Global Distribution and Seasonal Variability of Low-Level Coastal Jets derived from ERA-Interim Reanalysis

Low-level coastal jets (LLCJ's) play an important role in the coastal weather and have significant impacts on ecology and a number of human activities in the coastal regions. Furthermore, meteorological conditions in the coastal regions are particularly different from the inland regions where the flows are determined by sharp land-sea temperature contrasts, coastal terrain, orientation of the coast etc. This makes the study of LLCJ's not only interesting but also equally challenging.

Unlike the inland low-level jets which have been extensively studied with their climatology, variability and global distribution well documented, more research needs to be done for the LLCJ's. Therefore, the purpose of this study is to document the global distribution, spatio-temporal structure and seasonal variability of the LLCJ's using the 6 hourly ERA-Interim reanalysis data at 1° resolution. 10 years of seasonal data (DJF and JJA) from 2002-2011 is used to identify the LLCJ's following a criteria based on vertical wind maxima and temperature profile. The results are analyzed to highlight the fundamental aspects and distinctive features of the LLCJ's across the globe including jet heights, wind speed, diurnal cycle etc.

Using the data analysis, global maps of the LLCJ's are constructed for the summer and winter seasons. These maps apart from highlighting the locations and frequency where LLCJ's are dominant also indicate few other places not studied in the context of LLCJ's before.