Top 10 journals.ametsoc.org Competitors

acp.copernicus.org

Abstract. Aerosol indirect radiative forcing (IRF), which characterizes how aerosols alter cloud formation and properties, is very sensitive to the preindustrial (PI) aerosol burden. Dimethyl sulfide (DMS), emitted from the ocean, is a dominant natural precursor of non-sea-salt sulfate in the PI and pristine present-day (PD) atmospheres. Here we revisit the atmospheric oxidation chemistry of DMS, particularly under pristine conditions, and its impact on aerosol IRF. Based on previous laboratory studies, we expand the simplified DMS oxidation scheme used in the Community Atmospheric Model version 6 with chemistry (CAM6-chem) to capture the OH-addition pathway and the H-abstraction pathway and the associated isomerization branch. These additional oxidation channels of DMS produce several stable intermediate compounds, e.g., methanesulfonic acid (MSA) and hydroperoxymethyl thioformate (HPMTF), delay the formation of sulfate, and, hence, alter the spatial distribution of sulfate aerosol and radiative impacts. The expanded scheme improves the agreement between modeled and observed concentrations of DMS, MSA, HPMTF, and sulfate over most marine regions, based on the NASA Atmospheric Tomography (ATom), the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA), and the Variability of the American Monsoon Systems (VAMOS) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) measurements. We find that the global HPMTF burden and the burden of sulfate produced from DMS oxidation are relatively insensitive to the assumed isomerization rate, but the burden of HPMTF is very sensitive to a potential additional cloud loss. We find that global sulfate burden under PI and PD emissions increase to 412 Gg S (+29 %) and 582 Gg S (+8.8 %), respectively, compared to the standard simplified DMS oxidation scheme. The resulting annual mean global PD direct radiative effect of DMS-derived sulfate alone is −0.11 W m−2. The enhanced PI sulfate produced via the gas-p

gmd.copernicus.org

Abstract. We have developed an open-source ray-tracing tool for space geodetic techniques. The software uses the geometric optics approximation to calculate the signal travel time delay induced by the atmosphere between two given points. The software called DNS (“Direct Numerical Simulation of signal travel time delay”) is written in Fortran and uses OpenMP to speed up computation. The input to the ray-tracing tool is 3D pressure, temperature and humidity fields. The Earth's magnetic field and electron density field are optional. For the neutral atmosphere (troposphere) the software accepts the NetCDF files from the atmospheric reanalysis ERA5 and the mesoscale model WRF. For the ionosphere the software accepts electron density fields derived from IRI and NeQuick. We review the current status of the software and test its performance. For example, the one-to-one comparison with the open-source software RADIATE shows the high speed and precision of our ray-tracing tool. We also show how our tool can be used to study higher-order ionospheric effects (L-band frequencies). The two outstanding features of the ray-tracing tool compared to previous model developments, i.e. the ability to handle both the troposphere and the ionosphere and do so efficiently, make it perfectly suited for geoscientific applications.

sciencedirect.com

sciencedirect is the world's leading source for scientific, technical, and medical research. explore journals, books and articles.

link.springer.com

providing access to millions of research articles and chapters from science, technology and medicine, and humanities and social sciences

frontiersin.org

Explore open access research in political science, analyzing governance, representation, policy, power dynamics and global politics.

nature.com

Nature is the foremost international weekly scientific journal in the world and is the flagship journal for Nature Portfolio. It publishes the finest ...

pnas.org

proceedings of the national academy of sciences (pnas), a peer reviewed journal of the national academy of sciences (nas) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.