Rainfall Stable Water Isotope Variability in Coastal Southwestern Western Australia and Its Relationship to Climate on Multiple Timescales

Griffiths, Alan D.; Treble, Pauline C.; Hope, Pandora; Rudeva, Irina

doi:10.1029/2021jd035433

Cited by 4 publications

(1 citation statement)

References 119 publications

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“…At the initial stage of precipitation isotope studies in the mid-20th century, the rainfall and snowfall were usually collected on a monthly basis, and the monthly variations of isotopes provide a reference to understand the meteorological and geographical effects controlling stable isotopes [7,8]. As a number of sampling networks were established, most recent studies analyzed the precipitation isotopes on a daily or event-based scale [9][10][11]. In addition, more frequent sampling on an hourly or sub-hourly scale has also aroused increasing attention, which provides an effective perspective to examine the atmospheric processes at a higher temporal resolution [12,13].…”

Section: Introductionmentioning

confidence: 99%

Diurnal Impact of Below-Cloud Evaporation on Isotope Compositions of Precipitation on the Southern Slope of the Altai Mountains, Central Asia

et al. 2022

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Precipitation is an important natural resource relating to regional sustainability in arid central Asia, and the stable oxygen and hydrogen isotopes provide useful tracers to understand precipitation processes. In this study, we collected the hourly meteorological data at several stations on the southern slope of the Altai Mountains in arid central Asia, from March 2017 to June 2022, and examined the diurnal impact of below-cloud evaporation on stable isotope compositions of precipitation. During nighttime, the changes in isotope compositions below cloud base are generally weak. The enhanced impact of below-cloud evaporation can be found after around 15:00, and the impact is relatively strong in the afternoon, especially from 18:00 to 22:00. Summer and spring usually have a larger impact of below-cloud evaporation than autumn, and the winter precipitation is generally not influenced by below-cloud evaporation. On an annual basis, the differences in evaporation-led isotope changes between daytime and nighttime are 1.1‰ for stable oxygen isotope compositions, 4.0‰ for stable hydrogen isotope compositions and 4.7‰ for deuterium excess. The period from 2:00 to 10:00 shows relatively low sensitivity to relative humidity, and from 14:00 to 22:00 the impacts are sensitive. Considering the fluctuations of precipitation isotope compositions, the impact of below-cloud evaporation does not greatly modify the seasonal environmental signals.

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Section: Introductionmentioning

confidence: 99%

Diurnal Impact of Below-Cloud Evaporation on Isotope Compositions of Precipitation on the Southern Slope of the Altai Mountains, Central Asia

et al. 2022

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The role of internal variability and external forcing on southwestern Australian rainfall: prospects for very wet or dry years

Rauniyar,

Hope,

Power

et al. 2023

Sci Rep

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The cool-season (May to October) rainfall decline in southwestern Australia deepened during 2001–2020 to become 20.5% less than the 1901–1960 reference period average, with a complete absence of very wet years (i.e., rainfall > 90th percentile). CMIP5 and CMIP6 climate model simulations suggest that approximately 43% of the observed multi-decadal decline was externally-forced. However, the observed 20-year rainfall anomaly in 2001–2020 is outside the range of both preindustrial control and historical simulations of almost all climate models used in this study. This, and the fact that the models generally appear to simulate realistic levels of decadal variability, suggests that 43% might be an underestimate. A large ensemble from one model exhibits drying similar to the observations in 10% of simulations and suggests that the external forcing contribution is indeed larger (66%). The majority of models project further drying over the twenty-first century, even under strong cuts to greenhouse gas emissions. Under the two warmest scenarios, over 70% of the late twenty-first century years are projected to be drier than the driest year simulated during the 1901–1960 period. Our results suggest that few, if any, very wet years will occur during 2023–2100, even if strong cuts to global emissions are made.

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Ubiquitous karst hydrological control on speleothem oxygen isotope variability in a global study

Treble

Baker

Abram

et al. 2022

Commun Earth Environ

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Speleothem oxygen isotopic (δ18O) records are used to reconstruct past hydroclimate yet records from the same cave do not always replicate. We use a global database of speleothem δ18O to quantify the replicability of records to show that disagreement is common worldwide, occurs across timescales and is unrelated to climate, depth or lithology. Our global analysis demonstrates that within-cave differences in mean speleothem δ18O values are consistent with those of dripwater, supporting a ubiquitous influence of flowpaths. We present a case study of four new stalagmite records from Golgotha Cave, southwest Australia, where the isotopic differences between them are informed by cave monitoring. It is demonstrated that karst hydrology is a major driver of within-cave speleothem and dripwater δ18O variability, primarily due to the influence of fractures on flowpaths. Applying our understanding of water movement through fractures assists in quantitative reconstruction of past climate variability from speleothem δ18O records.

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Rainfall Stable Water Isotope Variability in Coastal Southwestern Western Australia and Its Relationship to Climate on Multiple Timescales

Cited by 4 publications

References 119 publications

Diurnal Impact of Below-Cloud Evaporation on Isotope Compositions of Precipitation on the Southern Slope of the Altai Mountains, Central Asia

Diurnal Impact of Below-Cloud Evaporation on Isotope Compositions of Precipitation on the Southern Slope of the Altai Mountains, Central Asia

The role of internal variability and external forcing on southwestern Australian rainfall: prospects for very wet or dry years

Ubiquitous karst hydrological control on speleothem oxygen isotope variability in a global study

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