A Comprehensive Analysis of the Changes in Precipitation Patterns over Beijing during 1960–2012
Table 4
Results of change point analysis for different series based on the Pettitt test.
Entire series (mm)
Change point
Prechange mean (mm)
Postchange mean (mm)
Ratio of changes1
Jan
2.2
2001
0.487
2.3
1.8
−0.23
Feb
4.6
1986
0.166
5.3
3.9
−0.30
Mar
9.0
1991
0.612
9.4
8.4
−0.11
Apr
20.5
1997
0.327
19
24.4
0.26
May
33.6
1976
0.042
22.9
38.6
0.47
Jun
77.2
1975
0.295
62.2
83.7
0.28
Jul
180.7
1998
0.060
195.7
139.2
−0.31
Aug
142.2
1996
0.024
161.8
96.7
−0.46
Sep
50.6
1985
0.540
44.7
56.3
0.23
Oct
22.2
1995
0.424
20
26.9
0.31
Nov
7.8
1967
1.121
3.2
8.6
0.69
Dec
2.2
1973
0.124
0.8
2.7
0.86
Spring
63.1
1976
0.147
49.8
69.4
0.31
Summer
400.1
1996
0.043
430.4
330.1
−0.25
Autumn
80.7
1988
0.690
73
89.9
0.21
Winter
8.9
1996
1.380
8.5
9.8
0.15
Annual
553.0
1996
0.398
573.5
505.6
−0.12
Note. 1The ratio of change is equal to the differences of mean precipitation between prior series and posterior series dividing the mean precipitation at the entire series. Significant abrupt change at a level of α = 0.10; significant abrupt change at level of α = 0.05.
