What are the current and future properties of coinciding aboveground, surface and belowground extreme high temperature pulses, and are these events meaningful?
Abstract
Both short duration temporal pulses and extended periods of statistically extreme high air temperatures ( ° C) have significant consequences for mesic and semiarid ecosystems. It follows that these aboveground extremes also initiate high temperature extremes at the soil surface and belowground in the soil profile. Surface temperatures often amplify high air temperatures, whereas high soil thermal diffusivity dampens them belowground, suggesting a potential divergence in the duration, timing and magnitude of extreme temperatures in the future. The degree to which extreme surface and belowground temperatures coincide with extreme air temperatures is not well-characterized, and it is not clear if they will intensify or even diminish in the future . U nderstanding how aboveground, surface and belowground high temperature extremes coincide may provide insight on climate change effects to ecosystems.
We used a validated ecosystem water balance model (SOILWAT2) to simulate temperature patterns for 32 sites comprising 8 ecosystem types in the central and western United States. Simulations occurred over historical time periods (1950-2010) and in downscaled scenarios of 21 st century climate change (2030-2099; 11 GCMs, RCP 8.5). We found that surface extremes often coincided with and were often of greater magnitude than air temperature extremes, whereas belowground extremes occurred less-frequently and were of lower magnitude . A ll three types of extreme temperatures (aboveground, surface, belowground) increased in scenarios of 21 st century climate change . Notably, surface extremes increased in both duration and magnitude, and b elowground extremes began to occur in deeper soil layers . Thus, w e expect the occurrence and intensity of coinciding above ground, surface and belowground high temperature extremes to increase in mesic and semiarid locations. These results suggest that research on the ecological impacts of increasing 21 st century temperatures should also evaluate surface and belowground extremes that may additionally shape ecological processes such as vegetation reproduction, disturbance recovery and hydrological regimes.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGC43F1323P
- Keywords:
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- 1622 Earth system modeling;
- GLOBAL CHANGE;
- 1630 Impacts of global change;
- GLOBAL CHANGE;
- 1637 Regional climate change;
- GLOBAL CHANGE;
- 4313 Extreme events;
- NATURAL HAZARDS