PROJECT TITLE :

Validation of Aqua-MODIS C051 and C006 Operational Aerosol Products Using AERONET Measurements Over Pakistan

ABSTRACT:

The aim of this study was to judge the performance of the Aqua-MODIS (MYD04) collections five.1 (C051) and half-dozen (C006) operational aerosol product over Pakistan. These embrace the Dark Target (DT) and the Deep Blue (DB) C051/C006 aerosol optical depth (AOD) observations at 10-km spatial resolution, and that were validated using seven years (2007–2013) AOD measurements from two AERONET stations located in Pakistan’s 2 largest cities, Lahore and Karachi. Lahore is an inland city, consisting of built-up areas and agricultural land and dominated by mainly fine aerosol particles. Karachi is an urban-coastal city with designed-up areas and clean land, and mainly full of coarse aerosol particles. The retrieval uncertainties and accuracy were evaluated using the expected error over land ($textEE:, pm 0.05 + 15percent $), the foundation-mean-sq. error (RMSE), the mean absolute error (MAE), and also the relative mean bias (RMB). It was found that the DT C051 AOD retrievals were significantly overestimated over both AERONET sites with mean overestimation of 21percent and 31percent for Lahore and Karachi, respectively. On the opposite hand, the DB C051 retrievals were underestimated by tenpercent and 35p.c for both cities. Almost like the DT C051, the C006 AOD retrievals were overestimated over Lahore, but significantly improved over Karachi, because the mean overestimation reduced from 31percent ($textRMB = 1.31$) to fourpercent ($textRMB = 1.04$) and the percentage of retrievals within the EE increased from thirty eight.forty sixp.c to sixty three.thirty threepercent. But, the DB C006 AOD retrievals have similar errors (RMSE and MAE) and the percentage of retrievals among the EE over both cities as C051, but they need additional mean underestimations. Spatio-temporal distributions showed that the DT and DB C006 - ere well correlated with Karachi and Lahore AERONET measurements, respectively. Therefore, these results suggest the utilization of the DT C006 algorithm over Karachi and therefore the DB C006 over Lahore for qualitative regional air quality applications due to differences in land cover characteristics and aerosol varieties.