Perturbation may 2010.
Tidal waves #19 and #20 come detached possibly because of sustained sun wind speed.
Perturbation may 2010.
.1 In the lagoon of Venice, two tide waves were late, possibly because of the conditions of the sun wind.
The position of the Moon.
.2 192010-05-04u0400: the passage of the Moon above the local meridian took place, being its declination south 21°02 (spatiole for the tide wind 19).
Graph of the solar wind speed.
The tide wave in Venice (punta Salute).
Legend of the tidal wave graphs.
On the numbers of the tidal waves.
Wave 19 High water times difference
water level
Forecasts (astronomical). 2010-05-04 u 1500 min. =
43
Forecasts A+M 2010-05-04 u 1350 min. +70
60
As recorded 2010-05-04 u 1500
69
Interval 19-20 Low water times
Forecasts (astronomical). 2010-05-04 u 1750 min. +190
34
Forecasts A+M 2010-05-04 u 1750 min. +190
45
As recorded 2010-05-04 u 2100
36
Onde 20 High water times
Forecasts (astronomical). 2010-05-04 u 2250 min. +120
49
Forecasts A+M 2010-05-04 u 2315 min. +95
70
As recorded 2010-05-05 u 0050
44
Interval 20-21 Low water times
Forecasts (astronomical). 2010-05-05 u 0655 min. -55
-9
Forecasts A+M 2010-05-05 u 0655 min. -55
5
As recorded 2010-05-05 u 0600
21
Forecasts A+M.
.4 From the forecasts A+M - those where both the astronomical situation and the weather conditions are taken into account - the water levels would have been much higher, throughout. This part of the forecasts proved correct, except for the troughs of two intervals, 19-20 and 20-21.
.5 The forecasts A+M were also for an earlier arrival of wave 19; this part of the forecasts proved incorrect.
Late arrivals for the waves 19 and 20.
.6 Compared with the forecasts A+M, the perturbation would have caused the wave 19 to be 70 minutes late, and the wave 20 to be at least 95 minutes.
The norm.
.7 Compared with the simple astronomical forecasts - those where the perturbations of all kinds are not taken into account - the odd number wave #19, generated late, and the even number wave #20, generated early, had to become one wave.
.8 Instead, because of the Sun perturbation, both waves were late: the wave 19 was about 60 minutes late, while the wave 20 was about 100 minutes late, with regard to the normal times.
The two waves 19 and 20 come detached.
.9 Consequently, as an exception, the two waves, 19 and 20, did not arrive as fused into one single wave. Compared with the norm, they detached themselves by 40 minutes.
.10 Between the waves 19 and 20, the interval gets accentuated: the water level gets reduced, compared with the meteo and astronomical forecasts. That's because of the delay of the wave 20.
.11 By contrast, and because of the same reason, during the interval 20-21, the water level gets increased.