T - puma.lu.lv

PENALTY FUNCTION FOR MEASURE OF CONTEMPORARY AND FUTURE CLIMATE DIFFERENCES
U.Bethers, D.Cepīte-Frišfelde, J.Seņņikovs, A.Timuhins ([email protected])
Laboratory for Mathematical Modelling of Environmental and Technological Processes, Faculty of Physics and Mathematics, University of Latvia
Abstract
The problem of finding the locations on the globe where contemporary climate matches
the future climate projections of particular region (Latvia) is addressed. The penalty
function is developed assuming usage of 30-year long time series of gridded climate
parameters. The penalty function is constructed for measurement of climate deviations
in two geographical locations; it accounts for seasonal cycle of temperature and
precipitation regime.
The result of the study was the distribution of the penalty function characterising the
deviation of the moderately, averagely and significantly changed Latvia climate from the
contemporary climate over the globe.
Where are the regions which represent the contemporary
climate of Latvia?
60°N
40°N
20°N
0°N
Annual mean precipitation in Riga according
to bias corrected (down-scaled) model run
results of EU ENSEMBLES project
Riga
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.05
0.025
0.01
0.005
0.0025
0
0.6
0.5
63°N
0.4
60°N
40°S
0.3
0.2
57°N
0.1
54°N
2.4
Precipitation, mm/day
60°S
Median
17%
83%
Contemporary climate deviation
150°W
2.2
lon ,lat
t0
0.05
0.025
51°N
0.01
48°N
0.005
45°N
90°W 60°W 30°W 0°E 30°E 60°E 90°E 120°E150°E
6°E
12°E 18°E 24°E 30°E 36°E 42°E 48°E 54°E
2.0
Where nowadays are the regions which represent the future
climate of Latvia? Images of areas with similar climate
1.8
19611990
19712000
19812010
19912020
20012030
20112040
20212050
20312060
20412070
20512080
20612090
20712100
How to measure climate deviation between the different
regions on the Earth?
How to determine the regions which represent the future
climate of the particular location nowadays?
We propose measuring deviations of the climate by comparing the normalized sum of differences in monthly
average temperatures T and precipitation intensities p averaged over time interval ti .
Tti
12
LV
ti , m
1
12 m
lon ,lat
ti
T
p
lon ,lat
t0 , m
p
LV
ti , m
p
1
60°N
40°N
20°N
66°N
lon,lat
Tti
120.5
maxlon,lat ( Ttilon,lat )
lon,lat
ti
p
The global contemporary data(ptlon,m,lat , Tt lon,m,lat ) from the ECMWF reanalysis data sets were used (ERA-40) .
The future climate projections (ptLV,m , Tt LV,m ) (t1,t2) for the Latvia were constructed by the following approach:
a) The ensemble of the regional climate model (RCM) runs from the EU ENSEMBLES project was considered.
b) The RCM outputs – temperature and precipitation – were bias corrected via statistical downscaling method
(Sennikovs and Bethers, 2009) for the contemporary climate represented by the observed data series over
the territory of Latvia. The downscaling method included the equalization of cumulative distribution
functions of the observed and modelled data series in a moving time window.
c) The bias correction method was applied for the future climate projections by RCMs.
d) The ranking of the magnitude of climate change by different models was performed for the ensemble of
future climate projections. Moderate, average and significant climate change were considered as the 17th,
50th and 83rd percentile of the ensemble members.
0
0
i
0°N
0.6
0.5
60°N 20°S
0.4
0.3
0.2
57°N
40°S
54°N
0.1
51°N
0.025
48°N
0.05
0.01
60°S
0.005
0.0025
42°N
Near future (2021-2050)
Average climate change
lon ,lat
t1
39°N
0°E
6°E
150°W
90°W 60°W 30°W 0°E 30°E 60°E 90°E 120°E150°E
12°E 18°E 24°E 30°E 36°E 42°E 48°E 54°E
60°N
40°N
20°N
66°N
i
0.7
0°N
0.6
63°N
0.5
60°N 20°S
0.4
0.3
0.2
57°N
40°S
54°N
0.1
51°N
0.025
48°N
45°N
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.05
0.025
0.01
0.005
0.0025
0
0
,lat
maxlon,lat ( ptlon
)
i
ti is one of the time intervals:
t0 - contemporary climate (1961-1990)
t1 - near future climate projections for Latvia (2021-2050)
t2 - far future climate projections for Latvia (2071-2100)
lon, lat is geographical location;
0.7
63°N
45°N
lon,lat
ti
0
39°N
1.4
lon ,lat
0.0025
42°N
0°E
1.6
1 12 lon ,lat
Tt0 ,m
12 m 1
Images of Latvian landscape
0.7
66°N
20°S
2.6
Landscapes of the similar climate
areas
0.05
0.01
60°S
0.005
0.0025
42°N
Far future (2071-2100)
Average climate change
lon ,lat
t2
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.05
0.025
0.01
0.005
0.0025
0
0
39°N
0°E
6°E
150°W
90°W 60°W 30°W 0°E 30°E 60°E 90°E 120°E150°E
12°E 18°E 24°E 30°E 36°E 42°E 48°E 54°E
Acknowledgements
This research was supported by the European Social Fund project „Establishment
of interdisciplinary scientist group and modelling system for groundwater
research” (Project Nr. 2009/0212/1DP/1.1.1.2.0/09/APIA/VIAA/060). Regional
climate model data provided through the ENSEMBLES data archive, funded by the
EU FP6 Integrated Project ENSEMBLES (Contract number 505539).
ESF project "Establishment of interdisciplinary scientist group
and modelling system for groundwater research“
Project nr. 2009/0212/1DP/1.1.1.2.0/09/APIA/VIAA/060