Comparison of AMSR-E and TMI sea surface temperature with Argo near-surface temperature over the Indian Ocean

Sea surface temperature (SST) measurements from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) are compared with near-surface temperature (foundation SST) in situ measurements obtained from Argo floats over the Indian Ocean. Spatial variation was compared for 2002-2006 and 11 floats were used for temporal variation collocated observations. The results show that TMI and AMSR-E SST measurements are slightly overestimated during the pre- and post-monsoon seasons and underestimated during the monsoon season. Statistical analysis shows that the SST from the AMSR-E is better correlated with the Argo foundation SST compared to the TMI. The standard deviation (SD) and root mean square error (RMSE) for AMSR-E SST are 0.58 degrees C and 0.35 degrees C, respectively, over the Equatorial Indian Ocean (EIO). The corresponding values for the TMI are 0.66 degrees C and 0.47 degrees C. Over the Arabian Sea the SD values are slightly higher compared to the EIO values, whereas RMSE values are less for both TMI and AMSR-E SST. These retrieval accuracies are above the expected retrieval accuracy. The seasonal average spatial distribution of AMSR-E SST shows a better match with the Argo foundation SST compared to TMI SST distributions. The robustness of the good spatial match during the monsoon season may be attributed to strong winds.