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Picea schrenkiana tree-ring chronologies development and vegetation index reconstruction for the Alatau Mountains, Central Asia

Tongwen Zhang
Tongwen Zhang
, 
Ruibo Zhang
Ruibo Zhang
, 
Bo Lu
Bo Lu
, 
Bulkajyr T. Mambetov
Bulkajyr T. Mambetov
, 
Nurzhan Kelgenbayev
Nurzhan Kelgenbayev
, 
Daniyar Dosmanbetov
Daniyar Dosmanbetov
, 
Bagila Maisupova
Bagila Maisupova
, 
Feng Chen
Feng Chen
, 
Shulong Yu
Shulong Yu
, 
Huaming Shang
Huaming Shang
 and 
Liping Huang
Liping Huang
   | Jun 02, 2018
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Published Online: Jun 02, 2018
Page range: 107 - 118
Received: Jan 08, 2018
Accepted: Apr 16, 2018
DOI: https://doi.org/10.1515/geochr-2015-0091
Keywords
© 2018 T. Zhang., published by Sciendo, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

(a) Location of the study area; (b) map of the study area; and (c) sampling sites: Amanboktek (AMA), Kikbay (KBZ), and Basika (BSK). The selected NDVI grid (44.932°–46.023°N, 78.986°–80.950°E) is represented by the dash-block diagram.
(a) Location of the study area; (b) map of the study area; and (c) sampling sites: Amanboktek (AMA), Kikbay (KBZ), and Basika (BSK). The selected NDVI grid (44.932°–46.023°N, 78.986°–80.950°E) is represented by the dash-block diagram.

Fig. 2

Gridded climatic and NDVI data for the Alatau Mountain: (a) Precipitation, mean temperature, mean maximum temperature and mean minimum temperature per month. Bars indicate precipitation (in mm), and curves with different colors represent mean temperature, mean minimum temperature and mean maximum temperature (in °C); (b) Monthly PDSI; (c) Monthly NDVI; (d) Annual precipitation during 1901–2015; (e–g) Annual mean temperature, annual mean minimum temperature and annual mean maximum temperature during 1901–2015; (h) Annual mean PDSI during 1901–2015; and (i) Annual mean NDVI during 1982–2006. Dashed lines represent trends in climate and NDVI data.
Gridded climatic and NDVI data for the Alatau Mountain: (a) Precipitation, mean temperature, mean maximum temperature and mean minimum temperature per month. Bars indicate precipitation (in mm), and curves with different colors represent mean temperature, mean minimum temperature and mean maximum temperature (in °C); (b) Monthly PDSI; (c) Monthly NDVI; (d) Annual precipitation during 1901–2015; (e–g) Annual mean temperature, annual mean minimum temperature and annual mean maximum temperature during 1901–2015; (h) Annual mean PDSI during 1901–2015; and (i) Annual mean NDVI during 1982–2006. Dashed lines represent trends in climate and NDVI data.

Fig. 3

Chronologies (thin lines) with their sample depth (dashed lines). Red and blue lines represent EPS and Rbar data: (a) AMA; (b) KBZ; (c) BSK; and (d) ARC.
Chronologies (thin lines) with their sample depth (dashed lines). Red and blue lines represent EPS and Rbar data: (a) AMA; (b) KBZ; (c) BSK; and (d) ARC.

Fig. 4

Pearson correlations between tree-ring chronologies and climatic data (precipitation, mean temperature, mean minimum temperature, mean maximum temperature, and PDSI). Lowercase and capitals represent months of the previous and current years, respectively.
Pearson correlations between tree-ring chronologies and climatic data (precipitation, mean temperature, mean minimum temperature, mean maximum temperature, and PDSI). Lowercase and capitals represent months of the previous and current years, respectively.

Fig. 5

Pearson correlation coefficients for the ARC chronology and monthly NDVI from April to October. J–O specifies the period from July to October.
Pearson correlation coefficients for the ARC chronology and monthly NDVI from April to October. J–O specifies the period from July to October.

Fig. 6

(a) Comparison between the reconstructed (red line) and observed (blue line) July–October NDVI. (b) July–October NDVI reconstruction for the Alatau Mountains since 1850 (solid line). The thick line represents the 21-year moving average. Ten red and ten blue dots represent the lowest and highest value years, respectively.
(a) Comparison between the reconstructed (red line) and observed (blue line) July–October NDVI. (b) July–October NDVI reconstruction for the Alatau Mountains since 1850 (solid line). The thick line represents the 21-year moving average. Ten red and ten blue dots represent the lowest and highest value years, respectively.

Fig. 7

Spatial correlation between the reconstructed NDVI series ana gridded July–October PDSI dataset. The solid circle represents the July–October NDVI reconstruction, and the dashed circles represent the four climatic reconstructions (SKZ, PNL, PIL, and PAK) used in the comparison analyses.
Spatial correlation between the reconstructed NDVI series ana gridded July–October PDSI dataset. The solid circle represents the July–October NDVI reconstruction, and the dashed circles represent the four climatic reconstructions (SKZ, PNL, PIL, and PAK) used in the comparison analyses.

Fig. 8

Graphical comparison of the NDVI reconstruction for the Alatau Mountains (black line) and four climatic reconstructions for Central Asia (SKZ: red line; PNL: blue line; PIL: gray line; PAK: green line).
Graphical comparison of the NDVI reconstruction for the Alatau Mountains (black line) and four climatic reconstructions for Central Asia (SKZ: red line; PNL: blue line; PIL: gray line; PAK: green line).

Fig. 9

Patterns of precipitation anomalies (shading; mm/month) and horizontal wind anomalies at 850hPa (vector; m/s) in (a) the high NDVI year of 1993, and (b) the low NDVI year of 2008. The red block indicates the location of the present study.
Patterns of precipitation anomalies (shading; mm/month) and horizontal wind anomalies at 850hPa (vector; m/s) in (a) the high NDVI year of 1993, and (b) the low NDVI year of 2008. The red block indicates the location of the present study.

Correlation coefficients for three chronologies over the common period of 1910–2016.

Original (n=107)High-frequency (n=95)Low frequency (n=95)
AMAKBZBSKAMAKBZBSKAMAKBZBSK
AMA10.783

Significant at p<0.001.

0.660

Significant at p<0.001.

10.842

Significant at p<0.001.

0.682

Significant at p<0.001.

10.641

Significant at p<0.001.

0.683

Significant at p<0.001.

KBZ/10.624

Significant at p<0.001.

/10.759

Significant at p<0.001.

/10.388

Significant at p<0.001.

BSK//1//1//1

Statistics of split-sample calibration-verification tests for the NDVI reconstruction.

StatisticCalibration (1982–1994)Verification (1995–2006)Calibration (1994–2006)Verification (1982–1993)Full calibration (1982–2006)
r0.670.410.440.680.58
R20.430.170.190.460.33
Radj2$\begin{array}{} \displaystyle {\it R}\rm ^{2}_{adj} \end{array}$0.38/0.12/0.30
RE/0.10/0.35/
CE/0.09/0.34/
t/3.01/3.49/

Statistical characteristics of chronologies over the common period of 1900–2010

StatisticAMAKBZBSKARC
Standard deviation (SD)0.1980.2240.4140.208
Mean sensitivity (MS)0.1800.1860.3790.180
First-order autocorrelation (AC1)0.3960.4960.5770.458
Interseries correlation (trees)0.4170.4840.7380.418
Interseries correlation (all series)0.4310.4880.7530.422
Mean within-tree correlation0.7860.8050.9610.808
Signal-to-noise ratio (SNR)9.85862.01218.29362.025
Expressed population signal (EPS)0.9080.9840.9480.984
The first principal component (PC#1)0.4920.5180.7990.461
First year EPS >0.851910185018801850

Verification results from the Leave-one-out and Bootstrap tests for the NDVI reconstruction.

StatisticCalibrationLeave-one-out Mean (Range)Bootstrap (100 Iterations) Mean (Range)
r0.580.58 (0.52–0.63)0.57 (0.34–0.77)
Squared multiple correlation (R2)0.330.33 (0.27–0.40)0.34 (0.12–0.60)
Adjusted squared multiple correlation (Radj2$\begin{array}{} \displaystyle {\it R}\rm ^{2}_{adj} \end{array}$)0.300.30 (0.24–0.37)0.31 (0.08–0.58)
Standard error (SE)0.0170.017 (0.015–0.018)0.16 (0.11–0.19)
F-value (F)11.4511.06 (8.10–14.56)13.21 (3.17–32.39)
Durbin-Watson (D/W)1.821.84 (1.60–2.05)1.22 (0.49–1.95)

Correlation coefficients between the NDVI and climatic reconstructions over the common period of 1850–2005.

Original(n = 156)High-frequency (n = 144)Low-frequency (n = 144)
SKZPNLPILPAKSKZPNLPILPAKSKZPNLPILPAK
NAM0.5070.460

Significant at p < 0.01

0.371

Significant at p < 0.01

0.197

Significant at p < 0.05

0.580

Significant at p < 0.01

0.508

Significant at p < 0.01

0.332

Significant at p < 0.01

0.189

Significant at p < 0.05

0.498

Significant at p < 0.01

0.326

Significant at p < 0.01

0.452

Significant at p < 0.01

0.190

Significant at p < 0.05

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Language:
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