• Issue

    Journal of Geophysical Research: Atmospheres: Volume 123, Issue 17

    8897-9975
    16 September 2018

Issue Information

Free Access

Issue Information

  • Pages: 8897-8900
  • First Published: 26 September 2018

Research Articles

Climate and Dynamics

Free Access

Earthquake Lights: Mechanism of Electrical Coupling of Earth's Crust to the Lower Atmosphere

  • Pages: 8901-8914
  • First Published: 28 June 2018
Key Points

  • Earthquake lights are studied based on enhancement of electric field near Earth's surface leading to conventional lightning-like gas discharges
  • The most likely setup is found to be when the upper pole of the source current dipole is located close to the Earth's surface
  • Large-scale dipole located 5 and 15 km beneath Earth's surface requires energy significantly exceeding that available in major earthquakes

Free Access

Localization Effects on the Dissipation of Gravity Wave Packets in the Upper Mesosphere and Lower Thermosphere

  • Pages: 8915-8935
  • First Published: 03 August 2018
Key Points

  • Gravity wave packets are strongly attenuated by dispersion before they reach the dissipative thermosphere
  • The central λz of a packet with broad spectra tends to evolve toward smaller values in time
  • Wave packets generated in dissipative regions, with wavelengths smaller than the scale height, can evolve to longer vertical wavelengths

Free Access

Persistence and Corresponding Time Scales of Soil Moisture Dynamics During Summer in the Babao River Basin, Northwest China

  • Pages: 8936-8948
  • First Published: 28 July 2018
Key Points

  • The AFA method is used to analyze soil moisture persistence
  • The persistence and corresponding time scales of soil moisture can be described using a three-phase concept diagram
  • Soil moisture persistence is influenced by net radiation and precipitation differently over these three phases

Free Access

Ranking CMIP5 GCMs for Model Ensemble Selection on Regional Scale: Case Study of the Indochina Region

  • Pages: 8949-8974
  • First Published: 28 July 2018
Key Points

  • Proposed framework is used to evaluate general circulation models and multimodel ensemble selection for impact assessment studies
  • The optimal ensemble subsets of this framework improve the precipitation data distribution compared to the full model ensemble for both in and out of sample
  • A simple and user-friendly decision graph of this framework for evaluating single model and model ensemble subsets is developed

Free Access

Impact of Convective Gravity Waves on the Tropical Middle Atmosphere During the Madden-Julian Oscillation

  • Pages: 8975-8992
  • First Published: 01 August 2018
Key Points

  • MJO affects forcing of convective gravity waves in the tropics
  • Source of convective gravity waves propagates eastward in the Indian Ocean and western Pacific region
  • Convective gravity wave forcing was found to be stronger during easterly QBO phase

Open Access

Statistical Characteristics of Gravity Waves With Near-Inertial Frequencies in the Antarctic Troposphere and Lower Stratosphere Observed by the PANSY Radar

  • Pages: 8993-9010
  • First Published: 13 July 2018
Key Points

  • A considerable proportion of gravity waves propagating energy downward are seen in the stratosphere above 15 km in winter
  • The distribution of horizontal phase velocity indicates that the source of gravity waves in the lower stratosphere is the polar night jet
  • Parameters of gravity waves have vertical dependencies and do not largely depend on season or their vertical group velocity direction

Free Access

Rossby Wave Breaking and Isentropic Stratosphere-Troposphere Exchange During 1981–2015 in the Northern Hemisphere

  • Pages: 9011-9025
  • First Published: 05 August 2018
Key Points

  • Both anticyclonic and cyclonic wave breaking events have become more frequent since 1981 at isentropic surfaces above 320 K
  • The summertime anticyclonic wave breaking events have shown a significant poleward shift since 1981 for most isentropic surfaces
  • The isentropic stratosphere-troposphere exchange and Rossby wave breaking have the same seasonality and occur in similar locations

Free Access

Forest Disturbance Feedbacks From Bedrock to Atmosphere Using Coupled Hydrometeorological Simulations Over the Rocky Mountain Headwaters

  • Pages: 9026-9046
  • First Published: 15 August 2018
Key Points

  • Widespread forest mortality impacts the development of moisture and energy throughout the convective boundary layer
  • Ensemble methods are necessary to appropriately quantify the likelihood of atmospheric response to land disturbance
  • Depth to water table controls the magnitude of disturbance-induced response in surface energy and lower atmosphere

Free Access

Improving Short-Term Rainfall Forecasts by Assimilating Weather Radar Reflectivity Using Additive Ensemble Perturbations

  • Pages: 9047-9062
  • First Published: 18 August 2018
Key Points

  • Direct assimilation of radar reflectivity with an ensemble Kalman filter is generally ineffective unless rainfall is forecast
  • We suggest adding ensemble perturbations correlated with wind, temperature, and water vapor for effective reflectivity assimilation
  • Adding ensemble perturbations at points where no rainfall was forecast improved short-term rainfall forecasts for tornadic supercells

Free Access

Arctic Sea Ice Melt Onset Timing From Passive Microwave-Based and Surface Air Temperature-Based Methods

  • Pages: 9063-9080
  • First Published: 25 August 2018
Key Points

  • Arctic sea ice melt onset dates are estimated from ground-based and satellite-based surface air temperature observations
  • A record of passive microwave-based melt onset dates is updated through the 2017 melt season
  • Temperature-based melt onset estimates are ~11 days later than the passive microwave-based melt onset date

Free Access

Role of SST Patterns on Surface Wind Modulation of a Heavy Midlatitude Precipitation Event

  • Pages: 9081-9096
  • First Published: 07 August 2018
Key Points

  • SST structures of the order O(km) significantly affect the surface wind field
  • The wind is accelerated (decelerated) over warmer (colder) sea areas in O(hr) time scales
  • Surface wind convergence can be locked to SST fronts

Free Access

The Radiative Feedback During the ENSO Cycle: Observations Versus Models

  • Pages: 9097-9108
  • First Published: 08 August 2018
Key Points

  • We conduct a comprehensive radiative feedback analysis for not only TOA but also surface and atmospheric budgets.
  • The analysis discloses positive atmospheric feedback strengthens ENSO through heating the atmosphere differentially.
  • A prominent and persistent GCM cloud feedback bias results from improper radiative sensitivity of clouds.

Free Access

Why Do Large-Scale Land Surface Models Produce a Low Ratio of Transpiration to Evapotranspiration?

  • Pages: 9109-9130
  • First Published: 17 August 2018
Key Points

  • We conducted virtual model experiments to explore what ecohydrological processes are critical to the resiliency of water availability for plant growth
  • Terrain-driven lateral water flow suppressed E more than T due to root uptake of deep water on mid-to-upper slopes, thus enhancing T/ET
  • LSMs need a more elaborate scheme of the water vapor diffusion from the rising/falling evaporating surface in the soil

Open Access

Quantifying the Impact of Subsurface-Land Surface Physical Processes on the Predictive Skill of Subseasonal Mesoscale Atmospheric Simulations

  • Pages: 9131-9151
  • First Published: 11 July 2018
Key Points

  • This study assesses the impact of lower boundary conditions with increasing complexity on the predictive skill of a weather forecast model
  • More detailed surface and subsurface processes improve soil moisture dynamics and energy partitioning but not necessarily ABL states
  • Synoptic conditions control precipitable water and precipitation in small model domains under weakly coupled land-atmosphere conditions

Free Access

Sources, Sinks, and Propagation Characteristics of the Quasi 6-Day Wave and Its Impact on the Residual Mean Circulation

  • Pages: 9152-9170
  • First Published: 27 August 2018
Key Points

  • WACCM + DART reproduces the Q6DW as observed by SABER and TIDI on TIMED satellite
  • Wind instabilities and intersecting critical layers in the high-latitude lower mesosphere favor a large Q6DW during equinoxes
  • The dissipative/breaking Q6DW weakens the residual mean circulation in the summer hemisphere but strengthens it in the winter hemisphere

Free Access

On the Upward Extension of the Polar Vortices Into the Mesosphere

  • Pages: 9171-9191
  • First Published: 18 August 2018
Key Points

  • Previous polar vortex climatologies extended to ~80 km providing an observational benchmark to evaluate the mesospheric vortex in GCMs
  • Polar winter descent rates are anticorrelated with vortex area at mesospheric altitudes
  • The mesospheric vortex contracts after extreme SSWs and shows unexpected late season broadening in years without SSWs

Free Access

The Coupled Dynamic and Thermodynamic Processes for Secondary Eyewall Formation

  • Pages: 9192-9219
  • First Published: 16 August 2018
Key Points

  • Prior to secondary eyewall formation, a column-integrated heating zone appears over secondary eyewall formation radii
  • Significant increases in low-level pressure gradient and radial and tangential winds occur near the column warming zone
  • The enhanced convergence of moisture and angular momentum at secondary eyewall formation radii leads to secondary eyewall formation

Open Access

Impact of Ice Surface and Volume Scatterings on the Microwave Sea Ice Apparent Emissivity

  • Pages: 9220-9237
  • First Published: 21 August 2018
Key Points

  • Influences of ice roughness and volume scattering-induced attenuation on the measured MW low-frequency brightness temperature were examined
  • Roughness effect on the emissivity appears insignificant; allowing Fresnel assumption can be used for MW low-frequency channels
  • Impact of ice-induced volume scattering on the sea ice emissivity is substantial, requiring a method to correct the apparent emissivity

Open Access

An Accurate Method for Correcting Spectral Convolution Errors in Intercalibration of Broadband and Hyperspectral Sensors

  • Pages: 9238-9255
  • First Published: 27 August 2018
Key Points

  • This paper quantifies and corrects two intersatellite calibration errors due to spectral gapping and finite spectral resolution
  • These errors are scene dependent and could be significant
  • The effectiveness of the correction method has been validated using both simulated and satellite-observed data

Open Access

An Extreme Rainfall Event in Coastal South China During SCMREX-2014: Formation and Roles of Rainband and Echo Trainings

  • Pages: 9256-9278
  • First Published: 25 July 2018
Key Points

  • Two successive storms consisting of multiple meso-β-scale rainbands produce 451 mm rainfall in 20 hr over coastal South China
  • A surface mesoscale outflow boundary (MOB) exerts profound influences on convective initiation and the subsequent echo and rainband trainings in the storm
  • Interactions among the rear inflow, unstable oceanic flow, and MOB result in rapid splitting and rebuilding of a bowing rainband, favoring the rainband training

Free Access

The Instantaneous Retrieval of Precipitation Over Land by Temporal Variation at 19 GHz

  • Pages: 9279-9295
  • First Published: 23 August 2018
Key Points

  • Observations from five polar-orbiting satellites are used to derive TB temporal variation at 19 GHz
  • TB temporal variation at 19 GHz correlates well with the instantaneous precipitation rate
  • TB temporal variation at 19 GHz primarily reflects the surface emissivity variation due to the precipitation impact

Free Access

The Excitation of Secondary Gravity Waves From Local Body Forces: Theory and Observation

  • Pages: 9296-9325
  • First Published: 23 May 2018
Key Points

  • Secondary GWs create fishbone structures in z-t plots and have the same periods, wavelengths, and azimuths above and below the knee
  • Polarization relations and broad spectra cause the temperature and vertical velocity spectra to peak at different periods and wavelengths
  • Secondary GWs with 6- to 10-hr periods and 6- to 14-km vertical wavelengths are identified in fishbone structures at z= 43–52 km in McMurdo lidar data

Free Access

Numerical Modeling of the Excitation, Propagation, and Dissipation of Primary and Secondary Gravity Waves during Wintertime at McMurdo Station in the Antarctic

  • Pages: 9326-9369
  • First Published: 23 May 2018
Key Points

  • Main point #1: Mountain waves break in the winter stratosphere over McMurdo, exciting secondary GWs with much larger horizontal wavelengths
  • Main point #2: Secondary GWs create fishbone structures in the stratosphere and have similar periods, wavelengths, and azimuths above and below the knee
  • Main point #3: Most of the wintertime GWs at z > 70 km above McMurdo are secondary GWs

Free Access

Simulated Lightning in a Convection Permitting Global Model

  • Pages: 9370-9377
  • First Published: 23 August 2018
Key Points

  • Global model captures diurnal phase of lightning
  • Spatial and seasonal distributions of lightning compare favorably to two observed data sets
  • The global model has excessive lightning over the tropical oceans

Free Access

Mitigation of Global Cooling by Stratospheric Chemistry Feedbacks in a Simulation of the Last Glacial Maximum

  • Pages: 9378-9390
  • First Published: 08 August 2018
Key Points

  • Including ozone chemistry feedbacks mitigates global cooling in a paleoclimate simulation under reduced CO2 and different orbital elements
  • This is due to ozone and related water vapor and cirrus cloud feedbacks, consistent with results of a previous study under increased CO2
  • Including ozone feedbacks brings our model results closer to the expectation value of geological proxy estimates

Free Access

An Ensemble Version of the E-OBS Temperature and Precipitation Data Sets

  • Pages: 9391-9409
  • First Published: 14 August 2018
Key Points

  • An improved uncertainty estimate is provided through the generation of multiple realizations
  • The new data set is broadly consistent with the original version
  • The largest differences occur in the precipitation grids

Free Access

Combined Influence of the Arctic Oscillation and the Scandinavia Pattern on Spring Surface Air Temperature Variations Over Eurasia

  • Pages: 9410-9429
  • First Published: 27 August 2018
Key Points

  • In the in-phase AO-SCAND years, spring AO and SCAND indices both have a strong (weak) relation with EOF1 (EOF2) of the spring Eurasian SAT
  • In the out-of-phase AO-SCAND years, the connection of the spring AO and SCAND indices with the EOF1 (EOF2) is insignificant (significant)
  • Changes in SAT anomalies are due to constructive and destructive superposition of atmospheric anomalies related to the spring AO and SCAND

Free Access

Leader Polarity-Reversal Feature and Charge Structure of Three Upward Bipolar Lightning Flashes

  • Pages: 9430-9442
  • First Published: 27 August 2018
Key Points

  • Initial sources for the polarity-reversal leader exhibit obvious height ascending and strong radiation power
  • The polarity-reversal leader is initiated at the end of one decayed branch of the preceding leader
  • Upward bipolar lightning flashes occurred at either a normal dipolar or an inverted dipolar charge structure

Open Access

Sea Breeze Sensitivity to Coastal Upwelling and Synoptic Flow Using Lagrangian Methods

  • Pages: 9443-9461
  • First Published: 30 August 2018
Key Points

  • Lagrangian method applied to weather model reveals synoptic flow impacts sea breeze onshore extent more than offshore in U.S. Mid-Atlantic
  • Upwelling did not greatly impact sea breeze onshore/offshore extent, but produced earlier, shallower, sharper, and stronger sea breeze
  • Results agree with sea breeze theory, proving utility of Lagrangian methods for sea breeze prediction, offshore wind resource assessment

Free Access

Distinguishing Anthropogenic CO2 Emissions From Different Energy Intensive Industrial Sources Using OCO-2 Observations: A Case Study in Northern China

  • Pages: 9462-9473
  • First Published: 30 August 2018
Key Points

  • CO2 enhancements from different energy intensive industrial sources are distinguishable from OCO-2 data
  • The cluster of iron and steel plants has higher CO2 emissions than that of coal-processing plants
  • Identification of industrial CO2 emission hotspots is possible from natural background using OCO-2 data

Free Access

Study of the Quasi-5-Day Wave in the MLT Region by a Meteor Radar Chain

  • Pages: 9474-9487
  • First Published: 31 August 2018
Key Points

  • 5DWs exhibit clear interannual and seasonal variations
  • TAO is comparable with AO and SAO in the 5DW amplitudes
  • The enhancements of 5DWs at middle latitudes are very likely associated with the 2013 SSW

Free Access

Study of Mean Wind Variations and Gravity Wave Forcing Via a Meteor Radar Chain and Comparison with HWM-07 Results

  • Pages: 9488-9501
  • First Published: 31 August 2018
Key Points

  • The year-to-year variations of the mean winds in the MLT region are mainly modulated by AO and SAO in the middle and low latitudes
  • The spring time reversal in zonal mean wind is consistent with the rapid changes of GWF
  • Large discrepancies are found between the observations and the HWM-07 during winter, in the meridional component and at the low latitude

Aerosol and Clouds

Open Access

Variations of Thunderstorm Charge Structures in West Texas on 4 June 2012

  • Pages: 9502-9523
  • First Published: 03 August 2018
Key Points

  • Normal and anomalous polarity storms happened nearby at the same time in the unusual environment documented herein
  • Parameter-based theories of environmental control of storm polarity struggled to predict the observed differences
  • Normal-polarity storms were clustered in regions of previous deep convection, moist midlevels and less potential for dry-air entrainment

Free Access

Characteristics of Lightning Flashes Associated With the Charge Layer Near the 0 °C Isotherm in the Stratiform Region of Mesoscale onvective Systems

  • Pages: 9524-9541
  • First Published: 05 August 2018
Key Points

  • Stratiform lightning flashes associated with the charge layer near the 0 °C isotherm have close relationship with the bright band
  • The difference between the reflectivity core in lightning area (MaxR) and the reflectivity at the FirstS increases with increasing in MaxR
  • The SL0s of the thunderstorm with infrequent SL0 activity tended to have stronger MaxR values

Free Access

Optical Properties and Spatial Variation of Tropical Cyclone Cloud Systems From TRMM and MODIS in the East Asia Region: 2010–2014

  • Pages: 9542-9558
  • First Published: 15 August 2018
Key Points

  • The optical properties and spatial distributions of 35 tropical cyclone cloud systems (TCCS) in East Asia are analyzed
  • The regress equations and an ideal fitting model along the radial distance to TC center have been constructed
  • The relationship of clouds and precipitations with aerosol optical thickness (AOT) is verified

Free Access

Cloud Optical Properties Over West Antarctica From Shortwave Spectroradiometer Measurements During AWARE

  • Pages: 9559-9570
  • First Published: 30 July 2018
Key Points

  • Shortwave spectral irradiance measurements from West Antarctica in austral summer 2015-2016 allow retrieval of cloud optical properties
  • The first 5 weeks of these measurements are consistent with current summertime climatological conditions
  • After 9 January 2016 these measurements sampled conditions possibly consistent with future warmer conditions and surface melt scenarios

Free Access

Radiosonde-Derived Temperature Inversions and Their Association With Fog Over 37 Melt Seasons in East Greenland

  • Pages: 9571-9588
  • First Published: 15 August 2018
Key Points

  • A novel dew point depression method is presented for the calculation of fog-top height from radiosonde profiles
  • Temperature inversions are 100-m deeper and twice as strong under fog conditions compared to nonfog conditions
  • Arctic sea fog over coastal east Greenland is often several hundred meters thick

Free Access

Influence of Wind Direction on Thermodynamic Properties and Arctic Mixed-Phase Clouds in Autumn at Utqiaġvik, Alaska

  • Pages: 9589-9603
  • First Published: 21 August 2018
Key Points

  • Arctic mixed-phase cloud occurrence frequency is 20–30% lower during southerly winds compared to other wind directions in early fall
  • The atmosphere is colder, drier, more stable, and has lower RH values during southerly winds than during northerly winds
  • When the ocean is open, Arctic mixed-phase clouds have a wider particle size distribution and stronger precipitation during northerly winds

Open Access

The Study of Inland Eyewall Reformation of Typhoon Fanapi (2010) Using Numerical Experiments and Vorticity Budget Analysis

  • Pages: 9604-9623
  • First Published: 24 August 2018
Key Points

  • The Fanapi eyewall breaks down over the Taiwan terrain and reforms again
  • Terrain and surface friction over land weaken the updraft and reduce the width and depth of vortical hot towers
  • Vortical hot towers in land cooperate with rainband through horizontal vorticity advection to rebuild Fanapi eyewall

Free Access

The Life Cycles of Ice Crystals Detrained From the Tops of Deep Convection

  • Pages: 9624-9634
  • First Published: 07 August 2018
Key Points

  • Large ice crystals fall out of anvil cirrus within a few hours
  • Small ice crystals grow by deposition of vapor
  • Ice crystal growth extends lifetime of anvil cirrus

Open Access

CCN Spectral Shape and Stratus Cloud and Drizzle Microphysics

  • Pages: 9635-9651
  • First Published: 04 August 2018
Key Points

  • Bimodal CCN affects cloud microphysics in stratus
  • Normalized concentration difference between modes (ndf) is a more objective classification metric for CCN modality
  • Bimodal CCN suppresses drizzle in stratus

Free Access

Continuous Assimilation of Lightning Data Using Time-Lagged Ensembles for a Convection-Allowing Numerical Weather Prediction Model

  • Pages: 9652-9673
  • First Published: 07 August 2018
Key Points

  • Describe a scheme to continuously assimilate lightning data for a cycled deterministic forecast system using time-lagged ensembles
  • Compute background error covariances using time-lagged ensembles
  • The lightning data assimilation scheme can improve short-term forecasts of severe convective systems

Free Access

Mapping the Lateral Development of Lightning Flashes From Orbit

  • Pages: 9674-9687
  • First Published: 27 August 2018
Key Points

  • Lightning imagers provide a 2-D composite view of the horizontal development of lightning flashes
  • Flash properties typically describe the most radiant group while group-level data document flash evolution and structure
  • Flash propagation encompasses velocity scales of 104 and 106 m/s, consistent with leader development

Free Access

Parameterized Vertical Concentration Profiles for Aerosols in the Marine Atmospheric Boundary Layer

  • Pages: 9688-9702
  • First Published: 03 September 2018
Key Points

  • A new 1-D model shows that particle concentrations in marine atmospheric boundary layer depend heavily on particle size and turbulence level
  • Linear net vertical flux profile in the mixed layer is essential for accurate prediction of concentration profiles above the surface layer

Free Access

Hygroscopicity of Organic Aerosols and Their Contributions to CCN Concentrations Over a Midlatitude Forest in Japan

  • Pages: 9703-9723
  • First Published: 26 April 2018
Key Points

  • Organics contributed to, on average, 38% of the aerosol water uptake
  • The hygroscopicity parameter of locally formed fresh BSOA was estimated to be 0.09
  • Per 1-μg/m3 increase of BSOA, the CCN concentration increased 23–299 cm−3 at 0.1–0.8% SS

Free Access

Triggered Lightning Return Stroke Luminosity up to 1 km in Two Optical Bands

  • Pages: 9724-9740
  • First Published: 28 August 2018
Key Points

  • Most detailed temporal and spatial characterization of triggered lightning luminosity ground to 1 km
  • Simultaneous measurements from two types of photodiodes with different bandwidths, 199 total luminosity waveforms captured during 15 strokes
  • The average upward speed of the initial luminosity at 20% of peak is 1.3e8 m/s, 4 times faster than the secondary peak upward speed

Composition and Chemistry

Free Access

Source Apportionment and Secondary Transformation of Atmospheric Nonmethane Hydrocarbons in Chengdu, Southwest China

  • Pages: 9741-9763
  • First Published: 17 August 2018
Key Points

  • Based on the multieffect assessment method, aromatics and alkenes played a leading role in secondary transformation
  • Western and southern Chengdu are the potential source regions of strong pollutant discharge of nonmethane hydrocarbons in Chengdu
  • The sources show seasonal differences, and vehicle exhaust is the primary source of nonmethane hydrocarbons in the Chengdu urban area

Open Access

A Lagrangian Model Diagnosis of Stratospheric Contributions to Tropical Midtropospheric Air

  • Pages: 9764-9785
  • First Published: 28 July 2018
Key Points

  • Processes contributing to the observed O3 enhancement in the tropical midtroposphere are diagnosed using a Lagrangian transport model
  • The leading process is found to be transport from the stratosphere via isentropic mixing across the subtropical jet
  • Biomass burning facilitated O3 production is also identified by correlations among O3, HCN, and CO for a fraction of the observations

Free Access

Links Between Carbon Monoxide and Climate Indices for the Southern Hemisphere and Tropical Fire Regions

  • Pages: 9786-9800
  • First Published: 18 July 2018
Key Points

  • The long record of satellite-measured CO from MOPITT enables study of interannual variability (IAV)
  • ENSO climate mode index is important, but we find that other modes are also required to predict CO IAV
  • Interaction of climate modes is necessary to explain CO variability

Free Access

SO2 Oxidation Kinetics Leave a Consistent Isotopic Imprint on Volcanic Ice Core Sulfate

  • Pages: 9801-9812
  • First Published: 20 August 2018
Key Points

  • Aerosols are physically separated from the SO2 pool during the oxidation process, and they preserve the isotopic signature during transport and deposition
  • Volcanic sulfate of stratospheric origin scatter on Δ33S versus Δ36S and δ34S versus Δ33S slopes of −1.56 (1σ = 0.25) and 0.09 (1σ = 0.02), respectively
  • The mechanism generating S-MIF in stratospheric sulfate remains uncertain; a combination of several mechanisms is needed to reproduce the observed signature

Free Access

NOx Lifetime and NOy Partitioning During WINTER

  • Pages: 9813-9827
  • First Published: 01 August 2018
Key Points

  • NOx is long lived during winter, with a longer daytime lifetime (29 hr) than nighttime lifetime (6.3 hr)
  • Wintertime NOx lifetime is controlled by the nighttime conversion of NOx to HNO3 via N2O5 heterogeneous chemistry
  • Fifteen percent of O3 is removed at night via the dark reactions of N2O5

Free Access

Constraining the Emission of Particulate Matter From Indonesian Peatland Burning Using Continuous Observation Data

  • Pages: 9828-9842
  • First Published: 17 August 2018
Key Point

  • Emission factor of PM from peatland burning in the equatorial Asian region is 2 times higher than the value in the emission inventory

Free Access

The Impact of Boreal Summer ENSO Events on Tropical Lower Stratospheric Ozone

  • Pages: 9843-9857
  • First Published: 23 August 2018
Key Points

  • Interannual variability in the lower stratospheric ozone is larger in the northern tropic than in the southern tropic during boreal summer
  • Ozone interannual variability during boreal summer is highly correlated with boreal summer ENSO events
  • Boreal summer ENSO modifies meridional advection of ozone through changes in the strength of the Asian summer monsoon anticyclone

Free Access

Reconstructed Precipitation Tritium Leads to Overestimated Groundwater Recharge

  • Pages: 9858-9867
  • First Published: 30 August 2018
Key Points

  • Four >15 m tritium profiles present a unique record of bomb tritium storage for evaluation of precipitation tritium reconstruction
  • The interpolation methods perform better than the reference curve methods because of the spatial scale for method development
  • Atmospheric tritium flux is greatly underestimated and subsequently results in overestimation of groundwater recharge

Free Access

Assessment of Regional Mercury Deposition and Emission Outflow in Mainland China

  • Pages: 9868-9890
  • First Published: 05 August 2018
Key Points

  • Recent changes in emission inventories have significant influences on atmospheric mercury outflow from China
  • Total mercury deposition in China is 422 Mg/year, about two thirds of deposition is contributed by domestic emissions
  • Elevated levels of aerosol and secondary air pollutants significantly enhance atmospheric mercury pollution

Free Access

An Updated Model Providing Long-Term Data Sets of Energetic Electron Precipitation, Including Zonal Dependence

  • Pages: 9891-9915
  • First Published: 03 August 2018
Key Points

  • A previously published model for radiation belt energetic electron precipitation has been updated and improved
  • The model includes dependences on the following: the geomagnetic index Ap, the L shell level relative to the plasmapause, and magnetic local time
  • It provides the energy spectrum of 30- to 1,000-keV precipitating electron flux for any period of time where the geomagnetic index Ap is supplied

Free Access

Validation of SABER v2.0 Operational Temperature Data With Ground-Based Lidars in the Mesosphere-Lower Thermosphere Region (75–105 km)

  • Pages: 9916-9934
  • First Published: 17 August 2018
Key Points

  • The first comparative study of SABER version 2.0 operational temperature retrieval product with high-resolution ground-based lidar profiles
  • A comparison of collocated multiyear seasonal average temperatures at nine locations (low, middle, and high latitudes) is presented
  • An overall agreement for SABER and lidar data sets, but the presence of relative SABER warm bias during polar summer requires further investigation

Free Access

Modeling of Atmospheric Aerosol Properties in the São Paulo Metropolitan Area: Impact of Biomass Burning

  • Pages: 9935-9956
  • First Published: 24 August 2018
Key Points

  • The fully coupled WRF-Chem model was applied and evaluated for the atmosphere over the metropolitan area of São Paulo
  • The WRF-Chem can reproduce observed temporal variations in meteorological conditions and chemical species
  • Inclusion of biomass burning emissions improves predictions of aerosol properties

Free Access

First MAX-DOAS Observations of Formaldehyde and Glyoxal in Phimai, Thailand

  • Pages: 9957-9975
  • First Published: 30 August 2018
Key Points

  • The glyoxal to formaldehyde ratio (RGF) suggesting changes in volatile organic compounds has been poorly understood
  • The mean RGF at Phimai, Thailand, was first estimated from 2-year observations to be 0.032 ± 0.005
  • The clear seasonal variation in RGF strongly suggests a lower RGF due to biomass burning