|
Читайте также: |
The comparison of the meteorological data means for the
eight year periods 1988–95 and 1996–2003 showed little
change in the humidity, a drop in the precipitation, and
rises in both temperature and wind speed (Table 2).
Themeans of the humidity, precipitation, temperature,
and wind speed for each month between 1988 and 2003
inclusive were compared to the monthly means over the
whole 16-year period. Individual months when the mean
humidity or precipitation was lower than, or the mean
temperature or wind speed was higher than, the 1988–
2003 means were identified (Table 3). Months when two
or more of these conditions coincided were also identified.
Onseveral occasions individual selected criteria varied
from the 16-year mean over several consecutive months,
SPHAGNUM MOSS: AN INDICATOR OF CLIMATE CHANGE IN THE SUB-ANTARCTIC 45
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
L
L
L
L
L
L
7 7 1
3 5
1 2
4 2 2
1 3
L
15 9
L
L
Skua Tarn
Skua Lake
Sandy Bay
Red River
Bauer Bay
Prion Lake
North Head
Major Lake
Hurd Point
Flynn Lake
Flat Creek
The Nuggets
Square Lake
Sellick Bay
Scoble Lake
Sandell Bay
Petrel Peak
Lake Ifould
Island Lake
Gentoo Flat
Eagle Point
Eagle Caves
Duck Lagoon
Davis Point
Aurora Cave
Whisky Creek
Tulloch Lake
Pyramid Peak
Mawson Point
Aurora Point
Waterfall Bay
Lusitania Bay
Langdon Point
Lake Tiobunga
Douglas Point
Caroline Cove
Waterfall Lake
Brothers Point
Mount Ainsworth
Handspike Point
Little Prion Lake
Perseverance Bluff
Jessie Niccol Creek
Elizabeth and Mary Point
4 81 000m. E
4 81 000m. E
4 90
4 90
5 00
5 00
5 05 000m. E
5 05 000m. E
39 28 000m. N
39 28 000m. N
29 29
39 30 39 30
31 31
32 32
33 33
34 34
35 35
36 36
37 37
38 38
39 39
39 40 39 40
41 41
42 42
43 43
44 44
45 45
46 46
47 47
48 48
49 49
39 50 39 50
51 51
52 52
53 53
54 54
55 55
56 56
57 57
58 58
59 59
39 60 39 60
61 61
62 62
63 63
64 64
39 65 000m. N
39 65 000m.
Scale: 1:150,000
N
Fig. 1. Distribution map of Sphagnum falcatulum on Macquarie Island, based on a 1 km square grid. The numbers
in the grid squares indicate the number of Sphagnum moss patches, and the numbers followed by L indicate the
number of large Sphagnum moss beds (≥3m2).
46 WHINAM AND COPSON
Table 1. Area (m2) of Sphagnum moss at each site by year. *November 1992 figures have been calculated by using
length and width measurements for each moss patch and do not have the same accuracy as subsequent area
measurements. – Indicates that the site was not established at that date.
Site Name & Tag No. Nov. 1992 Nov. 1996 Nov. 1998 Nov. 1999 Mar. 2004
Douglas Point 26 – – 2.3 3.4 2.1
Douglas Point 69 – 0.9 0.9 1.9 0.0
Eagle Point 70 4.8 2.0 2.8 2.6 2.5
Green Gorge 38 0.5 2.0 2.4 3.2 0.0
Green Gorge 52 0.2 0.0 0.0 0.0 0.0
Green Gorge 53 0.2 0.2 0.1 0.1 0.1
Green Gorge 62 28.1 22.8 23.5 32.3 29.3
Green Gorge 63 – 0.4 0.5 0.6 0.8
Green Gorge 77 12.9 7.1 7.4 7.5 7.5
Handspike 36 (1) 16.7 8.9 8.9 8.9 6.4
Handspike 36 (2) 15.3 0.0 0.0 0.0 0.0
Handspike 81 2.3 1.2 1.1 1.2 2.3
Mawson Point 67 3.9 4.9 4.4 0.0 0.0
Mawson Point 68 – 3.9 8.0 0.0 1.0
Scoble Lake 12 351.0 0.0 0.0 0.0 0.0
Square Lake 31 5.4 0.0 0.0 0.0 0.0
Above Square Lake 32a 0.4 0.3 0.3 0.0 0.0
Above Square Lake 32b – 0.2 0.0 0.0 0.0
Above Square Lake 33 0.1 0.0 0.0 0.0 0.2
Above Tulloch Lake 34 1.3 3.9 3.5 5.1 5.0
Above Tulloch Lake 66 – 0.2 0.3 0.3 0.4
Brothers Lake 64 – 0.5 0.0 0.1 0.0
West Brothers Lake 65 0.2 0.2 0.1 0.1 0.0
AVERAGE AREA 27.7 2.7 2.9 2.9 2.5
Fig. 2. Photograph from same fixed photo-point as Figure 3, taken at Green Gorge catchment in 1992, showing new
patches of Sphagnum moss appearing.
SPHAGNUM MOSS: AN INDICATOR OF CLIMATE CHANGE IN THE SUB-ANTARCTIC 47
Fig. 3. Photograph from same fixed photo-point as Figure 2, taken at Green Gorge catchment in 1996, showing new
patches of Sphagnum moss appearing.
Table 2. Means of meteorological data (based on monthly
means) for the periods 1988–95, 1996–2003, and 1988–
2003.
1988–95 1996–2003 1988–2003
Humidity (%) 85.8 85.9 85.8
Precipitation (mm) 1062.9 1047.7 1055.3
Temperature (◦C) 4.8 5.0 4.9
Wind speed (mps) 9.5 10.3 9.9
Table 3. Number of occasions and ways that monthly
means of selected meteorological events varied from the
1988 to 2003 16-year mean.
1988–95 1996–2003 1988–2003
Lower mean 43 (45%) 46 (48%) 89 (46%)
humidity
Lower mean 50 (52%) 53 (55%) 103 (54%)
precipitation
Higher mean 39 (41%) 56 (58%) 95 (49%)
temperature
Higher mean 31 (32%) 65 (68%) 96 (50%)
wind speed
but they rarely coincided with extended periods of
variation in any of the other criteria. An example of
variation in a single criteria occurred between November
1988 to October 1989 when there were 12 consecutive
months with the temperature above the 16-year mean.
However, while lower-than-mean precipitation occurred
on seven of these months and higher-than-mean wind
speeds on six, only on two separate months did all three
defined variations occur together.
On only 10 months during the 1988–2003 period did
lower means for both humidity and precipitation coincide
with higher means for both temperature and wind speeds.
Two of these months occurred in the 1988–95 period
(September 1993 and March 1994), one in March 1996,
two in 1997, and five in 1999. In 1999 this coincidence of
defined variations occurred over four consecutive months
(August–November) during a period of 14 consecutive
months (April 1999–May 2000) with lower-than-mean
humidity and higher-than-mean wind speeds. From May
1999 to November 1999, this coincidence occurred in
seven consecutive months with higher-than-mean temperatures
(the 1999 survey was undertaken in mid to late
November). These drier conditions may have resulted in
a lowering of the watertable during this time. During
this period, the authors, along with several scientists
experienced in fieldwork conditions on Macquarie Island
(Patricia Selkirk, personal communication; the late D.A.
Adamson, personal communication) observed drier walking
conditions.
Дата добавления: 2014-12-18; просмотров: 44 | Поможем написать вашу работу | Нарушение авторских прав |