the iglos campaign 2002 at summit (greenland) untersuchung
TRANSCRIPT
Stabile Grenzschicht über polaren EisschildenGünther HeinemannUmweltmeteorologie Universität Trier
Polare Eisschilde
Klein and Heinemann (2002)Heinemann (1995)
1000 km
The IGLOS campaign 2002 at Summit (Greenland)The IGLOS campaign 2002 at Summit (Greenland)( Investigation of the Greenland boundary Layer Over Summit )Experiment: 29 June - 25 July 2002
Drüe and Heinemann (2007)© Heinemann Greenland SUMMIT station (3250m)
Untersuchung der stabilen Grenzschicht (SBL) unter homogenen Bedingungen
© HeinemannPolar 2 (AWI)
Polar 2 at SUMMIT station
Meteopod
Meteopod 100 Hz© Heinemann
ETH 50m tower
© Heinemann
• Temperature, humidity, wind at 8 levels• Turbulence at 4 levels• Incoming and outgoing radiation fluxes at
4 levels
© Heinemann
© Heinemann
Ultrasonic Anemometer
Neutrale Grenzschicht
© Heinemann
Stabile Grenzschicht (SBL)
© Heinemann
Stabile Grenzschicht (SBL)
© Heinemann
Typical flight strategy Box 30km x 30kmHorizontal along-wind runs
30 km constant heighttwo series at four levelssaw-tooth patternhigh vertical profile
3m mast
50m mast
wind
6 flight missions in the SBL(stable boundary layer)
Drüe and Heinemann (2007)
Vertical profilesSBL2
Radiative SBL cooling ( ≈ 0.6 K/h ) is significant in the SBLTurbulence yields a much smaller contribution
Drüe and Heinemann (2007)
Horizontal profiles at 30m (SBL6)
Turbulence is intermittent Turbulent eventfraction. Diamonds: IGLOS cases, squares: Doran (2004).
Drüe and Heinemann (2007)
Katabatischer Wind über Eisschilden
Constancy0.8-0.9>0.9
NORLAM simulations25 km resolution10m wind Jan 1990Heinemann and Klein (2002)
Sample=4
Wintertime near-surface wind Greenland
Orography contour interval 500 m
Katabatischer Wind in Grönland (Piteraq)
Piteraq event Tasiilaq1970: Gusts up to 72 m/s
Loewe (1972) Loewe (1972)Rasmussen (1989)
KABEG experiment April and May 1997
Polar 2 (AWI)
-51.0 -50.5 -50.0 -49.5 -49.0 -48.5 -48.0 -47.5Lon in deg
67.2
67.4
67.6
67.8
Lat i
n de
g
A1 A2 A3 A4
SU2
Kabeg flight pattern 220497 K1
Pa
Q2a
Q2b Q1b
Q1a
Pb
S
100 kmHeinemann (1999)
Inversion
Katabatischer Druckgradient
Synoptischer Druckgradient
© Heinemann
26 April 1997
1 2 3 4istat
0
2
4
6
8
10
12
14
16
18
20
22
LST
15 m/s
-51.0 -50.5 -50.0 -49.5 -49.0 -48.5 -48.0 -47.5Lon in deg
67.2
67.4
67.6
67.8
Lat i
n de
g
A1 A2 A3 A4
SU2
Kabeg flight pattern 220497 K1
Pa
Q2a
Q2b Q1b
Q1a
Pb
S
100 km
Heinemann and Falk (2002)
A4: mean over 7 days
ΔT
0 2 4 6 8 10 12 14 16 18 20 22 24time in UTC
-6
-2
2
6
ΔT i
n °C
-60
-20
20
Q i
n W
/m2
115
135
155
175
dd in
deg
dd
Q
(weak synoptic forcing)A4: mean over 7 days
ΔT
0 2 4 6 8 10 12 14 16 18 20 22 24time in UTC
-6
-2
2
6
ΔT i
n °C
-60
-20
20
Q i
n W
/m2
115
135
155
175
dd in
deg
dd
Q
(weak synoptic forcing)
A2
500
1000
1500
2000
iceedge
Tundra Ice sheet40 kmIce sheet
Inversion
Rotor
Gravity wavesStrong turbulence cold
warm
Aircraft measurements of the katabatic wind system
Heinemann (2008)
ff
TP1 220497, 0740 UTC
10 15 20ff in m s-1
0
100
200
300
heig
ht in
m
0
100
200
300-4 1 6 °C
Windstärke 9
Heinemann (2002)
ff
PT1220497
v
u
0
100
200
300-15 -10 -5 0
u in m/s
74km
5 10 15 20v, ff in m/s
0
100
200
300R
adar
hei
ght i
n m
ff
TP1 220497, 0740 UTC
10 15 20ff in m s-1
0
100
200
300
heig
ht in
m
0
100
200
300-4 1 6 °C
Heinemann (2002)
Topography (isolines every 50 m) and selected wind vectors at heights of 30, 100, 200 and 400 m above the topography for 13 May 1997
20 m/s 30 m100 m200 m400 m
Q2Q1
Tb Tb
TaTa
-51.0 -50.5 -50.0 -49.5 -49.0 -48.5 -48.0 -47.5Lon in deg
67.2
67.4
67.6
67.8
Lat i
n de
g
A1 A2 A3 A4
SU2
Kabeg flight pattern 13.5.97 K1
Pa
Q3b
Q3aQ2a
Q2b Q1b
Q1a
Pb
Heinemann (2002)
Aircraft: Regimes of the katabatic wind system
500
1000
1500
2000
iceedge
Tundra Ice sheet40 kmIce sheet
Rotor
Linear gravitywaves
Inversion8 10 12 14 16 18 20
km
500
700
900
Hei
ght i
n m
Inland iceTundra
Aircraft
Iceedge
8 10 12 14 16 18 20km
-25
-15
-5
u in
m/s
500
700
900
Hei
ght i
n m
Inland iceTundra
Aircraft
Iceedge
Hydraulic jump
h
21 Ugh
Frcw
c
θθθ−
=
Froude number
Fr>1Fr<1
Heinemann (2002)
Downslope wind
Itaipu Dam (Siemens)
Fr>1
Fr<1
Inversion
Katabatischer Druckgradient
Synoptischer Druckgradient
© Heinemann
FS
Δθm
7 11 15 19Vm in m/s
0
10
20
30
40
acc.
in m
/s2 .
10-4
4
6
8
10
Δθ m
in
°C
FT
Druckgradient-Terme und Wind aus Flugzeugmessungen
Heinemann (1999)
Synoptisch
Katabatisch
Inversionsstärke
0
1
2
2e b
ias
in m
²/s²
200
80
40
2012
4
Diag.Prog.
BIAS
Comparisons of Lokalmodell simulations (2.8km) and aircraft measurements KABEG
TKE bias (0-150m) for all KABEG profiles in the katabatic SBL
Asympthotic mixing length in m
LM standard
Measurements
Nach Krebsbach (2002)
10d accumulation bysnow drift (kg/m²)LM14+SNOWPACK3-12 July 2002 (IGLOS)
HebbinghausHebbinghaus and and Heinemann (2006)Heinemann (2006)
( )SvAcc Hrr
•∇−=Snow drift S
Simulation der Schneedrift mit LM/SNOWPACK
Local scaling for KABEG data
0 10 20z/Λ
0
1
2
3
σ w/u
*L
125825102654
40 15 5
a)
Variances verticalwind (about 250 data points, 6 flights)
0 1 2 3 4
z/Λ
0
1
2
3
σw/u
*L
221 141 82 56 4967
Cabauw data, Nieuwstadt (1984)Data collected within 18 months(data from Duynkerke, 2001)
0 1 2 3 4z/Λ
0
1
2
3
σ w/u
*L
12 58 25 10 2654
b) KABEG
Parametrisierung der SBL
σa
*L aa
C= = >$ /const for z Λ 1
Heinemann (2004)
Katabatischer Wind Antarktis
Sample=2
RACMO 55 km 1980-1993 winter monthsJJAVan Lipzig (2003)
Orography contour interval 1000 m
Wintertimenear-surfacewind Antarctica
Profile of thepoleward mass fluxacross thegrounding line
Van Lipzig and van den Broeke (2002)
RACMO 55km (1957-2002)Annual average sublimation (-E0 in mm/a)
Van den Broeke (2005)
Schlussfolgerungen● Die polaren Eisschilde eignen sich sehr gut
zur Untersuchung:- der sehr stabilen Grenzschicht mitintermittierender Turbulenz- der stabilen Grenzschicht mit vollausgebildeter Turbulenz (katabatischer Wind)
● katabatischer Wind bedeutsam fürMassenbilanz der Eisschilde und für den globalen Impulshaushalt