Extreme Wet Events As Important As Extreme Dry Events in Controlling Spatial Patterns of Vegetation Productivity
Abstract
Understanding plant responses to hydrologic extremes is critical for projections of the future terrestrial carbon uptake. While droughts and pluvials (wet extremes) are both becoming more frequent and intense, each can affect plants in a multitude of different ways, and comparing their relative impacts on carbon fluxes can therefore be complex. Though prior studies have assessed the impacts of the most extreme wet and dry events on the globally averaged carbon uptake and found the effect of droughts to dominate, it is not clear whether this is also true at regional scales. Here we take a location-based approach to evaluate where wet and dry extremes most affect carbon uptake, after controlling for potentially confounding impacts of temperature and radiation. We present a set of simple metrics to weigh the cumulative impacts of anomalously wet versus anomalously dry extreme events on vegetation productivity over the period 1981 to 2015, and map these using remotely sensed soil moisture and NDVI as proxies for water availability and plant productivity, respectively. We find that regions where the impact of wet extremes dominates are just as common as regions where drought impacts dominate. Further, we identify and explain regional patterns in the likelihood of wet and dry extremes to either stimulate or hinder photosynthesis. This work suggests the need for an improved understanding of the impacts of pluvials on net carbon fluxes at regional scales.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B21G2407F
- Keywords:
-
- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 1631 Land/atmosphere interactions;
- GLOBAL CHANGE;
- 1813 Eco-hydrology;
- HYDROLOGY