Climate Monitoring and Prediction

CW3E climate theme is centered around understanding the role of extreme weather events in affecting water supplies, floods, debris flows and public health and finding similarities between these events to better predict them in the future. In addition, this research also examines extreme weather events in global climate models to understand how these events are projected to change in the future. Much of this work is done in collaboration with CNAP, California Nevada Applications Program. Through the careful examination of historical data from weather observing stations, satellites, reanalysis data sets and cataloguing big impact events CW3E research examines the historical variability, how these events may be changing and the impacts of a certain type of events. For example, current projects aim to understand how extreme precipitation events, including atmospheric rivers and closed-lows, contribute to floods, landslides and debris flow, and if there are specific characteristics of these historical events that cause these events to be high impact events (Figure 1). Results from another project have shown the precipitation in the future is likely to become more variable with the extremes becoming more extreme which has implications for future planning (Figure 2). CW3E climate related research is intended to better inform predicative capabilities by examining historical records and inform decision makers on the projected occurrence of extreme events.

Figure 1. A composite of the integrated water vapor (shaded), integrated water vapor flux (vectors) and 500 hPa heights (contours) for 19 precipitation events that caused post-fire debris flows in the Transverse Ranges. As shown by the arrows, the precipitation events that most often cause post-fire debris flows are caused by integrated water vapor flux from southwesterly direction. This is one example by examining the historical record, climate research can highlight common features amongst the events that have the largest impacts in a region. Figure from Oakley et al. (submitted).
Figure 2. Projected RCP8.5 changes in water-year mean contributions of precipitation from the wettest 5% of wet days (red), remaining wet days (green), and total precipitation (black), between 1951–2000 and 2046–2095, in climate-change projections by ten climate models (From Dettinger, San Francisco Estuary and Watershed Science, 14(2), 2016).
Contact: Julie Kalansky (