In-Sik Kang

Saudi-KAU Coupled Global Climate Model: Description and Performance

BackgroundA new coupled global climate model (CGCM) has been developed at the Center of Excellence for Climate Change Research (CECCR), King Abdulaziz University (KAU), known as Saudi-KAU CGCM.PurposeThe main aim of the model development is to generate seasonal to subseasonal forecasting and long-term climate simulations.MethodsThe Saudi-KAU CGCM currently includes two atmospheric dynamical cores, two land components, three ocean components, and multiple physical parameterization options. The component modules and parameterization schemes have been adopted from different sources, and some have undergone modifications at CECCR. The model is characterized by its versatility, ease of use, and the physical fidelity of its climate simulations, in both idealized and realistic configurations. A description of the model, its component packages, and parameterizations is provided.ResultsResults from selected configurations demonstrate the model’s ability to reasonably simulate the climate on different time scales. The coupled model simulates El Niño-Southern Oscillation (ENSO) variability, which is fundamental for seasonal forecasting. It also simulates Madden-Julian Oscillation (MJO)-like disturbances with features similar to observations, although slightly weaker.ConclusionsThe Saudi-KAU CGCM ability to simulate the ENSO and the MJO suggests that it is capable of making useful predictions on subseasonal to seasonal timescales.

Decadal Climate Variability and Predictability: Challenges and Opportunities

AbstractThe study of Decadal Climate Variability (DCV) and Predictability is the interdisciplinary endeavor to characterize, understand, attribute, simulate, and predict the slow, multiyear variations of climate at global (e.g., the recent slowdown of global mean temperature rise in the early 2000s) and regional (e.g., decadal modulation of hurricane activity in the Atlantic, ongoing drought in California or in the Sahel in the 1970s–80s, etc.) scales. This study remains very challenging despite decades of research, extensive progress in climate system modeling, and improvements in the availability and coverage of a wide variety of observations. Considerable obstacles in applying this knowledge to actual predictions remain.This short article is a succint review paper about DCV and predictability. Based on listed issues and priorities, it also proposes a unifying theme referred to as “drivers of teleconnectivity” as a backbone to address and structure the core DCV research challenge. This framework goes be...

Multidecadal Changes in the Relationship of Storm Frequency over Euro-Mediterranean Region and ENSO During Boreal Winter

BackgroundThe El Niño–Southern Oscillation (ENSO) influence over Euro-Mediterranean boreal winter season (December to February) precipitation anomalies has changed along the twentieth century.PurposeThe precipitation anomalies are closely associated with storm track frequency. The changing relationship between the interannual variability of storm track frequency and ENSO is investigated at interannual and multidecadal timescales.MethodsThe Melbourne University cyclone tracking scheme (MS) is applied to reanalyse 200-hPa geopotential height (Z200) datasets to track the winter storms over the Euro-Mediterranean region for the period 1950–2016.ResultsThe maximum of climatological storm track frequency is found to prevail in the study domain with large interannual variability. The multidecadal changes show a phase shift in the relationship between storm track frequency and ENSO from the 1950s to the recent decades. The storm track frequency is negatively correlated (−0.24) to ENSO for the early period (1950–1979), whereas it is positively correlated with a maximum correlation value of 0.44 for the recent period (1987–2016). The correlation departure (0.68) between the two periods shows a significant change in the multidecadal relationship between storm track frequency and ENSO.ConclusionThe ENSO-associated significant changes are noted in the upper and lower tropospheric height anomalies over the North Atlantic and Euro-Mediterranean sector in the recent period with respect to the earlier period, which may largely influencing the storm activityxa0(Frequency/Intensity) and precipitation anomalies over the Euro-Mediterranean region. The findings of this study can have important implications in Euro-Mediterranean seasonal predictability.