This course aims to 1) understand the polar climate change and its interaction with regional and global atmospheric circulations, 2) cover some materials of Chapter 12 - Middle Atmosphere Dynamics - in Holton’s “An Introduction to Dynamic Meteorology” (I will try!), and 3) train students to use simple atmospheric models to investigate Arctic-midlatitude connections.

Course Requirements

Willingness to lead discussion for reading materials and participate in group cooperation, and basic FORTRAN programing and plotting skills (Python preferred because we will use a machine learning package written in Python!).

Tentative Topics

  • Overview of Arctic

    • Geography, climatology and meteorology

    • A case study for Siberian record-breaking warming

    • Explorations

  • Snow and Permafrost

  • Glacier and Sea-level Rise

  • Sea Ice

    • Dynamics and thermodynamics

    • Modelling and prediction

    • Past, recent, and future changes

  • Cause and Effect of Arctic Amplification

    • Local vs remote impacts

    • Mechanisms: climate forcings, climate feedbacks, and poleward energy transport

    • Debates on Arctic-midlatitude linkages

  • Polar Stratospheric circulation

    • Polar vortex and stratospheric sudden warming

    • Stratosphere-troposphere coupling

Tentative Schedule

  • Week1, 9/23 (四4): Introduction

  • Week1, 9/27 (一67): Overview of Arctic

  • Week2, 9/30 (四4): LBM introduction; machine location and account

  • Week2, 10/4 (一67): Permafrost + IPCC

  • Week3, 10/7 (四4): IPCC; LBM paper review

  • Week3, 10/11 (一67): 國慶日/雙十節彈性放假

  • Week4, 10/14 (四4): LBM paper review

  • Week4, 10/18 (一67): Snow + IPCC

  • Week5, 10/21 (四4): IPCC; LBM paper review

  • Week5, 10/25 (一67): Glacier + IPCC

  • Week6, 10/28 (四4): IPCC; LBM paper review

  • Week6, 11/1 (一67): Sea ice + IPCC

  • Week7, 11/4 (四4): IPCC; LBM paper review

  • Week7, 11/8 (一67): Sea ice + IPCC

  • Week8, 11/11 (四4): IPCC; LBM paper review

  • Week8, 11/15 (一67): LBM technical

  • Week9, 11/18 (四4): LBM technical; group discussion

  • Week9, 11/22 (一67): Cause of Arctic amplification + IPCC

  • Week10,11/25 (四4): Cause of Arctic amplification + IPCC

  • Week10,11/29 (一67): Cause of Arctic amplification + paper discussion

  • Week11,12/2 (四4): Cause of Arctic amplification + paper discussion

  • Week11,12/6 (一67): Cause of Arctic amplification + paper discussion

  • Week12,12/9 (四4): Cause of Arctic amplification + paper discussion

  • Week12,12/13 (一67): Effect of Arctic amplification + paper discussion

  • Week13,12/16 (四4): Effect of Arctic amplification + paper discussion

  • Week13,12/20 (一67): Effect of Arctic amplification + paper discussion

  • Week14,12/23 (四4): Effect of Arctic amplification + paper discussion

  • Week14,12/27 (一67): Final project presentation

  • Week15,12/30 (四4): Final project presentation

  • Week15,1/3 (一67): Final project presentation

  • Week16,1/6 (四4): Wrap-up

Relevant Texts and References

Bibliography

BS20

Russell Blackport and James A Screen. Weakened evidence for mid-latitude impacts of Arctic warming. Nature Climate Change, pages 1–2, 2020. URL: https://doi.org/10.1038/s41558-020-00954-y.

CSF+14

Judah Cohen, James A Screen, Jason C Furtado, Mathew Barlow, David Whittleston, Dim Coumou, Jennifer Francis, Klaus Dethloff, Dara Entekhabi, James Overland, and others. Recent Arctic amplification and extreme mid-latitude weather. Nature Geoscience, 7(9):627–637, 2014. URL: https://doi.org/10.1038/ngeo2234.

FV12

Jennifer A Francis and Stephen J Vavrus. Evidence linking Arctic amplification to extreme weather in mid-latitudes. Geophysical Research Letters, 2012. URL: https://doi.org/10.1029/2012GL051000.

GKA+18

Hugues Goosse, Jennifer E Kay, Kyle C Armour, Alejandro Bodas-Salcedo, Helene Chepfer, David Docquier, Alexandra Jonko, Paul J Kushner, Olivier Lecomte, François Massonnet, and others. Quantifying climate feedbacks in polar regions. Nature Communications, 9(1):1–13, 2018. URL: https://doi.org/10.1038/s41467-018-04173-0.

HK81

Brian J Hoskins and David J Karoly. The steady linear response of a spherical atmosphere to thermal and orographic forcing. Journal of Atmospheric Sciences, 38(6):1179–1196, 1981. URL: https://doi.org/10.1175/1520-0469(1981)038<1179:TSLROA>2.0.CO;2.

JH95

Feifei Jin and Brian J Hoskins. The direct response to tropical heating in a baroclinic atmosphere. Journal of Atmospheric Sciences, 52(3):307–319, 1995. URL: https://doi.org/10.1175/1520-0469(1995)052<0307:TDRTTH>2.0.CO;2.

KCA+18

Marlene Kretschmer, Dim Coumou, Laurie Agel, Mathew Barlow, Eli Tziperman, and Judah Cohen. More-persistent weak stratospheric polar vortex states linked to cold extremes. Bulletin of the American Meteorological Society, 99(1):49–60, 2018. URL: https://doi.org/10.1175/BAMS-D-16-0259.1.

MKW+19a

Masato Mori, Yu Kosaka, Masahiro Watanabe, Hisashi Nakamura, and Masahide Kimoto. A reconciled estimate of the influence of arctic sea-ice loss on recent eurasian cooling. Nature Climate Change, 9(2):123–129, 2019. URL: https://doi.org/10.1038/s41558-018-0379-3.

MKW+19b

Masato Mori, Yu Kosaka, Masahiro Watanabe, Bunmei Taguchi, Hisashi Nakamura, and Masahide Kimoto. Reply to: is sea-ice-driven eurasian cooling too weak in models? Nature Climate Change, 9(12):937–939, 2019. URL: https://doi.org/10.1038/s41558-019-0636-0.

MKW+21

Masato Mori, Yu Kosaka, Masahiro Watanabe, Bunmei Taguchi, Hisashi Nakamura, and Masahide Kimoto. Reply to: eurasian cooling in response to arctic sea-ice loss is not proved by maximum covariance analysis. Nature Climate Change, 11(2):109–111, 2021. URL: https://doi.org/10.1038/s41558-020-00983-7.

SB19

James A Screen and Russell Blackport. Is sea-ice-driven eurasian cooling too weak in models? Nature Climate Change, 9(12):934–936, 2019. URL: https://doi.org/10.1038/s41558-019-0635-1.

SDS+18

James A Screen, Clara Deser, Doug M Smith, Xiangdong Zhang, Russell Blackport, Paul J Kushner, Thomas Oudar, Kelly E McCusker, and Lantao Sun. Consistency and discrepancy in the atmospheric response to arctic sea-ice loss across climate models. Nature Geoscience, 11(3):155–163, 2018. URL: https://doi.org/10.1038/s41561-018-0059-y.

SBA+18

Malte F Stuecker, Cecilia M Bitz, Kyle C Armour, Cristian Proistosescu, Sarah M Kang, Shang-Ping Xie, Doyeon Kim, Shayne McGregor, Wenjun Zhang, Sen Zhao, and others. Polar amplification dominated by local forcing and feedbacks. Nature Climate Change, 8(12):1076–1081, 2018. URL: https://doi.org/10.1038/s41558-018-0339-y.

Tin91

Mingfang Ting. The stationary wave response to a midlatitude sst anomaly in an idealized gcm. Journal of Atmospheric Sciences, 48(10):1249–1275, 1991. URL: https://doi.org/10.1175/1520-0469(1991)048<1249:TSWRTA>2.0.CO;2.

TH90

Mingfang Ting and Isaac M Held. The stationary wave response to a tropical sst anomaly in an idealized gcm. Journal of Atmospheric Sciences, 47(21):2546–2566, 1990. URL: https://doi.org/10.1175/1520-0469(1990)047<2546:TSWRTA>2.0.CO;2.

ZCS21

Giuseppe Zappa, Paulo Ceppi, and Theodore G Shepherd. Eurasian cooling in response to arctic sea-ice loss is not proved by maximum covariance analysis. Nature Climate Change, 11(2):106–108, 2021. URL: https://doi.org/10.1038/s41558-020-00982-8.

Polar Climate Change Overview of Arctic