# Presentation: 693213

## Global Air-Sea Coupled Modes: Recent Evolution, Current Status and Prediction

**Update prepared by**
**Climate Prediction Center / NCEP**
**   ****June 6, 2007**

## Outline

**  ****Overview **
**  ****Recent Evolution and Current Conditions**
** ****Pacific Ocean**
** ****Indian Ocean **
** ****Atlantic**** Ocean**
**SST Predictions by NCEP Climate Forecast System**

## Overview

-  During the last  few months, a weak La Nina condition developed in the Pacific. The negative SST anomalies in the eastern Pacific during May 2007 are consistent with local negative heat content anomalies, which are associated with persistent easterly wind anomalies since December 2006 (slides 1, and 13-14).
-  Warm SST anomalies developed in the equatorial Indian Ocean in May 2007 where negative heat content and easterly anomalies are observed, suggesting the warm SST anomalies are associated with air-sea thermodynamic interaction (slides 20, 22 and 23).
-  Enhanced warm SST anomalies near west coast of Africa and weak westerly anomalies in the equatorial Atlantic are observed in May 2007 (slides 2 and 30).
-  The persisting cold anomalies in the Gulf of Alaska region during the last six months weakened slightly in May 2007 (slide 11).
- The triple-pole SST pattern in North Atlantic has been persistent since February 2007 (slide 28).

## Global Ocean SST Departures (oC)(Climatology 1971-2000)

**Global Ocean ****SST ****Departures (****oC****)****(Climatology 1971-2000)**

**May 2007**

**Positive SST departures extend from the coast of Spain to Caribbean Sea, near the east coast of Argentina, and west coast of Africa.  Negative SST departures are observed along the east coast of North America.**

**Negative SST departures are present over the Gulf of Alaska.**

**Positive SST departures are present in the equatorial Indian Ocean,  southeast of Madagascar, and near the coast of Somali and Arabia. **

**Positive SST departures are observed in the equatorial western Pacific, central-western subtropical Pacific, negative SST departures are present in the eastern equatorial Pacific. **

## Global Ocean SST Departure Tendency (oC)(Climatology 1971-2000)

**Global Ocean ****SST ****Departure Tendency (****oC****)****(Climatology 1971-2000)**

**SST anomalies increased in the equatorial Indian Ocean and northeast of Madagascar. **

**Substantial cooling near the southeast coast of North America.**

**SST anomalies decreased in the eastern Pacific, and increased in the subtropical central western Pacific. **

## Tropical Sea Surface Height Departures (cm)(Climatology 1982-2004)

**Tropical ****S****ea Surface Height Departures (cm)****(Climatology 1982-2004)**

**May2007**

**Negative SSH departures are present in the eastern equatorial Pacific, and positive SSH departures in the equatorial western Pacific and subtropical Pacific. **

**Positive SSH departures are present in the west-southern subtropical Indian Ocean and negative SSH departures are present in the east-southern subtropical Indian Ocean. **

**SSH is from the Global Ocean Data**
**Assimilation System (GODAS)**
**(****http://www.cpc.ncep.noaa.gov/products/****GODAS)**

**Positive SSH departures are present in Gulf of Guinea region. **

## Sea Surface Height Departure Tendency (cm)(Climatology 1982-2004)

**S****ea Surface**** ****Height Departure Tendency (cm)****(Climatology 1982-2004)**

**SSH increased in the Gulf of Guinea region.**

**SSH decreased in the far eastern equatorial Indian. **

## Tropical  Cyclone Heat Potential 

**Climatology: TCHP    1982-2004**
**Tropical Cyclone Heat Potential (TCHP),  which measures potential energy stored from the surface to the depth of 26oC isotherm,  is derived from the Global Ocean Data**
**Assimilation System (GODAS)**
**(****http://www.cpc.ncep.noaa.gov/products/****GODAS)**

**TCHP has the largest amplitude in the western Pacific and tropical Indian Ocean. Currently, TCHP is above-average in the western Pacific with a maximum extending from west of New Guinea to 160oW and 10oS.**
**A east-west dipole of TCHP anomalies is located along 10oS in the Indian Ocean.**
**The tropical Atlantic is close to normal conditions in May 2007.**

**Tropical **** Cyclone Heat Potential **

## Pacific Ocean

## Pacific Ocean SST Departures (oC)(Climatology 1971-2000)

**Pacific Ocean ****SST ****Departures (****oC****)****(Climatology 1971-2000)**

## Recent Evolution of SST Departures in the Central and Eastern Pacific

**During ****the past 12 months, the zonal average SSTs in 160****o****E-150****o****W have been above-average between 20****o****S and 2****o****N with anomalies greater than ****+1o**** during September to December 2006, accompanied by northern midlatitude positive and southern midlatitude negative anomalies. **

**During ****the past 12 months, the zonal average SSTs in 150oW-100oW have been above-average between 10oS and 5oN during September 2006 to January 2007, and below-average afterwards. The SSTs between 40oN and 60oN** **have been below-average from December 2006 to April 2007, and those between 50oS-35oS have been above-average during December 2006  to February 2007.   **

**Time**

**Latitude**

**Recent Evolution of SST ****Departures ****in the Central and Eastern Pacific**

## Recent Evolution of Pacific NINO SST Indices

** ****NINO 4 SST increased gradually from 0.5oC in August to 1.4oC in November-December, and then decreased rapidly in January 2007 to about 0.5oC. It is below 0.5oC in May 2007.**
** ****NINO 3.4 increased from near neutral in July to about 1.3oC in November-December, and then decreased rapidly to near neutral in February 2007, and remains neutral since then.  The anomaly started to become negative in May 2007.**
** ****NINO 3 increased from near neutral in July to about 1.1oC in November-December, and then decreased rapidly to below-average in March 2007. It is in below -0.5oC in May 2007.**
** ****NINO 1+2 increased from near neutral conditions in June to about 1.4oC in October, and then decreased gradually. It became below-average since March 2007. **

## Recent Evolution of Equatorial Pacific SST (shaded) and Surface Zonal Wind (contour) Departures

**Recent Evolution of Equatorial ****Pacific ****SST**** (shaded)**** ****and Surface Zonal Wind (contour) Departures**

**Longitude**

**Time**

**Between ****July**** 2006 and December 2006, positive SST anomalies increased across the equatorial Pacific between 160oE and the South American coast.**
**During January-February 2007, SST anomalies decreased everywhere east of the Date Line.**
**During December 2006 -May 2007, easterly wind anomalies are present between 160oE and 160oW.**

**Above-average SST departures are accompanied by westerly wind anomalies to the west of SST anomalies.**

**Climatology: SST    1971-2000**
**Reanalysis-2 850 mb winds  1979-1995**

## Recent Evolution of Equatorial Pacific Upper Ocean (0-300m) Heat Content and Surface Zonal Wind Departures

**Recent Evolution of Equatorial Pacific ****Upper Ocean (0-300m) Heat Content**** ****and Surface Zonal Wind Departures**

**Longitude**

**Time**

**During January-****May**** 2007, ****easterly wind anomalies were present between 160oE-160oW, consistent with the  negative heat content anomalies in the eastern Pacific.**

**Three episodes of Kelvin waves, the warm**_** **_**phases of which are indicated by the dashed lines,  were evident in heat content departures during May to December 2006. They were forced by westerly wind anomalies (contour) in the western-central Pacific.**
**One Kevin wave episode, the negative phase of which is indicated by the dotted line,  was initiated in late December 2006 by strong easterly wind anomalies.**

**Climatology: Heat Content    1982-2004**
**Reanalysis-2  850 mb wind    1979-1995**
**Heat Content is from the Global Ocean Data**
**Assimilation System (GODAS)**
**(****http://www.cpc.ncep.noaa.gov/products/****GODAS)**

## Recent Evolution of Equatorial Pacific Upper Ocean (0-300m) Heat Content and Surface Zonal Current Departures

**Longitude**

**Time**

**During January-****May**** 2007, ****negative heat content anomalies are persistent in the eastern Pacific, while ****negative surface zonal current anomalies decreased substantially in early March. **

**Three episodes of Kelvin waves, the ****warm**_** **_**phases of which are indicated by the dashed lines****, were evident in not only heat content (shaded) but also surface zonal current (contour) departures during May to December 2006.**
**One Kevin wave episode, the negative phase of which is indicated by the dotted line,  was initiated in late December 2006 and had signatures in both heat content and surface zonal current anomalies.**

**Climatology: Heat Content    1982-2004**
**      ****Surface Zonal Current    1979-1995**
**Surface zonal currents are from Ocean Surface Current Analyses – Realtime (http://www.oscar.noaa.gov)**

**Recent Evolution of Equatorial Pacific ****Upper Ocean (0-300m) Heat Content**** ****and Surface Zonal Current Departures**

## Historical Evolution of Western, Central and Eastern Equatorial Pacific Heat Content and NINO3.4 SST Departures

-  **The  ****western ****equatorial ****(120oE-160oE, 2oS-2oN) ****upper ocean (0-300 m) heat content ****anomalies (shaded) are out of phase with NINO3.4 (curve). ****But the 2004/05 and 2006/07 El Ninos are exceptions.**
** ****The central equatorial (160oE-150oW, 2oS-2oN) heat content anomalies are ****greatest prior to and during the early stages of a Pacific warm (El Niño) episode and least prior to and during the early stages of a cold (La Niña) episode.**** **
** ****The ****eastern equatorial (150oW-100oW, 2oS-2oN) heat content anomalies are largely in phase with NINO3.4, but ****leads the later by a few months during onsets of La Nina and decays of El Nino. **

**Climatology: SST    1971-2000**
**                      ****Heat Content  1982-2004**

**Historical Evolution of Western, Central and Eastern Equatorial ****Pacific ****Heat Content and NINO3.4 SST Departures**

## Recent Evolution of Western, Central and Eastern Equatorial Pacific Heat Content and NINO3.4 SST Departures

** ****The central equatorial (160oE-150oW, 2oS-2oN) heat content anomalies remained above 0.5oC increased slowly from Jun to November 2006 and then decreased rapidly during November-December 2006. It has been close to normal conditions since February 2007.**
** ****The ****eastern equatorial (150oW-100oW, 2oS-2oN) heat content anomalies had increased from Jun to December 2006 with a few large fluctuations and then decreased rapidly to -1oC in February 2007. ****Note that negative heat content anomalies have not lead to substantial negative NINO3.4 anomalies yet. **

**Recent Evolution of Western, Central and Eastern Equatorial ****Pacific ****Heat Content and NINO3.4 SST Departures**

## Tropical Pacific OLR and Wind Anomalies

**Negative OLR anomalies (enhanced convection and precipitation, blue shading) were observed in the far eastern Pacific north of the equator, while positive OLR anomalies (suppressed convection, orange shading) were present in the equatorial central-eastern Pacific.**

**Weak low-level (850-hPa) easterly wind anomalies were observed across the central equatorial Pacific****, and weak lower-level westerly wind anomalies were observed in the eastern Pacific north of the equator.**

**Equatorial upper-level (200-hPa) westerly (easterly) anomalies are observed to the west (east) of 140W.**

**Climatology: OLR    1979-1995**
**                      ****Winds  1979-1995**

## Indian Ocean

## Indian Ocean SST Departures (oC)(Climatology 1971-2000)

**Indian Ocean ****SST ****Departures (****oC****)****(Climatology 1971-2000)**

**Positive SST departures are present in the equatorial Indian Ocean,  southeast of Madagascar, and near the coast of Somali and Arabia. **

## Recent Evolution of Indian Ocean Dipole Indices

** ****Negative ****SETIO was observed in September-November-December 2006. It has been above normal most of the time since December 2006.  It is about 0.5oC near the end of May 2007.  **
**WTIO has been about 0.5oC above average since November 2006.**
** ****DMI increased rapidly from neutral to +1.5oC in August 2006, persisted during September-October, and then decreased rapidly in November-December 2006. It has been close to normal conditions since January 2007. **

**SETIO: SST anomaly in 90oE-110oE, 10oS-0.**
**WTIO:  SST anomaly in 50oE-70oE, 10oS-10oN.**
**DMI = WTIO - SETIO**

## Recent Evolution of Equatorial Indian SST (shaded) and Surface Zonal Wind (contour) Departures

**Longitude**

**Time**

**Recent Evolution of Equatorial ****Indian ****SST**** (shaded)**** ****and Surface Zonal Wind (contour) Departures**

**Between ****September and****  ****Nove****mber 2006, negative SST anomalies**** developed in the far eastern equatorial Indian Ocean, accompanied by easterly wind anomalies in the central-eastern Indian Ocean. **
**During Jun-December 2006,** **SSTs in the central Indian Ocean were mostly above-average, and warm anomalies extended to the western Indian Ocean during August-December 2006.**
**Since January 2007, SSTs are above-average in the western Indian Ocean, accompanied by weak westerly wind anomalies in the central-eastern Indian Ocean.**
**The warm anomalies extended into the central Indian Ocean but with appearance of easterly winds in May 2007.**

**Climatology: SST    1971-2000**
**                       ****850 mb winds  1979-1995**

## Recent Evolution of Equatorial Indian Upper Ocean (0-300m) Heat Content and Surface Zonal Wind Departures

**Longitude**

**Time**

**Westward propagating Rossby waves, indicated by dashed and dotted lines for positive and negative phases, were observed between November 2006 and March 2007. **
**In response to the westerly wind anomalies since late March 2007, positive heat content anomalies were generated in the far eastern Indian Ocean in late April and early May 2007.**
**In late May 2007, negative heat content anomalies developed in association with easterly anomalies in the central Indian Ocean.**

**Negative heat content anomalies in the eastern Indian Ocean were accompanied by easterly wind anomalies in the central Indian Ocean in June 2006, and during mid August to November 2006.**

**Recent Evolution of Equatorial ****Indian**** ****Upper Ocean (0-300m) Heat Content**** ****and Surface Zonal Wind Departures**

**Climatology: Heat Content    1982-2004**
**                       ****850 mb wind    1979-1995**
**Heat Content is from the Global Ocean Data**
**Assimilation System (GODAS)**
**(****http://www.cpc.ncep.noaa.gov/products/****GODAS)**

##   Recent Evolution of Heat Content (shaded) and SST (contour) Departures along 10oS in the Indian Ocean

**  ****Recent Evolution of Heat Content**** ****(shaded) and SST (contour) Departures along ****10****o****S**** in the Indian Ocean**

**Longitude**

**Time**

**Negative SST anomalies less than -1oC collocated with negative heat content anomalies near the coast of Java during June-July 2006. **
**Pronounced westward propagating Rossby waves, indicated by dashed and dotted lines for positive and negative phases, were observed during August 2006 to May 2007.**
**Positive SST anomalies in the central Indian Ocean and negative SST anomalies in the eastern Indian Ocean propagated westward along with westward propagating heat content anomalies during August – October 2006.**
**SST departures in the eastern Indian Ocean transitioned from negative to positive in middle November, while positive SST departures in the central Indian Ocean were persistent since November 2006.**

## Tropical Indian OLR and Wind Anomalies

**Negative OLR anomalies (enhanced convection and precipitation, blue shading) were observed in the Bay of Bengal and Arabian Sea. Positive OLR anomalies were observed in the tropical Indian Ocean off the equator.**

**Anomalous lower-level (850-hPa) easterlies, southwesterlies, and westerlie****s were observed in the equatorial central Indian Ocean, western Arabian Sea, and the Bay of Bengal****.**

**U****pper-level (200-hPa) ****winds are near normal in the tropical Indian Ocean.**

**Climatology: OLR    1979-1995**
**                      ****Winds  1979-1995**

**Tropical ****Indian ****OLR and Wind Anomalies**

## Atlantic Ocean

## Atlantic Ocean SST Departures (oC)(Climatology 1971-2000)

**Positive SST departures extend from the west coast of Spain to Caribbean Sea, near the east coast of Argentina, and west coast of Africa.  Negative SST departures are observed along the east coast of North America.**

## Recent Evolution of SST Departures in the North-western Atlantic

**During ****the past 12 months, the zonal average SSTs in 80oW-40oW between 0 and 25oN** **have been mostly above-average.**
**Above-average SSTs greater than +2oC were observed between 40oN and 60oN during May to November 2006.  Starting December 2006, the anomalies decreased to about +1oC in 50oN-60oN, but switched to negative anomalies near 40oN.**
**The triple-pole SST pattern has been persistent since February 2007. **

**Recent Evolution of SST ****Departures in the North-western Atlantic**

## Recent Evolution of Tropical Atlantic SST Indices(Climatology 1971-2000)

** ****During the past 12 months, TNA has been above-average. TNA is about 0.25oC in May 2007**
** ****TSA is about 0.4oC in May 2007. **
** ****The north-south gradient mode is neutral in May 2007.**
** ****Atlantic NINO is about 0.5oC in May 2007. **

## Tropical Atlantic OLR and Wind Anomalies

**                      ****Winds  1979-1995**

**Negative OLR anomalies less than -20 W/m****2**** (enhanced convection and precipitation, blue shading) were observed in ****Gulf of Guinea and southern Sahara. **

**Anticyclonic u****pper-level (200-hPa) ****anomalies were observed in the northern subtropical Atlantic.**

**Tropical ****Atlantic ****OLR and Wind Anomalies**

**Weak lower-level (850-hPa) ****westerly anomalies were observed in the equatorial Atlantic****.**

## SST Predictions by NCEP Climate Forecast System

## SST Outlook: NCEP CFS Forecast Issued 6 Jun 2007

- The CFS ensemble mean (thick blue line) indicates a transition from neutral to La Niña conditions during the next 2-3 months.

## Nino34 SST forecast from NCEP CFS

**Forecasts From Different initial conditions**

## CFS forecast of Nino34 SST

**0-month Lead**

**1-month Lead**

**2-month Lead**

**4-month Lead**

**3-month Lead**

**For FMA 2007 as the Target; Forecasts From Different Leads**

**CFS forecast of Nino34 SST**

## Ocean temperatures at the equator (K)

## Summary

-  During the last  few months, a weak La Nina condition developed in the Pacific. The negative SST anomalies in the eastern Pacific during May 2007 are consistent with local negative heat content anomalies, which are associated with persistent easterly wind anomalies since December 2006 (slides 1, and 13-14).
-  Warm SST anomalies developed in the equatorial Indian Ocean in May 2007 where negative heat content and easterly anomalies are observed, suggesting the warm SST anomalies are associated with air-sea thermodynamic interaction (slides 20, 22 and 23).
-  Enhanced warm SST anomalies near west coast of Africa and weak westerly anomalies in the equatorial Atlantic are observed in May 2007 (slides 2 and 30).
-  The persisting cold anomalies in the Gulf of Alaska region during the last six months weakened slightly in May 2007 (slide 11).
- The triple-pole SST pattern in North Atlantic has been persistent since February 2007 (slide 28).