L4 surface chlorophyll data

These plots were generated with a mixture of data. For the period between 1999 and the present HPLC chlorophylls have been used. For the earlier period (1992 - 1999), chlorophylls determined using fluorometric techniques were utilised. The left hand plot shows the considerable annual and interannual variability in retrievals of chlorophyll at L4. On the right the monthly averages have been calculated (solid line) and the maximum and minimum departure from this. The asterisks represent the satellite retrievals of chlorophyll at L4 with the error bars representing the maximum and minimum values.