There is large uncertainty in the future regional sea level change under anthropogenic climate change. Our study presents and uses a novel design of ocean general circulation model (OGCM) experiments to investigate the ocean's response to surface buoyancy and momentum flux perturbations without atmosphere‐ocean feedbacks (e.g., without surface restoring or bulk formulae), as part of the Flux‐Anomaly‐Forced

The goal of this study is to understand the mechanisms controlling the isotopic composition of the water vapor near the surface of tropical oceans, at the scale of about a hundred kilometers and a month. In the tropics, it has long been observed that the isotopic compositions of rain and vapor near the surface are more depleted when the precipitation rate is high. This is called the “amount effect

Three new equilibrium mid‐Pliocene (MP) simulations are implemented with the Community Climate System Model version 4 (CCSM4) and Community Earth System Model versions 1.2 (CESM1.2) and 2 (CESM2). All simulations are carried out with the same boundary and forcing conditions following the protocol of Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). These simulations reveal amplified MP climate

This paper describes the GISS‐E2.1 contribution to the Coupled Model Intercomparison Project, Phase 6 (CMIP6). This model version differs from the predecessor model (GISS‐E2) chiefly due to parameterization improvements to the atmospheric and ocean model components, while keeping atmospheric resolution the same. Model skill when compared to modern era climatologies is significantly higher than in previous

This study conducts an analysis of the polar numerical noise in the barotropic shallow‐water version of the Grid‐point Atmospheric Model of IAP LASG (GAMIL‐SW) and provides a good solution to the problem. GAMIL‐SW suffers from numerical noise in the polar region in some ideal test cases, which is likely to be detrimental to the full physical model. The noise is suspected to be related to the nonlinear

Traditional parameterizations of convection are a large source of error in weather and climate prediction models and the assumptions behind them become worse as resolution increases. Multi‐fluid modeling is a promising new method of representing sub‐ and near‐grid‐scale convection allowing for net mass transport by convection and non‐equilibrium dynamics. The air is partitioned into two or more fluids

Tian (2015) found that CMIP3 and CMIP5 climate models with too much precipitation in a region of the Southeast Pacific (due to a double‐ITCZ bias) tend to have lower climate sensitivities, and suggested that this might form the basis of an 'emergent constraint' which could rule out lower values of climate sensitivity. However, no physical mechanism has been proposed to explain this relationship. Here

Most submesoscale motions‐‐fronts, eddies, filaments, even large internal waves‐‐are sufficiently rapidly rotating and stratified as to be strongly influenced by potential vorticity dynamics. Below the Ozmidov scale where turbulence overturns and isotropizes, potential vorticity is not commonly considered. Here, it is shown that in Large Eddy Simulations, the velocity gradients, buoyancy gradients

Earth System models enable a broad range of climate interactions that physical climate models are unable to simulate. However, the extent to which adding Earth System components changes or improves the simulation of the physical climate is not well understood. Here we present a broad multi‐variate evaluation of the North Atlantic climate system in historical simulations of the UK Earth System Model

A multimodel, multiresolution ensemble using Coupled Model Intercomparison Project Phase 6 (CMIP6) High Resolution Model Intercomparison Project (HighResMIP) coupled experiments is used to assess the performance of key aspects of the North Atlantic circulation. The Atlantic Meridional Overturning Circulation (AMOC), and related heat transport, tends to become stronger as ocean model resolution is enhanced

In this study, we analyze the realism with which tropical cyclones (TCs) are simulated in the fully coupled low‐ and high‐resolution Energy Exascale Earth System Model (E3SM) version 1, with a focus on the latter. Compared to the low‐resolution (grid spacing of ∼1°), the representation of TCs improves considerably in the high‐resolution configuration (grid spacing of ∼0.25°). Significant improvements

Convective clustering, the spatial organization of tropical deep convection, can manifest itself in two ways: through a decrease in the total area covered by convection and/or through a decrease in the number of convective areas. Much of our current understanding of convective clustering comes from simulations in idealized radiative convective equilibrium (RCE) configurations. In these simulations

A series of high‐resolution three‐dimensional simulations of the diurnal cycle of deep convection over land are performed using the new Met Office NERC cloud‐resolving model. This study features scattered convection. A memory function is defined to identify the effects of previous convection in modifying current convection. It is based on the probability of finding rain at time t 0 and at an earlier

In climate models, the subgrid‐scale orography (SSO) parameterization imposes a blocked flow drag at low levels that is opposed to the local flow. In IPSL‐CM6A‐LR, an SSO lift force is also applied perpendicular to the local flow to account for the effect of locally blocked air in narrow valleys. Using IPSL‐CM6A‐LR sensitivity experiments, it is found that the tuning of both effects strongly impacts

Current moist physics parameterization schemes in general circulation models (GCMs) are the main source of biases in simulated precipitation and atmospheric circulation. Recent advances in machine learning make it possible to explore data‐driven approaches to developing parameterization for moist physics processes such as convection and clouds. This study aims to develop a new moist physics parameterization

Sea ice formation processes occur on subgrid scales, and the detailed physics describing the processes are therefore not generally represented in climate models. One likely consequence of this is the premature closing of areas of open water in model simulations, which may result in a misrepresentation of heat and gas exchange between the ocean and atmosphere. This work demonstrates the implementation

Global water resource assessment has been conducted primarily for surface water and shallow groundwater (unconfined aquifers). Groundwater is a major water resource worldwide. Nevertheless, future water resource assessment integrating surface water and groundwater has not been carried out at the global scale. Large grid sizes are used in global‐scale models due to computer resource constraints. Underground

Localization is essential to effectively assimilate satellite radiances in ensemble Kalman filters. However, the vertical location and separation from a model grid point variable for a radiance observation are not well defined, which results in complexities when localizing the impact of radiance observations. An adaptive method is proposed to estimate an effective vertical localization independently

A team effort to develop a Community Integrated Earth System Model (CIESM) was initiated in China in 2012. The model was based on NCAR Community Earth System Model (Version 1.2.1) with several novel developments and modifications aimed to overcome some persistent systematic biases, such as the double Intertropical Convergence Zone problem and underestimated marine boundary layer clouds. Aerosols' direct

Rising temperatures and changing dynamics can both moisten the air, making it difficult to disentangle these interrelated drivers of water cycle change. However, work by Camille Risi and colleagues presents a new way to distinguish their effects. Using large‐eddy simulations with water isotopic tracers, they show that while warming the sea surface increases the ratio of isotopically heavy‐to‐light

Many problems in climate science require the identification of signals obscured by both the “noise” of internal climate variability and differences across models. Following previous work, we train an artificial neural network (ANN) to predict the year of a given map of annual‐mean temperature (or precipitation) from forced climate model simulations. This prediction task requires the ANN to learn forced

We demonstrate that an extended eddy‐diffusivity mass‐flux (EDMF) scheme can be used as a unified parameterization of subgrid‐scale turbulence and convection across a range of dynamical regimes, from dry convective boundary layers, through shallow convection, to deep convection. Central to achieving this unified representation of subgrid‐scale motions are entrainment and detrainment closures. We model

We present a new cloud scheme for the ECHAM‐HAM global climate model (GCM) that includes prognostic cloud fraction, and allows for sub‐ and supersaturation with respect to ice separately in the cloud‐free and cloudy air. Stratiform clouds form by convective detrainment, turbulent vertical diffusion, and large‐scale ascent. For each process, the corresponding cloud fraction is calculated and the individual

Continuous Structural Parameterization (CSP) is a proposed method for approximating different numerical model parameterizations of the same process as functions of the same gridscale variables. This allows systematic comparison of parameterizations with each other and observations or resolved simulations of the same process. Using the example of two convection schemes running in the Met Office Unified

The Earth's climate is rapidly changing. Over the past centuries, aerosols, via their ability to absorb or scatter solar radiation and alter clouds, played an important role in counterbalancing some of the greenhouse gas (GHG) caused global warming. The multicentury anthropogenic aerosol cooling effect prevented present‐day climate from reaching even higher surface air temperatures and subsequent more

The impacts of rising carbon dioxide (CO2) concentration and ocean feedbacks on the Madden‐Julian Oscillation (MJO) are investigated with the Community Atmospheric Model Version 5 (CAM5) in an idealized aquaplanet configuration. The climate response associated with quadrupled CO2 concentrations and sea surface temperature (SST) warming are examined in both the uncoupled CAM5 and a version coupled to

This work is motivated by the identification of the land‐atmosphere interactions as one of the key sources of uncertainty in climate change simulations. It documents new developments in related processes, namely boundary layer/convection/clouds parameterizations and land surface parameterization in the Earth System Model of the Institut Pierre Simon Laplace (IPSL). Simulations forced by Sea Surface

Spinning up a highly complex, coupled Earth system model (ESM) is a time consuming and computationally demanding exercise. For models with interactive ice‐sheet components, this becomes a major challenge, as ice sheets are sensitive to bi‐directional feedback processes and equilibrate over glacial timescales of up to many millennia. This work describes and demonstrates a computationally tractable,

Gravity waves (GWs) generated by tropical convection are important for the simulation of large‐scale atmospheric circulations, for example, the quasi‐biennial oscillation (QBO), and small‐scale phenomena like clear‐air turbulence. However, the simulation of these waves still poses a challenge due to the inaccurate representation of convection, and the high computational costs of global, cloud‐resolving

In order to improve the simulation accuracy, it is effective to use a data assimilation technique which is capable of reproducing more realistic simulated states by incorporating observational data into simulation models. One of the simplest ones among data assimilation techniques is a Newtonian relaxation‐type nudging method which has been widely used in mesoscale meteorological models. In this study

We generated a large number 105,000 of aggregates composed of various monomer types and sizes using an aggregation model. Combined with hydrodynamic theory, we derived ice particle properties such as mass, projected area, and terminal velocity as a function of monomer number and size. This particle ensemble allows us to study the relation of particle properties with a high level of detail which is

Stochastic parameterizations are increasingly being used in climate modeling to represent subgrid‐scale processes. While different parameterizations are being developed considering different aspects of the physical phenomena, less attention is given to technical and numerical aspects. In particular, empirical orthogonal functions (EOFs) are employed when a spatial structure is required. Here, we provide

No abstract is available for this article.

Quantifying variability in the ocean carbon sink remains problematic due to sparse observations and spatiotemporal variability in surface ocean pCO2. To address this challenge, we have updated and improved ECCO‐Darwin, a global ocean biogeochemistry model that assimilates both physical and biogeochemical observations. The model consists of an adjoint‐based ocean circulation estimate from the Estimating

The present study describes the atmospheric component of the sixth‐generation climate models of the Centre National de Recherches Météorologiques (CNRM), namely, ARPEGE‐Climat 6.3. It builds up on more than a decade of model development and tuning efforts, which led to major updates of its moist physics. The vertical resolution has also been significantly increased, both in the boundary layer and in

Lakes differ from lands in water availability, heat capacity, albedo, and roughness, which affect local surface‐atmospheric interactions. This study modified a multilevel upper ocean model (UOM) for lake applications and evaluated its performance in Lake Taihu (China) with comprehensive measurements against three popular one‐dimensional (1‐D) lake models. These models were based on different concepts

Computational requirements often impose limitations on the spatial and temporal resolutions of atmospheric CO2 inversions, increasing aggregation and representation errors. This study enables higher spatial and temporal resolution inversions with spatial and temporal error structures similar to those used in other published inversions by representing the prior flux error covariances as a Kronecker

Over the last centuries, human activities have exerted increasing pressures on the environment, leading to drastic alterations in the functioning of freshwater bodies (e.g ., eutrophication). Global biogeochemical models have proven crucial to investigate interactions between humans, hydrology and water quality of surface freshwaters. However, most do not account for high‐resolution spatial and temporal

This study presents the global climate model IPSL‐CM6A‐LR developed at Institut Pierre‐Simon Laplace (IPSL) to study natural climate variability and climate response to natural and anthropogenic forcings as part of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). This article describes the different model components, their coupling, and the simulated climate in comparison to previous

The Radiative‐Convective Equilibrium Model Intercomparison Project (RCEMIP) is an intercomparison of multiple types of numerical models configured in radiative‐convective equilibrium (RCE). RCE is an idealization of the tropical atmosphere that has long been used to study basic questions in climate science. Here, we employ RCE to investigate the role that clouds and convective activity play in determining

Representing climate‐crop interactions is critical to Earth system modeling. Despite recent progress in modeling dynamic crop growth and irrigation in land surface models (LSMs), transitioning these models from field to regional scales is still challenging. This study applies the Noah‐MP LSM with dynamic crop‐growth and irrigation schemes to jointly simulate the crop yield and irrigation amount for

Simultaneous calculation of atmospheric processes is faster than calculating processes one at a time. This type of parallelism is beneficial or perhaps even necessary to provide good performance on modern supercomputers, which achieve faster performance through increased processor count rather than improved clock speed. The scalability of the Energy Exascale Earth System Model (E3SM) Atmosphere Model

One‐dimensional radiative transfer solvers are computationally much more efficient than full three‐dimensional radiative transfer solvers but do not account for the horizontal propagation of radiation and thus produce unrealistic surface irradiance fields in models that resolve clouds. Here, we study the impact of using a 3‐D radiative transfer solver on the direct and diffuse solar irradiance beneath

This paper introduces for the first time the concept of Bayesian model averaging (BMA) with multiple prior structures, for rainfall‐runoff modeling applications. The original BMA model proposed by Raftery et al. (2005, https://doi.org.10.1175/MWR2906.1) assumes that the prior probability density function (pdf) is adequately described by a mixture of Gamma and Gaussian distributions. Here we discuss

Quantifying contributions of errors in model structure and parameters to biases in a land surface model (LSM) is critical for model improvement. This paper investigated the uncertainties in parameterizations and parameters in the Noah with multiparameterization (Noah‐MP) LSM with dynamic vegetation using eddy flux data. First, we conducted full factorial experiments of eight land subprocesses, followed

Riparian environments are highly dynamic ecosystems that support biodiversity and numerous services and that are conditioned by anthropogenic activities and climate change. In this work, we propose an integrated methodology that combines different research approaches ‐‐ field studies, numerical and analytical modeling ‐‐ in order to calibrate an ecohydrological stochastic model for riparian vegetation

Neural networks have become increasingly prevalent within the geosciences, although a common limitation of their usage has been a lack of methods to interpret what the networks learn and how they make decisions. As such, neural networks have often been used within the geosciences to most accurately identify a desired output given a set of inputs, with the interpretation of what the network learns used

The Community Earth System Model version 2.1 (CESM2.1) is used to investigate the evolution of the Greenland ice sheet (GrIS) surface mass balance (SMB) under an idealized CO2 forcing scenario of 1 % increase until stabilization at 4 x pre‐industrial at model year 140. In this simulation, the SMB calculation is coupled with the atmospheric model, using a physically‐based surface energy balance scheme

Stable water isotopes are data‐rich tracers of the hydrological cycle, and, recently, the advent of isotope‐enabled climate models has allowed for investigations into the utility of water isotopes for tracking changes in the large‐scale atmospheric circulation. Amongst the suite of published isotope‐enabled climate models, those with intermediate complexity offer the benefits of efficiency, allowing

Climate simulations for the North Atlantic and Europe for recent and future conditions simulated with the regionally coupled ROM model are analyzed and compared to the results from the MPI‐ESM. The ROM simulations also include a biogeochemistry and ocean tides. For recent climate conditions, ROM generally improves the simulations compared to the driving model MPI‐ESM. Reduced oceanic biases in the

This paper describes the development of New Zealand's Earth System Model (NZESM) and evaluates its performance against its parent model (United Kingdom Earth System Model, UKESM) and observations. The main difference between the two earth system models is an embedded high‐resolution (1/5°) nested region over the oceans around New Zealand in the NZESM. Due to this finer ocean model mesh, currents such

Although fundamental to the planetary radiative balance, aerosol impacts are highly uncertain in climate simulations because of the uneven distribution of aerosol sources and the complex interactions with radiation and clouds that are difficult to represent in climate models. This study proposes that aquaplanet configurations represent an idealized framework to investigate aerosol effects. As a simple

In order to improve the physical consistency between shallow and deep convection, we modify the deep convective closure in the Community Atmosphere Model version 5 (CAM5) coupled with a third‐order turbulence closure parameterization (i.e., Cloud Layers Unified by Binormals [CLUBB]). The revised closure reserves a portion of the total convective available potential energy for shallow convection via

Vegetation leaf phenology, often reflected by the dynamics in leaf area index (LAI), influences a variety of land surface processes. Robust models of vegetation phenology are pivot components in both land surface models and dynamic global vegetation models but remain challenging in terms of the model accuracy. This study develops a semiprognostic phenology model that is suitable for simulating time

Climate models contain atmospheric and oceanic components that are coupled together to simulate the thermodynamic and dynamic processes during air‐sea interactions. Community Earth System Model (CESM, version 1.2.1) is a state‐of‐the‐art coupled model that is widely used and participates in Coupled Model Intercomparison Projects. Community Atmospheric Model (CAM), the atmospheric component of CESM

We introduce a new version of the Earth System Regional Climate RegCM‐ES model and evaluate its performances for the first time over the Mediterranean region. The novel aspect of this coupled system is the possibility to simulate the dynamics of the marine ecosystem through a biogeochemical model, BFM (Biogeochemical Flux Model), coupled on‐line with the ocean circulation model MITgcm (MIT general

Cloud and precipitation systems are simulated with a multi‐scale modeling framework (MMF) and compared over the tropics and subtropics against the Tropical Rainfall Measuring Mission (TRMM) Radar‐defined Precipitation Features (RPFs) product. A methodology, in close analogy to the TRMM RPFs, is developed to produce simulated precipitation features (PFs) from the output of the embedded two‐dimensional

No abstract is available for this article.

Prior research indicates that land‐use and land‐cover change (LULCC) in the Central United States (US) has led to significant changes in surface climate. The spatial resolution of simulations is particularly relevant in this region due to its influence on model skill in capturing mesoscale convection systems (MCSs) and on representing the spatial heterogeneity. Recent advances in Earth System Models

An empirical model calibration approach is presented that aims to approximate missing biosphere processes in a global land surface model without the need for substantial model structural changes. The strategy is implemented here using the NASA Catchment‐CN land surface model and Moderate Resolution Imaging Spectroradiometer (MODIS) observations of the fraction of absorbed photosynthetically active