Impact of groundwater – soil moisture interaction on evolution of evapotranspiration and air temperature under climate change

Groundwater (GW) constitutes by far the largest volume of liquid freshwater on Earth. The most active part is soil moisture (SM), which plays a key role on land/atmosphere interactions. But GW is often stored in deep reservoirs below the soil as well, where it presents slow horizontal movements along hillslopes toward the river network. They end up forming baseflow with well-known buffering effects on streamflow variability, but they also contribute to sustain higher SM values, especially in the lowland areas surrounding streams, which are among the most frequent wetlands. &#160;As a result, GW-SM interactions may influence the climate system, in the past but also in the future, with a potential to alleviate anthropogenic warming, at least regionally, owing to enhanced evapotranspiration rate (ET) or higher soil thermal inertia for instance. To assess where, when, and how much GW-SM interaction affects the climate change trajectories, we use coupled land-atmosphere simulations with the IPSL-CM6 climate model, developed by the Institut Pierre Simon Laplace for CMIP6. &#160;We contrast the results of two long-term simulations (1979-2100), which share the same sea surface temperature and radiative forcing, using the SSP5-8.5 scenario (i.e. the most pessimistic) for 2015-2100. The two simulations differ by their configuration of the land surface scheme ORCHIDEE: in the default version, there is no GW-SM interaction, while this interaction is permitted in the second simulation, within a so-called lowland fraction, fed by surface and GW runoff from the rest of the grid-cell. For simplicity, this lowland fraction is set constant over time, but varies across grid-cells based on a recently designed global scale wetland map.&#160; Within this framework, we analyse the impact of the GW-SM interaction on climate change trajectories, focusing on the response of evapotranspiration rates and near-surface air temperatures. The GW-SM interaction can modulate the response to climate change by amplifying, attenuating, or even inverting the climate change trend. Based on yearly mean values over land, we find that the GW-SM interaction amplifies the response of evapotranspiration to climate change, as the mean evapotranspiration rate increases 50% faster over 1980 - 2100 in the simulation with GW-SM interaction. In contrast, the mean warming over land is 1% weaker, shifting from 6.4 to 6.3 &#176;C/100 years; thus attenuated, if the GW-SM interaction is accounted for. In both cases, these values hide important differences across climates and seasons, with mitigation or amplification for both variables, indicating the need for regional and seasonal assessment. We will also further explore how GW-SM interaction impacts the future evolution of heatwaves, in terms of duration and frequency.&#160;

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Land-surface feedbacks on temperature and precipitation in CMIP6-LS3MIP projections

10.5194/egusphere-egu21-12175 ◽

2021 ◽

Author(s):

Franco Catalano ◽

Andrea Alessandri ◽

Wilhelm May ◽

Thomas Reerink

Keyword(s):

Climate Change ◽

Soil Moisture ◽

Land Surface ◽

Hydrological Cycle ◽

Climate Change Signal ◽

Moisture Change ◽

Climate Conditions ◽

Temperature And Precipitation ◽

Systematic Biases ◽

The Impact

The Land Surface, Snow and Soil Moisture Model Intercomparison Project (LS3MIP) aims at diagnosing systematic biases in the land models of CMIP6 Earth System Models and assessing the role of land-atmosphere feedbacks on climate change. Two components of experiments have been designed: the first is devoted to the assessment of the systematic land biases in offline mode (LMIP) while the second component is dedicated to the analysis of the land feedbacks in coupled mode (LFMIP). Here we focus on the LFMIP experiments. In the LFMIP protocol (van den Hurk et al. 2016), which builds upon the GLACE-CMIP configuration, two sets of climate-sensitivity projections have been carried out in amip mode: in the first set (amip-lfmip-pdLC) the land feedbacks to climate change have been disabled by prescribing the soil-moisture states from a climatology derived from &#8220;present climate conditions&#8221; (1980-2014) while in the second set (amip-lfmip-rmLC) 30-year running mean of land-surface state from the corresponding ScenarioMIP experiment (O&#8217;Neill et al., 2016) is prescribed. The two sensitivity simulations span the period 1980-2100 with sea surface temperature and sea-ice conditions prescribed from the first member of historical and ScenarioMIP experiments. Two different scenarios are considered: SSP1-2.6 (f1) and SSP5-8.5 (f2).In this analysis, we focus on the differences between amip-lfmip-rmLC and amip-lfmip-pdLC at the end of the 21st Century (2071&#8211;2100) in order to isolate the impact of the soil moisture changes on surface climate change. The (2071-2100) minus (1985-2014) temperature change is positive everywhere over land and the climate change signal of precipitation displays a clear intensification of the hydrological cycle in the Northern Hemisphere. Warming and hydrological cycle intensification are larger in SSP5-8.5 scenario. Results show large differences in the feedbacks between wet, transition and semi-arid climates. In particular, over the regions with negative soil moisture change, the 2m-temperature increases significantly while the cooling signal is not significant over all the regions getting wetter. In agreement with Catalano et al. (2016), the larger effects on precipitation due to soil moisture forcing occur mostly over transition zones between dry and wet climates, where evaporation is highly sensitive to soil moisture. The sensitivity of both 2m-temperature and precipitation to soil moisture change is much stronger in the SSP5-8.5 scenario.

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Nitrate aerosols today and in 2030: a global simulation including aerosols and tropospheric ozone

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-5043-2007 ◽

2007 ◽

Vol 7 (19) ◽

pp. 5043-5059 ◽

Cited By ~ 181

Author(s):

S. E. Bauer ◽

D. Koch ◽

N. Unger ◽

S. M. Metzger ◽

D. T. Shindell ◽

...

Keyword(s):

Climate Change ◽

Greenhouse Gas ◽

Radiative Forcing ◽

Air Pollutant ◽

Main Role ◽

Aerosol Formation ◽

Near Surface ◽

Sulphate Aerosols ◽

The Future ◽

Nitrate Aerosol

Abstract. Nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario) atmospheric compositions. A set of sensitivity experiments was carried out to quantify the individual impact of emission- and physical climate change on nitrate aerosol formation. We found that future nitrate aerosol loads depend most strongly on changes that may occur in the ammonia sources. Furthermore, microphysical processes that lead to aerosol mixing play a very important role in sulphate and nitrate aerosol formation. The role of nitrate aerosols as climate change driver is analyzed and set in perspective to other aerosol and ozone forcings under pre-industrial, present day and future conditions. In the near future, year 2030, ammonium nitrate radiative forcing is about −0.14 W/m² and contributes roughly 10% of the net aerosol and ozone forcing. The present day nitrate and pre-industrial nitrate forcings are −0.11 and −0.05 W/m², respectively. The steady increase of nitrate aerosols since industrialization increases its role as a non greenhouse gas forcing agent. However, this impact is still small compared to greenhouse gas forcings, therefore the main role nitrate will play in the future atmosphere is as an air pollutant, with annual mean near surface air concentrations, in the fine particle mode, rising above 3 μg/m³ in China and therefore reaching pollution levels, like sulphate aerosols.

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Amplified warming induced by large-scale application of water-saving techniques

Environmental Research Letters ◽

10.1088/1748-9326/ac4b52 ◽

2022 ◽

Author(s):

Jing Fu ◽

Shaozhong Kang ◽

Lu Zhang ◽

Xiaolin Li ◽

Pierre Gentine ◽

...

Keyword(s):

Climate Change ◽

Land Surface ◽

Large Scale ◽

Global Climate ◽

Substantial Reduction ◽

Water Saving ◽

Irrigated Agriculture ◽

Near Surface ◽

Irrigation Water Use ◽

The Impact

Abstract Large-scale agricultural activities can exacerbate global climate change. In the past three decades, over 5 Mha of cultivated land have been equipped with Water-Saving Techniques (WST) in Northwest China to cope with water scarcity. However, the effect of WST on local climate and its mechanisms are not yet understood. Here we quantified the local climatic effect by comparing temperature and humidity at controlled and irrigated sites before and after the large-scale implementation of WST. Results show that the substantial reduction in irrigation water use has led to an average increase of 0.3°C in growing-season temperature and reduced relative humidity by 2%. Near-surface air temperature responds nonlinearly to percentage area of WST and a threshold value of 40% is found before any noticeable warming effect over the study area. Moreover, it is found that regions with relatively humid climates respond more significantly to WST. This study reveals the mechanism of WST on near-surface climate and highlights the importance of incorporating this feedback into sustainable water management and land-surface models for assessing the impact of irrigated agriculture on regional climate change.

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A strategy for climate evaluation of aircraft technology: an efficient climate impact assessment tool – AirClim

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-12185-2007 ◽

2007 ◽

Vol 7 (4) ◽

pp. 12185-12229 ◽

Cited By ~ 4

Author(s):

V. Grewe ◽

A. Stenke

Keyword(s):

Climate Change ◽

Radiative Forcing ◽

Climate Impact ◽

Climate Impacts ◽

Assessment Tools ◽

Nox Emissions ◽

Near Surface ◽

Temperature Changes ◽

Concentration Changes ◽

The Impact

Abstract. Climate change is a challenge to society and to cope with requires assessment tools which are suitable to evaluate new technology options with respect to their impact on climate. Here we present AirClim, a model which comprises a linearisation of the processes occurring from the emission to an estimate in near surface temperature change, which is presumed to be a reasonable indicator for climate change. The model is designed to be applicable to aircraft technology, i.e.~the climate agents CO2, H2O, CH4 and O3 (latter two resulting from NOx-emissions) and contrails are taken into account. It employs a number of precalculated atmospheric data and combines them with aircraft emission data to obtain the temporal evolution of atmospheric concentration changes, radiative forcing and temperature changes. The linearisation is based on precalculated data derived from 25 steady-state simulations of the state-of-the-art climate-chemistry model E39/C, which include sustained normalised emissions at various atmospheric regions. The results show that strongest climate impacts from ozone changes occur for emissions in the tropical upper troposphere (60 mW/m²; 80 mK for 1 TgN emitted), whereas from methane in the middle tropical troposphere (–2.7% change in methane lifetime; –30 mK per TgN). The estimate of the temperature changes caused by the individual climate agents takes into account a perturbation lifetime, related to the region of emission. A comparison of this approach with results from the TRADEOFF and SCENIC projects shows reasonable agreement with respect to concentration changes, radiative forcing, and temperature changes. The total impact of a supersonic fleet on radiative forcing (mainly water vapour) is reproduced within 5%. For subsonic air traffic (sustained emissions after 2050) results show that although ozone-radiative forcing is much less important than that from CO2 for the year 2100. However the impact on temperature is of comparable size even when taking into account temperature decreases from CH4. That implies that all future measures for climate stabilisation should concentrate on both CO2 and NOx emissions. A direct comparison of super- with subsonic aircraft (250 passengers, 5400 nm) reveals a 5 times higher climate impact of supersonics.

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How Has Human-Induced Climate Change Affected California Drought Risk?

Journal of Climate ◽

10.1175/jcli-d-15-0260.1 ◽

2015 ◽

Vol 29 (1) ◽

pp. 111-120 ◽

Cited By ~ 61

Author(s):

Linyin Cheng ◽

Martin Hoerling ◽

Amir AghaKouchak ◽

Ben Livneh ◽

Xiao-Wei Quan ◽

...

Keyword(s):

Climate Change ◽

Soil Moisture ◽

Radiative Forcing ◽

Root Zone ◽

Agricultural Drought ◽

Late Nineteenth Century ◽

Drought Risk ◽

Near Surface ◽

Moisture Availability

Abstract The current California drought has cast a heavy burden on statewide agriculture and water resources, further exacerbated by concurrent extreme high temperatures. Furthermore, industrial-era global radiative forcing brings into question the role of long-term climate change with regard to California drought. How has human-induced climate change affected California drought risk? Here, observations and model experimentation are applied to characterize this drought employing metrics that synthesize drought duration, cumulative precipitation deficit, and soil moisture depletion. The model simulations show that increases in radiative forcing since the late nineteenth century induce both increased annual precipitation and increased surface temperature over California, consistent with prior model studies and with observed long-term change. As a result, there is no material difference in the frequency of droughts defined using bivariate indicators of precipitation and near-surface (10 cm) soil moisture, because shallow soil moisture responds most sensitively to increased evaporation driven by warming, which compensates the increase in the precipitation. However, when using soil moisture within a deep root zone layer (1 m) as covariate, droughts become less frequent because deep soil moisture responds most sensitively to increased precipitation. The results illustrate the different land surface responses to anthropogenic forcing that are relevant for near-surface moisture exchange and for root zone moisture availability. The latter is especially relevant for agricultural impacts as the deep layer dictates moisture availability for plants, trees, and many crops. The results thus indicate that the net effect of climate change has made agricultural drought less likely and that the current severe impacts of drought on California’s agriculture have not been substantially caused by long-term climate changes.

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Mechanisms of Climate Change in the Semiarid African Sahel: The Local View

Journal of Climate ◽

10.1175/2009jcli3123.1 ◽

2010 ◽

Vol 23 (3) ◽

pp. 743-756 ◽

Cited By ~ 64

Author(s):

Alessandra Giannini

Keyword(s):

Climate Change ◽

Land Surface ◽

Southern Oscillation ◽

Net Energy ◽

Moist Static Energy ◽

Near Surface ◽

Vertical Stability ◽

First Case ◽

Static Energy ◽

The Impact

Abstract Application of the moist static energy framework to analyses of vertical stability and net energy in the Sahel sheds light on the divergence of projections of climate change. Two distinct mechanisms are sketched. In one, anthropogenic warming changes continental climate indirectly: warming of the oceans increases moist static energy at upper levels, affecting vertical stability globally, from the top down, and driving drying over the Sahel, in a way analogous to the impact of El Niño–Southern Oscillation on the global tropical atmosphere. In the other, the increase in anthropogenic greenhouse gases drives a direct continental change: the increase in net terrestrial radiation at the surface increases evaporation, favoring vertical instability and near-surface convergence from the bottom up. In both cases the surface warms, but in the first precipitation and evaporation decrease, while in the second they increase. In the first case, land surface warming is brought about by the remotely forced decrease in precipitation and consequent decrease in evaporation and increase in net solar radiation at the surface. In the second, it is brought about by the increase in net terrestrial radiation at the surface, amplified by the water vapor feedback associated with an increase in near-surface humidity.

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Impact of climate change on renewable energy over the Mediterranean and Canary Islands: SOCLIMPACT H2020 project.

10.5194/egusphere-egu21-4218 ◽

2021 ◽

Author(s):

Claudia Gutiérrez ◽

Alba de la Vara ◽

Juan Jesús González-Alemán ◽

Miguel Ángel Gaertner

Keyword(s):

Climate Change ◽

Renewable Energy ◽

Canary Islands ◽

Land Surface ◽

Mitigation Strategies ◽

Offshore Wind ◽

Impact Of Climate Change ◽

The Future ◽

The Mediterranean ◽

The Impact

The enhanced vulnerability of insular regions to climate change highlights the importance of undertaking adaptation and mitigation strategies according to the specific singularities of the islands. Islands are highly dependent on energy imports and the transition to a system with higher shares of renewable energies, in order to reduce greenhouse gas emissions in these regions, can also reduce the external energy dependence. In this context, the assessment of the impact of climate change on renewable energy resources during the 21st century is crucial for policymakers and stakeholders, due to the increasing vulnerability of the system to climate variability. The aim of this work is to provide an overview of wind and photovoltaic (PV) resources, their variability and complementarity between them, as well as their future changes, in the Euro-Mediterranean and Canary islands. Due to the limitations in land surface availability in the islands for the installation of renewable energy capacity, the analysis is extended to offshore wind and photovoltaic energy, which may have an important role in the future increases of renewable energy share. Variability is assessed through the analysis of energy droughts (low-productivity periods). In addition, a case study for optimization of wind and solar combination over the Canary islands is performed. In that sense, a sensitivity test is developed to find the optimal combination of PV and wind that reduce energy droughts and the persistence of that conditions at a local scale. To that end, we use climate variables from a series of regional climate simulations derived from Euro-CORDEX and MENA-CORDEX for the RCP2.6 and RCP8.5 emission scenarios and for the periods 2046-2065 and 2081-2100. The obtained results are very dependent on the region analyzed. Whereas an overall decrease is projected in wind resource over the Mediterranean islands for the future, an increase is projected for the Canarian archipelago. Changes in PV productivity are small in any case, as well as variability changes. These results, which are part of the SOCLIMPACT H2020 project, highlight the importance of targeting climate information and give condensed and valuable data to facilitate climate-related policy decision making for decarbonization and Blue Growth in the islands.

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Assimilation of ASCAT near-surface soil moisture into the French SIM hydrological model

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-8-5427-2011 ◽

2011 ◽

Vol 8 (3) ◽

pp. 5427-5464 ◽

Cited By ~ 4

Author(s):

C. Draper ◽

J.-F. Mahfouf ◽

J.-C. Calvet ◽

E. Martin ◽

W. Wagner

Keyword(s):

Soil Moisture ◽

Real Time ◽

Land Surface ◽

Hydrological Model ◽

Surface Soil ◽

Root Zone ◽

Degree Of Saturation ◽

Surface Soil Moisture ◽

Near Surface ◽

The Mean

Abstract. The impact of assimilating near-surface soil moisture into the SAFRAN-ISBA-MODCOU (SIM) hydrological model over France is examined. Specifically, the root-zone soil moisture in the ISBA land surface model is constrained over three and a half years, by assimilating the ASCAT-derived surface degree of saturation product, using a Simplified Extended Kalman Filter. In this experiment ISBA is forced with the near-real time SAFRAN analysis, which analyses the variables required to force ISBA from relevant observations available before the real time data cut-off. The assimilation results are tested against ISBA forecasts generated with a higher quality delayed cut-off SAFRAN analysis. Ideally, assimilating the ASCAT data will constrain the ISBA surface state to correct for errors in the near-real time SAFRAN forcing, the most significant of which was a substantial dry bias caused by a dry precipitation bias. The assimilation successfully reduced the mean root-zone soil moisture bias, relative to the delayed cut-off forecasts, by close to 50 % of the open-loop value. The improved soil moisture in the model then led to significant improvements in the forecast hydrological cycle, reducing the drainage, runoff, and evapotranspiration biases (by 17 %, 11 %, and 70 %, respectively). When coupled to the MODCOU hydrogeological model, the ASCAT assimilation also led to improved streamflow forecasts, increasing the mean discharge ratio, relative to the delayed cut off forecasts, from 0.68 to 0.76. These results demonstrate that assimilating near-surface soil moisture observations can effectively constrain the SIM model hydrology, while also confirming the accuracy of the ASCAT surface degree of saturation product. This latter point highlights how assimilation experiments can contribute towards the difficult issue of validating remotely sensed land surface observations over large spatial scales.

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Climate change impacts model parameter sensitivity – implications for calibration strategy and model diagnostic evaluation

Hydrology and Earth System Sciences ◽

10.5194/hess-25-1307-2021 ◽

2021 ◽

Vol 25 (3) ◽

pp. 1307-1332

Author(s):

Lieke Anna Melsen ◽

Björn Guse

Keyword(s):

Climate Change ◽

Hydrological Model ◽

Climate Change Impacts ◽

The United States ◽

Parameter Sensitivity ◽

Hydrological Models ◽

The Future ◽

The Mean ◽

The Impact

Abstract. Hydrological models are useful tools for exploring the impact of climate change. To prioritize parameters for calibration and to evaluate hydrological model functioning, sensitivity analysis can be conducted. Parameter sensitivity, however, varies over climate, and therefore climate change could influence parameter sensitivity. In this study we explore the change in parameter sensitivity for the mean discharge and the timing of the discharge, within a plausible climate change rate. We investigate whether changes in sensitivity propagate into the calibration strategy and diagnostically compare three hydrological models based on the sensitivity results. We employed three frequently used hydrological models (SAC, VIC, and HBV) and explored parameter sensitivity changes across 605 catchments in the United States by comparing GCM(RCP8.5)-forced historical and future periods. Consistent among all hydrological models and both for the mean discharge and the timing of the discharge is that the sensitivity of snow parameters decreases in the future. Which other parameters increase in sensitivity is less consistent among the hydrological models. In 45 % to 55 % of the catchments, dependent on the hydrological model, at least one parameter changes in the future in the top-5 most sensitive parameters for mean discharge. For the timing, this varies between 40 % and 88 %. This requires an adapted calibration strategy for long-term projections, for which we provide several suggestions. The disagreement among the models on the processes that become more relevant in future projections also calls for a strict evaluation of the adequacy of the model structure for long-term simulations.

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The GLACE-Hydrology Experiment: Effects of Land–Atmosphere Coupling on Soil Moisture Variability and Predictability

Journal of Climate ◽

10.1175/jcli-d-19-0598.1 ◽

2020 ◽

Vol 33 (15) ◽

pp. 6511-6529

Author(s):

Sanjiv Kumar ◽

Matthew Newman ◽

David M. Lawrence ◽

Min-Hui Lo ◽

Sathish Akula ◽

...

Keyword(s):

Soil Moisture ◽

Land Surface ◽

Radiative Forcing ◽

Climate Model ◽

Signal To Noise Ratio ◽

Boreal Summer ◽

Runoff Variability ◽

The Impact ◽

Soil Moisture Variability ◽

Moisture Variability

AbstractThe impact of land–atmosphere anomaly coupling on land variability is investigated using a new two-stage climate model experimental design called the “GLACE-Hydrology” experiment. First, as in the GLACE-CMIP5 experiment, twin sets of coupled land–atmosphere climate model (CAM5-CLM4.5) ensembles are performed, with each simulation using the same prescribed observed sea surface temperatures and radiative forcing for the years 1971–2014. In one set, land–atmosphere anomaly coupling is removed by prescribing soil moisture to follow the control model’s seasonally evolving soil moisture climatology (“land–atmosphere uncoupled”), enabling a contrast with the original control set (“land–atmosphere coupled”). Then, the atmospheric outputs from both sets of simulations are used to force land-only ensemble simulations, allowing investigation of the resulting soil moisture variability and memory under both the coupled and uncoupled scenarios. This study finds that in midlatitudes during boreal summer, land–atmosphere anomaly coupling significantly strengthens the relationship between soil moisture and evapotranspiration anomalies, both in amplitude and phase. This allows for decreased moisture exchange between the land surface and atmosphere, increasing soil moisture memory and often its variability as well. Additionally, land–atmosphere anomaly coupling impacts runoff variability, especially in wet and transition regions, and precipitation variability, although the latter has surprisingly localized impacts on soil moisture variability. As a result of these changes, there is an increase in the signal-to-noise ratio, and thereby the potential seasonal predictability, of SST-forced hydroclimate anomalies in many areas of the globe, especially in the midlatitudes. This predictability increase is greater for soil moisture than precipitation and has important implications for the prediction of drought.

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