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Title: A drought indicator reflecting ecosystem responses to water availability: The Normalized Ecosystem Drought Index

Abstract

Drought, one of the most destructive natural disasters is projected by numerous studies to become more severe and widespread under climate change. These water limitations will have profound effects on terrestrial systems across the globe. Yet, most of the existing drought monitoring indices are based on drought stress derived from environmental conditions rather than ecosystem responses. Here, we propose using a new approach, the Normalized Ecosystem Drought Index (NEDI), coupled with modified Variable Interval Time Averaging (VITA) method, to quantify drought severity according to ecosystem transitional patterns with water availability. The method is inspired by Sprengel’s and Liebig’s Law of the Minimum for plant nutrition. Eddy covariance measurements from 60 AmeriFlux sites that cross 8 International Geosphere–Biosphere Programme (IGBP) vegetation types were used to validate the use of NEDI coupled to VITA. The results show that NEDI can reasonably depict both drought stress posed by the environment and drought responses presented by various ecosystems. Water availability becomes a dominant limiting factor for ecosystem evapotranspiration when NEDI falls below zero, and normalized evapotranspiration strength generally decreases with decreasing NEDI under this regime. The widely used self-calibrating Palmer Drought Severity Index (sc-PDSI) and Standardized Precipitation Index (SPI) have difficulty capturing ecosystem responsesmore » to water availability, although they can reasonably represent drought conditions detected in the environment. The normalization feature employed in NEDI makes it feasible to compare drought severity over different regions, seasons and vegetation types. The new drought index also provides a valuable tool for irrigation and water distribution management practices which may enhance water conservation efforts as drought conditions become more prevalent.« less

Authors:
 [1];  [2];  [3];  [4]
  1. Univ. of California, Davis, CA (United States). Dept. of Land, Air and Water Resources; Univ. of New Hampshire, Durham, NH (United States). Earth System Research Center; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Climate and Ecosystem Sciences Division
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Joint Program on the Science and Policy of Global Change
  3. Univ. of Alabama, Tuscaloosa, AL (United States). Dept. of Biological Sciences
  4. Univ. of California, Davis, CA (United States). Dept. of Land, Air and Water Resources
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Davis, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Univ. of Alabama, Tuscaloosa, AL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF)
OSTI Identifier:
1493255
Grant/Contract Number:  
AC02-05CH11231; EF1137306/MIT; 5710003122; 1561139; 1233006
Resource Type:
Accepted Manuscript
Journal Name:
Agricultural and Forest Meteorology
Additional Journal Information:
Journal Volume: 250-251; Journal ID: ISSN 0168-1923
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; drought; AmeriFlux; evapotranspiration; ecosystem response

Citation Formats

Chang, Kuang-Yu, Xu, Liyi, Starr, Gregory, and Paw U, Kyaw Tha. A drought indicator reflecting ecosystem responses to water availability: The Normalized Ecosystem Drought Index. United States: N. p., 2017. Web. doi:10.1016/j.agrformet.2017.12.001.
Chang, Kuang-Yu, Xu, Liyi, Starr, Gregory, & Paw U, Kyaw Tha. A drought indicator reflecting ecosystem responses to water availability: The Normalized Ecosystem Drought Index. United States. doi:10.1016/j.agrformet.2017.12.001.
Chang, Kuang-Yu, Xu, Liyi, Starr, Gregory, and Paw U, Kyaw Tha. Wed . "A drought indicator reflecting ecosystem responses to water availability: The Normalized Ecosystem Drought Index". United States. doi:10.1016/j.agrformet.2017.12.001. https://www.osti.gov/servlets/purl/1493255.
@article{osti_1493255,
title = {A drought indicator reflecting ecosystem responses to water availability: The Normalized Ecosystem Drought Index},
author = {Chang, Kuang-Yu and Xu, Liyi and Starr, Gregory and Paw U, Kyaw Tha},
abstractNote = {Drought, one of the most destructive natural disasters is projected by numerous studies to become more severe and widespread under climate change. These water limitations will have profound effects on terrestrial systems across the globe. Yet, most of the existing drought monitoring indices are based on drought stress derived from environmental conditions rather than ecosystem responses. Here, we propose using a new approach, the Normalized Ecosystem Drought Index (NEDI), coupled with modified Variable Interval Time Averaging (VITA) method, to quantify drought severity according to ecosystem transitional patterns with water availability. The method is inspired by Sprengel’s and Liebig’s Law of the Minimum for plant nutrition. Eddy covariance measurements from 60 AmeriFlux sites that cross 8 International Geosphere–Biosphere Programme (IGBP) vegetation types were used to validate the use of NEDI coupled to VITA. The results show that NEDI can reasonably depict both drought stress posed by the environment and drought responses presented by various ecosystems. Water availability becomes a dominant limiting factor for ecosystem evapotranspiration when NEDI falls below zero, and normalized evapotranspiration strength generally decreases with decreasing NEDI under this regime. The widely used self-calibrating Palmer Drought Severity Index (sc-PDSI) and Standardized Precipitation Index (SPI) have difficulty capturing ecosystem responses to water availability, although they can reasonably represent drought conditions detected in the environment. The normalization feature employed in NEDI makes it feasible to compare drought severity over different regions, seasons and vegetation types. The new drought index also provides a valuable tool for irrigation and water distribution management practices which may enhance water conservation efforts as drought conditions become more prevalent.},
doi = {10.1016/j.agrformet.2017.12.001},
journal = {Agricultural and Forest Meteorology},
number = ,
volume = 250-251,
place = {United States},
year = {2017},
month = {12}
}

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