Projected changes in droughts and extreme droughts in Great Britain strongly influenced by the choice of drought index

Hydrology and earth system sciences, Год журнала: 2023, Номер 27(5), С. 1151 - 1171

Опубликована: Март 16, 2023

Abstract. Droughts cause enormous ecological, economical and societal damage, they are already undergoing changes due to anthropogenic climate change. The issue of defining quantifying droughts has long been a substantial source uncertainty in understanding observed projected trends. Atmosphere-based drought indicators, such as the Standardised Precipitation Index (SPI) Evapotranspiration (SPEI), often used quantify characteristics their changes, sometimes sole metric representing drought. This study presents detailed systematic analysis SPI- SPEI-based projections differences for Great Britain (GB), derived from most recent set regional United Kingdom (UK). We show that choice indicator decisive influence on resulting frequency, extent, duration seasonality using scenarios 2 4 ∘C above pre-industrial levels. increases frequency extent far greater based SPEI than SPI. Importantly, compared with all intensities, isolated extreme increase more respect also expected pronounced distribution event durations. Further, intensification seasonal cycle is reflected an increasing occurrence years (extremely) dry summers combined wetter-than-average winters. Increasing summer form main contribution annual droughts, especially SPEI. These results atmospheric index strongly influences inferred change projections, comparable impact model parameters or warming level; therefore, potential users these indices should carefully consider importance evapotranspiration intended context. stark between highlight need better understand interplay evaporative demand, moisture availability impacts under changing climate. region-dependent by two levels have important implications adaptation efforts GB, further stress rapid mitigation.

Язык: Английский

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Diagnosing evapotranspiration responses to water deficit across biomes using deep learning

New Phytologist, Год журнала: 2023, Номер 240(3), С. 968 - 983

Опубликована: Авг. 25, 2023

Summary Accounting for water limitation is key to determining vegetation sensitivity drought. Quantifying effects on evapotranspiration (ET) challenged by the heterogeneity of types, climate zones and vertically along rooting zone. Here, we train deep neural networks using flux measurements study ET responses progressing drought conditions. We determine a stress factor (fET) that isolates reductions from atmospheric aridity other covarying drivers. regress fET against cumulative deficit, which reveals control whole‐column moisture availability. find variety stress. Responses range rapid declines 10% its water‐unlimited rate at several savannah grassland sites, mild in most forests, despite substantial deficits. Most sensitive are found arid warm sites. A combination regulation stomatal hydraulic conductance access belowground reservoirs, whether groundwater or soil moisture, could explain different behaviors observed across This not captured standard land surface model, likely reflecting simplifications representation storage.

Язык: Английский

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Ecosystems in China have become more sensitive to changes in water demand since 2001

Communications Earth & Environment, Год журнала: 2023, Номер 4(1)

Опубликована: Ноя. 28, 2023

Abstract Changes in heat and moisture significantly co-alter ecosystem functioning. However, knowledge on dynamics of responses to climate change is limited. Here, we quantify long-term sensitivity based weighted ratios vegetation productivity variability multiple variables from satellite observations, greater values which indicate more yields per hydrothermal condition change. Our results show exhibits large spatial increases with the aridity index. A positive temporal trend found 61.28% study area 2001 2021, largely attributed declining vapor pressure deficit constrained by solar radiation. Moreover, carbon dioxide plays a dual role; moderation promotes fertilization effects, whereas excess may suppress growth triggering droughts. findings highlight stress between land atmosphere one key prerequisites for stability, offsetting part negative effects heat.

Язык: Английский

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Widespread Increasing Ecosystem Water Limitation During the Past Three Decades in the Yellow River Basin, China

Journal of Geophysical Research Biogeosciences, Год журнала: 2023, Номер 128(2)

Опубликована: Янв. 20, 2023

Abstract Terrestrial ecosystems provide crucial ecosystem services to human beings, and their functions are largely dependent on soil moisture availability. Although many studies have evaluated the effects of vegetation climate changes at scale, in water limitation remain poorly understood. This study spatiotemporal Yellow River Basin (YRB)—the second largest river basin China—during 1982–2016 identified major drivers by establishing index (ELI) using moisture, transpiration, net radiation, air temperature. The results show a significant widespread increase YRB during 35‐year period. Temporally, areas with positive ELI (water‐limited regime) exhibited upward trend ( p < 0.01). Spatially, above 75.0% total showed an ELI. Almost all trends over this Further analysis two different but comparable methods, partial correlation Lindeman‐Merenda‐Gold, that change was driver limitation, contributions more than 35.0%. Air temperature atmospheric CO 2 contributed comparably ELI, followed precipitation changes. These findings improve understanding pattern underlying mechanisms greening warming YRB.

Язык: Английский

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Past and projected future patterns of fractional vegetation coverage in China

The Science of The Total Environment, Год журнала: 2023, Номер 902, С. 166133 - 166133

Опубликована: Авг. 9, 2023

Язык: Английский

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