We use the rain gauge at Lyttelton as indicating the rainfall at Port Levy,
but is it the most appropriate site?
Below shows the rainfall for the last year at various sites nearby. The locations of these gauges are shown in the figure beneath. You can see how variable the rainfall is between sites. This is especially true of the most rainy month recently (May 2009).
May 2009 was the rainiest May at ChCh Aero since 1961. The totals for the month are listed in the table below. What is interesting is the large discrepancy between the sites on the Peninsula. Examination of the daily record indicates that there were two southerly storms. In the first between 6 and 12-May, the rainfall at ChCh Aero, Lyttelton and Le Bons was roughly the same, but the rainfall at Little Akaloa was 2/3 of the others. In the second storm between 19 and 26-May, the rainfall at Le Bons was twice that at Little Akaloa and 3/2 that at ChCh Aero and Lyttelton. A reason for these differences could be that the exposure of ChCh Aero and Lyttelton to southerlies is about the same, but Le Bons is more exposed and Little Akaloa is somewhat sheltered.
|Lyttelton Port||ChCh Aero||Little Akaloa||Le Bons|