I believe this is the paper that describes the data set:
In their Climate Indices webpage, the Royal Netherlands Meteorological Institute (KNMI) has an interesting historical data set available for downloading: Atlantic Meridional Overturning Circulation (AMOC).
Climate Indices webpage:
ORA-S3, MOC [Sv] Meridional Overturning Circulation at 26N webpage:
MOC Data in text form:
The monthly data set begins in January 1961 and ends in December 2005. The units are Sverdrup (Sv), where 1 Sv is equal to a volume flow rate of 10^6 cubic meters per second. The notation “ORA-S3” at the top of the data page indicates the source, which is the European Centre for Medium-Range Weather Forecasts (ECMRF). Their webpage:
Chasing the data set farther, the ECMRF’s ORA-S3 System is described beginning on page 9 of their Autumn 2007 newsletter:
Enough with the background.
ATLANTIC MERIDIONAL OVERTURNING CIRCULATION DATA
Figures 1 and 2 illustrate the Atlantic Meridional Overturning Circulation (AMOC) Data from January 1961 to December 2005. In Figure 1, the data is raw. The data has been smoothed with a 12-month running average filter in Figure 2 to remove the monthly noise. At first glance, the graph of the data set doesn’t appear similar to any other data I’ve run across to date, and the 1972 spike does not to correlate with any of the usual suspects: volcanic aerosols or ENSO.
The representation of AMOC bears no resemblance to the AMO. Refer to Figure 3.
The AMOC curve does not appear to have a basis in the High Latitude North Atlantic SST anomalies, Figure 4. Since that’s the area of AMOC subsidence, it seemed possible there might be a correlation. There’s not.
Maybe we need to change the appearance.
INVERTED ATLANTIC MERIDIONAL OVERTURNING CIRCULATION DATA
In Figure 5, the AMOC data has been inverted (multiplying it by -1). There are times when the inverted AMOC data may correlate with ENSO.
Figure 6 is a comparative graph of Inverted AMOC and NINO3.4 SST anomalies. I have not scaled the NINO3.4 data. I simply shifted it, changing its temperature range. Prior to 1977, there seems to be no correlation between NINO3.4 and Inverted AMOC. But, from the early 1977 to present, they correlate very well, with the exceptions of in-phase then out-of-phase response to the 1997/98 El Nino. What took place just before 1977? The Great Pacific Climate Shift of 1976.
Keep in mind that the AMOC data has been inverted in Figure 6 and that it illustrates that an increase in NINO3.4 SST anomaly causes a decrease in AMOC flow during most ENSO events from 1977 to present.
The source of the AMOC data is discussed in the Introduction of this post.
The Smith and Reynolds Extended Reconstructed SST (ERSST.v2) data is available through the NOAA National Operational Model Archive & Distribution System (NOMADS).http://nomads.ncdc.noaa.gov/#climatencdc