Hydroclimatic seasonality recorded by tree ring δ18O signature across a Himalayan altitudinal transect

Brunello, Camilla Francesca; Andermann, Christoff; Helle, Gerhard; Comiti, Francesco; Tonon, Giustino; Tiwari, Achyut; Hovius, Niels

doi:10.1016/j.epsl.2019.04.030

Cited by 22 publications

(28 citation statements)

References 65 publications

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“…Changes are moderate in a 2C warmer world, while in a 3C warmer world a clear distinction is visible between the south‐eastern regions (East Himalaya and Hengduan Shan and Southern Tibet) and the other regions. This is in correspondence with observed increases in pre‐monsoon precipitation during last decades (Brunello et al ., 2019).…”

Section: Resultsmentioning

confidence: 99%

Using large ensemble modelling to derive future changes in mountain specific climate indicators in a 2 and 3°C warmer world in High Mountain Asia

Bonekamp

Wanders

Wiel

et al. 2020

Intl Journal of Climatology

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Natural disasters in High Mountain Asia (HMA) are largely induced by precipitation and temperatures extremes. Precipitation extremes will change due to global warming, but these low frequency events are difficult to analyse using (short) observed time series. In this study, we analysed large 2000 year ensembles of present day climate and of a 2 and 3 C warmer world produced with the EC-Earth model. We performed a regional assessment of climate indicators related to temperature and precipitation (positive degree days, accumulated precipitation, [preand post-] monsoon precipitation), their sensitivity to temperature change and the change in return periods of extreme temperature and precipitation in a 2 and 3 C warmer climate. In general, the 2 C warmer world shows a homogeneous response of changes in climate indicators and return periods, while distinct differences between regions are present in a 3 C warmer world and changes no longer follow a general trend. This non-linear effect can indicate the presence of a tipping point in the climate system. The most affected regions are located in monsoondominated regions, where precipitation amounts, positive degree days, extreme temperature, extreme precipitation and compound events are projected to increase the most. Largest changes in climate indicators are found in East Himalaya, followed by the Hindu Kush and West and Central Himalaya regions. Western regions will experience drier summers and wetter winters, while monsoon dominated regions drier winters and wetter summers and northern regions a wetter climate year round. We also found that precipitation increases in HMA in a 3 C warmer world are substantially larger (13%) compared to the global average (5.9%). Additionally, the increase in weather extremes will exacerbate natural hazards with large possible impacts for mountain communities. The results of this study could provide important guidance for formulating climate change adaptation strategies in HMA.

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Section: Resultsmentioning

confidence: 99%

Using large ensemble modelling to derive future changes in mountain specific climate indicators in a 2 and 3°C warmer world in High Mountain Asia

Bonekamp

Wanders

Wiel

et al. 2020

Intl Journal of Climatology

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“…Besides, nonmonsoon season precipitation has larger chances to be accumulated on low-latitude glaciers compared with relatively warmer summers. Nonmonsoon season precipitation isotope signal has been previously separated from an ice core drilled on southeast TP (Zhao et al, 2017) and tree rings from central Himalayas (Brunello et al, 2019). Therefore, interpretation of paleo-precipitation δ 18 O records from those regions with significant nonmonsoon season precipitation should both consider the potential bias toward precipitation events and the different precipitation regimes during the two seasons.…”

Section: Discussionmentioning

confidence: 99%

What Causes the Postmonsoon ¹⁸O Depletion Over Bay of Bengal Head and Beyond?

Cai

Tian

2020

Geophysical Research Letters

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Modern observations from Bay of Bengal (BOB) head have shown that precipitation δ18O value reaches the lowest stage during late postmonsoon when the summer monsoon has weakened or retreated, complicating the traditional interpretation of low δ18O value as strong monsoon. We show that this postmonsoon 18O depletion phenomenon exists from BOB periphery to the southeast and south Tibetan Plateau. Accumulative precipitation along back‐trajectory still explains daily precipitation δ18O variability during both the monsoon and nonmonsoon, thus indicating that longer‐term weighted‐mean δ18O is biased toward synoptic conditions during precipitation events. Further, we propose that transport of moisture from the east (west) of the India‐Burma Trough leads to depleted (enriched) 18O during the postmonsoon (premonsoon). Our results reconcile the apparent contradiction but beg the consideration of potential bias and influence of different precipitation regimes in paleo archives.

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“…Indeed, existing tree-ring data from the Swiss Alps (Keel et al, 2016) and the Rocky Mountains in the western United States (Helliker et al, 2018) have shown that incorporating a temperature-dependent ε bio into mechanistic modeling would produce a better fit for observed δ 18 O c . Furthermore, in a study from the trans-Himalayan region (Chhumuja at an elevation of 4400 m above sea level) where growing season temperature is lower than 10 • C, a tree-ring δ 18 O c record was found to be best fitted with a relative humidity of 64%, despite the nearby station-observed values between 70% and 100% during the monsoon season (Brunello et al, 2019). This discrepancy could be alternatively explained by a higher ε bio at a low growing-season temperature.…”

Section: Implications For Paleoclimate and Plant Physiology Studiesmentioning

confidence: 93%

Temperature-Dependent Oxygen Isotope Fractionation in Plant Cellulose Biosynthesis Revealed by a Global Dataset of Peat Mosses

Xia

2020

Front. Earth Sci.

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The oxygen isotope composition (δ 18 O) of plant cellulose has been widely used to study ecohydrological processes of ecosystems as well as to reconstruct past climate conditions in terrestrial climate archives. These applications are grounded on a key assumption that the biochemical fractionation during cellulose synthesis is a constant around +27 and is not affected by environmental factors. Here we revisit the influence of temperature on biochemical fractionation factor during cellulose synthesis using a global compilation of Sphagnum cellulose δ 18 O data. Sphagnum (peat mosses) are known for inhabiting waterlogged peatlands and possessing unique physiological strategy in that their cellulose δ 18 O could closely reflect growing-season precipitation δ 18 O. Although within-site cellulose δ 18 O variability shows a median standard deviation of 0.7-0.8 resulting from different degrees of evaporative enrichment of 18 O in metabolic leaf water, this evaporative enrichment should be a small quantity due to the external capillary "water buffer" in Sphagnum mosses. Using site-specific minimum cellulose δ 18 O data that most likely reflect the signal of unevaporated source water, we show that the apparent enrichment factor between cellulose and precipitation δ 18 O increases with decreasing air temperature. In particular, the apparent enrichment factor could reach values as high as +32 when growth temperature is below 5 • C. This observational dataset extends the support for the temperature-dependent oxygen isotope fractionation in plant cellulose synthesis previously demonstrated in laboratory experiment, with implications for paleoclimate and plant physiology studies that employ cellulose δ 18 O measurements, particularly in alpine regions.

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Hydroclimatic seasonality recorded by tree ring δ18O signature across a Himalayan altitudinal transect

Cited by 22 publications

References 65 publications

Using large ensemble modelling to derive future changes in mountain specific climate indicators in a 2 and 3°C warmer world in High Mountain Asia

Using large ensemble modelling to derive future changes in mountain specific climate indicators in a 2 and 3°C warmer world in High Mountain Asia

What Causes the Postmonsoon ¹⁸O Depletion Over Bay of Bengal Head and Beyond?

Temperature-Dependent Oxygen Isotope Fractionation in Plant Cellulose Biosynthesis Revealed by a Global Dataset of Peat Mosses

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Hydroclimatic seasonality recorded by tree ring δ18O signature across a Himalayan altitudinal transect

Cited by 22 publications

References 65 publications

Using large ensemble modelling to derive future changes in mountain specific climate indicators in a 2 and 3°C warmer world in High Mountain Asia

Using large ensemble modelling to derive future changes in mountain specific climate indicators in a 2 and 3°C warmer world in High Mountain Asia

What Causes the Postmonsoon 18O Depletion Over Bay of Bengal Head and Beyond?

Temperature-Dependent Oxygen Isotope Fractionation in Plant Cellulose Biosynthesis Revealed by a Global Dataset of Peat Mosses

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What Causes the Postmonsoon ¹⁸O Depletion Over Bay of Bengal Head and Beyond?