Using SST for improved mesoscale modelling of the
coastal zone
Ioanna Karagali, Rogier Floors, Andrea Hahmann, Guillaume Lea,
and many others
June 5 - 10 2016, Washington DC, USA
GHRSST XVII Science Team Meeting
1/18
Outline
1
Introduction
2
The RUNE Experiment
3
Modelling
4
Summary
GHRSST XVII Science Team Meeting
2/18
Motivation
Many offshore wind farms
planned in near-coastal
waters:
high winds
easier connection to
the grid
Model uncertainty of the
coastal wind climate is
large:
roughness changes
stability changes
Is the accuracy of
mesoscale models in
capturing the coastal
flows, accurate?
GHRSST XVII Science Team Meeting
3/18
RUNE
How can mesoscale
models be enhanced to
better predict near-shore
wind resources?
Reducing Uncertainty of Near-shore
wind resource Estimates (RUNE)
If and how can the
uncertainty of modelled
near-shore wind ressource
estimates be reduced
using short-term in situ
lidar measurements
If yes –> By how much?
Campaign duration: November 2015 - February 2016
GHRSST XVII Science Team Meeting
4/18
1
Introduction
2
The RUNE Experiment
3
Modelling
4
Summary
GHRSST XVII Science Team Meeting
5/18
Measurement Set-up
220
200
1 dual Doppler system
180
160
Resolution ∼50 m
height [m]
140
120
100
80
Scanning for ∼1 s
60
40
6266
6265
20
6264
6263
6262
0
438
1 sector scanning system
Resolution ∼200 m
6261
440
6260
442
444
northings [km]
6259
446
448
6258
450
eastings [km]
Figure: 3D overview of the measurements. Blue points:
range gates from the scanning LIDAR, black points:
dual Doppler, vertical lines: profiling LIDARs.
Scanning for ∼45 s at 60°
4 profiling LIDARS
Resolution ∼20 m
Figure: Loctions of the onshore LIDARs, the floating
LIDAR and the wave buoy.
GHRSST XVII Science Team Meeting
6/18
Example of Measurements
Figure: Carrier to Noise Ratio (CNR) as a function of distance (left) and scanning pattern
(right).
GHRSST XVII Science Team Meeting
7/18
1
Introduction
2
The RUNE Experiment
3
Modelling
4
Summary
GHRSST XVII Science Team Meeting
8/18
WRF
2 SST products
Daily DMI L4 SST 0.02 deg
Daily OI SST v2 0.25 deg
2 land use classifications
USGS
CORINE (250 m)
2 PBL schemes
MYJ
YSU
4 spatial resolution set-ups
18, 6, 2 km
12, 4, 1.3 km
9, 3, 1 km
13.5, 4.5, 1.5, 0.5 km
GHRSST XVII Science Team Meeting
Figure: Domain configuration for the RUNE
sensitivity simulations
9/18
Example of land uses and resolution
Figure: Inner domains at various horizontal resolutions with
the CORINE land use.
Figure: USGS (top) & CORINE.
GHRSST XVII Science Team Meeting
10/18
Sensitivity of the coastal gradient
Figure: Wind speed evolution from offshore (left) to onshore (right) for different heights
GHRSST XVII Science Team Meeting
11/18
Sensitivity Tests
Figure: Mean wind speed profile from the cup anemometers (c) and different WRF set-ups,
at Høvsøre. Right: RMSE of the wind speed profile between measurements and WRF
simulations.
GHRSST XVII Science Team Meeting
12/18
Combined LIDARs, WRF & TerraSAR-X
Figure: LIDAR Dual & Sector scans, Profilers, WRF & TerraSAR-X on December 10 2015,
06:00.
GHRSST XVII Science Team Meeting
13/18
WRF vs LIDARs
Figure: Mean wind speed using 3368 10-min measurements with 100% availability of the
DD up to a distance of 2 km offshore and onshore (total 5 km).
GHRSST XVII Science Team Meeting
14/18
WRF vs LIDARs
Figure: Mean wind speed using 1904 10-min measurements with 100% availability of the DD
up to a distance of 5 km offshore and onshore (total 7 km - not filtered by wind direction).
GHRSST XVII Science Team Meeting
15/18
1
Introduction
2
The RUNE Experiment
3
Modelling
4
Summary
GHRSST XVII Science Team Meeting
16/18
Summary
NS_BS_L4_SST now routinely processed as input for WRF
At 50 m, YSU PBL simulations agree well with observations
Jump at the coastline for 100 & 150 m heights, due to instrument
limitation
Offshore wind speed difference ∼0.3 m s−1 due to resolution
GHRSST XVII Science Team Meeting
17/18
Thank you!
GHRSST XVII Science Team Meeting
18/18