ENSO and Monsoons October 20.

ENSO and MonsoonsENSO and Monsoons

October 20October 20

http://www.pmel.noaa.gov/tao/elnino/nino-home.html#

05

10152025

3035

Winter(JFM)

Spring(AMJ)

Summer(JAS)

Fall(OND)

-50510152025303540

50-y mean

El Niño mean, 1950–99La Niña mean, 1950–99

50-y mean

Discharge (m3s-1)

Precipitation (in.)Tampa Bay area

Hillsborough River

El Niño mean, 1950–99La Niña mean, 1950–99

ENSO IndicesENSO Indiceshttp://ioc3.unesco.org/oopc/state_of_the_oceanhttp://ioc3.unesco.org/oopc/state_of_the_ocean

/all//all/

Niño 1+2

Indian Ocean is different from other basins – bounded by Asian land mass to the north- leads to seasonal monsoon climate-Indian peninsula densely populated(see http://www.crseo.ucsb.edu/esrg/IOM2/Start2_IOM.html)

Differential heating/cooling of Tibet Plateau and Indian Ocean drives monsoon wind systems

From Schott and McCreary, 2001, Progress In Oceanography Volume 51, Issue 1 , Pages 1-123

From Schott and McCreary, 2001, Progress In Oceanography Volume 51, Issue 1 , Pages 1-123

From Schott and McCreary, 2001, Progress In Oceanography Volume 51, Issue 1 , Pages 1-123

Mean is Meaningless!

Image of the MODIS/Terra sea surface temperature (SST) and SeaWinds vectors from the week beginning on April 22, 2004

MODIS 11 µm SST from the month of July, 2003

A schematic representation of identified current branches during the Southwest Monsoon, including some choke point transport numbers (Sv=106m3s−1). Current branches indicated are the South Equatorial Current (SEC), South Equatorial Countercurrent (SECC), Northeast and Southeast Madagascar Current (NEMC and SEMC), East African Coast Current (EACC), Somali Current (SC), Southern Gyre (SG) and Great Whirl (GW) and associated upwelling wedges, Socotra Eddy (SE), Ras al Hadd Jet (RHJ) and upwelling wedges off Oman, West Indian Coast Current (WICC), Laccadive High and Low (LH and LL), East Indian Coast Current (EICC), Southwest and Northeast Monsoon Current (SMC and NMC), South Java Current (JC) and Leeuwin Current (LC). From Schott and McCreary, 2001, Progress In Oceanography Volume 51, Issue 1 , Pages 1-123

Southwest (Summer) Monsoon Currents

Northeast (Winter) Monsoon Currents

From Schott and McCreary, 2001, Progress In Oceanography Volume 51, Issue 1 , Pages 1-123

Near-Surface Circulation and Salinity in Somali Current showing Great Whirl, Southern Gyre, and Socotra Eddy (from IFM-Univ. Kiel - http://www.ifm.uni-kiel.de/fb/fb1/po1/research/woce/woce-io.html)

From Schott and McCreary, 2001, Progress In Oceanography Volume 51, Issue 1 , Pages 1-123

http://www7320.nrlssc.navy.mil/http://www7320.nrlssc.navy.mil/global_nlom32/ind.htmlglobal_nlom32/ind.html

Chlorophyll from CZCS

April 1979 Composite

August 1979 Composite

Eastward Wyrtki Jets form along equator during Spring and Fall Monsoon TransitionsDriven by W-E (westerly) winds in resonance with Equatorial Kelvin and Rossby Waves

From Schott and McCreary, 2001, Progress In Oceanography Volume 51, Issue 1 , Pages 1-123

Mean velocity sections across Indian Ocean western boundary currents for a) Northeast Madagascar Current at Cape Amber (westward is positive); b) Southeast Madagascar Current at 23°S (southward is positive), both from Swallow et al. (1988); and c) Somali Current on the equator (northward is positive) during the summer monsoon (left), during the winter monsoon (middle) and annual mean (right; from Schott et al., 1990)

Indian Ocean Dipole ModeFrom TOPEX altimeter

The development of the Indian Ocean Dipole Mode according to Webster et al. (1999, their Fig. 4).

Break/Active Monsoon

From Krishnan et al., GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L08711, doi:10.1029/2006GL025811, 2006