DOAS measurements of tropospheric bromine oxide in mid-latitudes

Episodes of elevated bromine oxide (BrO) concentration are known to occur a t high Latitudes in the Arctic boundary layer and to lead to catalytic dest ruction of ozone at those latitudes; these events have not been observed at Lower latitudes. With the use of differential optical absorption spectrosc opy (DOAS), Locally high BrO concentrations were observed at mid-latitudes at the Dead Sea, Israel, during spring 1997. Mixing ratios peaked daily at around 80 parts per trillion around noon and were correlated with Low bound ary-layer ozone mixing ratios.