climatology lecture 8
DESCRIPTION
Climatology Lecture 8. Variability of the General Circulation. Richard Washington. Lecture Outline. El Nino - Southern Oscillation (ENSO): definition impacts on climate ways of measuring ENSO some past ENSO events North Atlantic Oscillation (NAO). Annual Average Rainfall mm/day. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/1.jpg)
Climatology Lecture 8
Richard Washington
Variability of the General Circulation
![Page 2: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/2.jpg)
Lecture Outline
• El Nino - Southern Oscillation (ENSO): • definition
• impacts on climate
• ways of measuring ENSO
• some past ENSO events
• North Atlantic Oscillation (NAO)
![Page 3: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/3.jpg)
Annual Average Rainfall mm/day
![Page 4: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/4.jpg)
![Page 5: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/5.jpg)
Dec 82
![Page 6: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/6.jpg)
SEP 97
![Page 7: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/7.jpg)
Nov 88
![Page 8: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/8.jpg)
![Page 9: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/9.jpg)
ENSO
• Ocean - Atmosphere Interaction
• Largest known source of climate variability
• Global changes to rainfall, winds, pressure and temperature, especially in the tropics
• Major El Nino event 1982/83 1997/98
• Sustained El Nino event 1991-1994
![Page 10: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/10.jpg)
Lecture Outline
• El Nino - Southern Oscillation (ENSO): • definition
• impacts on climate
• ways of measuring ENSO
• some past ENSO events
• North Atlantic Oscillation (NAO)
![Page 11: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/11.jpg)
El Nino La Nina
• pressure higher (than normal) at Darwin
• pressure lower (than normal) in the C.Pacific
• westerlies (weak easterlies) across Pacific
• wet C.Pacificdry W.Pacific
• pressure lower (than normal) at Darwin
• pressure higher (than normal) in the C.Pacific
• strong easterlies across Pacific
• dry C.Pacificwet W.Pacific
![Page 12: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/12.jpg)
![Page 13: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/13.jpg)
![Page 14: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/14.jpg)
![Page 15: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/15.jpg)
![Page 16: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/16.jpg)
![Page 17: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/17.jpg)
El Nino La Nina
• WET East Africa (Oct-Dec)
• DRY southern Africa (Dec- March)
• DRY Sahel (July-Sep)
• DRY East Africa (Oct-Dec)
• WET southern Africa (Dec-March)
• WET Sahel (July-Sep)
![Page 18: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/18.jpg)
Lecture Outline
• El Nino - Southern Oscillation (ENSO): • definition
• impacts on climate
• ways of measuring ENSO
• some past ENSO events
• North Atlantic Oscillation (NAO)
![Page 19: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/19.jpg)
Tahiti
Darwin
Southern Oscillation Index Centres
![Page 20: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/20.jpg)
![Page 21: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/21.jpg)
![Page 22: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/22.jpg)
![Page 23: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/23.jpg)
![Page 24: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/24.jpg)
![Page 25: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/25.jpg)
SEP 97
![Page 26: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/26.jpg)
![Page 27: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/27.jpg)
![Page 28: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/28.jpg)
![Page 29: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/29.jpg)
![Page 30: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/30.jpg)
![Page 31: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/31.jpg)
![Page 32: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/32.jpg)
http://www.pmel.noaa.gov/tao/realtime.html
![Page 33: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/33.jpg)
Lecture Outline
• El Nino - Southern Oscillation (ENSO): • definition
• impacts on climate
• ways of measuring ENSO
• some past ENSO events
• North Atlantic Oscillation (NAO)
![Page 34: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/34.jpg)
(A)
(C)
(D)
(B)
INDEX CYCLE
![Page 35: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/35.jpg)
North Atlantic Oscillation
• Pattern of Climate Variability that determines weather and climate in N.Atlantic
• Controls much of the month to month variability of temerpature and rainfall in N.W. Europe
![Page 36: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/36.jpg)
North Atlantic Setting
• High Pressure over the Azores
• Low Pressure over Iceland
• Westerly wind
• low pressure systems (rain) travel in the westerlies
![Page 37: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/37.jpg)
North Atlantic Oscillation
• Azores high and Icelandic Low are the centres
• Azores high can weaken or strengthen
• Icelandic low can weaken or strengthen
![Page 38: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/38.jpg)
![Page 39: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/39.jpg)
North Atlantic Oscillation
• High Phase• Azores High strong• Icelandic Low deep• westerlies strong• wind and rain • mild conditions in UK• dry conditions in
Spain
• Low Phase• Azores high weak• Icelandic Low shallow• westerlies weak• clear and still• cold and dry• wet conditions in
Spain
![Page 40: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/40.jpg)
![Page 41: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/41.jpg)
![Page 42: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/42.jpg)
![Page 43: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/43.jpg)
![Page 44: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/44.jpg)
![Page 45: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/45.jpg)
![Page 46: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/46.jpg)
Temperature
![Page 47: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/47.jpg)
![Page 48: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/48.jpg)
Rainfall
![Page 49: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/49.jpg)
![Page 50: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/50.jpg)
![Page 51: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/51.jpg)
![Page 52: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/52.jpg)
Readings: NAO• Barry and Chorley 1997 pg 146-148, 281-282• Morton, O. (1998). The storm in the machine. New
Scientist 157: 22-27.• * Hurrell, J.W. (1995). Decadal trends in the North
Atlantic oscillation: regional temperatures and precipitation. Science 269: 676-679.
• Lamb, P.J. and Peppler, R.A. (1987). North Atlantic Oscillation: Concept and an application. Bulletin American Meteorological Society 68: 1218-1225.
• Washington, R. and Palmer, M. 1999 North Atlantic Oscillation, Geography Review
![Page 53: Climatology Lecture 8](https://reader036.vdocuments.us/reader036/viewer/2022062315/5681403d550346895dabaf58/html5/thumbnails/53.jpg)
Past Paper Questions…
• What circulation anomalies would lead to EITHER a cold month in winter OR a warm month in summer in NW Europe (2003)
• Explain the circumstances and mechanisms which would produce relatively warm, wet winters in the British Isles. (2001)
• In what ways do ocean temperatures influence the operation of atmospheric processes? (2001)
• Show the importance of ocean-atmosphere interactions for understanding interannual climatic variability in the tropics. (2000)
• Outline the North Atlantic Oscillation and its role in influencing climate (1999)
• Describe one important pattern of climate variability. (1998)• Water plays a crucial role in the workings of weather and climate. Disucss
(1997)• What role do the oceans play in the general circulation of the atmosphere?
(1996)