Changes in Reference Evapotranspiration and Its Contributing Factors in Jiangsu, a Major Economic and Agricultural Province of Eastern China
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Area and Data Source
2.2. Penman–Monteith FAO 56 Model for ETref Estimation
2.3. Statistical Test for Trend Analysis
2.4. Spatial Interpolation Method for ETref
2.5. Calculation of Sensitivity Coefficient
2.6. Detrending Method
3. Results
3.1. Spatial Distribution of Seasonal and Annual ETref
3.2. Temporal Trends in Seasonal ETref and Climatic Factors
3.3. Sensitivity Coefficients of ETref to Climatic Factors
3.4. Contributions of Climatic Factors to the Trends in ETref
3.5. Evaporation Paradox Analysis with Trends of TA and ETref
4. Discussions
4.1. Change Trend of ETref and Its Contributing Factors
4.2. Evaporation Paradox
4.3. Influence on Agricultural Production and Water Management
5. Conclusions
- (1)
- Decreasing and increasing trends were identified in Jiangsu province at seasonal and annual scales. A significant declining trend of ETref was observed in the Huaibei region, while other regions demonstrated a slight rising trend of ETref. ETref also showed a significant increasing tendency in spring and a decreasing tendency in summer.
- (2)
- VP was the most sensitive climatic factor, followed by TA, SD, and WS in each region. ETref was more sensitive to TA and SD in the summer but less so in the winter; however, the sensitivities of WS and VP to ETref were the opposite in Jiangsu province.
- (3)
- The contribution of ETref was a synergistic effect of various climatic factors; significantly decreasing WS and SD were the most crucial factors contributing to the decreasing trend in ETref, while TA was the main contributing factor for the increasing trend in ETref, followed by WS and SD. The non-significant trend in VP made the smallest contribution to the trend of ETref; however, it could not be ignored due to the variability and the effect of the contribution to ETref, as well as being the most sensitive factor to ETref, especially in winter.
- (4)
- It was evident that the phenomenon of evaporation paradox was apparent in Jiangsu province, especially in the summer and in the Huaibei region in the autumn.
- (5)
- In summary, these results will provide a theoretical background and practical guidance for future water resource distribution and management and lay the basis for the future study of agricultural water requirements and economic development in the whole of Jiangsu province in the scenario of climate change.
Acknowledgments
Author Contributions
Conflicts of Interest
Appendix A.
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Region | TA (°C) | RH (%) | WS (m·s−1) | SD (h) | ETref (mm) |
---|---|---|---|---|---|
Huaibei | 14.30 | 72.96 | 2.54 | 2250.34 | 898.66 |
Jianghuai | 15.15 | 77.41 | 2.94 | 2098.33 | 883.72 |
Sunan | 15.94 | 77.71 | 2.85 | 1986.46 | 899.74 |
Whole | 15.09 | 76.15 | 2.79 | 2116.07 | 892.24 |
Region | Spring | Summer | Autumn | Winter | Annual | |||||
---|---|---|---|---|---|---|---|---|---|---|
β | Z | β | Z | β | Z | β | Z | β | Z | |
Huaibei | 0.039 | 0.09 | −1.093 *** | −4.31 | −0.300 ** | −2.66 | −0.076 | −0.84 | −1.468 *** | −3.53 |
Jianghuai | 0.675 ** | 3.18 | −0.581 * | −1.97 | 0.125 | 1.35 | 0.067 | 0.94 | 0.207 | 0.67 |
Sunan | 0.815 *** | 3.89 | −0.597 + | −1.80 | 0.307 ** | 2.99 | 0.073 | 0.94 | 0.592 | 1.18 |
Whole | 0.526 ** | 2.70 | −0.701 ** | −2.92 | 0.046 | 0.61 | 0.014 | 0.12 | −0.245 | −0.74 |
Variable | Season | Huaibei | Jianghuai | Sunan | Whole |
---|---|---|---|---|---|
TA (°C·a−1) | Spring | 0.0348 *** | 0.0382 *** | 0.0439 *** | 0.0391 *** |
Summer | 0.0053 | 0.0113 | 0.0151 * | 0.0111 | |
Autumn | 0.0221 *** | 0.0261 *** | 0.0336 *** | 0.0267 *** | |
Winter | 0.0390 *** | 0.0319 *** | 0.0333 *** | 0.0344 *** | |
Annual | 0.0242 *** | 0.0267 *** | 0.0310 *** | 0.0274 *** | |
VP (kPa·a−1) | Spring | 0.000858 | −0.000089 | −0.000865 | 0.000022 |
Summer | −0.000753 | −0.001831 * | −0.002048 ** | −0.001572 * | |
Autumn | 0.000762 | 0.000396 | −0.000248 | 0.000382 | |
Winter | 0.000667 | 0.000682 | 0.000658 | 0.000644 | |
Annual | 0.000512 | −0.000223 | −0.000563 | −0.000007 | |
WS (m·s−1·a−1) | Spring | −0.0398 *** | −0.0293 *** | −0.0307 *** | −0.0332 *** |
Summer | −0.0297 *** | −0.0194 *** | −0.0217 *** | −0.0230 *** | |
Autumn | −0.0301 *** | −0.0228 *** | −0.0244 *** | −0.0251 *** | |
Winter | −0.0334 *** | −0.0281 *** | −0.0310 *** | −0.0305 *** | |
Annual | −0.0341 *** | −0.0250 *** | −0.0268 *** | −0.0279 *** | |
SD (h·a−1) | Spring | −0.0042 | 0.0079 | 0.0071 | 0.0049 |
Summer | −0.0442 *** | −0.0392 *** | −0.0417 *** | −0.0420 *** | |
Autumn | −0.0207 ** | −0.0092 | −0.0104 + | −0.0121 * | |
Winter | −0.0238 *** | −0.0170 ** | −0.0151 ** | −0.0190 ** | |
Annual | −0.0239 *** | −0.0152 *** | −0.0169 *** | −0.0179 *** |
Region | Spring | Summer | Autumn | Winter | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
TA | VP | WS | SD | TA | VP | WS | SD | TA | VP | WS | SD | TA | VP | WS | SD | |
Huaibei | 1.69 | −0.70 | −2.97 | −0.37 | 0.14 | 0.23 | −1.53 | −4.10 | 1.17 | −0.62 | −3.46 | −1.28 | 2.99 | −2.39 | −5.59 | −0.64 |
Jianghuai | 1.97 | 0.04 | −1.56 | 0.53 | 0.36 | 0.74 | −0.81 | −3.69 | 1.29 | −0.37 | −2.11 | −0.36 | 2.51 | −2.25 | −3.26 | −0.58 |
Sunan | 2.21 | 0.74 | −1.73 | 0.51 | 0.59 | 0.85 | −1.12 | −4.09 | 1.64 | 0.10 | −2.23 | −0.66 | 2.52 | −2.16 | −3.46 | −0.75 |
Whole | 1.95 | −0.02 | −2.05 | 0.24 | 0.35 | 0.62 | −1.11 | −3.91 | 1.34 | −0.32 | −2.52 | −0.70 | 2.65 | −2.27 | −3.98 | −0.64 |
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Chu, R.; Li, M.; Shen, S.; Islam, A.R.M.T.; Cao, W.; Tao, S.; Gao, P. Changes in Reference Evapotranspiration and Its Contributing Factors in Jiangsu, a Major Economic and Agricultural Province of Eastern China. Water 2017, 9, 486. https://doi.org/10.3390/w9070486
Chu R, Li M, Shen S, Islam ARMT, Cao W, Tao S, Gao P. Changes in Reference Evapotranspiration and Its Contributing Factors in Jiangsu, a Major Economic and Agricultural Province of Eastern China. Water. 2017; 9(7):486. https://doi.org/10.3390/w9070486
Chicago/Turabian StyleChu, Ronghao, Meng Li, Shuanghe Shen, Abu Reza Md. Towfiqul Islam, Wen Cao, Sulin Tao, and Ping Gao. 2017. "Changes in Reference Evapotranspiration and Its Contributing Factors in Jiangsu, a Major Economic and Agricultural Province of Eastern China" Water 9, no. 7: 486. https://doi.org/10.3390/w9070486
APA StyleChu, R., Li, M., Shen, S., Islam, A. R. M. T., Cao, W., Tao, S., & Gao, P. (2017). Changes in Reference Evapotranspiration and Its Contributing Factors in Jiangsu, a Major Economic and Agricultural Province of Eastern China. Water, 9(7), 486. https://doi.org/10.3390/w9070486