| 1. |
- Feng, X. Y., et al.
(författare)
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Tree-ring cellulose oxygen isotopes indicate atmospheric aridity in the western Kunlun Mountains
- 2022
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X. ; 137
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Tidskriftsartikel (refereegranskat)abstract
- As an important indicator of atmospheric aridity, the vapor pressure deficit (VPD) is being paid increasing attention in global change researches during recent decades. However, available proxy data with the capability to represent VPD is still scarce in the globe. Herein we demonstrated a "hidden " frequency-dependent indication of tree-ring cellulose oxygen isotope (delta(OTRC)-O-18) to atmospheric aridity in the western Kunlun Mountains, Central Asia. In applying correlation and partial correlation analysis, frequency-dependent climatic drivers triggering the delta(OTRC)-O-18 values were detected. For the raw data with inter-decadal variability, delta(OTRC)-O-18 variations mainly indicated May-August precipitation (Local: r = -0.59, p < 0.001; Moisture source: r = -0.53, p < 0.001), evapotranspiration (ET) (Local: r = -0.57, p < 0.001; Moisture source: r = -0.51, p < 0.001). After a 5-year high-pass filter, the delta(OTRC)-O-18 series revealed highly significant correlation with May-August VPD (Local: r = 0.82, p < 0.001; Moisture source: r = 0.80, p < 0.001). The partial correlation further confirmed the strong linkages with high-frequency VPD when the impact of any additional eco-climatological variable (precipitation, temperature, ET, soil moisture 0-40 cm) was excluded. In contrast, if the effect of May-August VPD was excluded, relationships between delta(OTRC)-O-18 and other variables turned insignificant. Collectively, it was concluded that delta 18OTRC from the western Kunlun Mountains may indicate VPD at timescales < 5 years. Our results suggest that frequency dependent climatic significances should be considered when interpreting multi-process determined delta(OTRC)-O-18 as a climate-proxy.
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| 2. |
- Wang, L., et al.
(författare)
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The 1820s Marks a Shift to Hotter-Drier Summers in Western Europe Since 1360
- 2022
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Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 49:15
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Tidskriftsartikel (refereegranskat)abstract
- Recent soil moisture (SM) reconstructions revealed plunging trends and enhanced SM-temperature couplings over the last two decades in dry regions. However, how SM changed and whether the land-atmosphere interaction was intensified over time in humid regions remained unknown. Here we reported the first six-century-long regional summer SM reconstruction (1360-2000 CE) in western Europe (WE) using three individual tree-ring delta O-18 chronologies in England and France. A sharp wet-to-dry change occurred around 1820, earlier than 1850-1900 CE, the commonly used historical baseline of anthropogenic climate changes. Enhanced coupling of SM-temperature followed, with stronger summer sea level pressure anomalies in dry years after the 1820s. Our results reveal that the hotter-drier regime has also become more frequent in humid WE under global warming.
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