Evaluation of GODAS Using RAMA Mooring Observations from the Indian Ocean |
| |
| Authors: | Vivek Kumar Pandey Prajvala Kurtakoti |
| |
| Institution: | 1. K. Banerjee Centre of Atmospheric and Ocean Studies, Institute of Interdisciplinary Studies, Nehru Science Centre , University of Allahabad , Allahabad , India;2. Centre of Atmospheric and Oceanic Sciences , Indian Institute of Science , Bangalore , India |
| |
| Abstract: | We present a comparison of the Global Ocean Data Assimilation System (GODAS) five-day ocean analyses against in situ daily data from Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA) moorings at locations 90°E, 12°N; 90°E, 8°N; 90°E, 0°N and 90°E, 1.5°S in the equatorial Indian Ocean and the Bay of Bengal during 2002–2008. We find that the GODAS temperature analysis does not adequately capture a prominent signal of Indian Ocean dipole mode of 2006 seen in the mooring data, particularly at 90°E 0°N and 90°E 1.5°S in the eastern India Ocean. The analysis, using simple statistics such as bias and root-mean-square deviation, indicates that standard GODAS temperature has definite biases and significant differences with observations on both subseasonal and seasonal scales. Subsurface salinity has serious deficiencies as well, but this may not be surprising considering the poorly constrained fresh water forcing, and possible model deficiencies in subsurface vertical mixing. GODAS reanalysis needs improvement to make it more useful for study of climate variability and for creating ocean initial conditions for prediction. |
| |
| Keywords: | VPS RAMA mooring CFS GODAS Indian Ocean dipole intra-seasonal variability tropical convergence zone |
|
|
