scholarly journals Decadal Changes of Connections among Snow cover in West Siberia, Eurasia Teleconnection and O<sub>3</sub>-related meteorology in North China

2021 ◽  
Author(s):  
Zhicong Yin ◽  
Yu Wan ◽  
Huijun Wang
Keyword(s):  
Heat Flux ◽  
Snow Cover ◽  
North China ◽  
Surface Ozone ◽  
West Siberia ◽  
Photochemical Reactions ◽  
Snow Cover Area ◽  
Natural Emissions ◽  
The Stability ◽  
Intense Solar Radiation

Abstract. Severe surface ozone (O3) pollution frequently occurred in North China and obviously damages human health and ecosystems. The meteorological conditions effectively modulate the variations in O3 pollution. In this study, the interannual relationship between O3-related meteorology and late-spring snow cover in West Siberia was explored, and the reasons of its decadal change were also physically explained. Before mid-1990s, less snow cover could enhance net heat flux and stimulate positive phase of the Eurasia (EU) teleconnection in summer. The positive EU pattern resulted in hot-dry air and intense solar radiation in North China, which could enhance the natural emissions of O3 precursors and photochemical reactions in the atmosphere closely related to high O3 concentrations. However, after the mid-1990s, the south edge of the dense snow cover area in West Siberia shifted northward by approximately 2° in latitude and accompanied radiation and heat flux also retreated toward the polar region. The connections among snow anomalies, EU pattern and surface O3 became insignificant and thus influenced the stability of the predictability.

scholarly journals Decadal changes of connections among late-spring snow cover in West Siberia, summer Eurasia teleconnection and O<sub>3</sub>-related meteorology in North China

2021 ◽  
Vol 21 (15) ◽  
pp. 11519-11530
Author(s):  
Zhicong Yin ◽  
Yu Wan ◽  
Huijun Wang
Keyword(s):  
Heat Flux ◽  
Snow Cover ◽  
North China ◽  
Surface Ozone ◽  
West Siberia ◽  
Photochemical Reactions ◽  
Late Spring ◽  
Snow Cover Area ◽  
The Stability ◽  
Intense Solar Radiation

Abstract. Severe surface ozone (O3) pollution frequently occurred in North China and obviously damages human health and ecosystems. The meteorological conditions effectively modulate the variations in O3 pollution. In this study, the interannual relationship between O3-related meteorology and late-spring snow cover in West Siberia was explored, and the reasons for its decadal change were also physically explained. Before mid-1990s, less snow cover could enhance net heat flux and stimulate positive phase of the Eurasian (EU) teleconnection in summer. The positive EU pattern resulted in hot, dry air and intense solar radiation in North China, which could enhance the natural emissions of O3 precursors and photochemical reactions in the atmosphere closely related to high O3 concentrations. However, after the mid-1990s, the southern edge of the dense snow cover area in West Siberia shifted northward by approximately 2∘ in latitude and accompanied radiation and heat flux also retreated toward the polar region. The connections among snow anomalies, EU pattern and surface O3 became insignificant and thus influenced the stability of the predictability.

scholarly journals Dominant patterns of summer ozone pollution in eastern China and associated atmospheric circulations

2019 ◽  
Vol 19 (22) ◽  
pp. 13933-13943 ◽  
Author(s):  
Zhicong Yin ◽  
Bufan Cao ◽  
Huijun Wang
Keyword(s):  
North China ◽  
Surface Ozone ◽  
Eastern China ◽  
Western Pacific Subtropical High ◽  
Ground Level ◽  
Photochemical Reactions ◽  
Western Pacific ◽  
Subtropical High ◽  
Ozone Pollution ◽  
Atmospheric Circulations

Abstract. Surface ozone has been severe during summers in the eastern parts of China, damaging human health and flora and fauna. During 2015–2018, ground-level ozone pollution increased and intensified from south to north. In North China and the Huanghuai region, the O3 concentrations were highest. Two dominant patterns of summer ozone pollution were determined, i.e., a south–north covariant pattern and a south–north differential pattern. The anomalous atmospheric circulations composited for the first pattern manifested as a zonally enhanced East Asian deep trough and as a western Pacific subtropical high, whose western ridge point shifted northward. The local hot, dry air and intense solar radiation enhanced the photochemical reactions to elevate the O3 pollution levels in North China and the Huanghuai region; however, the removal of pollutants was decreased. For the second pattern, the broad positive geopotential height anomalies at high latitudes significantly weakened cold air advection from the north, and those extending to North China resulted in locally high temperatures near the surface. In a different manner, the western Pacific subtropical high transported sufficient water vapor to the Yangtze River Delta and resulted in a locally adverse environment for the formation of surface ozone. In addition, the most dominant pattern in 2017 and 2018 was different from that in previous years, which is investigated as a new feature.

scholarly journals Dominant Patterns of Summer Ozone Pollution in Eastern China and Associated Atmospheric Circulations

2019 ◽  
Author(s):  
Zhicong Yin ◽  
Bufan Cao ◽  
Huijun Wang
Keyword(s):  
North China ◽  
Surface Ozone ◽  
Eastern China ◽  
Photochemical Reactions ◽  
Air Pollutant ◽  
Subtropical High ◽  
Ozone Pollution ◽  
West Pacific ◽  
Atmospheric Circulations ◽  
West Pacific Subtropical High

Abstract. Surface ozone, a man-made air pollutant, has been severe during summers in the eastern parts of China, damaging human’s health and flora and fauna. During 2015–2018, ground-level ozone pollution increased year by year and intensified from south to north. In North China and Huanghuai region, the O3 concentrations were highest. Two dominant patterns of summer ozone pollution were determined, i.e., a south-north covariant pattern and a south-north differential pattern. The anomalous atmospheric circulations composited for the first pattern manifested as a zonally enhanced East Asia deep trough and as a west Pacific subtropical high whose western ridge point shifted northward. The local hot, dry air and intense solar radiation enhanced the photochemical reactions to elevate the O3 pollution levels in North China and Huanghuai region. For the second pattern, the broad positive geopotential height anomalies at high latitudes significantly weakened cold air activity, and those extending to North China resulted in locally high temperature near the surface. In a different manner, the west Pacific subtropical high transported sufficient water vapor to the Yangtze River Delta and resulted in locally adverse environment for the formation of surface ozone. Furthermore, the implications for the interannual differences in summer O3 pollution have also proven to be meaningful.

scholarly journals Arctic sea ice, Eurasia teleconnection pattern and summer surface ozone pollution in North China

2018 ◽  
Author(s):  
Zhicong Yin ◽  
Huijun Wang ◽  
Yuyan Li ◽  
Xiaohui Ma ◽  
Xinyu Zhang
Keyword(s):  
Sea Ice ◽  
North China ◽  
Surface Ozone ◽  
Seasonal Prediction ◽  
Teleconnection Pattern ◽  
Photochemical Reactions ◽  
Arctic Sea Ice ◽  
Ozone Pollution ◽  
Arctic Sea ◽  
Surface O3

Abstract. Summer surface O3 pollution has rapidly intensified recently, damaging human and ecosystem health. In 2017, the summer mean maximum daily average 8 h concentration of ozone was greater than 150 μg/m3 in North China. Here, we show that in addition to anthropogenic emissions, the Eurasia teleconnection pattern (EUTP), a major globally significant atmospheric teleconnection pattern, influences surface O3 pollution in North China. The local meteorological conditions associated with the EUTP positive phase supported intense and efficient photochemical reactions to produce more surface O3. The associated southerlies over North China transported surrounding O3 precursors to superpose local emissions. Solar radiation and high temperature dramatically enhanced O3 photochemical reactions. Furthermore, due to the close connection between the preceding May Arctic sea ice and summer EUTP, approximately 60 % of the interannual variability of summer surface O3 pollution was attributed to Arctic sea ice to the north of Eurasia. This finding aids in the seasonal prediction of O3 pollution.

scholarly journals A Response of Snow Cover to the Climate in the Northwest Himalaya (NWH) Using Satellite Products

2021 ◽  
Vol 13 (4) ◽  
pp. 655
Author(s):  
Animesh Choudhury ◽  
Avinash Chand Yadav ◽  
Stefania Bonafoni
Keyword(s):  
Snow Cover ◽  
Land Surface ◽  
Significant Negative Correlation ◽  
Shuttle Radar Topography Mission ◽  
Vital Role ◽  
Snow Cover Area ◽  
Study Region ◽  
Northwest Himalaya ◽  
The Past ◽  
Average Annual Temperature

The Himalayan region is one of the most crucial mountain systems across the globe, which has significant importance in terms of the largest depository of snow and glaciers for fresh water supply, river runoff, hydropower, rich biodiversity, climate, and many more socioeconomic developments. This region directly or indirectly affects millions of lives and their livelihoods but has been considered one of the most climatically sensitive parts of the world. This study investigates the spatiotemporal variation in maximum extent of snow cover area (SCA) and its response to temperature, precipitation, and elevation over the northwest Himalaya (NWH) during 2000–2019. The analysis uses Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra 8-day composite snow Cover product (MOD10A2), MODIS/Terra/V6 daily land surface temperature product (MOD11A1), Climate Hazards Infrared Precipitation with Station data (CHIRPS) precipitation product, and Shuttle Radar Topography Mission (SRTM) DEM product for the investigation. Modified Mann-Kendall (mMK) test and Spearman’s correlation methods were employed to examine the trends and the interrelationships between SCA and climatic parameters. Results indicate a significant increasing trend in annual mean SCA (663.88 km2/year) between 2000 and 2019. The seasonal and monthly analyses were also carried out for the study region. The Zone-wise analysis showed that the lower Himalaya (184.5 km2/year) and the middle Himalaya (232.1 km2/year) revealed significant increasing mean annual SCA trends. In contrast, the upper Himalaya showed no trend during the study period over the NWH region. Statistically significant negative correlation (−0.81) was observed between annual SCA and temperature, whereas a nonsignificant positive correlation (0.47) existed between annual SCA and precipitation in the past 20 years. It was also noticed that the SCA variability over the past 20 years has mainly been driven by temperature, whereas the influence of precipitation has been limited. A decline in average annual temperature (−0.039 °C/year) and a rise in precipitation (24.56 mm/year) was detected over the region. The results indicate that climate plays a vital role in controlling the SCA over the NWH region. The maximum and minimum snow cover frequency (SCF) was observed during the winter (74.42%) and monsoon (46.01%) season, respectively, while the average SCF was recorded to be 59.11% during the study period. Of the SCA, 54.81% had a SCF above 60% and could be considered as the perennial snow. The elevation-based analysis showed that 84% of the upper Himalaya (UH) experienced perennial snow, while the seasonal snow mostly dominated over the lower Himalaya (LH) and the middle Himalaya (MH).

Impact of the Horizontal Heat Flux in the Mixed Layer on an Extreme Heat Event in North China: A Case Study

2018 ◽  
Vol 36 (2) ◽  
pp. 133-142 ◽  
Author(s):  
Ying Na ◽  
Riyu Lu ◽  
Bing Lu ◽  
Min Chen ◽  
Shiguang Miao
Keyword(s):  
Heat Flux ◽  
Mixed Layer ◽  
North China ◽  
Extreme Heat ◽  
Extreme Heat Event ◽  
Heat Event

Assessing the quality of a real-time Snow Cover Area product for hydrological applications

2012 ◽  
Vol 127 ◽  
pp. 271-287 ◽  
Author(s):  
G. Thirel ◽  
C. Notarnicola ◽  
M. Kalas ◽  
M. Zebisch ◽  
T. Schellenberger ◽  
...  
Keyword(s):  
Snow Cover ◽  
Real Time ◽  
Snow Cover Area ◽  
Area Product ◽  
Hydrological Applications

The optical behaviour of snow during a melting season at Ny Ålesund (Svalbard, Norway)

2021 ◽  
Author(s):  
Roberto Salzano ◽  
Christian Lanconelli ◽  
Giulio Esposito ◽  
Marco Giusto ◽  
Mauro Montagnoli ◽  
...  
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Full Range ◽  
Time Lapse ◽  
Test Site ◽  
Remotely Sensed ◽  
Optical Behaviour ◽  
Remotely Sensed Data ◽  
Snow Cover Area ◽  
Significant Information

&lt;p&gt;&lt;span&gt;Polar areas are the most sensitive targets of &lt;/span&gt;&lt;span&gt;the &lt;/span&gt;&lt;span&gt;climate change and the continuous monitoring of the cryosphere represents a critical issue. The satellite remote sensing can fill this gap but further integration between remotely-sensed multi-spectral images and field data is crucial to validate retrieval algorithms and climatological models. The optical behaviour of snow, at different wavelengths, provides significant information about the micro-physical characteristics of the surface and this allow to discriminate different snow/ice covers. The aim of this work is to present an approach based on combining unmanned observations on spectral albedo and on the analysis of time-lapse images of sky and ground conditions in a&lt;/span&gt;&lt;span&gt;n &lt;/span&gt;&lt;span&gt;Ar&lt;/span&gt;&lt;span&gt;c&lt;/span&gt;&lt;span&gt;tic &lt;/span&gt;&lt;span&gt;test-site &lt;/span&gt;&lt;span&gt;(Svalbard, Norway). Terrestrial photography can provide, in fact, important information about the cloud cover and support the discrimination between white-sky or clear-sky illuminating conditions. Similarly, time-lapse cameras can provide a detailed description of the snow cover, estimating the fractional snow cover area. The spectral albedo was obtained by a narrow band device that was compared to a full-range commercial system and to remotely sensed data acquired during the 2015 spring/summer period at the &lt;/span&gt;&lt;span&gt;Amundsen - Nobile&lt;/span&gt;&lt;span&gt; Climate Change Tower (Ny &lt;/span&gt;&lt;span&gt;&amp;#197;&lt;/span&gt;&lt;span&gt;lesund). The results confirmed the possibility to have continuous observations of the snow surface (microphisical) characteristics and highlighted the opportunity to monitor the spectral variations of snowed surfaces during the melting period. It was possible, &lt;/span&gt;&lt;span&gt;therefore,&lt;/span&gt;&lt;span&gt; to estimate spectral indexes, such as NDSI and SWIR albedo, and to found interesting links between both features and air/ground temperatures, wind-speed and precipitations. Different melting phases were detected and different processes were associated with the observed spectral variations.&lt;/span&gt;&lt;/p&gt;

scholarly journals The Strengthening Relationship between Eurasian Snow Cover and December Haze Days in Central North China after the Mid-1990s

2017 ◽  
Author(s):  
Zhicong Yin ◽  
Huijun Wang
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
North China ◽  
Surface Wind ◽  
Surface Radiation ◽  
Radiative Cooling ◽  
Atmospheric Circulations ◽  
Haze Pollution ◽  
The Relationship ◽  
Haze Days

Abstract. The haze pollution in December has become increasingly serious over recent decades and imposes damage on society, ecosystems, and human health. In addition to anthropogenic emissions, climate change and variability were conducive to haze in China. In this study, the relationship between the snow cover over East Europe and West Siberia (SCES) and the number of haze days in December in central North China was analyzed. This relationship significantly strengthened after the mid-1990s, which is attributed to the effective connections between the SCES and the Eurasian atmospheric circulations. During 1998–2016, the SCES significantly influenced the soil moisture and land surface radiation, and then, the combined underlying drivers of enhanced soil moisture and radiative cooling moved the East Asia jet stream northward and induced anomalous, anti-cyclonic circulation over central North China. Modulated by such atmospheric circulations, the local lower boundary layer, the decreased surface wind and the more humid air were conducive to the worsening dispersion conditions and frequent haze occurrences. In contrast, from 1979 to 1997, the linkage between the SCES and soil moisture was negligible. Furthermore, the correlated radiative cooling was distributed narrowly and far from the key area of snow cover. The associated atmospheric circulations with the SCES were not significantly linked with the ventilation conditions over central North China. Consequently, the relationship between the SCES and the number of hazy days in central North China was insignificant before the mid-1990s but has strengthened and has become significant since then.

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