Asymmetrical Time-Lagged Response of Vegetation to Drought and Extreme Precipitation Across China
In this study, a study area was chosen in China to analyze the lagged response relationship between normalized difference vegetation index (NDVI) and extreme precipitation/drought from 1982 to 2015. A logistical function was applied to explain the increase in NDVI with mean annual precipitation in n...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Atmosphere |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4433/16/3/240 |
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| Summary: | In this study, a study area was chosen in China to analyze the lagged response relationship between normalized difference vegetation index (NDVI) and extreme precipitation/drought from 1982 to 2015. A logistical function was applied to explain the increase in NDVI with mean annual precipitation in nine sub-regions, and the inflection point of precipitation was found to be very close to the threshold value for separating arid or humid regions. NDVI had a strong positive correlation with drought and extreme precipitation in the arid regions, while in humid regions, it presented a strong correlation with drought during 2000–2015; however, a weak correlation with drought was found before the 21st century. In this study, we quantified the time-lagged response of vegetation to drought (LTRD) and extreme precipitation (LTREP). Then, we defined four gradients (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>D</mi></mrow><mrow><mo>∂</mo><mi>P</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>D</mi></mrow><mrow><mo>∂</mo><mi>T</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>P</mi></mrow><mrow><mo>∂</mo><mi>P</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>P</mi></mrow><mrow><mo>∂</mo><mi>T</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula>) to quantify the precipitation and temperature gradients with the lag-time response to drought or extreme precipitation, respectively. Decreasing gradients were observed for humid regions with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>D</mi></mrow><mrow><mo>∂</mo><mi>P</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula> = −0.19 month·100 mm<sup>−1</sup> for “wetting” and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>D</mi></mrow><mrow><mo>∂</mo><mi>T</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula> = −0.13 month·K<sup>−1</sup> for “warming”, while increasing gradients were found in the same regions with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>P</mi></mrow><mrow><mo>∂</mo><mi>P</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula> = +0.18 month·100 mm<sup>−1</sup> for “wetting” and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mrow><mo>∂</mo><mi>L</mi><mi>T</mi><mi>R</mi><mi>E</mi><mi>P</mi></mrow><mrow><mo>∂</mo><mi>T</mi></mrow></mfrac></mstyle></mrow></semantics></math></inline-formula> = +0.14 month·K<sup>−1</sup> for “warming”. These results suggest that the lagging responses of vegetation to extreme precipitation and droughts exhibit opposing regional patterns across China. |
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| ISSN: | 2073-4433 |