Many people use NOAA and Australia’s BOM websites to monitor El Nino-Southern Oscillation (ENSO) and to examine maps of where ENSO events impact regional temperature and precipitation. The Japan Meteorological Agency (JMA) also monitors ENSO, but they present 3 sea surface temperature-based indices. One of the regions is located in the eastern equatorial Pacific, as we’re used to, but the second one is in the western tropical Pacific, north of the equator, and the third covers the tropical Indian Ocean. What I found most interesting is that the maps of the temperature and precipitation “tendencies” rarely, if ever, show opposing effects during positive and negative phases. For example, when looking at the tendency maps for responses to NINO3 region temperatures, the seasonal impacts of La Niña are not the opposite of El Niño. No surprise there: La Niña is not the opposite of El Niño.
Unlike other presentations, the JMA maps also show temperature and precipitation impacts for Europe.
The data and “tendency maps” presented in this post are products of the Tokyo Climate Center (TCC) division of the Japan Meteorological Agency (JMA). For a starting place, see their overall El Nino Monitoring and Outlook webpage. In the upper right-hand corner of the “Main Products” menu is pink box housing “ENSO Impact” links. Clicking on the Global Climate link brings you to the webpage titled “World Climate Associated with El Niño and La Niña Events”. At the bottom of that webpage is a map (Figure 1) which shows the three regions where JMA monitors sea surface temperatures.
THE THREE REGIONS
The NINO3 region is located on the eastern equatorial Pacific, covering the coordinates of 5S-5N, 150W-90W. It’s slightly east of the NINO3.4 region (5S-5N, 170W-120W) used by NOAA for their ONI index. The sea surface temperature anomalies of the NINO3 region are one of the commonly used indices for the timing, strength and duration of El Niño and La Niña events, because the sea surface temperatures there are directly impacted by the coupled ocean-atmosphere processes that cause those events. The other two regions shown in Figure 1 are not as common.
I have not been able to find a simple explanation at the JMA website for why they selected the “NINO West” region as one of their indices—other than they have found the variations in sea surface temperatures alter temperatures and precipitation throughout the world. The selection of that region appears to be an attempt to capture aftereffects of the warm water left over from El Niños. The NINO-West region is bordered by the coordinates of 0-15N, 130E-15E. Sea surface temperatures in that region warm in response to La Niña events and in response to the leftover warm waters that are returned to the west at the end of El Niño events (the latter of which occurs during the transition from El Niño to La Niña. Refer to the animation showing the Rossby wave here.) They also cool in response to El Niño events, but not to the degree that the eastern equatorial Pacific warms. Logically, the sea surface temperatures of the NINO-West region vary inversely, though not proportionally, with the NINO3 temperatures. And as we’ll see later in this post, the impacts on global precipitation and temperature in response to the warming and cooling of the NINO-West region are not the opposite of the NINO3 region.
We can find explanations for why temperatures are monitored in the Indian Ocean Basin Wide (IOBW) region, which are based on the coordinates of the tropical Indian Ocean (20S-20N, 40E-100E). (As opposed to using the acronym, I’m going to hyphenate Indian-Ocean-Basin-Wide.) A paper that discusses the Indian-Ocean-Basin-Wide index is Tachetto et al (2011) The contribution of Indian Ocean sea surface temperature anomalies on Australian summer rainfall during El Niño events. Tachetto et al (2011) write, referring to the lagged effects of El Niño events on the sea surface temperatures of the tropical Indian Ocean:
Xi et al. (2009) hypothesized that the ENSO-induced Indian Ocean warming acts as a capacitor for the Indo-western Pacific climate. The peak of El Niño events during late austral spring-early summer leads to a warming of the tropical Indian Ocean (‘charging’ the capacitor). The basin-wide warming is maintained via ocean-atmosphere interactions within the tropical Indian Ocean as described by Du et al. (2009) and persists through austral winter after the eastern Pacific SST anomalies have dissipated. The persistent Indian Ocean basin wide warming then acts as a discharging capacitor, exerting a delayed influence on the northwestern Pacific climate via a Gill-Matsuno response. Recently, Huang et al. (2010) showed that the tropical Indian Ocean and the Northwest Pacific climate relationship has strengthened since the mid-1970 due to the intensification and persistence of the El Niño-induced Indian Ocean SST anomalies during the boreal summer.
The JMA presents the sea surface temperature-based NINO3 and NINO-West data in a number of formats, but they only provide the Indian-Ocean-Basin-Wide data as a deviations from sliding 30-year base periods. Refer to their JMA data page here. Because the Indian-Ocean-Basin-Wide data is only presented in that format, I’ve presented the other two indices in it as well in the following comparisons.
THEREFORE, YOU HAVE TO KEEP IN MIND THAT THE FOLLOWING GRAPHS DO NOT PRESENT SEA SURFACE TEMPERATURE ANOMALIES.
Figures 2 and 3 illustrate the 3 ENSO-related indices. Both graphs present the data smoothed with 12-month running-average filters. Figure 2 starts in January 1949, while Figure 3 starts in January 1980 to provide a closer view of the more recent data. Again, for their respective regions, they represent the deviations from the sliding 30-year base periods of sea surface temperatures. The NINO3 region has the greatest variability because it is directly impacted by the warm water released by El Niños and because it is directly impacted by the additional upwelling of cool subsurface waters during La Niñas. The variations of the Indian-Ocean-Basin-Wide index are of the same sign as the NINO3 data—meaning they warm during El Niños and cool during La Niñas—but the Indian-Ocean-Basin-Wide index lags the NINO3 data. On the other hand, the NINO-West data is inversely related to the NINO3 data, meaning it cools during El Niños and warms during La Niñas.
For illustrative purposes, the same data for the same periods are illustrated in Figures 4 and 5, but the data have been standardized in those graphs. The standard deviation for the NINO3 data is 0.86 deg C, for the NINO-West data it’s 0.29 deg C and for the Indian-Ocean-Basin-Wide data, it’s 0.25 deg C.
The JMA presents their global maps for how surface temperatures and precipitation tend to respond during positive and negative phases of the three indices. They furnish their maps for each phase and for each season:
The methods used to create the maps are presented here.
I thought it would be interesting and helpful to present the positive and negative phases for each season alongside one another. As you’ll see, the phases, like El Niños and La Niñas, are not opposites.
One final note: I have not found a discussion of when indices dominate—though ENSO is the strongest mode of natural variability.
INTERESTED IN LEARNING MORE ABOUT EL NIÑO AND LA NIÑA?
Sea surface temperature data during the satellite era and ocean heat content data since 1955 indicate that La Niña and El Niño events work as a recharge-discharge oscillator–that they are not simply noise as portrayed by the climate science community. That data also indicates the oceans have warmed naturally and that El Niño and La Niña are responsible for much of the warming. I’ve searched sea surface temperature records and ocean heat content data for more than 4 years (more than 3 years for the ocean heat content data), and I can find no evidence of an anthropogenic greenhouse gas signal. That is, the warming of the global oceans has been caused by Mother Nature, not anthropogenic greenhouse gases.
I’ve recently published my e-book (pdf) about the phenomena called El Niño and La Niña. It’s titled Who Turned on the Heat? with the subtitle The Unsuspected Global Warming Culprit, El Niño Southern Oscillation. It is intended for persons (with or without technical backgrounds) interested in learning about El Niño and La Niña events and in understanding the natural causes of the warming of our global oceans for the past 31 years. Because land surface air temperatures simply exaggerate the natural warming of the global oceans over annual and multidecadal time periods, the vast majority of the warming taking place on land is natural as well. The book is the product of years of research of the satellite-era sea surface temperature data that’s available to the public via the internet. It presents how the data accounts for its warming—and there are no indications the warming was caused by manmade greenhouse gases. None at all.
Who Turned on the Heat? was introduced in the blog post Everything You Ever Wanted to Know about El Niño and La Niña… …Well Just about Everything. The Updated Free Preview includes the Table of Contents; the Introduction; the beginning of Section 1, with the cartoon-like illustrations; the discussion About the Cover; and the Closing.
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