Variation in MERRA-2 aerosol optical depth over the Yangtze River Delta from 1980 to 2016
- 245 Downloads
In this study, 765 instantaneous MERRA-2 (second Modern-Era Retrospective analysis for Research and Applications) aerosol optical depth (AOD) values at 550 nm were compared with those of a sky radiometer in Hefei (31.90° N, 117.17° E) for the different seasons from March 2007 to February 2010. The correlation coefficients (R) were 0.88, 0.83, 0.88, and 0.80 in spring, summer, autumn, and winter, respectively. The MERRA-2 AOD is also compared with MODIS Aqua AOD in the entire Yangtze River Delta, and good agreement has been obtained. The MERRA-2 AOD product was used to analyze the spatial distribution and temporal variation of the annual, seasonal and monthly means of the AOD over the Yangtze River Delta region from 1980 to 2016 (37 years). The mean values of the MERRA-2 AOD during the study period show that the AOD (between 0.45 and 0.55) in the northern area of the Yangtze River Delta was higher than that (between 0.30 and 0.45) of the southern area. The northwest part of the Yangtze River Delta had the highest mean AOD values (between 0.50 and 0.55). The AOD increased slowly in the 1980s and 1990s, followed by a rapid increase between 2001 and 2010. An AOD decrease can be seen from 2011 to 2016. The mean AOD in each month is discussed. High AOD was observed in March, April, and June, while low AOD could be seen in September, October, November, and December. Three different area types (large cities, medium-sized cities, and remote areas) had nearly the same annual AOD variation. Large cities had the highest AOD (about 0.48), while remote areas had the lowest (about 0.42). In summer, the AOD in remote areas was much lower than that in cities. The AOD variational trend over the Yangtze River Delta was studied during two periods. The increasing trend could be seen over the entire Yangtze River Delta in each month from 1980 to 2009. A decreasing trend was found all over the Yangtze River Delta in January, February, March, July, October, and November, whereas in other months, some parts witnessed increasing AOD while others saw a decreasing trend between 2010 and 2016.
KeywordsMERRA-2 AOD Yangtze River Delta Sky radiometer
This work was supported by grants from the National Key R & D Program Pilot Projects of China (2016YFA0601901), the National Key Research and Development Program of China (2016YFA0602003), the National Key Project of Basic Research (2014CB441201), the National Natural Science Foundation of China (41590874 and 41375153), the CAMS Basis Research Project (2017Z011, 2016Z01, and 2014R17), and the Climate Change Special Fund of CMA (CCSF201504).
- Che HZ, Shi GY, Zhang XY, Arimoto R, Zhao JQ, Xu L, Wang B, Chen ZH (2005) Analysis of 40 years of solar radiation data from China, 1961–2000. Geophys Res Lett 32(L06803):2341–2352Google Scholar
- Che HZ, Zhang X, Chen H, Damiri B, Goloub P, Li Z, Zhang X, Wei Y, Zhou H, Dong F, Li D, Zhou T (2009a) Instrument calibration and aerosol optical depth validation of the China Aerosol Remote Sensing Network. J Geophys Res 114(D03206)Google Scholar
- Che HZ, Zhang X, Xia X, Goloub P, Holben B, Zhao H, Wang Y, Zhang X, Wang H, Blarel L, Damiri B, Zhang R, Deng X, Ma Y, Wang T, Geng F, Qi B, Zhu J, Yu J, Chen Q, Shi G (2015) Ground-based aerosol climatology of China: aerosol optical depths from the China aerosol remote sensing network (CARSNET) 2002-2013. Atmos Chem Phys 15:7619–7652CrossRefGoogle Scholar
- Che HZ, Gui K, Chen Q, Zheng Y, Yu J, Sun T, Zhang X, Shi G (2016) Calibration of the 936 nm water-vapor channel for the China aerosol remote sensing NETwork (CARSNET) and the effect of the retrieval water-vapor on aerosol optical property over Beijing, China. Atmos pollut Res 7(5):743–753CrossRefGoogle Scholar
- Cheng TT, Zhang RJ, Han, ZW, Fang W (2008) Relationship between ground-based particle component and column aerosol optical property in dusty days over Beijing. Geophys Res Lett 35(L20808):288–299Google Scholar
- Eck TF, Holben BN, Dubovik O, Smirnov A, Goloub P, Chen HB, Chatenet B, Gomes L, Zhang XY, Tsay SC, Ji Q, Giles D, Slutsker I (2005) Columnar aerosol optical properties at AERONET sites in central eastern Asia and aerosol transport to the tropical mid-Pacific. J Geophys Res 110(D06202):887–908Google Scholar
- Huang L, Chen M, Hu J (2016) Twelve-year trends of PM10 and visibility in the Hefei metropolitan area of China. Adv Meteorol 2016(4810796):1–9Google Scholar
- Li Z, Xia X, Cribb M, Mi W, Holben B, Wang P, Chen H, Tsay S, Eck TF, Zhao F, Dutton EG, Dickerson RE (2007) Aerosol optical properties and their radiative effects in northern China. J Geophys Res 112(D22S01):321–341Google Scholar
- Xin J, Wang Y, Li Z, Wang P, Hao W, Nordgren BL, Wang S, Liu G, Wang L,Wen T, Sun Y, Hu B (2007) Aerosol optical depth (AOD) and Angstrom exponent of aerosols observed by the Chinese Sun Hazemeter Network from August 2004 to September 2005. J Geophys Res 112 (D05203):1703–1711Google Scholar