We evaluate the Community Atmosphere Model Version 5 (CAM5) with a higher-order turbulence closure scheme, named Cloud Layers Unified By Binomials (CLUBB), and a Multiscale Modeling Framework, referred as the “super-parameterization” (SP) with two different microphysics configurations to investigate their influences on rainfall simulations over Southern Amazonia. The two different microphysics configurations in SP are the one-moment cloud microphysics without aerosol treatment (SP1) and two-moment cloud microphysics coupled with aerosol treatment (SP2).

Black carbon (BC) and organic carbon (OC) aerosols are important components of fine particulate matter (PM2.5) in polluted urban environments. Quantifying the contribution of fossil fuel and biomass combustion to BC and OC concentrations is critical for developing and validating effective air quality control measures and climate change mitigation policy. We used radiocarbon (14C) to measure fossil and contemporary biomass contributions to BC and OC at three locations in Salt Lake City, Utah, USA during 2012-2014, including during winter inversion events.

A field observation of dust devils was conducted at Xiaotang over the Taklimakan Desert (TD), China, from 7 to 14 July 2014. The measurements of dust devil opacity with the digital optical method and the observed atmospheric boundary layer conditions were applied to investigate the dust devils’ formation mechanism, vertical structure, and dust emissions.

Recent Mediterranean droughts have highlighted concerns that climate change may be contributing to observed drying trends, but natural climate variability in the region is still poorly understood. We analyze 900 years (1100–2012) of Mediterranean drought variability in the Old World Drought Atlas (OWDA), a spatiotemporal tree ring reconstruction of the June-July-August self-calibrating Palmer Drought Severity Index.

The 2014–2015 Bárðarbunga-Veiðivötn fissure eruption at Holuhraun produced about 1.5 km3 of lava, making it the largest eruption in Iceland in more than 200 years. Over the course of the eruption, daily volcanic sulfur dioxide (SO2) emissions exceeded daily SO2 emissions from all anthropogenic sources in Europe in 2010 by at least a factor of 3. We present surface air quality observations from across Northern Europe together with satellite remote sensing data and model simulations of volcanic SO2 for September 2014.

Aimed at reducing deficiencies in representing the Madden-Julian oscillation (MJO) in general circulation models (GCMs), a global model evaluation project on vertical structure and physical processes of the MJO was coordinated. In this paper, results from the climate simulation component of this project are reported. It is shown that the MJO remains a great challenge in these latest generation GCMs. The systematic eastward propagation of the MJO is only well simulated in about one fourth of the total participating models.

Unprecedented, widespread, and devastating hailstorms occurred during February and March 2014 over north peninsular India (study area). A diagnostic study has been carried out to understand the causes for the same. Over the study area the atmosphere was convectively unstable due to the incursion of warm and moist air from Bay of Bengal and Arabian Sea which was overlaid by cold and dry midlatitude westerlies caused due to the unusual upper oceanic heat content of the Pacific Ocean.

On 8 August 2010 in the northwestern Chinese province of Gansu, a rainstorm-triggered debris flow devastated the small county of Zhouqu. A modeling study, using a new multiple-phase scalable and extensible geofluid model, suggests that the cause is an intersection of several events.

Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption, influence on liquid, mixed-phase, and ice clouds, and deposition on snow and ice.

Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with oneand four-dimensional models to derive the regional
aerosol forcing resulting from the direct, the semidirect and the two indirect effects.