The 3 depictions of El Niño

Earlier this week I attended a talk by George Adamson of Kings College London, titled “Gilbert Walker, the Moché and an angry sea god: the two histories of El Niño”.  For those of you who weren’t there, he opened with the three different representations of El Niño that simply come from searching in Google Images.

The first type is scientific images and diagrams, such as can be seen in my previous post. The second type is photos showing the shocking human and environmental impact, such as:

Source: Live Mint

“El Nino in 2009 turned India’s monsoon patchy, leading to the worst drought in nearly four decades

 and helping push global sugar prices to their highest in nearly 30 years.”

Source: Armor Glass
“Houston, June 2001 - 30,000 became homeless after the storm flooded over 70,000 houses and
destroyed 2,744 homes.”

These photos really hit home the devastation that El Niño brings to crops, homes, and more. I believe they have also contributed to developing a third kind of representation:

Source: Paul Duginski, Los Angeles Times, August 2015

Source: INKCINCT

Being associated with powerful masculine destruction, El Niño has been personified, and characterised in the form of cartoons as shown above. They are in stark contrast to the real effects of El Niño and bring a sense of humour and light relief, to an otherwise destructive occurrence.

I found these different representations of El Niño fascinating so wanted to share them with you – I hope you do also! A quote from the talk by George Adamson which I think sums this up nicely; “El Niño is both a force upon, and a product of society”.

El Niño – Latest Images

The latest images of the current El Niño have been released from NASA, which I find both surprising and intriguing. Surprising because in the middle of the Pacific the extremes of the scale are in such close proximity to each other; intriguing because... well it just is!

Source: Jet Propulsion Lab, NASA

These images have been created by taking the average of 10 days worth of data, from the 12^th – 21^st October 2015. The data used to construct them are sea surface height residuals. A residual (also referred to as the irregular component) is the remaining component after seasonality and trends have been removed from a time series. The seasonality aspect is a systematic, calendar related effect, whilst a trend is a long term movement in a particular direction. The residual that remains shows short term fluctuations which are unsystematic and usually unpredictable. This is how the uncharacteristic sea surface height data is captured and displayed as above. Hence, the areas coloured green-light blue in the images have anomalies of 0 mm, meaning their levels are normal and can be explained by the seasonal and trend components. This method of modelling is powerful because it breaks down the data into manageable parts for discovering underlying characteristics, and, forecasting relies on previous observations. However, it can have its limitations if the data available only covers a short period of time relative to the process.

But, we’re looking at sea level heights here, isn’t El Niño to do with temperatures? Well, there is a strong correlation between sea surface height anomalies and the thermal structure of the ocean. The steric changes in the ocean (temperature and density) cause the sea levels to fluctuate accordingly. Warmer water has a lower density therefore a greater volume than colder water, conversely, the higher the sea level, the warmer the water. This animation shows sea surface height and temperature anomalies in the Pacific Ocean from October 1992 to August 2002.

All of the data used to construct these images and animations has been recorded by the Jason-2 satellite, for the Ocean Surface Topography Mission (OSTM). Launched in 2008, the OSTM/Jason-2 satellite altimeter mission aims to provide scientists with a multi-decadal climate record for analysis of global sea level rise and a better understanding of the relationship between ocean circulation and climate change (Lambin et al, 2010).

So, bear with me, and let’s see how this progresses over the coming weeks.

Advanced Warning – get shovels and sledges at the ready

The UK has been hit with the warning of heavy snowfall this winter. Fantastic fun for some, terrible trouble for others. Whatever it means for you, it means one thing for the Pacific Ocean – rising temperatures.

In my last post I mentioned how a small change in ocean temperatures can have a catastrophic effect on our planet, well, every two to seven years sea surface temperatures offshore of north-western South America increase above average. Often 2 to 3^oC higher than normal (Glantz, 2001)! This is what is known as El Niño (Spanish for “the boy”) and what we are currently experiencing. El Niño is one half of the El Niño-Southern Oscillation (ENSO) cycle. The opposite phase, when unusually cool waters occur, is called La Niña (Spanish for “the girl”). These have globally affecting weather and climate consequences. Effects of the El Niño are wide reaching and can often be felt around the globe for over a year (Lizumi et al, 2014). Past instances resulted in flooding in Peru & Bolivia and droughts in Indonesia & Australia (Nakagawa et al, 2010).

So what causes this Spanish boy to show himself?

Usually, strong winds blow from East to West along the equator. With this, about half a metre’s worth of water builds up in the Western Pacific. To replace the water that’s been lost the Eastern current pulls up cold water from deep below. Hence, temperatures are typically cooler in the Eastern Pacific as opposed to the Western. However, during an El Niño the winds weaken, and the circulation of water lessens. This results in the Eastern Pacific being warmer than usual. That isn’t the end of the story... warm waters result in weaker winds, weaker winds result in warmer waters, and so on. Like a hamster on a tread mill, round and round. This positive feedback loop is what makes the El Niño grow.

 

You may remember the last time the effects of El Niño were felt in the UK – the winter of 2009/10. I remember it well; the first winter away at university. Unfortunately the roads were piled high with snow and lessons were cancelled, so like any sensible fresher I spent the time participating in a week long snow ball fight. Productive. Well, prepare yourself now, because news reports are claiming this to be the worst El Niño in recorded history.

Photograph: Me on swing being pelted with snow, 2010

Some people are looking forward to this event for another reason, not just the possibility of a few days off of work. Kasha Patel at NASA's Goddard Space Flight Center states that “the 2015-16 El Niño event will be better observed from space than any previous El Niño” due to the fact that since the El Niño of 1997/98, (the strongest on record), NASA has launched 19 Earth-observing missions, all currently in orbit. Not only will the satellite data show us what is happening currently, but the mass of data recorded can be assimilated into current models to improve them. Models rely on data, the more available, the better likelihood of an accurate model. As well as the data itself the observations are sure to increase the understanding we have of El Niño’s. After all, a useful model cannot be built solely from data without any understanding of the processes in force.

 

If you’re a betting kind of person, bookies have updated their odds of having a White Christmas in various places around the UK and Ireland. Now, just don’t go blaming me if you don’t win. And if you do win...

Oceans: The Great Unknown

We know less about the dark blue expanse that covers over 70% of our planet, than we do about space. How crazy is that? The oceans are our planets largest ecosystem. According to the National Oceanic and Atmosphere Administration, to date, we have explored approximately 5% of our oceans. 5% of something that is the lifeblood of Earth and humankind! 5% of something that has been mopping up the carbon dioxide we’ve been pumping into the atmosphere since we began burning fossil fuels! For these reasons my exploration into the oceans begins. Specifically, the warming of the oceans which has accelerated since the Industrial Revolution.  

The oceans have been somewhat neglected when it comes to thinking about our warming planet, until now. A small increase in water temperature takes a massive amount of energy in comparison to the equivalent increase in land temperature.  To put things into perspective, when the oceans temperatures dropped by only a seemingly insignificant 1-2 degrees  the Earth was plunged into what is known as the Little Ice Age.  

If, like me, you’ve ever taken a dip in the water off of UK shores, you would be excused at thinking the water a degree or two warmer might make things a whole lot more bearable. But in reality what do rising sea temperatures around the world mean to the world we live? Over the next few months I will delve into the different implications this is having and discuss the different modelling techniques used to analyse data. 

It’s time to Sea The Bigger Picture. 

Components of  global warming for the period 1993 to 2003 calculated from IPCC AR4 5.2.2.3

Source: John Cook, Skeptical Science