Why is pacific ocean so cold

Bottom map shows what the waters are actually doing; the equatorial waters are remaining relatively cool. Seager et al. Why are the state-of-the-art climate models out of line with what we are seeing?

This is not a new problem. Through multiple model generations, climate models have simulated cold tongues that are too cold and which extend too far west. There is also spuriously warm water immediately to the south of the model cold tongues, instead of cool waters that extend all the way to the cold coastal upwelling regions west of Peru and Chile.

These over-developed cold tongues in the models lead to equatorial environments that have too high relative humidity and too low wind speeds. These make the sea surface temperature very sensitive to rising greenhouse gases. Hence the model cold tongues warm a lot over the past decades. In the real world, the sensitivity is lower and, in fact, some of heat added by rising greenhouse gases is offset by the upwelling of cool water from below.

Thus the real-world cold tongue warms less than the waters over the tropical west Pacific or off the equator to the north and south. This pattern of sea-surface temperature change then causes the trade winds to strengthen, which lifts the cold subsurface water upward, further cooling the cold tongue. It was common then to make the problem simpler by assuming within the model the climatological mean state and simply simulating perturbations from that.

We used that approach. By doing so, we were able to show within our one simple model that, if we assume the real-world climatological state, the response to rising greenhouse gases is warming everywhere, but not in the cold tongue.

In contrast, if we assume the biased climatological state in the complex state-of-the-art models, the response to rising greenhouse gases has enhanced warming in the cold tongue. Hence this trip down modeling memory lane allows us to diagnose what is wrong with the complex models currently being used for climate projections and impact assessments. One thing at a time! However, we do know that ENSO behavior depends on the mean state around which it is perturbing things. If we are right that the tropical Pacific is moving to a state where the waters are warming everywhere but not in the cold tongue, and cold subsurface waters are being lifted closer to the surface, then ENSO will almost certainly change in amplitude, frequency and other ways.

We need to find out. They are many. The sea-surface temperature of the equatorial Pacific influences climate and its variability worldwide. Generally, warming of the atmosphere increases the amount of moisture the air can hold, and intensifies moisture transport. This tends to make subtropical dry zones drier and tropical and mid-latitude wet zones wetter. But on top of those changes there will be regional changes. It will also create a wetting tendency in east Africa, but a drying tendency in equatorial South America and the Sahel.

If, instead, we are right and the cold tongue will not warm as much, then drying in southwest North America, subtropical South America and east Africa could be more severe than the complex models project. At the same time, equatorial South America and the Sahel might see wetter conditions. In developing climate impact assessments, scenarios should not be limited to the complex models.

This cold water makes fog form. The moisture condenses into fog. The water along the coast of California is cold for a couple of reasons. First, the California Current brings cold water from Alaska southward along the coast.

And second, cold water from the deep ocean comes up to the surface through a process called upwelling. From March through September, wind blows southward along the coast. This wind, combined with the rotation of the earth, creates surface currents that move water from the coast out into the ocean.

Something has to fill in the space that was left behind when the surface waters moved out to sea. So water from the deep ocean is sucked to the surface. The water from the deep ocean is full of nutrients. Upwelling is super important for ocean dwelling creatures—the nutrients in the water feed the phytoplankton and move on up the food web.

The lush kelp forests along the California coast exist because of upwelling. Ben Davis August 1, Why is the West Coast so cold? Why West Coast beaches are colder than East Coast beaches? Are West Coast beaches colder? Why is the weather better on the West Coast? What is the West Coast known for? Why is New York so cold? Why is the East Coast humid and the West Coast not? Why is there no humidity on the West Coast? What is the least humid state in the US? Why is the West drier than the East?

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