Figure 4

Seasonal cycle box plots by week for 38 districts in Niger between 1986 and 2008 for a) dust concentration, b) dust optical depth at 550 nm, c) zonal wind speed, d) meridional wind speed, e) wind speed, f) absolute humidity, g) temperature, h) relative humidity. Each box shows the range in which the central 50% of the data fall. The box borders show the first and third quartiles and the crossbar shows the median. Values (outliers) exceeding the quartile values by more than factor of 1.5, the interquartile distance, are marked as crosses. Data were derived from a long-term simulation from 1986 to 2006 with the NMMB/BSC-Dust model (Pérez et al. 2011).