The Community Land Model Version 5: Description of New Features, Benchmarking, and Impact of Forcing Uncertainty

Journal of Advances in Modeling Earth Systems, Journal Year: 2019, Volume and Issue: 11(12), P. 4245 - 4287

Published: Oct. 19, 2019

The Community Land Model (CLM) is the land component of Earth System (CESM) and used in several global regional modeling systems. In this paper, we introduce model developments included CLM version 5 (CLM5), which default for CESM2. We assess an ensemble simulations, including prescribed prognostic vegetation state, multiple forcing data sets, CLM4, CLM4.5, CLM5, against a range metrics from International Benchmarking (ILAMBv2) package. CLM5 includes new updated processes parameterizations: (1) dynamic units, (2) parameterizations structure hydrology snow (spatially explicit soil depth, dry surface layer, revised groundwater scheme, canopy interception processes, fresh density, simple firn model, Scale Adaptive River Transport), (3) plant hydraulics hydraulic redistribution, (4) nitrogen cycling (flexible leaf stoichiometry, N optimization photosynthesis, carbon costs uptake), (5) crop with six types time-evolving irrigated areas fertilization rates, (6) urban building energy, (7) isotopes, (8) stomatal physiology. New optional features include demographically structured (Functionally Assembled Terrestrial Ecosystem Simulator), ozone damage to plants, fire trace gas emissions coupling atmosphere. Conclusive establishment improvement or degradation individual variables challenged by uncertainty, parametric structural complexity, but multivariate presented here suggest general broad CLM4 CLM5.

Language: Английский

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A first assessment of the impact of the extreme 2018 summer drought on Central European forests

Basic and Applied Ecology, Journal Year: 2020, Volume and Issue: 45, P. 86 - 103

Published: April 29, 2020

In 2018, Central Europe experienced one of the most severe and long-lasting summer drought heat wave ever recorded. Before 2003 millennial was often invoked as example a "hotter drought", classified event in for last 500 years. First insights now confirm that 2018 climatically more extreme had greater impact on forest ecosystems Austria, Germany Switzerland than drought. Across this region, mean growing season air temperature from April to October 3.3°C above long-term average, 1.2°C warmer 2003. Here, we present first assessment heatwave European forests. response event, ecologically economically important tree species temperate forests showed signs stress. These symptoms included exceptionally low foliar water potentials crossing threshold xylem hydraulic failure many observations widespread leaf discoloration premature shedding. As result stress, caused unprecedented drought-induced mortality throughout region. Moreover, unexpectedly strong drought-legacy effects were detected 2019. This implies physiological recovery trees impaired after leaving them highly vulnerable secondary impacts such insect or fungal pathogen attacks. consequence, triggered by events is likely continue several Our indicates common are waves previously thought. occur frequently with progression climate change, might approach point substantial ecological economic transition. also highlights urgent need pan-European ground-based monitoring network suited track individual mortality, supported remote sensing products high spatial temporal resolution track, analyse forecast these transitions.

Language: Английский

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Soil moisture dominates dryness stress on ecosystem production globally

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: Sept. 29, 2020

Abstract Dryness stress can limit vegetation growth and is often characterized by low soil moisture (SM) high atmospheric water demand (vapor pressure deficit, VPD). However, the relative role of SM VPD in limiting ecosystem production remains debated difficult to disentangle, as are coupled through land-atmosphere interactions, hindering ability predict responses dryness. Here, we combine satellite observations solar-induced fluorescence with estimates show that dominant driver dryness on across more than 70% vegetated land areas valid data. Moreover, after accounting for SM-VPD coupling, effects much smaller large areas. We also find strongest semi-arid ecosystems. Our results clarify a longstanding question open new avenues improving models allow better management drought risk.

Language: Английский

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Hanging by a thread? Forests and drought

Science, Journal Year: 2020, Volume and Issue: 368(6488), P. 261 - 266

Published: April 16, 2020

Trees are the living foundations on which most terrestrial biodiversity is built. Central to success of trees their woody bodies, connect elevated photosynthetic canopies with essential belowground activities water and nutrient acquisition. The slow construction these carbon-dense, skeletons leads a generation time, leaving forests highly susceptible rapid changes in climate. Other long-lived, sessile organisms such as corals appear be poorly equipped survive changes, raises questions about vulnerability contemporary future climate change. emerging view that, similar corals, tree species have rather inflexible damage thresholds, particularly terms stress, especially concerning. This Review examines recent progress our understanding how looks for growing hotter drier atmosphere.

Language: Английский

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Observed increasing water constraint on vegetation growth over the last three decades

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: June 18, 2021

Abstract Despite the growing interest in predicting global and regional trends vegetation productivity response to a changing climate, changes water constraint on (i.e., limitations growth) remain poorly understood. Here we conduct comprehensive evaluation of growth extratropical Northern Hemisphere between 1982 2015. We document significant increase over this period. Remarkably divergent were found with deficit areas significantly expanding, surplus shrinking. The constraints associated was also consistent decreasing time scarcity, suggesting stronger susceptibility drought. observed shortened period for areas, exposure humid conditions. These be attributable temperature, solar radiation, precipitation, atmospheric CO 2 . Our findings highlight need more explicit consideration influence under warming climate.

Language: Английский

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Quantifying impacts of the 2018 drought on European ecosystems in comparison to 2003

Biogeosciences, Journal Year: 2020, Volume and Issue: 17(6), P. 1655 - 1672

Published: March 27, 2020

In recent decades, an increasing persistence of atmospheric circulation patterns has been observed. the course associated long-lasting anticyclonic summer circulations, heatwaves and drought spells often coincide, leading to so-called hotter droughts. Previous droughts caused a decrease in agricultural yields increase tree mortality. Thus, they had remarkable effect on carbon budgets negative economic impacts. Consequently, quantification ecosystem responses better understanding underlying mechanisms are crucial. this context, European year 2018 may be considered key event. As first step towards its causes consequences, we here assess anomalies patterns, maximum temperature, climatic water balance as potential drivers which quantified by remote sensing using MODIS vegetation indices (VIs) normalized difference index (NDVI) enhanced (EVI). To place within climatological compare features remotely sensed response with extreme hot 2003. The was characterized dipole, featuring extremely dry weather conditions north Alps but comparably cool moist across large parts Mediterranean. Analysing five dominant land cover classes, found significant positive effects VI response. Negative impacts appeared affect area 1.5 times larger significantly stronger July compared August 2003, i.e. at respective peak drought. Moreover, higher sensitivity pastures arable forests both years. We explain coupling prevailing dipole: while generally water-limited ecosystems Mediterranean experienced above-average balance, less drought-adapted central northern Europe record conclusion, study quantifies yet unprecedented event, outlines hotspots drought-impacted areas should given particular attention follow-up studies, provides valuable insights into heterogeneous

Language: Английский

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Implementing Plant Hydraulics in the Community Land Model, Version 5

Journal of Advances in Modeling Earth Systems, Journal Year: 2019, Volume and Issue: 11(2), P. 485 - 513

Published: Jan. 31, 2019

Abstract Version 5 of the Community Land Model (CLM5) introduces plant hydraulic stress (PHS) configuration vegetation water use, which is described and compared with corresponding parameterization from CLM4.5. PHS updates root uptake to better reflect theory, advancing physical basis model. The new prognostic potential, modeled at root, stem, leaf levels. Leaf potential replaces soil as for stomatal conductance stress, used implement uptake, replacing a transpiration partitioning function. Point simulations tropical forest site (Caxiuanã, Brazil) under ambient conditions partial precipitation exclusion highlight differences between previous CLM implementation. description simulation results are contextualized list benefits limitations model formulation, including hypotheses that were not testable in versions Key include reductions moisture biases relative control both conditions, correcting excessive dry season implements gradient allows redistribution compensatory utilizing larger portion column buffer shortfalls precipitation. structure, bases on could have significant implications vegetation‐climate feedbacks, increased sensitivity photosynthesis atmospheric vapor pressure deficit.

Language: Английский

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Mechanisms of woody-plant mortality under rising drought, CO2 and vapour pressure deficit

Nature Reviews Earth & Environment, Journal Year: 2022, Volume and Issue: 3(5), P. 294 - 308

Published: March 29, 2022

Language: Английский

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Climate Change Risks to Global Forest Health: Emergence of Unexpected Events of Elevated Tree Mortality Worldwide

Annual Review of Plant Biology, Journal Year: 2022, Volume and Issue: 73(1), P. 673 - 702

Published: March 1, 2022

Recent observations of elevated tree mortality following climate extremes, like heat and drought, raise concerns about change risks to global forest health. We currently lack both sufficient data understanding identify whether these represent a trend toward increasing mortality. Here, we document events sudden unexpected drought in ecosystems that previously were considered tolerant or not at risk exposure. These underscore the fact may affect forests with force future. use as examples highlight current difficulties challenges for realistically predicting such uncertainties future condition. Advances remote sensing technology greater availably high-resolution data, from field assessments satellites, are needed improve prediction responses change. Expected final online publication date Annual Review Plant Biology, Volume 73 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates revised estimates.

Language: Английский

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Long-term thermal sensitivity of Earth’s tropical forests

Science, Journal Year: 2020, Volume and Issue: 368(6493), P. 869 - 874

Published: May 21, 2020

Thermal sensitivity of tropical trees A key uncertainty in climate change models is the thermal forests and how this value might influence carbon fluxes. Sullivan et al. measured stocks fluxes permanent forest plots distributed globally. This synthesis plot networks across climatic biogeographic gradients shows that dominated by high daytime temperatures. extreme condition depresses growth rates shortens time resides ecosystem killing under hot, dry conditions. The effect temperature worse above 32°C, a greater magnitude thus risks loss stocks. Nevertheless, are likely to remain higher moderate if they protected from direct impacts such as clearance, logging, or fires. Science , issue p. 869

Language: Английский

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