AIRS observes El Niño and La Niña

In 2016 a significant El Niño developed in the Pacific Ocean and we can see its effect on Earth's atmosphere in the images below, made with data acquired by the Atmospheric Infrared Sounder on NASA's Aqua satellite and produced by NASA's Jet Propulsion Laboratory. 

El Niño is a climate cycle in the Pacific Ocean with a global impact on weather patterns. It's characterized by unusually warm ocean temperatures in the equatorial Pacific, in contrast to La Niña which is characterized by unusually cold ocean temperatures in this same region. 

Scroll down the page to view El Niño's effect on:
relative humidity
cirrus clouds
outgoing longwave radiation

El Niño's effect on Relative Humidity

Storm tracks located in the tropics through the middle latitudes are typically moist, with drier air found in between these storm tracks. The current El Niño has led to higher relative humidity in the eastern tropical and subtropical Pacific, but it's brought much drier conditions to Indonesia and southeast Asia which makes these regions susceptible to drought and fires.

relative humidty at 500hpa February 2016
The map above shows relative humidity in Earth's middle troposphere, located in the section of the atmosphere at a height of approximately 18,000 feet (3.5 miles or 5,500 meters) where the atmospheric pressure is approximately 500 hectopascals. This map conveys "anomalies", or areas that are different from average conditions. Blue indicates areas that are moister than average, red shows areas that are drier.

Map of the average distribution of relative humidity in the middle troposphere for the month of February.<span>
Map of the average distribution of relative humidity in the middle troposphere for the month of February.

Movie: You can also view a time series of relative humidity anomaly as it moves from February 2015 through February 2016.


Cirrus clouds are ice clouds that occur in Earth’s upper troposphere and they are typically found between 6-10 miles in altitude. They are often associated with tropical convection and wintertime storms in the midlatitudes. The change in the pattern of cirrus cloud frequency is similar to the pattern shifts in relative humidity and outgoing longwave radiation. There has been a large increase in cirrus cloud frequency in the eastern Pacific and over the southern-tier of the U.S. and Mexico over the last several months. This is also associated with a more active subtropical jet stream that is very typical of a strong El Niño.

cirrus cloud frequency
The map above shows how the frequency of cirrus clouds differs from the average amount. Blue signifies less cirrus than normal, red signifies more than normal.

cirrus cloud frequency
The February monthly average of the frequency of cirrus clouds.

EL NIÑO'S EFFECT ON outgoing longwave radiation

Outgoing Longwave Radiation (OLR) is the thermal radiation, or heat energy, that radiates from Earth's surface and atmosphere and goes out to space. OLR depends on temperature, moisture, and clouds, and it's usually largest over the subtropical desert regions and the subtropical oceans. OLR is lower in the high latitudes and in the cloudy and moist portions of the tropics. El Niño has caused a shift in the regular pattern:  there is reduced OLR in the tropical eastern Pacific which causes increased convective storms and moisture, and there is a strong increase in OLR in the tropical western Pacific. This shift in the convection pattern effects on the winter storm track in California and is typical of a strong El Niño.

outgoing longwave radiation anomaly
The map above shows the amount of outgoing longwave radiation that differs from the average. Blue signifies less than normal, red signifies more than normal.

outgoing longwave radiation