STI CLIMATE BULLETIN - OSTI R2O
e-Communications
Update on Service Improvement and Operation to Research Challenges
CPC Director Keynote at 47th NOAA CDPW, Logan, Utah
NOAA Climate Prediction Center (CPC) Director David DeWitt delivered a keynote speech entitled “Recent Sub-Seasonal to Seasonal (S2S) Progress at CPC” at the opening session of the 47th NOAA Annual Climate Diagnostics and Prediction Workshop (CDPW) in Logan, Utah on October 25, 2022. After a comprehensive review of recent advancement in climate prediction services, such as extreme event key messages, rapid onset drought, and consolidation of forecast tools, Dr. DeWitt put a special focus on the challenges of forecast skill improvement and called the research community for support.
- According to the study by NOAA drought task force, the West of the U.S. is experiencing the most severe 22-year mega drought for the last 800 years or even further back. Dr. Hailan Wang and collaborators at CPC showed the precipitation anomalies for the 2000 to 2018 versus the long-term average of 1900 to 1999 in the West - basically an above normal trend that is happening with global warming, a cold Pacific Decadal Oscillation (PDO) and a warm Atlantic Multidecadal Oscillation (AMO) (Fig.1). Recall the study by Dr. Siegfried Schubert and colleagues circa 2011 that said warm trend, cold PDO or warm AMO, each of those patterns separately would favor dryness essentially in this region. Now in the western U.S., we see all the three are combining. Here is the challenge. Assuming this in fact is a good diagnosis by the research community, can we predict the PDO? Do we see a chance that it is actually going to shift to a positive phase, which then hopefully favors more rain in the West; or are we going to see a cold AMO, which we have not seen in a very long time? Since the trend will not go down anytime soon, we have got the above mentioned two possibilities to reverse the long-term trend. It does not mean there may not be a strong El Niño that will produce significantly above normal precipitation in the western US, but this long-term pattern that is drier than it has been historically in the West is a challenge for us to discuss societally.
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Fig. 1 Mean difference of 2000-2018 minus 1900-1999 of GPCP Precipitation (top left), NASA GISS Surface Temperature (top right), NOAA ERSSTv5 sea surface temperature (bottom left), and the global SST variability leading modes of Trend, PDO and AMO as indicated (bottom right). |
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INTERNAL ACCESS
- The real-time attribution diagnostics predictability activity at CPC is led by Dr. Arun Kumar with Dr. Mingyue Chen and other folks involved. This product comes out once a month. It’s been available since 2016 and it reviews observations and the prediction of the most recent season. Figure 2 shows an example of the forecast of temperature anomalies in February 2021, which came from the NCEP Climate Forecast System (CFS) (the European Center or the NASA model or the GFDL SPEAR model did about the same). In December 2020, there was no cold anomaly over the U.S., and the February forecast was not good from the end of December initial condition. However, if you fast forward one month later and forecast from the end of January, the cold threat pattern was largely produced. There was a strong sudden stratospheric warming (SSW) event that occurred in winter 2020/21. Can we at some point predict it in future? This is a challenge, because this sort of extra weighting of the dice limits our ability to make predictions. People could predict an SSW event about two weeks ahead in research. Can we predict it longer ahead than two weeks? That is something important for our forecasters to predict temperature variability on monthly and seasonal time scales.
To promote new products for climate monitoring and decision support, Dr. DeWitt also recommended the significantly improved satellite precipitation product CMORPH2 for its global coverage, higher spatial resolution, extended historical record, reduced latency, more accurate for cold season, and phase data included. Besides, he highly praised the development of heat health early warning service by CPC International Desk for Northern Africa, primarily Senegal, through directly interacting with both the meteorological service as well as the health department. It is expected to be expanded to other parts of Africa and shortly to other parts of the world.
(Rearranged by Jiayu Zhou)
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Fig. 2 2021 February surface temperature anomaly of observation (top), CFSv2 forecast from the initial conditions of December (middle), and CFSv2 forecast from the initial condition of the last three days of January (bottom). |
