Meso-Scale climatic variability?

1. Meso-Scale climatic variability? • Only recently have we identified meso-scale cycles such as ENSO (El Nino Southern Oscillation Event) “...in the late 1960s a Norwegian meteorologist, Jacob Bjerknes, was the first to see a connection between unusually warm sea-surface temperatures and the weak easterlies and heavy rainfall that accompany low-index conditions” http://library.thinkquest.org/20901/overview_1.htm • The North Atlantic Oscillation “Probably the biggest and most powerful of these climate phenomena is the aptly named North Atlantic Oscillation (NAO). While the North Atlantic Oscillation doesn't generate the catastrophic floods, climate changes, and carnage associated with El Niño, its effects are much more consistent and nearly as widespread.” http://earthobservatory.nasa.gov/Study/NAO/

3. Eckman Spiral & Upwelling Figure 11.19 Figure 11.18 The Coriolis force directs surface water to the right of southward blowing winds along California's coast. This creates an Eckman spiral of ocean transport which removes water from the coast, and is then replaced by the upwelling of deeper water.

4. Cold Water Upwelling Maps of west coast sea surface temperature indicate regions of significantly cooler water that has up welled from below. Figure 11.17

6. Causes

8. El Niño Conditions • Interactive el niño • http://www.gfdl.noaa.gov/products/vis/gallery/ • Thermocline

9. NORMAL VS ENSO FACTS

10. Menlo Park, CAelevated sea level from the 1982 El Niño and large storm waves

12. Fires in Indonesia caused by droughts

13. CNN report

14. El Niño Facts • First discovered in 1795 • Most recent and severe El Niños were in: 1953, '57-'58, '65, '72-'73, '76-'77, '82-'83, '87-'88, and '97-'98, '02-'03 • Implies El Niño occurs in cycles • Occurs every 2 to 10 years • Lasts from 3 to 15 months • Often results in natural disasters • Normally develops in the western tropical Pacific • El Niño means The Little Boy or Christ. This name was used for the tendency of the phenomenon to arrive around Christmas.

15. https://www.fnmoc.navy.mil/products/OTIS/US058VMET-GIFwxg.OTIS.glbl_sstclimate.gifhttps://www.fnmoc.navy.mil/products/OTIS/US058VMET-GIFwxg.OTIS.glbl_sstclimate.gif

16. Meso Scale climatic cycles… ENSO http://www.cdc.noaa.gov/map/clim/sst_olr/sst_anim.shtml

17. Ocean Oscillations Figure 11.20A In the southern Pacific Ocean, high pressure in the east pushes surface winds, and waters, toward the low in the west. This Walker Circulation becomes disrupted during El Nino events, which impacts upwelling and rains.

18. El Nino Kelvin Wave Figure 11.21 Satellite imagery shows the eastward movement of higher ocean levels, or Kelvin wave, in white and red colors, caused by the reversal of the Walker Circulation and El Nino event.

19. Pacific Decadal Oscillation Figure 11.26A

20. El Nino Ocean Temperature Satellite data of sea surface temperature (SST) illustrate the difference between a non-El Nino year, with cool easterly waters, and the warmer SST El Nino year. Figure 11.22A

22. ENSO Index Figure 11.23 El Nino Southern Oscillation (ENSO) intensity has been tracked using 6 parameters, including air and sea temperature, sea level pressure, wind speed and direction, and cloudiness. A graph of the ENSO index shows eastern Pacific warm El Nino and cool La Nina years.

23. US El Nino Impacts Figure 11.24A US Winter weather is impacted by El Nino & La Nina events. During El Nino, a persistent trough of low pressure in the north Pacific steers wet weather in the southern US, while La Nina brings a blocking high south of Alaska that pushes the cold weather of the Polar jet into the western states.

24. Global El Nino Impacts The El Nino Southern Oscillation (ENSO) is part of a planetary ocean-atmosphere interaction, and can take several years to run its course. ENSO causes abnormalities around the globe. Figure 11.25

27. 45 degrees N… halfway between equator and pole

29. 57.5 degrees North (same latitude as Moscow and Hudson’s Bay… semi-tropical gardens on the coast of Scotland

31. http://www7320.nrlssc.navy.mil/hhc/ias/sst.ias.20040313.gif http://www7320.nrlssc.navy.mil/hhc/