Variability of particulate organic carbon in inland waters observed from MODIS Aqua imagery

Surface concentrations of particulate organic carbon (POC) in shallow inland lakes were estimated using MODIS Aqua data. A power regression model of the direct empirical relationship between POC and the atmospherically Rayleigh-corrected MODIS product (R-rc,R-645-R-rc,R-1240)/(R-rc,R-859-R-rc,R-1240) was developed (R-2 = 0.72, RMSE= 35.86 mu gL(-1), p < 0.0001, N = 47) and validated (RMSE = 44.46 mu gL(-1), N= 16) with field data from 56 lakes in the Middle and Lower reaches of the Yangtze River, China. This algorithm was applied to an 11 year series of MODIS data to determine the spatial and temporal distribution of POC in a wide range of lakes with different trophic and optical properties. The results indicate that there is a general increase in minimum POC concentrations in lakes from middle to lower reaches of the Yangtze River. The temporal dynamics of springtime POC in smaller lakes were found to be influenced by local meteorological conditions, in particular precipitation and wind speed, while larger lakes were found to be more sensitive to air temperature.