scholarly journals Synoptic-scale potential vorticity intrusion over northeastern China during winter and its influence on surface air temperature

2019 ◽  
Vol 12 (4) ◽  
pp. 286-293
Author(s):  
Tingting ZHU ◽  
Jiangyu MAO
Keyword(s):  
Air Temperature ◽  
Potential Vorticity ◽  
Surface Air Temperature ◽  
Northeastern China ◽  
Synoptic Scale

Understanding the Soil Temperature Variability at Different Depths: Effects of Surface Air Temperature, Snow Cover, and the Soil Memory

2021 ◽  
Author(s):  
Haoxin Zhang ◽  
Naiming Yuan ◽  
Zhuguo Ma ◽  
Yu Huang
Keyword(s):  
Soil Temperature ◽  
Snow Cover ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Thermal Conditions ◽  
Northeastern China ◽  
Memory Effects ◽  
Causality Analysis ◽  
Time Lagged ◽  
Warming Hiatus

<p>The soil temperature (ST) is closely related to the surface air temperature (AT), but their coupling may be affected by other factors. In this study, by using linear analysis and nonlinear causality analysis—convergent cross mapping (CCM) and its time-lagged version (time-lagged CCM), significant effects of the AT on the underlying ST were found, and the time taken to propagate downward to 320 cm can be up to 10 months. Besides the AT, the ST is also affected by memory effects—namely, its prior thermal conditions. At deeper depth (i.e., 320 cm), the effects of the AT from a particular season may be exceeded by the soil memory effects from the last season. At shallower layers (i.e., < 80 cm), the effects of the AT may be blocked by the snow cover, resulting in a poorly synchronous correlation between the AT and the ST. In northeastern China, this snow cover blockage mainly occurs in winter and then vanishes in the subsequent spring. Due to the thermal insulation effect of the snow cover, the winter ST at layers above 80 cm in northeastern China were found to continue to increase even during the recent global warming hiatus period. These findings may be instructive for better understanding ST variations, as well as land−atmosphere interactions.</p>

scholarly journals Intra-seasonal variation of surface air temperature in Nepal Himalayas

MAUSAM ◽  
2022 ◽  
Vol 53 (3) ◽  
pp. 281-288
Author(s):  
KENICHI UENO ◽  
ADARSHA P. POKHREL
Keyword(s):  
Seasonal Variation ◽  
Air Temperature ◽  
Monsoon Season ◽  
Surface Air Temperature ◽  
Circulation Pattern ◽  
Synoptic Scale ◽  
Local Circulation ◽  
Pressure System ◽  
Surface Temperature Variation ◽  
Unique Surface

Intra-seasonal variation of surface air temperature observed by the automatic weather station at Syangpoche in Khumbu region, Nepal Himalayas, is analyzed.  In the monsoon season, temperature was nearly constant with large decrease in insolation due to monsoon clouds.  On the other hand, large intra-seasonal variation existed in the winter with increase in temperature associated with passing synoptic scale high-pressure system which disturb local circulation pattern as well as decrease in temperature due to the nighttime strong radiative cooling under the condition of snow covers.  Monsoon clouds and deep valley system caused unique surface temperature variation.

scholarly journals Seasonally changing contribution of sea ice and snow cover to uncertainty in multi-decadal Eurasian surface air temperature trends based on CESM simulations

2021 ◽  
Author(s):  
Zhaomin Ding ◽  
Renguang Wu
Keyword(s):  
Sea Ice ◽  
Air Temperature ◽  
Western Siberia ◽  
Russian Far East ◽  
Far East ◽  
Surface Air Temperature ◽  
The Caspian Sea ◽  
Sea Ice Concentration ◽  
Northern Siberia ◽  
The Impact

AbstractThis study investigates the impact of sea ice and snow changes on surface air temperature (SAT) trends on the multidecadal time scale over the mid- and high-latitudes of Eurasia during boreal autumn, winter and spring based on a 30-member ensemble simulations of the Community Earth System Model (CESM). A dynamical adjustment method is used to remove the internal component of circulation-induced SAT trends. The leading mode of dynamically adjusted SAT trends is featured by same-sign anomalies extending from northern Europe to central Siberia and to the Russian Far East, respectively, during boreal spring and autumn, and confined to western Siberia during winter. The internally generated component of sea ice concentration trends over the Barents-Kara Seas contributes to the differences in the thermodynamic component of internal SAT trends across the ensemble over adjacent northern Siberia during all the three seasons. The sea ice effect is largest in autumn and smallest in winter. Eurasian snow changes contribute to the spread in dynamically adjusted SAT trends as well around the periphery of snow covered region by modulating surface heat flux changes. The snow effect is identified over northeast Europe-western Siberia in autumn, north of the Caspian Sea in winter, and over eastern Europe-northern Siberia in spring. The effects of sea ice and snow on the SAT trends are realized mainly by modulating upward shortwave and longwave radiation fluxes.

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