Browse Articles

Potential Predictability of the Tropical Cyclone Frequency Over the Western North Pacific With 50‐km AGCM Ensemble Experiments

  •  30 March 2021

Key Points

  • Using a 50‐km AGCM, tropical cyclone (TC) activity over the western North Pacific (WNP) was investigated

  • In JJA, AGCM experiments captures observed interannual variability of TC activity over the WNP

  • In SON, the correlation between the observed and simulated TC frequency variability is less significant

Changes in Below‐Cloud Evaporation Affect Precipitation Isotopes During Five Decades of Warming Across China

  •  28 March 2021

Key Points

  • Below‐cloud evaporation effect on precipitation isotopes is assessed nationwide

  • The variability of below‐cloud evaporation effect is controlled by the warming climate

  • Enhanced below‐cloud evaporation may affect interpretation of long‐term isotope records

Tree Rings Reveal the Impacts of the Northern Hemisphere Temperature on Precipitation Reduction in the Low Latitudes of East Asia Since 1259 CE

  •  27 March 2021

Key Points

  • The precipitation reconstruction since 1259 CE is the longest annual‐resolution reconstruction for the low latitudes of East Asia

  • There are five 70‐year significant decreasing trends and each was accompanied by an increase in the Northern Hemisphere temperature

  • Precipitation decreased on the second year after large tropical eruptions through the influences of ENSO and Asian summer monsoon

Future Changes in Early Spring Wind Speed and Surface Warming Acceleration in Snow‐Covered Areas

  •  27 March 2021

Key Points

  • Long‐term high‐resolution simulations project future changes in local wind speed and air temperature over complex terrain

  • Collapse of the stable near‐surface atmospheric layer due to reduced snowcover strengthens wind and drives increases in surface temperature

  • The presence or absence of the stable layer under current climate conditions influences the local response to future warming

The Atlantic Jet Response to Stratospheric Events: A Regime Perspective

  •  26 March 2021

Key Points

  • Following sudden stratospheric warmings, the Atlantic jet spends more time in its southern jet regime and less time in its northern jet regime

  • Following strong polar vortex events, the Atlantic jet spends more time in its northern regime and less time in its southern regime

  • Tropospheric composites following stratospheric forcing are consistent with these changes in the Atlantic jet regime frequencies

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Issue Information

  •  24 March 2021
Open access

Model and Satellite Analysis of Transport of Asian Anthropogenic Pollution to the Arctic: Siberian and Pacific Pathways and Their Meteorological Controls

  •  24 March 2021

Key Points

  • Eleven events of anthropogenic black carbon from East Asia to the Arctic were identified by an integrated satellite and model analysis

  • Two transport patterns from East Asia were identified; Siberia and the North Pacific en route to the Arctic

  • Low pressures passing through Siberia and high pressures staying around the Bering Sea had key roles in Siberian and Pacific route events

Mesospheric Mountain Wave Activity in the Lee of the Southern Andes

  •  23 March 2021

Key Points

  • Numerous mesospheric mountain waves observed in the lee of the Southern Andes, a major gravity waves hotspot, under wintertime conditions

  • Mountain wave occurrence is highly correlated with the eastward phase of the semi‐diurnal tide in the upper mesosphere

  • Mountain wave momentum fluxes can reach very large values, revealing their major impact on the upper atmosphere

High‐Energy Radiation From Natural Lightning Observed in Coincidence With a VHF Broadband Interferometer

  •  23 March 2021

Key Points

  • X‐ray bursts were detected simultaneously with a lightning imaging obtained with a very high frequency (VHF) broadband interferometer

  • A strong temporal correspondence has been observed between the high‐energy radiation and the most intense VHF pulses

  • Measurements suggest an extensive spatial origin of Terrestrial Gamma‐ray Flashes (TGFs) due to a multiplicity of high‐energy sources

Respective Advantages of “Top‐Down” Based GPM IMERG and “Bottom‐Up” Based SM2RAIN‐ASCAT Precipitation Products Over the Tibetan Plateau

  •  23 March 2021

Key Points

  • Soil Moisture TO RAIN‐Advanced SCATterometer (SM2RAIN‐ASCAT) estimates daily rainfall better in grassland areas, and the Global Precipitation Measurement‐Integrated MultisatellitE Retrievals for GPM (GPM IMERG) product outperforms in forests

  • SM2RAIN‐ASCAT estimates light to moderate rainfall more accurately than GPM IMERG, but it cannot detect heavy rainfall events

  • Due to relatively frequent fluctuations of ASCAT soil moisture product, SM2RAIN‐ASCAT frequently reports false rainfall in dry conditions

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Stratospheric impacts of continuing CFC‐11 emissions simulated in a chemistry‐climate model

  •  9 April 2021

Key Points

  • Continuing CFC‐11 emissions will cause additional future stratospheric ozone depletion.

  • Largest statistically significant ozone depletion occurs in the global and Antarctic spring total column, and global upper stratosphere.

  • Additional ozone depletion due to continuing CFC‐11 emissions will cause small changes in stratospheric temperature and circulation.

Revision of “Dependence of climate states of gray atmosphere on solar constant: From the runaway greenhouse to the snowball states” by Ishiwatari et al. (2007)

  •  8 April 2021

Key Points

  • We re‐performed solar constant dependence experiment of Ishiwatari et al. (2007) which was retracted due to a model bug.

  • We revised the climate regime diagram for gray atmosphere drawn in solar constant ‐ ice line latitude plane.

  • We confirmed that the snowball state, the partially ice‐covered state, and the runaway greenhouse state coexist for some solar constants.

Observational signal of the interaction between mountain–plain wind and urban breeze under weak synoptic systems

  •  8 April 2021

Key Points

  • Criteria to identify valley wind episodes from ground‐based observations were proposed and evaluated.

  • Interactions between mountain–plain wind and urban breeze were found from surface observations.

  • The interaction can modulate the reversal times of diurnal mountain–plain winds.

Diagnosing non‐Gaussian temperature distribution tails using back‐trajectory analysis

  •  8 April 2021

Key Points

  • Air parcel back trajectories help explain the pathways for non‐Gaussian temperature distribution tails at select extratropical locations.

  • Extreme temperatures in locations with non‐Gaussian temperature distribution tails can occur with a range of meteorological mechanisms.

  • Tail non‐Gaussianity is governed by the proximity of the location to influential geography and climatologically anomalous air source regions.

Characteristics of Electric Currents in Upward Lightning Flashes from a Windmill and its Lightning Protection Tower in Japan, 2005 ‐ 2016

  •  8 April 2021

Key Points

  • The lightning protection tower showed no meaningful protection for self‐initiated negative upward lightning.

  • Self‐initiated negative upward lightning have larger peak value and shorter rise time during initial stage.

  • Negative upward lightning tend to exhibit pulsation in current waveform under a larger rate of current rise.

Future decreases in thermospheric neutral density in low Earth orbit due to carbon dioxide emissions.

  •  8 April 2021

Key Points

  • Thermospheric neutral density at 500 km altitude lowers by over 80 percent with a high ground‐level carbon dioxide concentration of 890 ppm.

  • Meeting the 1.5 degrees Paris agreement target limits the reduction in neutral density at 400 km since the year 2000 to around 28 percent.

  • Objects in LEO will have orbital lifetimes around 30 percent longer at the 1.5 degrees target than comparable objects from the year 2000.

Characteristic features of the clouds producing thunderstorm ground enhancements

  •  7 April 2021

Key Points

  • The technique of electric cloud structure estimation based on WRF simulation of a convective event is developed.

  • A dipole structure with a positive lower layer is typical for the thunderclouds producing intense thunderstorm ground enhancements (TGEs).

  • Snow and graupel particles are the main charge carriers in the mountain conditions of TGE occurrence.

Dual carbon isotope‐based source apportionment and light absorption properties of water‐soluble organic carbon in PM2.5 over China

  •  7 April 2021

Key Points

  • The fossil fuel contribution and corresponding MAE365 value of WSOC were higher in northern than southern China.

  • Higher 14C and 13C of WSOC in cold seasons may be related to corn residue burning.

  • Primary coal combustion emissions and secondary fossil WSOC generated under high NOX conditions increase MAE365 of WSOC in cold seasons.

Open access

Elevation‐dependent warming over the Tibetan plateau from an ensemble of CORDEX‐EA regional climate simulations

  •  7 April 2021

Key Points

  • Elevation‐dependent warming will happen in the future with its magnitude and structure varying with seasons

  • Surface albedo feedback is the primary contributor to elevation‐dependent warming and the dominant source of uncertainty in its projections.

  • The projected elevation‐dependent warming depends not only on the driving global climate model but also on the internal model physics.

An Aerosol Climatology and Implications for Clouds at a Remote Marine Site: Case Study over Bermuda

  •  7 April 2021

Key Points

  • While anthropogenic influence is lowest in winter, cloud drop number concentrations are close to peak values along with high sea salt levels

  • Bimodal volume size distributions with a dominant coarse mode peak that shifts to smaller sizes in spring/summer due in part to dust

  • Extreme pollution events show the sensitivity of remote marine sites like Bermuda to continental outflow of urban emissions, dust, and smoke

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The Complex Refractive Index of Volcanic Ash Aerosol Retrieved From Spectral Mass Extinction

Key Points

  • The complex refractive indices of eight samples of volcanic ash aerosol were retrieved from measurements of spectral mass extinction and size and showed considerable variability
  • Verification retrievals were performed on measurements of high‐purity silica aerosol. The Rayleigh CDE scattering model outperformed Mie theory
  • Nonspherical scattering effects can have a significant impact on refractive indices derived from extinction spectra

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Application of USDM statistics in NLDAS‐2: Optimal blended NLDAS drought index over the continental United States

Key Points

  • To develop an objective approach to blend NLDAS drought indices
  • To establish the linkage between USDM statistics and NLDAS drought indices
  • To reconstruct long‐term OBNDI

Open access

Measurements of the complex refractive index of volcanic ash at 450, 546.7, and 650 nm

Key Points

  • Complex refractive index data for 11 volcanic ash samples
  • Explanation of methods used to find complex refractive indices
  • Verification of methods through measurement of a calibration material

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