Active layer and Permafrost monitoring programme in Northern Victoria Land. Mauro Guglielmin (1)
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Active layer and Permafrost monitoring Active layer and Permafrost monitoring programme in Northern Victoria Land. programme in Northern Victoria Land. Mauro Guglielmin Mauro Guglielmin (1) (1) (1) Sciencies Faculty, Insubria University, Via J.H.Dunant 3 21100 (1) Sciencies Faculty, Insubria University, Via J.H.Dunant 3 21100 Varese Italy Varese Italy
description
Active layer and Permafrost monitoring programme in Northern Victoria Land. Mauro Guglielmin (1) (1) Sciencies Faculty, Insubria University, Via J.H.Dunant 3 21100 Varese Italy. Guglielmin M., Active Layer …. Introduction - PowerPoint PPT Presentation
Transcript of Active layer and Permafrost monitoring programme in Northern Victoria Land. Mauro Guglielmin (1)
Active layer and Permafrost monitoring programme in Northern Active layer and Permafrost monitoring programme in Northern Victoria Land. Victoria Land. Mauro GuglielminMauro Guglielmin (1) (1)
(1) Sciencies Faculty, Insubria University, Via J.H.Dunant 3 21100 Varese Italy(1) Sciencies Faculty, Insubria University, Via J.H.Dunant 3 21100 Varese Italy
Guglielmin M., Active Layer …
Introduction
Active layer and permafrost are key indicators of climate change within the cryosphere. The monitoring of these two indicators has been performed and is still going on through several international programmes such as the Circumpolar Active Layer Monitoring (CALM) and Permafrost and Climate in Europe (PACE) that are focussed mainly in the Arctic or in Europe.
In Antarctica the data available are very scarce.
This paper shows the first results of a programme carried out in Northern Victoria Land and founded by the Italian Antarctic Research Programme since 1996.
Guglielmin M., Active Layer …
Distribution of active layer study sites (+) and boreholes (star)
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Distribution of active layer study sites (+) and boreholes (star)
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Study sites
location
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Study sites
location
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Boulder Clay (74°44’45’’S -
164°01’17’’E, at 205 m a.s.l ) Calm Grid ( 100 x 100) and Permafrost station
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Oasi (74°42’S – 164°06’E at 80 m a.s.l.) : Climate station and Borehole (15.5 m) monitored
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Simpson Crags (74°26’S- 164°01’E at 830 m a.s.l.):
CALM GRID (100 x 100) and Permafrost station
Mount Keinath ( 74° 33’ S – 1 ° E at 1100 m a.s.l.): Permafrost station
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Methods
In the two grids (100 x 100 m) the measurements have been performed in each grid point, according both to the CALM protocol (Nelson et al., 1998), by annual probing of the maximum thickness of seasonal thaw, and to the RiSCC protocol (Guglielmin, 2003), by annual measurements of temperature at different depths.
Permafrost monitoring is going through the automatic measurements of temperature within borehole at different depths from 2 cm to 15.5 m). At the same time the main climatic parameters (i.e. air temperature, solar radiation) are recorded (Guglielmin and Dramis, 1999; Guglielmin, 2003).
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Locality N. Ground
Temperature
Depth (cm)
Air Temperature
(+1.5 m)
Incoming Global
Radiation
Additional sensors
Boulder Clay
6 2, 30, 60,160,
260, 360
Yes Yes no
Simpson Crags
6 2, 30, 160,
260,540,800
Yes Yes Yes
Wsd, Sn
Mount Keinath
4 2, 30, 60, 100
Yes Yes no
Oasi 16 2, 30, 60,
To 1550
Yes Yes Yes
Wsd, Sn, Hum, CNR1
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Summer Temperature
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-10
-5
0
5
10
31/12/1998 30/01/1999 01/03/1999
Time (day)
Tem
pera
ture
(°C
)
Air Temp BC
BC 2 cm
Air temp SM
SM 2cm
ResultsSummer ground surface temperature (GST) is mainly correlated with air temperature even if, GST at different sites, can be higher or lower than air temperature
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-40
-35
-30
-25
-20
-15
-10
-5
0
01/05/1999 31/05/1999 30/06/1999 30/07/1999 29/08/1999
Tem
per
atu
re (
°C)
0
5
10
15
20
25
Win
d s
pee
d (
m/s
)
Air temp SM
SM 2cm
SM speed
In winter too GST is well correlated with air temperature and is generally smoothed respect to it. Also during the episodes of sudden strong winds known as “coreless winter” the GST variations are much smaller than air fluctuactions because of the snow fall cover the ground surface during these episodes
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Experimental Field Manipulation of Snow cover (Boulder Clay, Jannuary 1998)
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-4
-2
0
2
4
6
8
Time (days)
GS
T (
°C)
10 cm 20 cm Snow Free Air
ResultsResultsSnow Cover can influence deeply the GST.
The manipulation of snow cover carried out at Boulder Clay shows that only 10 cm of snow can decrease the GST until 8 °C on daily average.
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Edmonson Point
0
5
10
15
Time (10')
Tem
per
atu
re (
°C)
wet moss
Barren soil
Vegetation cover exerts a buffering effect on the GST, changing the energy balance and the snow cover permanence and heigth
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Results
Impacts of climatic factors on ground surface temperature
- Solar radiation
Incoming radiation and GST (1Jan -1Mar)
0
50
100
150
200
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350
400
450
-15
-10
-5
0
5
10BC RadSM RadSM 2cmBC 2 cm
GST seems not to be strongly influenced by the incoming radiation at least on the daily average
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Example of Radiative Balance and the effect of snow cover recorded during
January 2003 at Oasi.
0
100
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1000
330 450
0
0,1
0,2
0,3
0,4
0,5K in
K outL in
L outSnow Cover
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Boulder Clay CALM GRID: surface topography
93.5
94
94.5
95
95.5
96
96.5
97
97.5
98
98.5
99
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Boulder Clay CALM GRID: albedo (%)
100 110 120 130 140 150 160 170 180 190100
110
120
130
140
150
160
170
180
190
200
5
10
15
20
80
Albedo (%)
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Boulder Clay CALM GRID: snow thickness (cm): 1999-2003.
100 110 120 130 140 150 160 170 180 190100
110
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100 110 120 130 140 150 160 170 180 190100
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0
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60
80
100
120
Snow cover (cm)
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Boulder Clay CALM GRID: Ground surface temperature (-2 cm depth) 1999-2003
100 110 120 130 140 150 160 170 180 190100
110
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170
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200
0
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0
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100 110 120 130 140 150 160 170 180 190100
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100 110 120 130 140 150 160 170 180 190100
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200
0
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GST (at 2 cm)
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Boulder Clay CALM GRID: Ground temperature at 10 cm of depth (1999-2003)
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100 110 120 130 140 150 160 170 180 190100
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Temperature at 10 cm of depth
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Boulder Clay CALM GRID: active layer thickness (frost probe method)
100 110 120 130 140 150 160 170 180 190100
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5
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0
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200
0
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200
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Active layerMeasured byFrost probe (cm)
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Boulder Clay CALM GRID: 0°C isotherm depth (thermal profile extrapolation)
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Boulder Clay CALM GRID:comparison frost probe and thermal extrapolation methods (summer 2002)
100 110 120 130 140 150 160 170 180 190100
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Frost probe:Range: 0-56Average:38
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0°C Isotherm depth:Range:0-86Average: 32
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Boulder Clay permafrost station:thermal regime between 2/12/1996 and 16/12/2002
60
18
03
00
2/12/199616/12/2002
4 0 - 4 - 8 - 12 - 16 - 20 - 24 - 28 - 32
Thermal regime measured at Boulder clay station between 27-12-1996And 16-12-2002
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Results
Ground surface temperature
Ground Surface Temperature at Boulder Clay
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-30
-25
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-10
-5
0
5
10
1/1/97 1/1/98 1/1/99 1/1/00 31/12/00 31/12/01 31/12/02
Time (days)
Mea
n D
aily
T (
°C)
GST variations at Boulder Clay permafrost station
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360 260 160 60 30 2 nday
1997 -17,59 -17,46 -17,34 -17,28 -17,15 -16,22 365
1998 -17,75 -17,47 -17,16 -17,02 -16,86 -16,14 365
1999 -16,57 -16,43 -16,46 -16,48 -16,45 -16,01 331
2000 -17,31 -17,12 -16,93 -16,84 -16,73 -16,51 358
2001 -17,80 -17,56 -17,23 -17,08 -16,91 -16,42 365
2002 -17,28 -17,22 -17,24 -17,27 -17,16 -16,68 350
Synthesis of Mean Annual Ground Temperatures recorded at Boulder Clay . 1999 misses one month of data (november)
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Temperature profile within Oasi borehole. The shifting of the curves is partially due to the thermal perturbance of the drilling operation only 1 week before the 1999 measurement
0
3
6
9
12
15
18
-20 -16 -12 -8 -4
Temperature (°C)
(de
pth
(m)
2000
1999
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Conclusions
1) GST is mainly controlled by air temperature although vegetation and snow cover exert an important buffering effect as already known for the Arctic ;
2) Thermal Offset is generally very limited (less than 0.5°C ) and Active Layer thickness is spatially extremely variable because of the high roughness of the surface (that influence strongly both vegetation and snow cover).
3) Permafrost table (PTD) and maximum thawing depths (MTD) can be very different, especially in the coastal areas where the deposits are rich in salt content.
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Conclusion
4) Active layer thickness with probing is not enough accurate because the lithology is mainly coarse.
5) For Climate monitoring purposes it is recommended the measurement of PTD instead of MTD, because it is easier and more strictly related to GST.
6) Considering the Annual average, the Permafrost thermal regime is almost stable while large variations occur at seasonal scale, especially within active layer.
7) More data are needed both to active layer and permafrost thermal conditions, especially combining areal informations (CALM GRID with RiSCC protocol) and authomatic monitoring of temperature in borehole.
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AcknowledgmentsAcknowledgments
Research was made possible by funds from the projects “Permafrost and Global Change in Antarctica I and II”, supported by Italian National Antarctic Project (PNRA). A special thank for the incredible logistic organization to PNRA and in particular to Ing. Mario Zucchelli that encouraged this research.
