GCOS GOOS WCRP/OOPC IX/3 

page 38 

ANNEX III 

SEA SURFACE TEMPERATURE VARIABILITY  

FOR 29 MAY 2003 THROUGH 26 MAY 2004 

Richard W. Reynolds 

National Climatic Data Center 

NESDIS, NOAA, Asheville, NC 

The  sea  surface  temperature  (SST)  variability  is  based  on  the  weekly  optimum 

interpolation (OI) analyses of Reynolds et al. (2002) and is shown as anomalies with respect 

to a1971 2002 climatological base period. To best demonstrate the changes between 2003 and 

a more typical period, figure 1 shows the mean and standard deviation of the weekly anomaly 

for the 14 year period beginning in 1990 and including 2003. The top panel in figure 1 shows 

the  mean  anomaly.  This  field  is  very  flat  with  indications  of  small  positive  anomalies 

occurring  primarily  in  the  tropics  and  in  the  North  Atlantic.  These  anomalies  are  primarily 

due to the overall global warming of SSTs that has been occurring since the 1970s. The lower 

panel shows strong SST anomaly variability in the eastern and central tropical Pacific due to 

ENSO events. This period includes the strong El Nino event of 1997 1998. In addition, there 

is  indication  of  important  variability  in  middle  latitudes,  especially  in  the  Northern 

Hemisphere. 

The  mean  and  standard  deviation  of  the  anomaly  for  29  May  2003  through  26  May 

2004  is  shown  in  figure  2.  The  upper  panel  of  figure  2  shows  that  the  mean  anomaly  has 

stronger  signals  than  the  same  panel  in  figure  1.  There  are  positive  anomalies  greater  than 

0.6

o

C in the central and western Pacific tropical Pacific and in most of the Atlantic north of 

30

o

S.  The  positive  anomalies  are  even  stronger  between  50

o

N  and  70

o

N  with  some  regions 

with  anomalies  above  1.8

o

C.  The  lower  panel  of  Figure  2  shows  the  anomaly  standard 

deviation.  Here  the  major  variability  occurs  in  northern  middle  latitudes  with  little  tropical 

Pacific variability because the weak El Nino event which ended in March 2003. The ENSO 

signal is much clearly much weaker than the signal shown in figure 1. 

Time  series  of  the  SST  anomalies  are  now  examined  in  two  regions  from  January 

1997  through  28  May  2004.  The  upper  panel  in  figure  3  shows  the  time  series  of  the  SST 

anomaly  averaged  over  most  the  North  Atlantic  between  50

o

N  and  70

o

N.  This  time  series 

shows  a  strong  positive  anomaly  >1

o

C  which  lasted  from  July  2003  through  the  end  of 

October  2003.  This  warming  is  the  oceanic  signature  of  the  heat  wave  which  occurred  in 

Europe  in  the  summer  of  2003.  During  this  period  the  Climate  Prediction  Center s  North 

Atlantic Oscillation (NAO) Index, which is defined from sea level pressure, showed a positive 

NAO  signal  which  is  associated  with  a  European  climate  which  is  cooler  and  wetter  than 

normal. However, the NAO link with climate is primarily for the winter season. Please note 

that there is a drop in the SST anomaly at the end of May 2004. This drop is over 1

o

C from 

the highest value in the summer of 2003. However, this drop brings the SSTs closer to normal 

and  is  and  clearly  suggests  that  the  7

o

C  drop  depicted  in  the  movie  "The  Day  After 

Tomorrow" is not occurring. 

The  lower  panel  of  figure  3  shows  a  time  series  of  SST  anomalies  in  the  tropical 

eastern  Pacific  between  10

o

S  and  10

o

N  for  a  region  often  referred  to  as  the  Nino 3  region. 

Here the strong El Nino warming of 1997 is clearly evident. In 2002 2003 there was a weak 

El  Nino  which  ended  in  March  2003.  The  Climate  Prediction  center  has  predicted  normal,