Following is a chart comparing the 2009-10 El Niño to other warm ENSO episodes that have occurred since 1950. The warm episodes are based on the Oceanic Niño Index (ONI) and are those specified in the CPC's tabulation of Cold & Warm Episodes by Season. A description of the parameters follows the chart. With the exception of 1951-52, a GWO phase space plot is included for each warm episode. Data for 2009-10 will be updated periodically.
|
Year
|
Nov-Mar
AAM
|
Peak MEI
|
Peak MEI Season
|
Peak
ONI
|
Peak ONI Season
|
L.A. Rain
|
GWO
Phase Plot
|
| 1951-521 |
-- |
0.856 |
JULAUG |
0.8 |
SON |
26.21 |
-- |
| 1957-582 |
0.773 |
1.470 |
DECJAN, JANFEB |
1.7 |
DJF |
21.13 |
|
| 1963-64 |
0.046 |
0.858 |
OCTNOV, DECJAN |
1.0 |
OND, NDJ |
7.93 |
|
| 1965-66 |
-0.748 |
1.485 |
JULAUG |
1.6 |
OND, NDJ |
20.44 |
|
| 1968-69 |
0.513 |
0.834 |
JANFEB |
1.0 |
DJF, JFM |
27.47 |
|
| 1972-733 |
-0.239 |
1.804 |
JUNJUL |
2.1 |
NDJ |
21.26 |
|
| 1976-77 |
-0.828 |
1.046 |
AUGSEP |
0.8 |
OND |
12.31 |
|
| 1977-78 |
1.008 |
1.007 |
SEPOCT, OCTNOV |
0.7 |
OND, NDJ, DJF |
33.44 |
|
| 1982-83 |
2.337 |
3.109 |
FEBMAR |
2.3 |
NDJ, DJF |
31.25 |
|
| 1986-874 |
0.019 |
2.128 |
APRMAY |
1.3 |
JFM |
7.66 |
|
| 1987-884 |
1.000 |
2.013 |
JULAUG |
1.6 |
JAS, ASO |
12.48 |
|
| 1991-92 |
0.808 |
2.246 |
MARAPR |
1.8 |
DJF |
21.00 |
|
| 1994-95 |
0.764 |
1.346 |
SEPOCT |
1.3 |
NDJ |
24.35 |
|
| 1997-98 |
1.481 |
2.882 |
JULAUG |
2.5 |
OND, NDJ |
31.01 |
|
| 2002-03 |
0.324 |
1.230 |
DECJAN |
1.5 |
OND |
16.49 |
|
| 2004-05 |
0.747 |
0.924 |
FEBMAR |
0.9 |
ASO |
37.96 |
|
| 2006-07 |
-0.322 |
1.288 |
OCTNOV |
1.1 |
OND, NDJ |
3.21 |
|
| 2009-105 |
0.304 |
1.502 |
JANFEB |
1.8 |
NDJ |
16.36 |
|
1. AAM and AAM tendency anomaly data for 1951-52 not available.
2. AAM anomaly is average for Jan-Mar 1958.
3. Several MEI values were near 1.8 during 1972-73.
4. Continuous episode from JAS 1986 to JFM 1988.
5. Data as of June 30, 2010. |
Nov-Mar AAM: The mean of the global relative atmospheric angular momentum anomaly for the period November 1 to March 31 of the following year. Data is from the GWO phase space data file linked on the Global Synoptic Dynamic Model page of the PSD Map Room Climate Products. Reference Weickmann and Berry, 2008.
Peak MEI: The peak seasonal value of the Multivariate ENSO Index (MEI). Reference Wolter and Timlin, 1993, 1998.
Peak MEI Season: The peak bi-monthly season(s) for which the MEI is computed.
Peak ONI: The peak Oceanic Niño Index (ONI) based on SST anomalies in the Niño 3.4 region. Reference Climate Prediction Center Cold & Warm Episodes by Season (1971-2000 climatology).
Peak ONI Season: The peak tri-monthly season(s) for which the ONI is computed.
L.A. Rain: The water year precipitation total in inches for Downtown Los Angeles (USC). Reference NWS Los Angeles/Oxnard Downtown Los Angeles Climate Page, 1921-2006 Water Year Rainfall.
GWO Phase Space Plot: Plot of global relative atmospheric angular momentum anomaly vs. global relative atmospheric angular momentum tendency anomaly for the period November 1 to March 31 of the following year. Data is from the GWO phase space data file linked on the Global Synoptic Dynamic Model page of the PSD Map Room Climate Products. Reference Weickmann and Berry, 2008.