Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New Study Ties African Drought to Ocean Temperatures


A strong link has been confirmed between sea surface temperatures and precipitation in Africa’s semi-arid Sahel, according to a new study published in Science on October 9th. The study was co-authored by Alessandra Giannini, a climate expert with the International Research Institute for Climate Prediction (IRI), a unit of the Earth Institute at Columbia University.

The time series in the figure above represents variations above or below the long-term mean of rainfall in the Sahel region of Africa (located just south of the Sahara, between 10N and 20N). The observed time series is the average of station observations in the region, while the modeled time series is an areal average of the model’s rendition of the variability. The similarity between the two is a measure of the success of the model in reproducing the observed variability, based on the influence of sea surface temperatures only on the global atmospheric circulation, and on Sahel rainfall. Image credit: Alessandra Giannini

Previously, it was not known how much land use changes may have led to the region’s recent history of prolonged drought, or whether variability in ocean temperatures was the primary driver of the region’s climate. The new study finds that “pervasive evidence” indicates that sea surface temperatures, particularly in the Indian Ocean, are the most powerful indicators of precipitation in the Sahel.

Tropical Pacific surface temperature variation, such as that occurring with the El Niño and Southern Oscillation phenomena, have an effect on the variation of year-to-year rainfall, while the Indian and possibly Atlantic Oceans, affect longer term trends. The new study tracked sea surface temperatures and precipitation rates from 1930-2000, the first time that ocean and climate trends have been studies on a decadal time scale.

If it is true that oceanic warming is the primary driver of precipitation in the Sahel, then by implication climatologists should be able to measure ocean temperatures and predict the likelihood of future precipitation in the Sahel.

As the paper’s authors write: “The recent drying trend in the semi-arid Sahel is attributed to warmer-than-average low latitude waters around Africa which, by favoring the establishment of deep convection over the ocean, weaken the continental convergence associated with the monsoon, and engender widespread drought from Senegal to Ethiopia.”

“What interests me particularly is the potential for seasonal predictions of precipitation in the Sahel, and all the implications and uses for such predictions,” says Giannini. One of the International Research Institute for Climate Prediction (IRI)’s unique strengths is in research connecting climate with health, agriculture, and other human factors affected by rainfall. For instance, at the IRI connections are being investigated between malaria (a wet season disease), meningitis (a dry season disease) and precipitation in Western Africa.

“Land surface factors do feed back into the climate system of the Sahel, but they are a consequence, not the cause, of variability in precipitation,” Giannini explains.

The International Research Institute for Climate Prediction is part of the Earth Institute at Columbia University, the world’s leading academic center for the integrated study of Earth, its environment, and society. The Earth Institute builds upon excellence in the core disciplines –earth sciences, biological sciences, engineering sciences, social sciences and health sciences –and stresses cross-disciplinary approaches to complex problems. Through its research training and global partnerships, it mobilizes science and technology to advance sustainable development, while placing special emphasis on the needs of the world’s poor.

Jennifer Freeman | Earth Institute News
Further information:

More articles from Earth Sciences:

nachricht Wandering greenhouse gas
16.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Unique Insights into the Antarctic Ice Shelf System
14.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>