Analysis of the Intra-Seasonal Oscillation in the Indian Ocean Using Surface Winds from Composite Satellite Data

Surface wind variability over the Indian Ocean from 1988 to 2016 is analyzed with regards to the 10 to 20 day Intra-Seasonal Oscillation (ISO) associated with the Indian Monsoon using CCMP V2.0 wind vectors (Wentz et al., 2015). To do this, an index for the ISO is developed and then applied to the wind field over the period of record. The 10 to 20 day oscillation in the Indian Ocean is irregular and the length of the cycle changes frequently. In order to properly analyze the ISO, the peak and trough for each cycle of the oscillation is identified and segmented over the cycle in order to determine wind variability each cycle of the ISO. On the 10 to 20 day time scale, monsoon and weather variability are visible and play an important role in surface wind fluctuations, making the ISO critical to our understanding, prediction, and modeling of monsoon events in the Indian Ocean. If models fail to capture the ISO signal, they will fail to capture the monsoon, and thus in developing a greater understanding of the role surface winds play in these 10 to 20 day oscillations, we might better be able to forecast these events in the future.

References

Wentz, F.J., J. Scott, R. Hoffman, M. Leidner, R. Atlas, J. Ardizzone, 2015: Remote Sensing Systems Cross-Calibrated Multi-Platform (CCMP) 6-hourly ocean vector wind analysis product on 0.25 deg grid, Version 2.0,. Remote Sensing Systems, Santa Rosa, CA. Available online at www.remss.com/measurements/ccmp.