New MAPP-funded research describes which climate patterns primarily influence U.S. seasonal mean precipitation and how the sources of predictability change seasonally and decadally. Abnormal precipitation patterns have the potential to drive natural disasters, like severe flooding or droughts, that pose a serious threat to human lives, property, food, and water supplies. With the economic and societal consequences that come from abnormal precipitation, it is important to understand what causes it and how predictable it is. Better prediction skill could lead to better preparation for the consequences of natural disasters and potentially less loss.
In a recent Journal of Climate paper MAPP-funded researcher, Bohua Huang of George Mason University, along with co-authors Chul-Su Shin and Arun Kumar of the NOAA Climate Prediction Center, analyzed a set of forecasts of past conditions during 1958-2017 using the NOAA Climate Forecast System version 2 (CFSv2). Their goal was to evaluate why prediction skill of U.S. seasonal precipitation has changed over time. They split the 60 years of forecasts into three subperiods corresponding to the positive phase of the Pacific Decadal Oscillation (PDO) during 1979-1999 and negative phases before and after. They found that winter-spring precipitation patterns are generally more skillful and that ENSO is the most dominant influence. During summer and fall, however, other oceanic factors play an active role. They also found that change in seasonal predictability over these decades is due to a modulation of ENSO predictability by other major climate patterns. The PDO was a dominant factor that enhanced prediction skill in 1979-1999 and reduced skill in 1958-1978. Since the 2000s, U.S. summer precipitation predictions have been affected by sea surface temperature anomalies in the tropical North Atlantic and their interplay with those in the tropical Pacific.
The Modeling, Analysis, Predictions, and Projections (MAPP) Program is a competitive research program in NOAA Research’s Climate Program Office. MAPP’s mission is to enhance the Nation’s and NOAA’s capability to understand, predict, and project variability and long-term changes in Earth’s system and mitigate human and economic impacts. To achieve its mission, MAPP supports foundational research, transition of research to applications, and engagement across other parts of NOAA, among partner agencies, and with the external research community. MAPP plays a crucial role in enabling national preparedness for extreme events like drought and longer-term climate changes.
For more information, please visit www.cpo.noaa.gov/MAPP.