Strengthening critical observations of the tropical ocean and atmosphere
The El Niño Southern Oscillation (ENSO) is a natural climate phenomenon driven in part by the variability of ocean surface temperatures, atmospheric pressure, and trade winds in the tropical Pacific Ocean. ENSO events, occurring every two to seven years on average, cause widespread shifts in precipitation patterns and weather and climate extremes that impact agriculture, marine ecosystems, human health, disaster preparedness, and other sectors across the world. Using observations of ocean temperature and surface winds in the tropical Pacific, scientists are able to predict the ENSO cycle up to 12 months in advance and can provide forewarning of potentially damaging weather and climate conditions in many parts of the world. Real-time monitoring of ocean and atmospheric conditions through the Tropical Pacific Observing System (TPOS) supports this capability, but recent deterioration of a moored buoy network has put ENSO predictions and associated services at risk. The TPOS 2020 Project, running from 2014 to 2020, will oversee the transition to a more resilient observing system to meet research and forecasting needs of today and the future, including ocean temperature measurements that contribute to ENSO predictions. The First Report of TPOS 2020 proposed a network redesign that incorporates advances in observing technologies, process understanding, and modeling to improve the capability to monitor and predict ENSO and its impacts[1].
The U.S. contribution to TPOS 2020 is supported by NOAA and NASA, with scientific input from the U.S. Climate Variability and Predictability Program. NOAA recently made a significant investment to advance observing technologies in the tropical Pacific region to enhance ENSO research and predictions[2]. In addition, new technologies are being tested in conjunction with NASA’s Salinity Processes in the Upper Ocean Regional Study 2 (SPURS-2) in the eastern tropical Pacific to improve understanding of interactions between the ocean and the atmosphere in these rain-dominated ocean regions, key to improving ENSO predictions (see figure)[3].
1 Cravatte, S., W. S. Kessler, N. Smith, S. E. Wijffels, and Contributing Authors, 2016: First Report of TPOS 2020. GOOS-215, 200 pp. http://tpos2020.org/first-report/
2 NOAA Climate Program Office. “NOAA announces $4.5 million in funding for new observing technologies for ENSO research and predictions.” http://tpos2020.org/noaa-announces-4-5m-funding-new-observing-technologies-enso-research-predictions/ (accessed August 21, 2018)
3 SPURS-2 Planning Group. 2015. From salty to fresh—Salinity Processes in the Upper-ocean Regional Study-2 (SPURS-2): Diagnosing the physics of a rainfall-dominated salinity minimum. Oceanography 28(1):150–159, http://dx.doi.org/10.5670/oceanog.2015.15
Forecasts of ocean surface current velocity in the Pacific Ocean off of Baja California generated in part using in-situ observations from NOAA’s Tropical Atmosphere Ocean (TAO) moored buoy array (green squares), which is part of the Tropical Pacific Observing System (TPOS), and from measurements collected during the SPURS-2 satellite deployment over the tropical Pacific Ocean (red square). Depicted is a strong westward-flowing South Equatorial Current driven by the trade winds that blow from east to west across the equatorial Pacific. Changes to the easterly trade winds influence the progression of ENSO events. Forecasting these changes is integral to improving predictive capabilities. Source: NASA/Jet Propulsion Laboratory.