Validation of satellite and model aerosol optical depth and precipitable water vapour observations with AERONET data over Pune, India

ABSTRACT

The present work concerns with a detailed study of the validation of the Moderate Resolution Imaging Spectroradiometer (MODIS) and model products, and investigates the spatial and temporal variations in the correlation coefficient of the validation results obtained from the analysis of Aerosol Robotic Network (AERONET) sun–sky radiometer data archived at Pune during 2005–2015. Combining the confidence intervals and prediction levels, the ground-based AERONET aerosol optical depth (AOD) at 550 nm and precipitable water vapour (PWV) have been used to validate the MODIS, model AOD (550 nm), and PWV (cm) observations. The correlation coefficients (r) of AOD for the linear regression fits are 0.73, 0.75, and 0.79, and of PWV are 0.88, 0.89, and 0.97 for Terra, Aqua, and model simulations, respectively. Month-to-month/seasonal variation of AOD (550 nm) and PWV observations of satellite and model observations are also compared with AERONET observations. Additionally, various statistical metrics, including the root mean square error, mean absolute error, and root mean bias values were calculated using AERONET, satellite, and model simulations data. Furthermore, a frequency distribution of AOD (550 nm) and PWV observations are studied from AERONET, satellite, and model data. The study emphasizes that the globally distributed AERONET observations help to improve the satellite retrievals and model predictions to enrich our knowledge of aerosols and their impact on climate, the hydrological cycle, and air quality.

Acknowledgements

The authors are grateful to the AERONET Group, NASA, USA, for their valuable support. One of the authors, K. Vijayakumar, gratefully acknowledges Council of Scientific and Industrial Research (CSIR), Government of India, New Delhi, for providing the Research Associate (RA) Fellowship. Thanks are due to the authorities at Sri Venkateswara University (SVU), Tirupati, and Amity University Haryana (AUH), Gurgaon (Manesar-Panchgaon). The authors would also like to thank the MODIS, ECMWF Science Team for providing excellent and accessible data products that made this study possible. Thanks are also due to the editor and the anonymous reviewers for their critical comments that helped to improve the quality of this article.

Disclosure statement

No potential conflict of interest was reported by the authors.