Figure 1

Study area and orographic features in Central Asia"

Table 1

Mean (mm), coefficient of variation (CV: %) and linear trend (K: mm/10a) of the seasonal precipitation over mountainous area, plain area and Central Asia during 1901-2013, 1951-2013 and 1979-2013"

Figure 2

Seasonal precipitation anomalies (a: MAM; b: JJA; c: SON and d: DJF) averaged over Central Asia during 1901-2013, where the reference period is 1961-1990. The thick curve line is the 11-year moving average result."

Figure 3

The decomposition results of annual precipitation time series over Central Asia, (a): MAM; (b): JJA; (c): SON and (d): DJF during the period of 1901-2013. The IMF1-IMF5 indicate the different periods of the annual precipitation time series, and the residue term r is the nonlinear trend obtained by the EEMD method."

Table 2

Hurst Index (H) of the seasonal precipitation over mountainous area, plain area and Central Asia during 1901-2013, 1951-2013 and 1979-2013"

Figure 4

Spatial distributions of the linear trends of the seasonal precipitation over Central Asia during the period of 1901-2013. Statistically significant linear trends at the 95% confidence level are indicated by cross (p<0.05)."

Table 3

Percentage areas (%) with the increasing trend, decreasing trend, significant increasing trend (SIT) and significant decreasing trend (SDT) at 95% confidence level of the four seasonal precipitation during 1901-2013, 1951-2013 and 1979-2013"

Figure 5

Same as Figure 4, but for the period of 1951-2013"

Figure 6

Same as Figure 4, but for the period of 1979-2013"

Figure 7

EOF-1 (left panel) of the seasonal precipitation anomalies (mm) and the corresponding time coefficients (right panel) over Central Asia during 1901-2013"

Figure 8

Inter-annual signals of the seasonal precipitation and Ni?o 3.4 index obtained by EEMD method during 1951-2013"

Figure 9

CC results of the inter-annual signals between seasonal precipitation and Ni?o 3.4 index during 1951-2013, (a) CC of the periods from year i to 2013 (i = 1951, …, 1984) and (b) 30-yr moving CC, where the vertical blue line is in the year 1966"

Table 4

CC results of the seasonal lags time series between the precipitation and Ni?o 3.4 index during 1951-2013, lag-i (i=0, 1, 2, 3, 4) means lag i seasons"

Figure 10

Spatial distributions of the correlation coefficients of the inter-annual signals between the seasonal precipitation and Ni?o 3.4 during 1951-2013, where the cross symbols are the correlation coefficient values significantly at 95% confidence level"

Table 5

El Ni?o and La Ni?a years used in the composite analyses"

Figure 11

The El Ni?o minus La Ni?a composite difference in seasonal precipitation: (a) MAM, (b) SON and (c) DJF during 1951-2013, where the cross symbols are the different values significantly at 95% confidence level"

Figure 12

The El Ni?o minus La Ni?a composite difference in moisture flux: (a) MAM, (b) SON and (c) DJF during 1951-2010"

Figure 13

ENSO-based composites of divergences of the total moisture fluxes for MAM, SON and DJF during 1950-2013. The contour interval is 5×10-6 kg/m2/s and the gray areas denote regions significant at the 95% level (p<0.05) by the student’s t-test. The zero contour is omitted and dashed lines are negative."

Figure 14

ENSO-based composites of geopotential height (HGT) (left column) and wind for MAM, SON and DJF at 850 hPa during 1950-2013. The contour interval is 5 m for HGT and the gray areas denote regions significant at the 95% level (p<0.05) by the student’s t-test. The zero contour is omitted and dashed lines are negative."

Figure 15

Same as Figure 14 but for 200 hPa"

Table 6

Comparison of decadal seasonal precipitation change rate (mm/10a or %/10a) of Central Asia from 1901 to 2013 from this study to rates reported in other studies, where + means increasing trend, - means decreasing trend, CMIP5 (Coupled Model Intercomparison Project, phase 5), MOPREDAS (Monthly Precipitation Database of Spain), USHCN v2.5 (U.S. Historical Climate Network, version 2.5), Climatic Research Unit (CRU) TS3.21 dataset, NH (Northern Hemispheres)"

Table 7

Correlation coefficient (CC) results between the seasonal precipitation and temperature during the three periods, and between the seasonal precipitation and the normalized difference vegetation index (NDVI) during 1982-2012, where the CC values are obtained by the linear least square method and ** significant at a 99% confidence level by student’s t test"