OS033-03
Roles of TAO/TRITON and Argo in tropical Pacific observing system: An OSSE study for multiple time scale variability

Friday, 11 December 2020: 16:10
Virtual
Jieshun Zhu, University of Maryland College Park, College Park, MD, United States, Stylianos Flampouris, IMSG/NOAA-NCEP-EMC, College Park, MD, United States, Guillaume Vernires, JCSDA/UCAR/NOAA, College Park, United States, Arun Kumar, NOAA/NCEP, College Park, MD, United States, Avichal Mehra, National Centers For Environmental Prediction-Environmental Modeling Center, College Park, MD, United States, Meghan F Cronin, NOAA PMEL, Seattle, WA, United States, Dongxiao Zhang, CICOES/University of Washington and NOAA/PMEL, Seattle, WA, United States, Samantha Wills, CICOES/University of Washington and NOAA/PMEL, Seattle, United States, Travis Cole Sluka, Joint Center for Satellite Data Assimilation, College Park, MD, United States, Jiande Wang, IMSG at NOAA/NWS/NCEP/EMC, College Park, MD, United States and Wanqiu Wang, NOAA, College Park, MD, United States
Recorded Presentation
Abstract:
The current tropical Pacific observing system (TPOS) was initially populated by the tropical atmospheric ocean (TAO) array in early-1980s. TAO array has been considered essential for operational seasonal predictions (particularly for ENSO monitoring and predictions). In the light of advances in new observing capabilities since the implementation of TAO (e.g., altimetry, Argo, etc.) and the challenges in maintaining the array (e.g., the 2012-2014 TAO “crisis”), the TPOS 2020 project was established in 2014, aiming to develop a more sustainable and resilient observing system for the tropical Pacific.

In the context of TPOS 2020, a series of ocean observing system simulation experiments (OSSEs) are conducted based on the new ocean data assimilation system that is under development at the Joint Center for Satellite Data Assimilation (JCSDA) and the Environmental Modeling Center (EMC)/National Centers for Environmental Prediction (NCEP). The atmospheric forcing and synthetic ocean observations are generated from a nature run, which is based on the modified CFSv2 with ocean vertical resolution of 1-meter near the ocean surface. To separate the effects of TAO/TRITON and Argo in TPOS, the synthetic observations were constructed following their present distributions, both separately and jointly. Our experiments include a free run without assimilating any observations, and assimilation runs with the TAO and Argo “observations” assimilated separately or jointly. The experiments were compared for variability at different time scales [low-frequency (>90days), intraseasonal (20~90days) and high-frequency (<20days)]. It was found that (1) both TAO and Argo effectively improve the estimation of mean states and low-frequency variations; (2) on the intraseasonal time scale, Argo presents significant improvements more so than TAO (except for regions close to TAO sites); (3) on the high-frequency time scale, both TAO and Argo present clear deficits (for TAO, limited improvements were present close to TAO sites).

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