Second warmest March on record; will La Niña be gone by hurricane season?
March 2008 was the 2nd warmest March for the the globe on record, according to statistics released by the National Climatic Data Center. Over the Northern Hemisphere, and over all of the globe's land areas, March 2008 was the warmest March in the 128-year global record. Only the presence of a moderately strong La Niña event that cooled ocean waters in the central and eastern equatorial Pacific prevented March 2008 from surpassing March 2002 as the warmest March on record. March broke a string of three straight months when the globe did not record a top ten warmest month ever. Between February 2006 and November 2007, the globe set top ten monthly warm temperature records for 22 straight months.
Figure 1. Departure of temperature from average (the anomaly) for March of 2008, the second warmest March on record for the globe. While the U.S. recorded slightly below average temperatures, much of Asia and Europe saw remarkably warm temperatures. Image credit: National Climatic Data Center.
How much cooling did La Niña give to the globe in March?
La Niña is a periodic cooling of the Equatorial waters of the Eastern Pacific that occurs every 3-7 years. The cooling is due to a natural cycle of anomalous winds from the east that act to push surface waters away from the coast of South America, allowing cold water from deep in the ocean to rise to the surface to replace the surface waters blown to the west. These cool waters often cause a noticeable drop in global temperatures. Conversely, when the opposite phenomena occurs--an El Niño event, which brings anomalously warm Sea Surface Temperatures (SSTs) to the Equatorial Eastern Pacific, enough heat is added to the atmosphere that global temperatures warm significantly. According to Trenberth et al. (2002), a typical El Niño event increases global temperatures by about 0.1°C. Exceptional El Niño events, such as occurred in 1997-1998 and 1982-1983, increase global temperatures by up to 0.2°C. El Niño events heat the atmosphere by causing changes in cloudiness and atmospheric circulation, and through direct radiation of heat from the ocean to the atmosphere. There is a lag of 3-6 months between the time an El Niño event occurs and the time the atmosphere heats in response. Similarly, when a La Niña event occurs, heat is drawn out of the atmosphere and the oceans are recharged with heat. Global temperatures cool, again with a lag of 3-6 months. The correlation between global temperature anomalies and El Niño/La Niña temperature anomalies can be plainly seen in Figure 2. Note that the correlation is not perfect--there are some El Niño/La Niña events that do not affect the global temperature much. For example, global temperatures did not cool much during the strong 1988-1989 La Niña event. Therefore, it is a good bet--but not certain one--that had we not had a strong La Niña event this winter, March 2008 would have been the warmest March on record, since it missed the record by only 0.04°C.
Figure 2. Comparison of temperature anomalies in the equatorial Pacific Ocean bounded by a box between 5°S, 5°N, 120°W, and 180°W (the Niño 3.4 region) and global temperatures for 1950-1998. Means for 1950-1976 and 1977-1998 (horizontal lines) are shown separately to highlight a climate shift that occurred in 1976/1977. The reasons for this shift are unknown. Note that when an El Niño event occurs, the globe tends to warm by about 0.1°C, and when a La Niña event occurs, the globe tends to cool. Image credit: American Geophysical Union's Journal of Geophysical Research.
Warmest month ever stats
It is interesting to compare what the phase of El Niño/La Niña was during each of the 12 record warmest months the globe has recorded. If we adjust for the 3-6 month lag between an El Niño/La Niña event and the monthly global temperature records, it turns out that nine of the twelve monthly records were set when an El Niño event occurred during the 3-6 month period prior to the record. Considering that climatologically El Niño conditions are present only about 25% of the time, El Niño has a major impact on when record global warmth will occur. The warmest year on record, 1998, occurred during the strongest El Niño of the past century. The table below compares the 12 monthly global temperature records with the temperature in the Niño 3.4 region (a 3-month average centered four months before the record was set). El Niño events, which occur when the Niño 3.4 index is greater than 0.4°C, are marked with an "E".
Record......Niño 3.4 index
-----------------------------
Jan 2007 +0.7 E
Feb 1998 +1.7 E
Mar 2002 -0.1
Apr 1998 +2.5 E
May 1998 +2.3 E
Jun 2005 +0.5 E
Jul 1998 +1.4 E
Aug 1998 +1.1 E
Sep 2005 +0.5 E
Oct 2003 +0.0
Nov 2004 +0.7 E
Dec 2003 +0.4
Figure 3. A La Niña event exists when ocean surface temperatures in the equatorial Pacific Ocean bounded by a box between 5°S, 5°N, 120°W, and 180°W (the Niño 3.4 region) are cooler than 0.4°C below average (based on means from 1971-2000). La Niña events between 0.5°C and 0.9°C are referred to as weak, 1.0°C and 1.4°C are moderate, and 1.5°C or cooler, strong. The winter of 2007-2008 saw strong La Niña conditions, but this has weakened to a moderate event in March. Image credit: NOAA Climate Prediction Center.
An El Niño by hurricane season?
Presence of El Niño conditions usually causes enhanced levels of wind shear over the Atlantic, reducing hurricane activity, so it would be nice to see an El Niño this Fall. The strong La Niña event we had over the past winter has weakened considerably in the past two months, and is now classified as a moderate event, according to the latest El Niño discussion issued by NOAA's Climate Prediction Center. There is some hope that an El Niño will develop by hurricane season. Two of the long-range computer models are now calling for an El Niño to develop by hurricane season (Figure 4), and none of them were calling for El Niño last month. However, there is probably not time for a full-fledged El Niño event to develop, and it is expected that we will have weak La Niña or neutral conditions this hurricane season. Since reliable El Niño records began in 1950, there has never been a switch over to El Niño by hurricane season from a La Niña as strong as the one we have now. Columbia University's International Research Institute is predicting that neutral El Niño conditions are most likely for the coming hurricane season (57% chance), with a 20% chance of an El Niño, and 23% chance of a La Niña. This is pretty much what climatology says--on average, we experience El Niño conditions 25% of the time and La Niña conditions 25% of the time.
Figure 4. Computer model forecasts of El Niño/La Niña made in April. The forecasts that go above the red line at +0.5°C denote El Niño conditions; -0.5°C to +0.5°C denote neutral conditions, and below -0.5°C denote La Niña conditions. Image credit: Columbia University's IRI.
References
Trenberth, K. E., J. M. Caron, D. P. Stepaniak, and S. Worley, >Evolution of El Niño, Southern Oscillation and global atmospheric surface temperatures", J. Geophys. Res., 107(D8), 4065, doi:10.1029/2000JD000298, 2002.
I'll be in Orlando next week for the American Meteorological Society's bi-annual hurricane conference, and plan to make some quick posts during the week to update everyone on the latest hurricane research. I may make one more post before then.
Jeff Masters
Reader Comments
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Sheri
Credit given,
LOL; don't worry you'll being seeing a LOT more naked swirls, and twisters :D all in due time. I mean, yes, this is a tropical weather blog for the most part but it's nice to talk about severe weather back at home during the offseason or inacive periods.
The LLJ (Lower Level Jet) will crank up at around nightfall in the plains, and this is when we can expect the tornadoes to get cranking.
It's interesting that you included a Fox News link about the supposed "end of global warming". In case you're not aware, Fox has an "agenda" and in the case of global climate change that agenda is to deny that it exists. Why? Because that is the current line of reasoning in conservative circles. There are numerous occurences of Fox News spreading disinformation regarding climate change. One is that if a particular area of the country has an unusual cold snap, that means there is no global warming. This, of course, is not a valid argument at all as a regional cold snap says nothing about global climate change any more than a regional heat wave. Dr Masters figures showing that March 2008 was the 2nd warmest on record are factual and there is no hidden agenda included.
/rant
There are certainly natural changes happening in the atmosphere.. there ALWAYS are. And yes, it's hard to tease out how much of the warming is from humans and how much is natural. But it is fallacy to refute a hypothesis just because you don't understand it fully. If people did that, no science would ever happen.
It HAS been proven that CO2 warms the atmosphere. it also is common fact that humans are increasing the CO2 levels. What isnt known is how all the complex feedback loops in the atmosphere and ecosystems of the earth will react to this CO2. If it stays in the atmosphere, it will trap more heat on the earth, and that will affect the climate. It isn't a 'theory', its commonly known science (as is evolution). People (read: republicans) tend to ignore or clumsily try to 'disprove' any science they don't like.
One can almost smell the SAlt a coming.
False Color Big Pic Link
Thats a good post, Inyo. @ 156.
Hot and dry here today. Currently 91 f, 52 % humid.
Cicadas are screeching in the bushes, calling for rain. If the plants could screech they would be doing that too.
They all show an upward trend.
Fox news has an agenda ? Surely not. Why would anyone report false and misleading information I wonder. LOL
Dont ask me, I've never had the pleasure.
From the UN study on Climate Change.
I think the CAP is about to bust in this area...MLCINH values have fallen below 50 J/kg and according to IR and WV imagery, thunderstorm initiation is imminent. This value indicates a weak cap. High dewpoints and warm temperature advection should take care of it rather quickly.
Further north, the cap is stronger and will take longer to be broken. Although it WILL be broken, as dewpoints continue to rise and warm air is fanned into the area.
ISOLATED TO SCT SVR TSTMS MAY DEVELOP BY 22Z OVER WCENTRAL/SWRN TX.
AREA IS BEING MONITORED FOR A POSSIBLE WW.
Its up to the sheep to believe which one to go with.
Dumb sheep...
Afternoon wannabe; ya, it isn't looking very good for the US so far. Hopefully something like the position of the bermuda/azores high will change but unfortunetly it doesn't seem that likely right now.
Hey Terra...Don't want to sound like a broken record, but, you are probably right...I have been saying (like some others on here as well as you) that I think that the single most important factor this year will be the position and strength of the BH; the storms, and particularly during the Cape Verde phase, will be there; everything is going to ride on the position of the high and I hope that the US East Coast and Caribbean do not become "target rich enviornments" with folks having to deal with multiple storms a few weeks apart..........
Even with the type of high that we have in position and strength, we'll have to monitor the frequency of the troughs coming of the U.S. A weaker high gives less ridging so if the trough frequency is high then storms will have a tendency to follow the flow around the high and go out into the mid Atlantic
If that were to happen, I could live with a season full of "fish storms" but, I could not live with the wishcasters (and Trolls) on Blog who would populate here wishing for US/Caribben stike....I would have to go AWOL from the Blog for a little while in that event and just watch TWC.....LOL
190. Drakoen 2:27 PM CST on April 24, 2008
Even with the type of high that we have in position and strength, we'll have to monitor the frequency of the troughs coming of the U.S. A weaker high gives less ridging so if the trough frequency is high then storms will have a tendency to follow the flow around the high and go out into the mid Atlantic
If that were to happen, I could live with a season full of "fish storms" but, I could not live with the wishcasters (and Trolls) on Blog who would populate here wishing for US/Caribben stike....I would have to go AWOL from the Blog from little while in that event and just watch TWC.....LOL
lol. The TWC will have Jim in Bermuda waiting for tropical cyclone Ike. The only problem with the troughiness is with the system that form in the Caribbean. The southerly stream would put the storms on a northerly track.
Hurricanes are like cars
My Momma always said: "Hurricanes are like a box of chocolates."
Hey Drak, will you be releasing your predictions within the coming weeks?
Yes I will be.
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