Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs
<p>Anthropogenic warming has been projected to increase global drought for the 21st century when calculated using traditional offline drought indices. However, this contradicts observations of the overall global greening and little systematic change in runoff over the past few decades and clim...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-06-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/24/2921/2020/hess-24-2921-2020.pdf |
| _version_ | 1818019519334973440 |
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| author | Y. Yang S. Zhang M. L. Roderick M. L. Roderick T. R. McVicar T. R. McVicar D. Yang W. Liu X. Li |
| author_facet | Y. Yang S. Zhang M. L. Roderick M. L. Roderick T. R. McVicar T. R. McVicar D. Yang W. Liu X. Li |
| author_sort | Y. Yang |
| collection | DOAJ |
| description | <p>Anthropogenic warming has been projected to increase global
drought for the 21st century when calculated using traditional offline
drought indices. However, this contradicts observations of the overall
global greening and little systematic change in runoff over the past few
decades and climate projections of future greening with slight increases in
global runoff for the coming century. This calls into question the drought
projections based on traditional offline drought indices. Here we calculate
a widely used traditional drought index (i.e., the Palmer Drought Severity Index, PDSI) using direct outputs from 16 Coupled Model Intercomparison Project Phase 5 (CMIP5) models (PDSI_CMIP5) such that the hydrologic consistency between PDSI_CMIP5 and CMIP5 models is maintained. We find that the PDSI_CMIP5-depicted drought increases (in terms of drought severity, frequency, and extent) are much smaller than that reported when PDSI is calculated
using the traditional offline approach that has been widely used in previous
drought assessments under climate change. Further analyses indicate that the
overestimation of PDSI drought increases reported previously using the
PDSI is primarily due to ignoring the vegetation response to
elevated atmospheric <span class="inline-formula">CO<sub>2</sub></span> concentration ([<span class="inline-formula">CO<sub>2</sub></span>]) in the traditional offline
calculations. Finally, we show that the overestimation of drought using the
traditional PDSI approach can be minimized by accounting for the effect of
<span class="inline-formula">CO<sub>2</sub></span> on evapotranspiration.</p> |
| first_indexed | 2024-04-14T07:53:21Z |
| format | Article |
| id | doaj.art-fc33a7bfd2ad40639d49d12522207207 |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-04-14T07:53:21Z |
| publishDate | 2020-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-fc33a7bfd2ad40639d49d125222072072022-12-22T02:05:08ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382020-06-01242921293010.5194/hess-24-2921-2020Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputsY. Yang0S. Zhang1M. L. Roderick2M. L. Roderick3T. R. McVicar4T. R. McVicar5D. Yang6W. Liu7X. Li8State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, ChinaState Key Laboratory of Earth Surface Process and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, ChinaResearch School of Earth Sciences, Australian National University, Canberra, ACT, AustraliaAustralian Research Council Centre of Excellence for Climate Extremes, Canberra, ACT, AustraliaAustralian Research Council Centre of Excellence for Climate Extremes, Canberra, ACT, AustraliaCSIRO Land and Water, Canberra, ACT, AustraliaState Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, ChinaKey Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, ChinaState Key Laboratory of Earth Surface Process and Resource Ecology, School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing, China<p>Anthropogenic warming has been projected to increase global drought for the 21st century when calculated using traditional offline drought indices. However, this contradicts observations of the overall global greening and little systematic change in runoff over the past few decades and climate projections of future greening with slight increases in global runoff for the coming century. This calls into question the drought projections based on traditional offline drought indices. Here we calculate a widely used traditional drought index (i.e., the Palmer Drought Severity Index, PDSI) using direct outputs from 16 Coupled Model Intercomparison Project Phase 5 (CMIP5) models (PDSI_CMIP5) such that the hydrologic consistency between PDSI_CMIP5 and CMIP5 models is maintained. We find that the PDSI_CMIP5-depicted drought increases (in terms of drought severity, frequency, and extent) are much smaller than that reported when PDSI is calculated using the traditional offline approach that has been widely used in previous drought assessments under climate change. Further analyses indicate that the overestimation of PDSI drought increases reported previously using the PDSI is primarily due to ignoring the vegetation response to elevated atmospheric <span class="inline-formula">CO<sub>2</sub></span> concentration ([<span class="inline-formula">CO<sub>2</sub></span>]) in the traditional offline calculations. Finally, we show that the overestimation of drought using the traditional PDSI approach can be minimized by accounting for the effect of <span class="inline-formula">CO<sub>2</sub></span> on evapotranspiration.</p>https://www.hydrol-earth-syst-sci.net/24/2921/2020/hess-24-2921-2020.pdf |
| spellingShingle | Y. Yang S. Zhang M. L. Roderick M. L. Roderick T. R. McVicar T. R. McVicar D. Yang W. Liu X. Li Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs Hydrology and Earth System Sciences |
| title | Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs |
| title_full | Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs |
| title_fullStr | Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs |
| title_full_unstemmed | Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs |
| title_short | Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs |
| title_sort | comparing palmer drought severity index drought assessments using the traditional offline approach with direct climate model outputs |
| url | https://www.hydrol-earth-syst-sci.net/24/2921/2020/hess-24-2921-2020.pdf |
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