• Issue

    Journal of Geophysical Research: Atmospheres: Volume 123, Issue 23

    13,031-13,621
    16 December 2018

Issue Information

Free Access

Issue Information

  • Pages: 13,031-13,032
  • First Published: 26 December 2018

Research Articles

Climate and Dynamics

Free Access

Signatures of Heavy Precipitation on the Thermodynamics of Clouds Seen From Satellite: Changes Observed in Temperature Lapse Rates and Missed by Weather Analyses

  • Pages: 13,033-13,045
  • First Published: 31 October 2018
Key Points

  • Model-independent analyses of radio occultation, RO, are developed to constrain lapse rates and stability inside clouds
  • RO observes how precipitation changes layerwise the lapse rates that define stability to convection in ways missed by weather analyses
  • Top of boundary layer inversions leading to refractivity gradients is sharper in nonprecipitating than precipitating scenes

Open Access

Parametric Sensitivity and Uncertainty Quantification in the Version 1 of E3SM Atmosphere Model Based on Short Perturbed Parameter Ensemble Simulations

  • Pages: 13,046-13,073
  • First Published: 23 October 2018
Key Points

  • Short PPE simulations provide a comprehensive picture of the behaviors of a new Earth system model associated with uncertain parameters
  • PPE using short simulations has some bearing on understanding parametric sensitivity of longer simulations
  • The difficulty in reducing biases in multiple variables simultaneously highlights the need of characterizing model embedded errors

Free Access

Analysis of Climate Trends and Leading Modes of Climate Variability for MENA Region

  • Pages: 13,074-13,091
  • First Published: 05 November 2018
Key Points

  • MENA region is very sensitive to the changes induced by the internal and external climate forcings
  • This paper focuses on the importance of trend in data and leading climate modes that play significant role in shaping MENA climate
  • Both the model and the observations indicate that positive phase of NAO and ENSO significantly cools central parts of MENA in winter

Free Access

Characteristics of Sundowner Winds Near Santa Barbara, CA, From a Dynamically Downscaled Climatology: Environment and Effects Aloft and Offshore

  • Pages: 13,092-13,110
  • First Published: 16 November 2018
Key Points

  • We use a numerically downscaled climatology to diagnose characteristics of downslope windstorms known as Sundowners that occur along the Central California coast
  • Sundowners are manifested as strong northerly downslope winds along the Santa Ynez Mountains that are part of a lee slope jet forced by internal gravity wave breaking aloft
  • The mountain wave is forced by the synoptically driven strong jet of north-northwesterly winds located just offshore, which propagates into and through the Santa Ynez Valley

Free Access

On the Harvest of Predictability From Land States in a Global Forecast Model

  • Pages: 13,111-13,127
  • First Published: 14 November 2018
Key Points

  • The degree of potential predictability from soil moisture information that is realized as forecast skill has been quantified for CFSv2
  • CFSv2 forecasts of temperature, humidity, surface fluxes, and boundary layer properties benefit from accurate soil moisture initialization
  • CFSv2 forecasts of clouds and precipitation are likely unrealistically insensitive to soil moisture

Open Access

Evaluations and Improvements of GLDAS2.0 and GLDAS2.1 Forcing Data's Applicability for Basin Scale Hydrological Simulations in the Tibetan Plateau

  • Pages: 13,128-13,148
  • First Published: 21 November 2018
Key Points

  • Evaluations and improvements of GLDAS2.0 and GLDAS2.1 forcing data's applicability for basin hydrological simulations in the Tibetan Plateau
  • GLDAS2.0 and GLDAS2.1 shows cooling and warming trends, respectively, and their precipitation have high uncertainty in the Tibetan Plateau
  • CMORPH-BLD offers the best precipitation on average, and combining it with GLDAS2.0 forcing data generates better runoff simulations

Free Access

The Role of Internal Variability in Twenty-First-Century Projections of the Seasonal Cycle of Northern Hemisphere Surface Temperature

  • Pages: 13,149-13,167
  • First Published: 21 November 2018
Key Points

  • Internal variability renders the detection of future changes in the seasonal cycle of surface temperature difficult over many regions
  • Europe, North Africa, and Siberia, however, exhibit remarkably robust and easily detectable changes across climate model ensembles
  • The robust changes over the three regions are primarily driven by changes in surface longwave and turbulent heat fluxes

Free Access

Interannual Variation and Regime Shift of the Evaporative Moisture Sources for Wintertime Precipitation Over Southern China

  • Pages: 13,168-13,185
  • First Published: 23 November 2018
Key Points

  • The moisture contribution from the South China Sea is modulated by the circulation pattern rather than evaporation from ocean surface
  • The two types of El Nino have distinct impacts on the moisture contribution
  • An eastward migration of the moisture source occurred during 1991/1992, owing to the Maritime Continent warming

Free Access

Dynamical Drivers of the Local Wind Regime in a Himalayan Valley

  • Pages: 13,186-13,202
  • First Published: 12 November 2018
Key Points

  • The atmospheric model represents the diurnal cycle of local valley winds well, with strong daytime up-valley winds and weak nighttime winds
  • The dominant physical drivers of the valley circulation come from the pressure gradient, advection, and turbulent vertical mixing
  • There is a consistent diurnal cycle in the drivers of the wind acceleration, but they are spatially variable and also affected by glaciers

Free Access

The Implications for Radiative Cloud Forcing via the Link Between Shallow Convection and Planetary Boundary Layer Mixing

  • Pages: 13,203-13,218
  • First Published: 28 November 2018
Key Points

  • PBL mixing and shallow convection are tightly linked in model
  • Intensity of diffusivity profile in shallow convection scheme can modulate cloud amount and radiation budget
  • NWP performance can conventionally be improved via a modification of shallow convection scheme

Free Access

Uncertainty Analysis of Simulations of the Turn-of-the-Century Drought in the Western United States

  • Pages: 13,219-13,237
  • First Published: 09 November 2018
Key Points

  • Deep convection parameters account for more than half the CAM4 ensemble variance in metrics used to quantify drought
  • We found optimal parameter values that may lead to a better reproduction of drought in CAM4
  • We reduce the uncertainty of the CAM4 simulation of a metric that quantifies the spatial extent of drought by 40%

Free Access

Improved Simulation of Frozen-Thawing Process in Land Surface Model (CLM4.5)

  • Pages: 13,238-13,258
  • First Published: 14 November 2018
Key Points

  • Simulation errors are evident in FT process, and CLM4.5 fails to simulate daily and diurnal variation features of soil moisture
  • Use of virtual temperature and phase change efficiency effectively improves daily and diurnal variations of soil moisture in FT process
  • Consideration of the impact of phase change on soil heat conduction can reduce some soil temperature biases

Open Access

Observations of Reduced Turbulence and Wave Activity in the Arctic Middle Atmosphere Following the January 2015 Sudden Stratospheric Warming

  • Pages: 13,259-13,276
  • First Published: 12 November 2018
Key Points

  • Low levels of turbulence in the upper mesosphere are observed in a disturbed Arctic atmosphere following an SSW
  • Low levels of turbulence coincide with low levels of gravity wave activity
  • Turbulence is found in both the topside and bottomside of MILs

Free Access

On the Need of a Unified Methodology for Processing Schumann Resonance Measurements

  • Pages: 13,277-13,290
  • First Published: 29 November 2018
Key Points

  • We obtain Schumann resonances from ELF station measurements
  • We define the analysis process of raw time domain data and likely influence of possible alternatives in the final Schumann resonance values
  • A format for sharing Schumann resonance-based data is proposed

Open Access

Estimates of Present-Day and Future Climatologies of Freezing Rain in Europe Based on CORDEX Regional Climate Models

  • Pages: 13,291-13,304
  • First Published: 30 November 2018
Key Points

  • Freezing rain increases in northern Europe and decreases in central Europe toward the future
  • Location-dependent climate change signals in seasonality of freezing rain were found
  • Modeled vertical temperature profiles are likely to explain model-based differences in results

Free Access

Inertia-Gravity Waves Revealed in Radiosonde Data at Jang Bogo Station, Antarctica (74°37′S, 164°13′E): 1. Characteristics, Energy, and Momentum Flux

  • Pages: 13,305-13,331
  • First Published: 08 November 2018
Key Points

  • Wind and temperature revealed in the first year-round radiosonde at Jang Bogo Station (a new Antarctic station since 2014) are investigated
  • Characteristics, energy, and momentum flux of inertia-gravity waves revealed in the radiosonde data at Jang Bogo Station are examined

Free Access

The Stratospheric Sudden Warming Event in February 2018 and its Prediction by a Climate System Model

  • Pages: 13,332-13,345
  • First Published: 21 November 2018
Key Points

  • The February 2018 major SSW event appeared after two radical deceleration periods related to enhanced troughs and Alaskan blocking
  • The deterministic limit to predictability of this SSW and the poleward eddy heat flux is 1–2 weeks, related to the well-predicted upward propagation of waves
  • The deterministic limit to predictability of the stratospheric circulation pattern also generalizes to other vortex split SSW events

Open Access

The Improved Freeze–Thaw Process of a Climate-Vegetation Model: Calibration and Validation Tests in the Source Region of the Yellow River

  • Pages: 13,346-13,367
  • First Published: 05 November 2018
Key Points

  • The freeze–thaw process in the vegetation-climate model AVIM was improved to form a new model known as AVIM_FSM
  • The freeze–thaw-related parameters were calibrated with the artificial intelligence particle swarm optimization (PSO) method
  • The AVIM_FSM model was validated and compared with the AVIM simulations using seasonal frozen soil observational data

Free Access

Influence of Central Siberian Snow-Albedo Feedback on the Spring East Asian Dust Cycle and Connection With the Preceding Winter Arctic Oscillation

  • Pages: 13,368-13,385
  • First Published: 29 November 2018
Key Points

  • The enhanced East Asian dust emission is associated with a cyclonic wind anomaly induced by Central Siberian mid-lower troposphere cooling
  • The Central Siberian cooling is attributed to local snow-albedo and cloud-albedo feedbacks
  • Winter Arctic Oscillation leads to changes in surface temperature in Siberia and induces positive snow-albedo and cloud feedbacks in spring

Aerosol and Clouds

Free Access

Strong Contrast in Remote Black Carbon Aerosol Loadings Between the Atlantic and Pacific Basins

  • Pages: 13,386-13,395
  • First Published: 05 November 2018
Key Points

  • Black carbon loadings over the remote Atlantic are generally comparable to those over the Pacific, except at low-altitude near the equator
  • AeroCom's model-ensemble average overestimates loadings, except in the lower troposphere of the equatorial Atlantic region
  • The direct radiative effect of BC over the remote Pacific and Atlantic in August is likely dominated by African biomass burning outflow

Free Access

A Study of Enhanced Heterogeneous Ice Nucleation in Simulated Deep Convective Clouds Observed During DC3

  • Pages: 13,396-13,420
  • First Published: 01 November 2018
Key Points

  • Enhanced heterogeneous ice nucleation in deep convective clouds with a cold cloud-base temperature may lead to optically thinner anvils
  • The impacts of enhanced heterogeneous ice nucleation are especially pronounced when the enhancement occurs at warmer temperatures
  • Our findings are likely most applicable to clouds in which warm-rain processes do not contribute much to the total precipitation

Free Access

Driving Factors of Aerosol Properties Over the Foothills of Central Himalayas Based on 8.5 Years Continuous Measurements

  • Pages: 13,421-13,442
  • First Published: 14 November 2018
Key Points

  • Long-term aerosol observations were conducted in the central Himalaya, and turbulence and water vapor were used to describe mixing layer diurnal cycle
  • Aerosol variables clearly present clusters of highest concentration during the afternoon hours in the premonsoon and postmonsoon season
  • Transport and valley wind influence to the atmospheric boundary layer are the predominant reasons for the poor performance of climate models

Free Access

Cloudiness and Solar Radiation During the Longest Total Solar Eclipse of the 21st Century at Tianhuangping (Zhejiang), China

  • Pages: 13,443-13,461
  • First Published: 15 November 2018
Key Points

  • With no solar radiation measurements and cloud direct visual observations an empirical model for global solar radiation has been derived
  • This model has been obtained under cloudy skies during the longest total solar eclipse of the 21st century at Tianhuangping (Zhejiang), China
  • The results indicate that the solar radiation model is quite acceptable and representative of that which could be have happened at that time

Free Access

Effects of Shape and Rotation of Sand Particles in Saltation

  • Pages: 13,462-13,471
  • First Published: 21 November 2018
Key Points

  • The trajectory of rotating elliptical sand is higher and longer than that of spherical sand
  • The drag force acted on rotating elliptical sand fluctuates periodically over time
  • Rotating elliptical sand has fewer midair colliding behaviors than spherical sand due to sand-air interaction

Free Access

A Versatile Method for Ice Particle Habit Classification Using Airborne Imaging Probe Data

  • Pages: 13,472-13,495
  • First Published: 08 November 2018
Key Points

  • A general and versatile method to automatically identify ice particle habit from airborne probe images is proposed
  • The method is successfully tested on three different airborne imaging probes
  • Good performance with classification accuracies >90% for each probe

Free Access

Validation of SOAR VIIRS Over-Water Aerosol Retrievals and Context Within the Global Satellite Aerosol Data Record

  • Pages: 13,496-13,526
  • First Published: 20 November 2018
Key Points

  • Based on comparisons to AERONET, the AOD uncertainty is consistent with expectations
  • Retrieved parameters related to aerosol particle size and type are also demonstrated to have skill
  • SOAR shows similar regional and temporal patterns to other satellite data sets

Composition and Chemistry

Free Access

Estimating Source Region Influences on Black Carbon Abundance, Microphysics, and Radiative Effect Observed Over South Korea

  • Pages: 13,527-13,548
  • First Published: 12 November 2018
Key Points

  • Black carbon vertical profiles observed in late spring 2016 in South Korea were consistent with strong regional sources
  • The profiles systematically measured over a single site varied due to meteorologically driven changes in transport
  • South Korea, China, and Russia were the major source region contributors to black carbon column direct radiative effect

Free Access

SO2 Observations and Sources in the Western Pacific Tropical Tropopause Region

  • Pages: 13,549-13,559
  • First Published: 14 November 2018
Key Points

  • We report new in situ observations of UT/LS SO2 above the western Pacific
  • Volcanic and anthropogenic SO2 in the UT/LS are identified
  • Low ozone above the western Pacific does not appear to be an important factor allowing SO2 transport into the UT/LS

Free Access

Biomass Burning Plumes in the Vicinity of the California Coast: Airborne Characterization of Physicochemical Properties, Heating Rates, and Spatiotemporal Features

  • Pages: 13,560-13,582
  • First Published: 31 October 2018
Key Points

  • Significant biomass burning (BB) layer stratification with majority of layers in the free troposphere within 100 m of the boundary layer top
  • A new smoke injection height method improved agreement for the vertical distribution of BB aerosol in the NAAPS model versus in situ data
  • Shortwave heating rate profiles demonstrate the combined effect of stratocumulus cloud and BB layers and their mutual interactions

Free Access

Space-Based Constraints on Terrestrial Glyoxal Production

  • Pages: 13,583-13,594
  • First Published: 10 November 2018
Key Points

  • We assess simulated global glyoxal production from six major sources
  • The GEOS-Chem model captures the global spatial variability in satellite retrievals of glyoxal and formaldehyde
  • Ratio of glyoxal to formaldehyde indicates that model glyoxal formation over high monoterpene-emitting regions is a factor of 3 too low

Free Access

Impact of Convective Activity on Precipitation δ18O in Isotope-Enabled General Circulation Models

  • Pages: 13,595-13,610
  • First Published: 20 November 2018
Key Points

  • iCAM5 can simulate the observed anticorrelation between stratiform rainfall fraction and precipitation oxygen isotope ratios
  • All models can simulate the observed relationship between outgoing longwave radiation and precipitation oxygen isotope ratios
  • The contribution of convective processes to precipitation oxygen isotope ratios is very site dependent

Free Access

Source Sector Attribution of CO2 Emissions Using an Urban CO/CO2 Bayesian Inversion System

  • Pages: 13,611-13,621
  • First Published: 20 November 2018
Key Points

  • Sector-based inversion of emissions was demonstrated by jointly assimilating CO and CO2 mole fractions over Indianapolis
  • Top-down multispecies measurements and high-resolution bottom-up sectoral emissions are in relative agreement over Indianapolis
  • Current uncertainties in sectoral emissions of non-CO2 trace gases limit our ability to quantify sectoral CO2 emissions