Figs. 1(c) and 2(e) show that the improved algorithm is more sensitive to small, cool fires, especially for observations at large scan angles (Tables 1 and 2). In the two fire events on September 29, 2003 and December 20–21, 2004, there are a total of 22 fire spots which are omitted by the MODIS contextual algorithm, but detected by the improved algorithm. The improved algorithm fails to detect small fires lacking a visible smoke plume unless they are within the potential fire area of other fires.