Abstract
Drought is a globally relevant hazard, and while various studies have investigated the relationship between droughts and different climate and ecosystem variables, they are often not global or they do not make use of direct soil moisture observations. Here we use satellite derived soil moisture observations from the Climate Change Initiative of the European Space Agency to quantify the relation between soil moisture drought and temperature, precipitation, evapotranspiration and vegetation during the peak of the growing season. Furthermore, we follow the temporal evolution of the buildup and recovery surrounding the drought peak. We find that in many regions longer-term precipitation deficits are the driving factors of large negative soil moisture anomalies. At the peak of the dry period large anomalies are found for precipitation, evapotranspiration, and temperature, while vegetation indices often show a delayed response. This delay is likely related to the limited information contained in the remotely sensed soil moisture signal on the deeper root zone, thus underestimating the available soil moisture for plants. Anomalies over grasslands are generally larger than over forests, likely linked to the ability of trees to better access water at deeper depths, and to save water during dry conditions. These results illustrate the relevance of remote-sensing based soil moisture as a new independent observation for studying land-vegetation-atmosphere dynamics at the global scale.
Original language | English |
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Pages (from-to) | 216-225 |
Number of pages | 10 |
Journal | Remote Sensing of Environment |
Volume | 203 |
DOIs | |
Publication status | Published - 15 Dec 2017 |
Externally published | Yes |
Funding
Financial support was provided by the ESA ’s Climate Change Initiative for Soil Moisture (contract no. 4000112226/14/I-NB ). We acknowledge the data providers of the following products; ESA CCI soil moisture ( http://www.esa-soilmoisture-cci.org ) and land cover ( http://www.esa-landcover-cci.org/ ), ERA-Interim precipitation and temperature ( http://www.ecmwf.int/ ), GLEAM evapotranspiration ( http://www.GLEAM.eu ). The MODIS LAI and FPAR data product were retrieved from the online Data Pool, courtesy of the NASA Land Processes Distributed Active Archive Center (LP DAAC), USGS/Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota ( https://lpdaac.usgs.gov/data_access/data_pool . SIS acknowledges partial support of the ERC DROUGHT-HEAT project. Appendix A
Funders | Funder number |
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DAAC | |
ERC DROUGHT-HEAT | |
EROS | |
ESA CCI | |
ESA ’s Climate Change Initiative for Soil Moisture | 4000112226/14/I-NB |
Earth Resources Observation and Science | |
National Aeronautics and Space Administration | |
U.S. Geological Survey | |
Engineering Research Centers | |
European Space Agency |
Keywords
- Drought event composites
- ESA Climate Change Initiative (CCI)
- Land cover
- Satellite derived soil moisture