joanna wibig dept. of meteorology and climatology university of lodz
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Precipitation variability in the second half of the 20th
century: changes in seasonality and extremes.
Joanna Wibig
Dept. of Meteorology and Climatology
University of Lodz
According to TAR IPCC (Folland et. al, 2001) precipitation in land areas of the Northern Hemisphere middle latitudes has increased. This increase was estimated on 12%. The changes in precipitation totals are connected with changes in their distribution between seasons. There are some indications that in warmer climate extreme precipitation events can be more frequent and the share of heavy precipitation events in annual totals shoud be greater.
INSPIRATIONS:
The aim of this presentation is to check these statements
• Has the total precipitation in Europe increased or decreased significantly and where such changes occurred?
• Has the seasonal distribution of precipitation changed significantly?
• Have the highest daily totals increased?
• Have the share of heavy precipitation events in total precipitation changed significantly?
• Are these changes related to circulation variability?
• Are these changes related to global or regional warming trends?
DATA:
The daily precipitation data in the period 1951-2000, mainly from the ECAD (European Climate Assessment Dataset)Klein Tank, A.M.G., et al., 2002. Daily dataset of 20th-century surface air temperature and precipitation series for the European Climate Assessment. Int. J. Climatol., 22: 1441-1453.
Polish records: Lodz, Szczecin, Suwalki, Wroclaw, Przemysl(Institute of Meteorology and Water Management)
2 0 0 2 0 4 0
2 0 0 2 0 4 0
4 0
5 0
6 0
7 0
4 0
5 0
6 0
7 0
Data localization
KNMI Climate Explorer Vinnikov global temperature monthly index (RusData-TMZ_global).htmK.M.Lugina, 1999: Some features of zonal changes in the surface air temperatures under the global warming. Bulletin of St. Petersburg University, series 7, Geology and Geography, vol. 4, No 28.St. Petersburg. [in Russian]
Temperature indices:
Climate Research UnitJones, P.D. and Moberg, A., 2003: Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001. J. Climate 16, 206-223.
•Global temperature anomalies (monthly and annual data)
•Northern Hemisphere temperature anomalies (monthly and
annual data
•30-60N band temperature anomalies (monthly data)
Circulation index:
Index of the NAO based on the difference of normalized sea level pressures (SLP) between Ponta Delgada, Azores and Stykkisholmur/Reykjavik, Iceland calculated on the base on three-monthly data (the interesting one and two earlier). The NAO Index Data were provided by the Climate Analysis Section, NCAR, Boulder, USA, Hurrell J W, 1995: Decadal Trends in the North Atlantic Oscillation: Regional Temperatures and Precipitation, Science: 269: 676-679.
Mann – Kendall test
n
2i
1i
1jji xxsignS
where
xxif1xxif0xxif1
xxsign
ji
ji
ji
ji
Under the null hypothesis of randomness the S
has a normal distribution with the mean value μs
and variance σs2 given by:
0s
18
5n21nn2s
Spearman rank-order correlation coefficient
NN
D61r 3s
N
1i
2SiRiD
Ri, Si – rank series of analysed series
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
year
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
CHANGES in PRECIPITATION TOTALS
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
W inter
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
CHANGES in PRECIPITATION TOTALS
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
D ecem ber
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
January
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
February
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
WINTER
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
Spring
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
CHANGES in PRECIPITATION TOTALS
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
M arch
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
April
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
M ay
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
SPRING
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
Sum m er
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
CHANGES in PRECIPITATION TOTALS
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
June
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
July
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
August
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
SUMMER
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
Autum n
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
CHANGES in PRECIPITATION TOTALS
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
Septem ber
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
O ctober
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
N ovem ber
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
AUTUMN
Amplitude
Indices of seasonality:
minmax RR
R max – the greatest monthly total
R min – the lowest monthly total
Quotient of winter to summer precipitation
JJA
DJFR
R
Quotient of autumn to spring precipitation
MAM
SONR
R
R DJF, R MAM, R JJA, R SON – winter, spring, summer and
autumn total precipitation, respectively
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
Amplitude
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.8
3
1.6
6
2.4
9
3.3
2
4.1
5
4.9
8
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
W inter/Summer
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
Autumn/Spring
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
daily max
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
daily max / annual total
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
daily 3 max / annual total
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
daily 10 max / annual total
-4.9
8
-4.1
5
-3.3
2
-2.4
9
-1.6
6
-0.8
3
-0.0
0
0.83
1.66
2.49
3.32
4.15
4.98
expressed in Mann-Kendall test values - values greater (lower) than 1.66 (-1.66) mean
statisticaly significant increase (decrease)
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
annual prec - NHtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
annual prec - globtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
annual prec - 30-60temp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
Rank correlation coefficients between annual precipitation totals and mean temperature of the zone 30-60 NH, all NH and global, respectively
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
annual prec - NHtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
annual prec - globtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
annual prec - 30-60temp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Regions of significant relations between annual precipitation totals and mean temperature of the zone 30-60 NH, all NH and global, respectively
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
winter prec - NHtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
spring prec - NHtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
summer prec - NHtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
autumn prec - NHtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
winter prec - NHtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
spring prec - NHtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
summer prec - NHtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
autumn prec - NHtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
January prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
March prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
January prec-NAO
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
March prec-NAO
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
April prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
May prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
April prec-NAO
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
May prec-NAO
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
June prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
August prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
June prec-NAO
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
August prec-NAO
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
October prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
November prec-NAO
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
October prec-NAO
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
November prec-NAO
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
The greatest one-day precipitation related to NH temperature anomalies
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
1 day extreme prec - NHtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
1 day extreme prec - NHtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
The share of 10 daily extremes in annual total in relation to NH temperature anomalies
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
10 day relative prec - NHtemp
-1.0
0
-0.8
0
-0.6
0
-0.4
0
-0.2
0
0.00
0.20
0.40
0.60
0.80
1.00
20 0 20 40
20 0 20 40
40
50
60
70
40
50
60
70
10 day relative prec - NHtemp
-0.2
0
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
The annual precipitation totals have a tendency to an increase in in the north of Europe and a decrease at the south, but these changes are statistically significant over the very small area of continent only.
Within seasons: the annual pattern is present on winter maps (DJFM). Tendency to drying in summer (generally nonsignificant but with warming tendency can be related to significant water deficit). In autumn tendency to wetter climate has appeared whereas during spring slight dryness can be observed (April and May).
There is a tendency to seasonal redistribution of precipitation during the year. The proportion of winter to summer precipitation inceases in the north and decreases at the south. The opposite is true when the proportion of autumn to spring precipitation is considered.
CONCLUSIONS:
The idea that the greater proportion of precipitation falls in heavy precipitation events is not confirmed in Europe.
There is an evident tendency that in warmer climate more precipitation will fall in the north and less in the south of Europe. This pattern is present also in winter and spring.
During winter the NAO is related to above normal precipitation in the central and northern part of Europe and below normal at the south. In summer and autumn the dry conditions dominate over southern and central Europe and only over the north it is a tendency to wetter conditions.
The work was supported by the Polish Ministry of Education and Sciences Under Grant PBZ-KBN-086/P04/2003
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