Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics (ROCKE-3D) is a three-dimensional General Circulation Model (GCM) developed at the NASA Goddard Institute ...for Space Studies for the modeling of atmospheres of solar system and exoplanetary terrestrial planets. Its parent model, known as ModelE2, is used to simulate modern Earth and near-term paleo-Earth climates. ROCKE-3D is an ongoing effort to expand the capabilities of ModelE2 to handle a broader range of atmospheric conditions, including higher and lower atmospheric pressures, more diverse chemistries and compositions, larger and smaller planet radii and gravity, different rotation rates (from slower to more rapid than modern Earth's, including synchronous rotation), diverse ocean and land distributions and topographies, and potential basic biosphere functions. The first aim of ROCKE-3D is to model planetary atmospheres on terrestrial worlds within the solar system such as paleo-Earth, modern and paleo-Mars, paleo-Venus, and Saturn's moon Titan. By validating the model for a broad range of temperatures, pressures, and atmospheric constituents, we can then further expand its capabilities to those exoplanetary rocky worlds that have been discovered in the past, as well as those to be discovered in the future. We also discuss the current and near-future capabilities of ROCKE-3D as a community model for studying planetary and exoplanetary atmospheres.
Modeling atmospheric chemistry at fine resolution globally is computationally expensive; the capability to focus on specific geographic regions using a multi scale grid is desirable. Here, we ...develop, validate, and demonstrate stretched grids in the GEOS-Chem atmospheric chemistry model in its high-performance implementation (GCHP). These multiscale grids are specified at runtime by four parameters that offer users nimble control of the region that is refined and the resolution of the refinement. We validate the stretched-grid simulation versus global cubed-sphere simulations. We demonstrate the operation and flexibility of stretched-grid simulations with two case studies that compare simulated tropospheric NO2column densities from stretched-grid and cubed-sphere simulations to retrieved column densities from the TROPOspheric Monitoring Instrument (TROPOMI). The first case study uses a stretched grid with a broad refinement covering the contiguous US to produces imulated columns that perform similarly to a C180 (∼50 km) cubed-sphere simulation at less than one-ninth the computational expense. The second case study experiments with a large stretch-factor for a global stretched-grid simulation with a highly localized refinement with∼10 km resolution for California. We find that the refinement improves spatial agreement with TROPOMI columns compared to a C90 cubed-sphere simulation of comparable computational demands. Overall we find that stretched grids in GEOS-Chem are a practical tool for fine resolution regional- or continental-scale simulations of atmospheric chemistry. Stretched grids are available in GEOS-Chem version 13.0.0
We examine the anthropogenically forced climate response for the 21st century representative concentration pathway (RCP) emission scenarios and their extensions for the period 2101–2500. The ...experiments were performed with ModelE2, a new version of the NASA Goddard Institute for Space Sciences (GISS) coupled general circulation model that includes three different versions for the atmospheric composition components: a noninteractive version (NINT) with prescribed composition and a tuned aerosol indirect effect (AIE), the TCAD version with fully interactive aerosols, whole‐atmosphere chemistry, and the tuned AIE, and the TCADI version which further includes a parameterized first indirect aerosol effect on clouds. Each atmospheric version is coupled to two different ocean general circulation models: the Russell ocean model (GISS‐E2‐R) and HYCOM (GISS‐E2‐H). By 2100, global mean warming in the RCP scenarios ranges from 1.0 to 4.5°C relative to 1850–1860 mean temperature in the historical simulations. In the RCP2.6 scenario, the surface warming in all simulations stays below a 2°C threshold at the end of the 21st century. For RCP8.5, the range is 3.5–4.5°C at 2100. Decadally averaged sea ice area changes are highly correlated to global mean surface air temperature anomalies and show steep declines in both hemispheres, with a larger sensitivity during winter months. By the year 2500, there are complete recoveries of the globally averaged surface air temperature for all versions of the GISS climate model in the low‐forcing scenario RCP2.6. TCADI simulations show enhanced warming due to greater sensitivity to CO2, aerosol effects, and greater methane feedbacks, and recovery is much slower in RCP2.6 than with the NINT and TCAD versions. All coupled models have decreases in the Atlantic overturning stream function by 2100. In RCP2.6, there is a complete recovery of the Atlantic overturning stream function by the year 2500 while with scenario RCP8.5, the E2‐R climate model produces a complete shutdown of deep water formation in the North Atlantic.
Key Points:
Global warming ranges from 1 to 4.5°C by 2100
Atlantic overturning circulation decreases by 2100
There is a collapse of the overturning in RCP8.5 in E2‐R models
Over the past 30 years, most climate models have grown from relatively simple representations of a few atmospheric processes to complex multidisciplinary systems. Computer infrastructure over that ...period has gone from punchcard mainframes to modern parallel clusters. Model implementations have become complex, brittle, and increasingly difficult to extend and maintain. Verification processes for model implementations rely almost exclusively on some combination of detailed analyses of output from full climate simulations and system-level regression tests. Besides being costly in terms of developer time and computing resources, these testing methodologies are limited in the types of defects they can detect, isolate, and diagnose. Mitigating these weaknesses of coarse-grained testing with finer-grained unit tests has been perceived as cumbersome and counterproductive. Recent advances in commercial software tools and methodologies have led to a renaissance of systematic fine-grained testing. This opens new possibilities for testing climate-modeling-software methodologies.
We describe a new generation of the high-performance
GEOS-Chem (GCHP) global model of atmospheric composition developed as part
of the GEOS-Chem version 13 series. GEOS-Chem is an open-source
...grid-independent model that can be used online within a meteorological
simulation or offline using archived meteorological data. GCHP is an
offline implementation of GEOS-Chem driven by NASA Goddard Earth Observing
System (GEOS) meteorological data for massively parallel simulations.
Version 13 offers major advances in GCHP for ease of use, computational
performance, versatility, resolution, and accuracy. Specific improvements
include (i) stretched-grid capability for higher resolution in user-selected
regions, (ii) more accurate transport with new native cubed-sphere GEOS
meteorological archives including air mass fluxes at hourly temporal
resolution with spatial resolution up to C720 (∼ 12 km), (iii)
easier build with a build system generator (CMake) and a package manager
(Spack), (iv) software containers to enable immediate model download and
configuration on local computing clusters, (v) better parallelization to
enable simulation on thousands of cores, and (vi) multi-node cloud
capability. The C720 data are now part of the operational GEOS forward processing (GEOS-FP) output stream, and a C180 (∼ 50 km)
consistent archive for 1998–present is now being generated as part of a new
GEOS-IT data stream. Both of these data streams are continuously being
archived by the GEOS-Chem Support Team for access by GCHP users. Directly
using horizontal air mass fluxes rather than inferring from wind data
significantly reduces global mean error in calculated surface pressure and
vertical advection. A technical performance demonstration at C720
illustrates an attribute of high resolution with population-weighted
tropospheric NO2 columns nearly twice those at a common resolution of
2∘ × 2.5∘.
Global modeling of atmospheric chemistry is a grand
computational challenge because of the need to simulate large coupled systems
of ∼100–1000 chemical species interacting with transport on all ...scales.
Offline chemical transport models (CTMs), where the chemical continuity
equations are solved using meteorological data as input, have usability
advantages and are important vehicles for developing atmospheric chemistry
knowledge that can then be transferred to Earth system models. However, they
have generally not been designed to take advantage of massively parallel
computing architectures. Here, we develop such a high-performance capability
for GEOS-Chem (GCHP), a CTM driven by meteorological data from the NASA
Goddard Earth Observation System (GEOS) and used by hundreds of research
groups worldwide. GCHP is a grid-independent implementation of GEOS-Chem
using the Earth System Modeling Framework (ESMF) that permits the same
standard model to operate in a distributed-memory framework for massive
parallelization. GCHP also allows GEOS-Chem to take advantage of the native
GEOS cubed-sphere grid for greater accuracy and computational efficiency in
simulating transport. GCHP enables GEOS-Chem simulations to be conducted with
high computational scalability up to at least 500 cores, so that global
simulations of stratosphere–troposphere oxidant–aerosol chemistry at C180
spatial resolution (∼0.5∘×0.625∘) or finer
become routinely feasible.
Approaches to measuring air and water quality are well established, but soil quality assessment protocols to be used in landscape monitoring efforts are largely non-existent. The concept of soil ...quality represents the integration of the physical, biological, and chemical aspects of soils. Limited attention has been given to the holistic assessment of soil quality in landscape and urban planning, as it is typically addressed only through chemical analyses. We describe the process used for the selection of soil quality indicators that are being offered as part of the new Cornell Soil Health Test. Over 1500 samples were collected from agricultural landscapes, including controlled experiments, and analyzed for 39 potential soil quality indicators. Four physical and four biological soil indicators were selected based on sensitivity to management, relevance to functional soil processes, ease and cost of sampling, and cost of analysis. Seven chemical indicators were selected as they constitute the standard soil fertility test. For potentially contaminated sites, additional chemical indicators were considered through a total elemental analysis. Test reports were developed to allow for overall soil quality assessment and the identification of specific soil constraints that may be remedied through management practices. The use of the new soil quality test is exemplified for three landscape scenarios in New York State: a vegetable farm, a town park, and a vacant urban lot. The protocol provides a comprehensive assessment of the soil’s ability to perform critical environmental functions at a relatively modest cost, and it helps target management and remediation approaches.
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