Transfer Operator Framework for Earth System Predictability and Water Cycle Extremes

AbstractSupervolcano eruptions have occurred throughout Earth’s history and have major environmental impacts. These impacts are mostly associated with the attenuation of visible sunlight by stratospheric sulfate aerosols, which causes cooling and deceleration of the water cycle. Supereruptions have been assumed to cause so-called volcanic winters that act as primary evolutionary factors through ecosystem disruption and famine, however, winter conditions alone may not be sufficient to cause such disruption. Here we use Earth system model simulations to show that stratospheric sulfur emissions from the Toba supereruption 74,000 years ago caused severe stratospheric ozone loss through a radiation attenuation mechanism that only moderately depends on the emission magnitude. The Toba plume strongly inhibited oxygen photolysis, suppressing ozone formation in the tropics, where exceptionally depleted ozone conditions persisted for over a year. This effect, when combined with volcanic winter in the extra-tropics, can account for the impacts of supereruptions on ecosystems and humanity.

Download Full-text

Using an Uncertainty Quantification Framework to Calibrate the Runoff Generation Scheme in E3SM Land Model V1

10.5194/gmd-2021-401 ◽

2021 ◽

Author(s):

Donghui Xu ◽

Gautam Bisht ◽

Khachik Sargsyan ◽

Chang Liao ◽

L. Ruby Leung

Keyword(s):

Uncertainty Quantification ◽

Water Cycle ◽

Computational Cost ◽

Model Performance ◽

Parametric Uncertainty ◽

Surrogate Models ◽

Earth System ◽

Runoff Generation ◽

Parameter Values ◽

Sensitive Parameters

Abstract. Runoff is a critical component of the terrestrial water cycle and Earth System Models (ESMs) are essential tools to study its spatio-temporal variability. Runoff schemes in ESMs typically include many parameters so model calibration is necessary to improve the accuracy of simulated runoff. However, runoff calibration at global scale is challenging because of the high computational cost and the lack of reliable observational datasets. In this study, we calibrated 11 runoff relevant parameters in the Energy Exascale Earth System Model (E3SM) Land Model (ELM) using an uncertainty quantification framework. First, the Polynomial Chaos Expansion machinery with Bayesian Compressed Sensing is used to construct computationally inexpensive surrogate models for ELM-simulated runoff at 0.5° × 0.5° for 1991–2010. The main methodological advance in this work is the construction of surrogates for the error metric between ELM and the benchmark data, facilitating efficient calibration and avoiding the more conventional, but challenging, construction of high-dimensional surrogates for ELM itself. Second, the Sobol index sensitivity analysis is performed using the surrogate models to identify the most sensitive parameters, and our results show that in most regions ELM-simulated runoff is strongly sensitive to 3 of the 11 uncertain parameters. Third, a Bayesian method is used to infer the optimal values of the most sensitive parameters using an observation-based global runoff dataset as the benchmark. Our results show that model performance is significantly improved with the inferred parameter values. Although the parametric uncertainty of simulated runoff is reduced after the parameter inference, it remains comparable to the multi-model ensemble uncertainty represented by the global hydrological models in ISMIP2a. Additionally, the annual global runoff trend during the simulation period is not well constrained by the inferred parameter values, suggesting the importance of including parametric uncertainty in future runoff projections.

Download Full-text

How Much Modification Can Earth’s Water Cycle Handle?

Eos ◽

10.1029/2020eo144039 ◽

2020 ◽

Vol 101 ◽

Author(s):

Aaron Sidder

Keyword(s):

Human Disturbance ◽

Water Cycle ◽

Earth System ◽

Planetary Boundaries

The planetary boundaries framework defines how much human disturbance various Earth system processes can take, but it may not adequately depict the water cycle or the extent to which we’ve altered it.

Download Full-text

Illuminating water cycle modifications and Earth system resilience in the Anthropocene

Water Resources Research ◽

10.1029/2019wr024957 ◽

2020 ◽

Vol 56 (4) ◽

Cited By ~ 8

Author(s):

Tom Gleeson ◽

Lan Wang‐Erlandsson ◽

Miina Porkka ◽

Samuel C. Zipper ◽

Fernando Jaramillo ◽

...

Keyword(s):

Water Cycle ◽

Earth System ◽

System Resilience

Download Full-text

Using radar observations to evaluate 3-D radar echo structure simulated by the Energy Exascale Earth System Model (E3SM) version 1

Geoscientific Model Development ◽

10.5194/gmd-14-719-2021 ◽

2021 ◽

Vol 14 (2) ◽

pp. 719-734

Author(s):

Jingyu Wang ◽

Jiwen Fan ◽

Robert A. Houze Jr. ◽

Stella R. Brodzik ◽

Kai Zhang ◽

...

Keyword(s):

General Circulation ◽

Water Cycle ◽

General Circulation Models ◽

Atmospheric Model ◽

Earth System Model ◽

Radar Reflectivity ◽

Department Of Energy ◽

System Model ◽

Earth System ◽

Radar Observations

Abstract. The Energy Exascale Earth System Model (E3SM) developed by the Department of Energy has a goal of addressing challenges in understanding the global water cycle. Success depends on correct simulation of cloud and precipitation elements. However, lack of appropriate evaluation metrics has hindered the accurate representation of these elements in general circulation models. We derive metrics from the three-dimensional data of the ground-based Next-Generation Radar (NEXRAD) network over the US to evaluate both horizontal and vertical structures of precipitation elements. We coarsened the resolution of the radar observations to be consistent with the model resolution and improved the coupling of the Cloud Feedback Model Intercomparison Project Observation Simulator Package (COSP) and E3SM Atmospheric Model Version 1 (EAMv1) to obtain the best possible model output for comparison with the observations. Three warm seasons (2014–2016) of EAMv1 simulations of 3-D radar reflectivity features at an hourly scale are evaluated. A general agreement in domain-mean radar reflectivity intensity is found between EAMv1 and NEXRAD below 4 km altitude; however, the model underestimates reflectivity over the central US, which suggests that the model does not capture the mesoscale convective systems that produce much of the precipitation in that region. The shape of the model-estimated histogram of subgrid-scale reflectivity is improved by correcting the microphysical assumptions in COSP. Different from previous studies that evaluated modeled cloud top height, we find the model severely underestimates radar reflectivity at upper levels – the simulated echo top height is about 5 km lower than in observations – and this result is not changed by tuning any single physics parameter. For more accurate model evaluation, a higher-order consistency between the COSP and the host model is warranted in future studies.

Download Full-text

Crystal balls into the future: are global circulation and water balance models ready?

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-374-41-2016 ◽

2016 ◽

Vol 374 ◽

pp. 41-51

Author(s):

Balázs M. Fekete ◽

Giovanna Pisacane ◽

Dominik Wisser

Keyword(s):

Water Management ◽

Water Cycle ◽

Probability Distributions ◽

Earth System ◽

Management Planning ◽

Global Circulation ◽

Global Circulation Models ◽

Brief Assessment ◽

The Future ◽

Water Management Planning

Abstract. Variabilities and changes due to natural and anthropogenic causes in the water cycle always presented a challenge for water management planning. Practitioners traditionally coped with variabilities in the hydrological processes by assuming stationarity in the probability distributions and attempted to address non-stationarity by revising this probabilistic properties via continued hydro-climatological observations. Recently, this practice was questioned and more reliance on Global Circulation Models was put forward as an alternative for water management plannig. This paper takes a brief assessment of the state of Global Circulation Models (GCM) and their applications by presenting case studies over Global, European and African domains accompanied by literature examples. Our paper demonstrates core deficiencies in GCM based water resources assessments and articulates the need for improved Earth system monitoring that is essential not only for water managers, but to aid the improvements of GCMs in the future.

Download Full-text

Floodplains representation in Land Surface Model : toward higher resolution

10.5194/egusphere-egu21-9735 ◽

2021 ◽

Author(s):

Anthony Schrapffer ◽

Jan Polcher ◽

Anna Sörensson ◽

Lluis Fita

Keyword(s):

Spatial Distribution ◽

Land Surface ◽

Water Cycle ◽

Upstream Region ◽

Surface Model ◽

Earth System ◽

Routing Scheme ◽

Overbank Flow ◽

The Impact ◽

Tropical Floodplains

Floodplains are flat regions close to rivers which are temporarily or permanently flooded. When they are next to large streamflow, their flooding is mainly related to the river overflow and, thus, to the precipitation occurring in the upstream regions. Large floodplains are important for the regional water cycle, the hydrological resources, the ecological services they provide and, when they are located in tropical regions, for their interaction with the atmosphere. Large tropical floodplains exist in the Amazon, the Mississippi, the Congo, the Paraguay and the Nile basins.&#160;On the one hand, floodplains are regions with scarce ground observations which lead to difficulties to assess the accuracy of the satellite products that limits their calibration. One the other hand, the dynamic of the floodplains is usually not integrated in Land Surface Models and even less in Earth System Models although they may be important for land-atmosphere interactions. There is a need to develop numerical schemes in order to be able to represent the impact of the floodplains on the water cycle. These schemes will also allow us to better understand the hydrological dynamics in these regions.&#160;The Land Surface component of the IPSL Earth System Model, ORCHIDEE (CMIP6 version) includes a river routing scheme with a floodplains scheme at a resolution of 0.5&#176;. This scheme allows the water from the precipitation over the upstream region to flood and evaporate over the floodplains. Recent developments in ORCHIDEE driven by the need for a higher resolution routing scheme, based on sub-grid hydrological units, allowed us to implement a floodplain scheme which improves the representation of the overbank flow and the spatial distribution of ponded water with respect to the CMIP6 version of ORCHIDEE.&#160;This study focuses on the Pantanal region which is the world&#8217;s largest tropical floodplains and is located in the La Plata Basin, in the Upper Paraguay River (South America). ORCHIDEE&#8217;s sensitivity to the activation of floodplain schemes has been assessed through simulations performed at various resolutions. These simulations have shown the importance of representing floodplains to simulate the water cycle in the area. Combining these simulations and observations, we estimated the evapotranspiration loss by models when the floodplains scheme is deactivated to 90 mm/year over the Pantanal. The higher resolution scheme shows realistic simulations of the river discharge over the floodplains and is expected to improve the spatial distribution of the flooded area and, thus, the representation of evapotranspiration.

Download Full-text

2. Recycling

Earth System Science: A Very Short Introduction ◽

10.1093/actrade/9780198718871.003.0002 ◽

2016 ◽

pp. 18-37

Author(s):

Tim Lenton

Keyword(s):

Closed System ◽

Water Cycle ◽

Biogeochemical Cycles ◽

System Support ◽

The Sun ◽

Earth System ◽

The Earth ◽

Global Biogeochemical Cycles

How does the Earth system support such a flourishing of life? A habitable climate and water are essential, but organisms also need energy and materials out of which to build their bodies. The Sun provides a plentiful supply of energy, which drives the water cycle and fuels the biosphere, via photosynthesis. However, due to an almost closed system, all the elements needed by life must be efficiently recycled within the Earth system, which then need energy to transform materials chemically and to move them physically around the planet. ‘Recycling’ introduces the life-sustaining global biogeochemical cycles of matter between the biosphere, atmosphere, ocean, land, and crust.

Download Full-text