scholarly journals Impact of Arctic amplification on declining spring dust events in East Asia

2019 ◽  
Vol 54 (3-4) ◽  
pp. 1913-1935 ◽  
Author(s):  
Jun Liu ◽  
Dongyou Wu ◽  
Guangjing Liu ◽  
Rui Mao ◽  
Siyu Chen ◽  
...  
Keyword(s):  
East Asia ◽  
Northern Hemisphere ◽  
Surface Wind ◽  
Northern China ◽  
Temperature Gradients ◽  
Arctic Amplification ◽  
Dust Event ◽  
Snow Cover Extent ◽  
Spring Dust ◽  
Dust Events

AbstractDust aerosols play key roles in affecting regional and global climate through their direct, indirect, and semi-direct effects. Dust events have decreased rapidly since the 1980s in East Asia, particularly over northern China, primarily because of changes in meteorological parameters (e.g. surface wind speed and precipitation). In this study, we found that winter (December–January–February) Arctic amplification associated with weakened temperature gradients along with decreased zonal winds is primarily responsible for the large decline in following spring (March–April–May) dust event occurrences over northern China since the mid-1980s. A dust index was developed for northern China by combining the daily frequency of three types of dust event (dust storm, blowing dust, and floating dust). Using the empirical orthogonal function (EOF) analysis, the first pattern of dust events was obtained for spring dust index anomalies, which accounts for 56.2% of the variability during 1961–2014. Moreover, the enhanced Arctic amplification and stronger Northern Hemisphere annular mode (NAM) in winter can result in the anticyclonic anomalies over Siberia and Mongolia, while cyclonic anomalies over East Europe in spring. These results are significantly correlated with the weakened temperature gradients, increased precipitation and soil moisture, and decreased snow cover extent in the mid-latitude over Northern Hemisphere. Based on the future predictions obtained from the Fifth Climate Models Intercomparison Project (CMIP5), we found that the dust event occurrences may continually decrease over northern China due to the enhanced Arctic amplification in future climate.

Impact of Arctic amplification on declining spring dust events in East Asia

2020 ◽  
Author(s):  
Xin Wang ◽  
Jun Liu
Keyword(s):  
East Asia ◽  
Northern Hemisphere ◽  
Surface Wind ◽  
Northern China ◽  
Temperature Gradients ◽  
Arctic Amplification ◽  
Dust Event ◽  
Snow Cover Extent ◽  
Spring Dust ◽  
Dust Events

<div> <div> <div> <div> <p>Dust aerosols play key roles in affecting the regional and global climate through their direct, indirect, and semi-direct effects. Dust events have decreased rapidly since the 1980s in East Asia, particularly over northern China, primarily because of changes in meteorological parameters (e.g. surface wind speed and precipitation). In this study, we found that winter (December– January–February) Arctic amplification associated with weakened temperature gradients along with decreased zonal winds is primarily responsible for the large decline in following spring (March–April–May) dust event occurrences over northern China since the mid-1980s. A dust index was developed for northern China by combining the daily frequency of three types of dust events (dust storm, blowing dust, and floating dust). Using the empirical orthogonal function (EOF) analysis, the first pattern of dust events was obtained for spring dust index anomalies, which accounts for 56.2% of the variability from 1961–2014. Moreover, the enhanced Arctic amplification and stronger Northern Hemisphere annular mode (NAM) in winter can result in the anticyclonic anomalies over Siberia and Mongolia, while cyclonic anomalies over East Europe in spring. These results are significantly correlated with the weakened temperature gradients, increased precipitation, and soil moisture, and decreased snow cover extent in the mid-latitude over Northern Hemisphere. Based on the future predictions obtained from the Fifth Climate Models Intercomparison Project (CMIP5), we found that the dust event occurrences may continually decrease over northern China due to the enhanced Arctic amplification in future climate.</p> </div> </div> </div> </div>

Transboundary Extreme Ultrafine Dust Events in East Asia under a Warmer Monsoon Climate

2020 ◽  
Author(s):  
Gwangyong Choi
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Northern China ◽  
Cold Season ◽  
Reanalysis Data ◽  
Monsoon Climate ◽  
Late 20Th Century ◽  
Spatio Temporal ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Dust Events

<p>Since the late 20th century East Asia has frequently experienced unprecedented transboundary extreme ultrafine dust events (TEUDEs) due to a fast economic development based on significant amount of fossil fuel consumption. In this study, spatio-temporal patterns of the TEUDEs in East Asia and the roles of synoptic climate patterns and changing large-scale atmospheric circulation systems in exacerbating the anthropogenic atmospheric pollution events causing considerable human deaths are examined. Analyses of the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra aerosol optical depth (AOD) data (2000-2019) clearly show that the pollutants are produced mainly in northern China and move toward central Korea and southern Japanese islands during cold seasons when coals consumption soars for heating. Synoptic climatic maps drawn from the NCEP-NCAR I reanalysis data for multiple TEUDEs demonstrate that a north clockwise- south anticlockwise wind vector anomaly pattern in cold seasons formed by less southward meandering of Siberian High pressure (SH) helps the stagnation of significant amount of ultrafine dusts over East Asia. It is also notable that the long-term poleward retreating trend of cold season circumpolar vortex, which is associated with less frequent gusty wind flow from the SH, may provide a favorable condition for intense, long-lasting TEUDEs across East Asia under a warmer monsoon climate.</p>

scholarly journals Northern Hemisphere spring snow cover variability and change over 1922–2010 including an assessment of uncertainty

2010 ◽  
Vol 4 (4) ◽  
pp. 2483-2512
Author(s):  
R. D. Brown ◽  
D. A. Robinson
Keyword(s):  
Snow Cover ◽  
Northern Hemisphere ◽  
Temperature Sensitivity ◽  
Northern China ◽  
The Tibetan Plateau ◽  
Climate Data ◽  
The Past ◽  
The North ◽  
Snow Cover Extent ◽  
The North Atlantic Oscillation

Abstract. An update is provided of Northern Hemisphere (NH) spring (March, April) snow cover extent (SCE) over the 1922–2010 period incorporating the new climate data record (CDR) version of the NOAA weekly SCE dataset, with annual 95% confidence intervals estimates from regression analysis and intercomparison of multiple datasets. The uncertainty analysis indicated a 95% confidence interval in NH spring SCE of ±5–10% over the pre-satellite period and ±3–5% over the satellite era. The multi-dataset analysis showed there are larger uncertainties monitoring spring SCE over Eurasia (EUR) than North America (NA) due to the more complex regional character of the snow cover variability with the largest dataset uncertainty located over eastern Eurasia in a large region extending from the Tibetan Plateau across northern China. Trend analysis of the updated SCE series provided evidence that NH spring snow cover extent has undergone significant reductions over the past ~90 years and that the rate of decrease has accelerated over the past 40 years. The rate of decrease in March and April NH SCE over the 1970–2010 period is ~7–8 million km2 per 100 years which corresponds to an 8–11% decrease in NH March and April SCE respectively from pre-1970 values. In March, most of the change is being driven by Eurasia (NA trends are not significant) but both continents exhibit significant SCE reductions in April. The observed trends in SCE are consistent with recent warming trends over northern mid-latitude land areas with NH SCE exhibiting significant negative correlations to air temperature anomalies in March and April. The NH spring SCE-temperature sensitivity has remained relatively stable over the period of record although there is some evidence of contrasting changes in temperature sensitivity over both continents in April. There is evidence that changes in atmospheric circulation around 1980 involving the North Atlantic Oscillation and Scandinavian Pattern have contributed to reductions in March SCE over Eurasia.

Physics of Changes in Synoptic Midlatitude Temperature Variability

2015 ◽  
Vol 28 (6) ◽  
pp. 2312-2331 ◽  
Author(s):  
Tapio Schneider ◽  
Tobias Bischoff ◽  
Hanna Płotka
Keyword(s):  
Global Warming ◽  
Surface Temperature ◽  
Northern Hemisphere ◽  
Potential Temperature ◽  
Temperature Variability ◽  
Temperature Gradients ◽  
Arctic Amplification ◽  
Near Surface ◽  
Temperature Variations ◽  
Temperature Variance

Abstract This paper examines the physical processes controlling how synoptic midlatitude temperature variability near the surface changes with climate. Because synoptic temperature variability is primarily generated by advection, it can be related to mean potential temperature gradients and mixing lengths near the surface. Scaling arguments show that the reduction of meridional potential temperature gradients that accompanies polar amplification of global warming leads to a reduction of the synoptic temperature variance near the surface. This is confirmed in simulations of a wide range of climates with an idealized GCM. In comprehensive climate simulations (CMIP5), Arctic amplification of global warming similarly entails a large-scale reduction of the near-surface temperature variance in Northern Hemisphere midlatitudes, especially in winter. The probability density functions of synoptic near-surface temperature variations in midlatitudes are statistically indistinguishable from Gaussian, both in reanalysis data and in a range of climates simulated with idealized and comprehensive GCMs. This indicates that changes in mean values and variances suffice to account for changes even in extreme synoptic temperature variations. Taken together, the results indicate that Arctic amplification of global warming leads to even less frequent cold outbreaks in Northern Hemisphere winter than a shift toward a warmer mean climate implies by itself.

scholarly journals Large-scale dust event in East Asia, as revealed by the Himawari-8 DUST RGB, lidar network observations, and field survey

2019 ◽  
Vol 99 ◽  
pp. 01004
Author(s):  
Kenji Kai ◽  
Yuki Minamoto ◽  
Kotaro Nakamura ◽  
Minrui Wang ◽  
Kei Kawai ◽  
...  
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Meteorological Data ◽  
Northern China ◽  
Dust Storms ◽  
Gobi Desert ◽  
Horqin Sandy Land ◽  
Sandy Land ◽  
Dust Event ◽  
Multiple Sources

A large-scale dust event occurred in East Asia during early May 2017, and transported dust was measured all over Japan. We performed an analysis of the entire dust event using multiple sources: a local ceilometer measurement, measurements from an optical particle counter in the Gobi Desert (Dalanzadgad, Mongolia), a study of Dust RGB imagery obtained from Himawari-8, lidar measurements from Japan, and meteorological data. Our results show that three extratropical low pressure systems occurred consecutively in Mongolia and generated dust storms in the Gobi Desert. Remarkably, the Dust RGB imagery shows both the occurrence and the transportation of the dust, and was able to detect two dust outbreaks in the Horqin Sandy Land of Northern China and their transportation to eastern Japan; this shows that the Horqin Sandy Land was one of the source regions of this dust event.

scholarly journals Comparison of the Synoptic Environments Conducive to Eastward versus Southeastward Transport of Asian Dust Events

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Fujung Tsai ◽  
Wei-Nai Chen
Keyword(s):  
East Asia ◽  
Lower Troposphere ◽  
Asian Dust ◽  
Maximum Pressure ◽  
Dust Event ◽  
Low Level ◽  
Surface Measurements ◽  
Dust Events ◽  
Weak Surface

Asian dust events that travel eastward and southeastward in the lower troposphere affect different areas near the coastal East Asia. To understand the synoptic differences between the two types of dust events, four dust events from 2006 to 2009 are selected for each type and the synoptic environment is compared. Surface measurements, trajectory analyses, and a regional dust model are also applied to further analyze each type. Results show that the strength of the low-level trough and the surface anticyclonic system are important in determining the transport route of dust event. A deep 700–850 hPa trough extending far south beyond 30°N associated with an intense surface anticyclone with maximum pressure greater than 1020 hPa over coastal East Asia favors southeastward movement of dust event. The prevailing northwesterlies or northerlies behind the deep trough and ahead of the intense surface anticyclone promote the southeastward movement of dust event. Since intense surface anticyclones often associated with strong dust events, severe dust activities tend to move southeastward. In contrast, a shallow trough accompanied by a weak surface high locating north of 30°N over the coastal East Asia favors an eastward transport route.

scholarly journals Lengthening of summer season over the Northern Hemisphere under 1.5°C and 2.0°C global warming

2021 ◽  
Author(s):  
Bo-Joung Park ◽  
Seung-Ki Min ◽  
Evan Weller
Keyword(s):  
Global Warming ◽  
East Asia ◽  
Northern Hemisphere ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Late Summer ◽  
Industrial Condition ◽  
Summer Season ◽  
Hot Days

Abstract Summer season has lengthened substantially across Northern Hemisphere (NH) land over the past decades, which has been attributed to anthropogenic greenhouse gas increases. This study examines additional future changes in summer season onset and withdrawal under 1.5℃ and 2.0℃ global warming conditions using multiple atmospheric global climate model (AGCM) large-ensemble simulations from the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) project. Five AGCMs provide more than 100 runs of 10-year length for three experiments: All-Hist (current decade: 2006-2015), Plus15, and Plus20 (1.5℃ and 2.0℃ above pre-industrial condition, respectively). Results show that with 1.5℃ and 2.0℃ warmer conditions summer season will become longer by a few days to weeks over entire NH lands, with slightly larger contributions by delay in withdrawal due to stronger warming in late summer. Stronger changes are observed more in middle latitudes than high latitudes and largest expansion (up to three weeks) is found over East Asia and the Mediterranean. Associated changes in summer-like day frequency is further analyzed focusing on the extended summer edges. The hot days occur more frequently in lower latitudes including East Asia, USA and Mediterranean, in accord with largest summer season lengthening. Further, difference between Plus15 and Plus20 indicates that summer season lengthening and associated increases in hot days can be reduced significantly if warming is limited to 1.5℃. Overall, similar results are obtained from CMIP5 coupled GCM simulations (based on RCP8.5 scenario experiments), suggesting a weak influence of air-sea coupling on summer season timing changes.

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