Hi, Jason.

Thanks very much for the information. That answers my question. I may e-mail the NOAA ESRL PSD folks to ask about the differences I saw. If I do I'll let you know what they say.

Thanks again.

Arliss

On Mon, Nov 3, 2014 at 11:52 AM, Jason Roberts <> wrote:

Bryan, Arliss,

 

To determine ONI episodes when binning rasters into ENSO phases, MGET uses this logic:

 

1.    Download this table: http://www.esrl.noaa.gov/psd/data/correlation/oni.data. This is the same URL that Bryan sent, and is the one that appears on this page under ONI. However, I see that it only goes through March 2013, while the ensoyears.html page that Arliss referenced (which I am familiar with) extends through summer 2014. Both tables supposedly originate with NOAA CPC. I’m not sure why the former one (that MGET uses) is not more up to date. If this is a problem, could you try contacting the NOAA ESRL PSD folks that host the oni.data page? If you do that, please CC me.

 

2.    Iterate through the table looking for spans of five or more consecutive months with values >= 0.5 or <= -0.5 and classify them as El Nino or La Nina episodes respectively. Spans of four or fewer months, and months with values between -0.5 and 0.5 are “normal” episodes. The five month threshold was based on the documentation on the ensoyears.html page.

 

Does that answer your question?

 

I have not looked at the detrend.nino34.ascii.txt file. It sounds like that is the basis from which CPC derives ONI. In any case, MGET does not read that file.

 

Jason

 

From: Arliss Winship - NOAA Affiliate [mailto:]
Sent: Monday, November 03, 2014 10:21 AM
To: Bryan Costa - NOAA Affiliate
Cc:
Subject: [mget-help] Re: Question about ENSO monthly binning

 

Hi, guys.

 

Yeah, I was mainly wondering whether the MGET tool uses the ONI index (and phases) from the table shown here:

 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml

 

Or if it calculates the ONI and identifies phases on the basis of the methods described on that webpage along with the monthly data served here:

 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/detrend.nino34.ascii.txt

 

The reason I ask is that the latter can produce slightly different results (e.g., phases) depending on the numerical precision of the calculations.

 

Thanks!

 

Arliss

 

 

 

On Mon, Nov 3, 2014 at 10:15 AM, Bryan Costa - NOAA Affiliate <> wrote:

Hi Jason,

 

I'm writing because I was hoping to get more information about how MGET tools use the ONI table to bin rasters into ENSO phases (Arliss, please feel to jump in). 

 

The reason that I ask is we'd like to bin other oceanographic products (namely eddy probabilities and HYCOM surface currents/temp) in the same way, and would like to make sure our methods are consistent across all our predictor variables.

 

Many thanks,

Bryan Costa

 

--

Bryan Costa

Geospatial Scientist

CSS-Dynamac 

 

NOAA|CCMA|Biogeography Branch

1305 East West Highway

N-SCI-1, SSMC 4, 9th Floor, #9232

Silver Spring, MD 20910

 

Phone: (301) 713-3028 x146

Fax: (301) 713-4384

Email:

http://ccma.nos.noaa.gov/about/biogeography/

 

The contents of this message are mine and do not necessarily reflect any position of NOAA

 

--

Arliss Winship

 

NOAA National Ocean Service (NOS)

National Centers for Coastal Ocean Science (NCCOS)

Center for Coastal Monitoring and Assessment (CCMA)

Biogeography Branch

Contractor, CSS-Dynamac Inc.

1305 East-West Hwy, SSMC-4, N/SCI-1, #9245

Silver Spring, MD 20910

USA

 

Tel: +1-(301)-713-3028 ext. 200

Fax: +1-(301)-713-4384

http://ccma.nos.noaa.gov/about/biogeography/

 

*******************************************

Disclaimer: Any views or opinions expressed in this message are those of the sender, and do not represent official views of NOAA, the United States Government or its agents, or CSS-Dynamac Inc.

--

Arliss Winship

NOAA National Ocean Service (NOS)

National Centers for Coastal Ocean Science (NCCOS)

Center for Coastal Monitoring and Assessment (CCMA)

Biogeography Branch

Contractor, CSS-Dynamac Inc.

1305 East-West Hwy, SSMC-4, N/SCI-1, #9245

Silver Spring, MD 20910

USA

Tel: +1-(301)-713-3028 ext. 200

Fax: +1-(301)-713-4384

http://ccma.nos.noaa.gov/about/biogeography/

*******************************************

Disclaimer: Any views or opinions expressed in this message are those of the sender, and do not represent official views of NOAA, the United States Government or its agents, or CSS-Dynamac Inc.