Title: The impact of climate change on wind waves
1The impact of climate change on wind waves
Barry Broman SMHI
- Using a simple model Hsf(wind,fetch,duration)
- 1189 points (1020 resolution)
- Fetches in 8 directions (N NE E SE S SW W NW)
- Estimated wind fields from observations and sea
level preasure 1980-2004 (hindcast) - Wind fields from RCMs (control, scenarios)
2- The wave climate is needed in order to classify
routes for ships of different kinds. There are
different classes depending on which wave height
is exceeded during 10 of the time i.e. the 90th
percentile. - When planning sea operations information of the
wave climate is needed. A changing climate will
have implications on such operations - Information on waves is also important for
estimations of erosion on the shore and the sea
bottom. - When prospecting new harbours and other
constructions in the sea there is need to know
the wave climate.
3significant wave height Hsmean of 33 highest
waves
4Nomogram Hsf(wind,fetch,duration)
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6Fetches in 8 directions (N NE E SE S SW W NW)
71181 points (1020 resolution)
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9Observed and estimated significant wave height
at Almagrundet 1984
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11 Significant wave heights (in m) in the control
climates RCAO-H (upper panels), RCAO-E (lower
panels), annual mean (left panels), and 90th
percentile (right panels).
12Changes of 90th percentiles of the significant
wave height (in m) in the scenarios compared to
the control simulations RCAO-H (upper panels),
RCAO-E (lower panels), B2 (left panels), and
A2 (right panels).
13Changes of annual mean significant wave heights
(in m) in the scenarios compared to the control
simulations RCAO-H (upper panels), RCAO-E
(lower panels), B2 (left panels), and A2 (right
panels).
14Mean Hs(m) December 2004 Different models
Fetch
Hypne
SWAN
1590th percentile Hs(m) December 2004 Different
models
Fetch
Hypne
SWAN
16Areas used for represantive windstations
17Hs (m) 90-level Calculated from representative
stations 1979-1994
October
November
December
18Diagrams used for planning
19Conclusions
- Results from the two control runs give similar
mean wave heights of 0-1.3 m - The corresponding 90th percentile shows waves of
the order 0-2.5 m with the highest waves in the
southern and eastern Baltic proper - The differences of the mean significant wave
height and the 90th percentile of the wave height
between control simulations (1961-1990) and hind
cast simulation (1980-2004) are in the range of
-0.2 and 0.2 m approximately - Changes of the 90th percentiles are significant
larger in RCAO-E than in RCAO-H