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Temperature and Snow-Mediated Moisture Controls of Summer Photosynthetic Activity in Northern Terrestrial Ecosystems between 1982 and 2011
- Source :
- Remote Sensing, Remote Sensing, MDPI, 2014, 6 (2), pp.1390-1431. ⟨10.3390/rs6021390⟩, Remote Sensing; Volume 6; Issue 2; Pages: 1390-1431, Remote Sensing, 2014, 6 (2), pp.1390-1431. ⟨10.3390/rs6021390⟩, Remote Sensing, Vol 6, Iss 2, Pp 1390-1431 (2014)
- Publication Year :
- 2014
- Publisher :
- HAL CCSD, 2014.
-
Abstract
- Recent warming has stimulated the productivity of boreal and Arctic vegetation by reducing temperature limitations. However, several studies have hypothesized that warming may have also increased moisture limitations because of intensified summer drought severity. Establishing the connections between warming and drought stress has been difficult because soil moisture observations are scarce. Here we use recently developed gridded datasets of moisture variability to investigate the links between warming and changes in available soil moisture and summer vegetation photosynthetic activity at northern latitudes (greater than 45N) based on the Normalized Difference Vegetation Index (NDVI) since 1982. Moisture and temperature exert a significant influence on the inter-annual variability of summer NDVI over about 29% (mean r(sup 2) = 0.29 +/ 0.16) and 43% (mean r(sup 2 = 0.25 +/- 0.12) of the northern vegetated land, respectively. Rapid summer warming since the late 1980s (approximately 0.7deg C) has increased evapotranspiration demand and consequently summer drought severity, but contrary to earlier suggestions it has not changed the dominant climate controls of NDVI over time. Furthermore, changes in snow dynamics (accumulation and melting) appear to be more important than increased evaporative demand in controlling changes in summer soil moisture availability and NDVI in moisture-sensitive regions of the boreal forest. In boreal North America, forest NDVI declines are more consistent with reduced snowpack rather than with temperature-induced increases in evaporative demand as suggested in earlier studies. Moreover, summer NDVI variability over about 28% of the northern vegetated land is not significantly associated with moisture or temperature variability, yet most of this land shows increasing NDVI trends. These results suggest that changes in snow accumulation and melt, together with other possibly non-climatic factors are likely to play a significant role in modulating regional ecosystem responses to the projected warming and increase in evapotranspiration demand during the coming decades.
- Subjects :
- 010504 meteorology & atmospheric sciences
Science
0207 environmental engineering
02 engineering and technology
drought
Atmospheric sciences
01 natural sciences
Normalized Difference Vegetation Index
scPDSI
NDVI3g
Evapotranspiration
snowpack
boreal forest
Arctic vegetation
020701 environmental engineering
0105 earth and related environmental sciences
Moisture
Vegetation
15. Life on land
Snow
soil moisture
Boreal
13. Climate action
Climatology
General Earth and Planetary Sciences
Environmental science
Terrestrial ecosystem
[SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology
Subjects
Details
- Language :
- English
- ISSN :
- 20724292
- Database :
- OpenAIRE
- Journal :
- Remote Sensing, Remote Sensing, MDPI, 2014, 6 (2), pp.1390-1431. ⟨10.3390/rs6021390⟩, Remote Sensing; Volume 6; Issue 2; Pages: 1390-1431, Remote Sensing, 2014, 6 (2), pp.1390-1431. ⟨10.3390/rs6021390⟩, Remote Sensing, Vol 6, Iss 2, Pp 1390-1431 (2014)
- Accession number :
- edsair.doi.dedup.....b16be262ac882bc31ce316166f6f67dc