Research Interests

My research focuses on understanding fundamental physical processes of climate variability, predictability, and change. A key goal of my reserach is to improve climate forecasts on seasonal-to-decadal timescales. This requires a better understanding of the mechanisms driving climate variability and climate change, as well as the development of improved climate prediction systems. In addition, I am very much interested in expanding the field of multi-year predictions to include other societally relevant variables and Earth system processes, including soil moisture, wildfire variability, forest growth and marine ecosystem productivity. Outcomes from these studies potentially cover agriculture, renewable energy, water management, fisheries stock assessment, and coastal planning, by providing reasonable predictions for precipitation, temperature, sea level rise, and wind patterns.

Credit: Y. Chikamoto

Tropical Trans-Basin Variability

Tropical trans-basin variability (TBV) is characterized by a zonal seesaw of atmosphere-ocean variations between the Pacific and the Atlantic/Indian Ocean basins (McGregor et al., 2014; Chikamoto et al., 2015). Although the tropical Pacific variability is a major driver to induce interannual-to-decadal climate variability in the other basins (Chikamoto and Tanimoto, 2005; 2006; Chikamoto et al., 2010), the atmosphere–ocean variability in the Atlantic and Indian Oceans can feed back to the Pacific through trans-basin interactions and global displacements of the Walker Circulation (Chikamoto et al., 2012; 2015). In contrast to the El Nino Southern Oscillation, the TBV shows low-frequency variations on decadal timescales because of the larger spatial scales. As a result, the TBV can be predictable up to 3 years in advance by the state-of-the-art climate prediction system. In view of the global impacts of the TBV on precipitation and sea-level anomalies, operational predictions of the TBV may translate into better assessments of risks in sectors, such as coastal and water management, forestry and agriculture.

Credit: F. J. Doblas-Reyes

Decadal Climate Prediction

Decadal climate prediction is a new challenge of forecasting climate conditions for upcoming several years. While global surface temperature shows a warming trend on centennial timescales associated with greenhouse gas increases, this warming trend is modulated by natural climate variability on interannual-to-decadal timescales (Mochizuki et al., 2012; Tatebe et al., 2012; Chikamoto et al., 2013; Doblas-Reyes et al., 2013). Successful decadal predictions mainly rely on long-term ocean memories, particularly in low-frequency climate phenomena in the higher latitude region, such as the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation (Mochizuki et al., 2010; Chikamoto et al., 2013; Doblas-Reyes et al., 2013). Recent works discover some decadal predictable processes of the land hydroclimate in North America (Chikamoto et al., 2015) and marine ecosystems in the North Pacific (Chikamoto et al., 2016).

Department of Plants, Soils and Climate, Utah State University
4820 Old Main Hill, Logan, UT 84322-4820, USA