Interannual variability of March snow mass over Northern Eurasia and its relation to the concurrent and preceding surface air temperature, precipitation and atmospheric circulation

2018 ◽  
Vol 52 (5-6) ◽  
pp. 2813-2836 ◽  
Author(s):  
Kunhui Ye
2008 ◽  
Vol 21 (22) ◽  
pp. 5807-5819 ◽  
Author(s):  
Hengchun Ye

Abstract Potential benefits or disadvantages of increasing precipitation in high-latitude regions under a warming climate are dependent on how and in what form the precipitation occurs. Precipitation frequency and type are equally as important as quantity and intensity to understanding the seasonality of hydrological cycles and the health of the ecosystem in high-latitude regions. This study uses daily historical synoptic observation records during 1936–90 over the former USSR to reveal associations between the frequency of precipitation types (rainfall, snowfall, mixed solid and liquid, and wet days of all types) and surface air temperatures to determine potential changes in precipitation characteristics under a warming climate. Results from this particular study show that the frequency of precipitation of all types generally increases with air temperature during winter. However, both solid and liquid precipitation days predominantly decrease with air temperature during spring with a reduction in snowfall days being most significant. During autumn, snowfall days decrease while rainfall days increase resulting in overall decreases in wet days as air temperature increases. The data also reveal that, as snowfall days increase in relationship to increasing air temperatures, this increase may level out or even decrease as mean surface air temperature exceeds −8°C in winter. In spring and autumn, increasing rainfall days switch to decreasing when the mean surface air temperature goes above 6°C. The conclusion of this study is that changes in the frequency of precipitation types are highly dependent on the location’s air temperature and that threshold temperatures exist beyond which changes in an opposite direction occur.


2019 ◽  
Vol 53 (3-4) ◽  
pp. 1805-1821 ◽  
Author(s):  
Shangfeng Chen ◽  
Renguang Wu ◽  
Linye Song ◽  
Wen Chen

2016 ◽  
Vol 11 (6) ◽  
pp. 065001 ◽  
Author(s):  
Tetsuya Hiyama ◽  
Hatsuki Fujinami ◽  
Hironari Kanamori ◽  
Takaya Ishige ◽  
Kazuhiro Oshima

2014 ◽  
Vol 27 (4) ◽  
pp. 1578-1599 ◽  
Author(s):  
Y. Tang ◽  
D. Chen ◽  
X. Yan

Abstract In this study, the potential predictability of the North American (NA) surface air temperature was explored using information-based predictability framework and Ensemble-Based Predictions of Climate Changes and their Impacts (ENSEMBLES) multiple model ensembles. Emphasis was put on the comparison of predictability measured by information-based metrics and by the conventional signal-to-noise ratio (SNR)-based metrics. Furthermore, the potential predictability was optimally decomposed into different modes by maximizing the predictable information (equivalent to the maximum of SNR), from which the most predictable structure was extracted and analyzed. It was found that the conventional SNR-based metrics underestimate the potential predictability, in particular in these areas where the predictable signals are relatively weak. The most predictable components of the NA surface air temperature can be characterized by the interannual variability mode and the long-term trend mode. The former is inherent to tropical Pacific sea surface temperature (SST) forcing such as El Niño–Southern Oscillation (ENSO), whereas the latter is closely associated with the global warming. The amplitude of the two modes has geographical variations in different seasons. On this basis, the possible physical mechanisms responsible for the predictable mode of interannual variability and its potential benefits to the improvement of seasonal climate prediction were discussed.


2021 ◽  
Author(s):  
Jouni Räisänen

AbstractThe effect of atmospheric circulation on monthly, seasonal and annual mean surface air temperature trends in the years 1979–2018 is studied by applying a trajectory-based method on the European Centre for Medium-Range Weather Forecasts ERA5 reanalysis data. To the extent that the method captures the effects of atmospheric circulation, the results suggest that circulation trends only had a minor impact on observed annual mean temperature trends in most areas. Exceptions include, for example, a decrease in annual mean warming by about 1 °C in western Siberia, and increased warming in central Europe and the Arctic Ocean. However, the effect of circulation trends on seasonal and particularly monthly temperature trends is more substantial. Subtracting the effect of circulation changes from the ERA5 temperature trends leaves residual trends with a smoother annual cycle than the original trends. The residual monthly mean temperature trends also tend to agree better with the multi-model mean temperature trends from models in the 5th Coupled Model Intercomparison Project (CMIP5) than the original ERA5 trends do, with a 42% decrease in the mean square difference over the global land area. However, the corresponding decrease in the mean square difference of the annual mean temperature trends is only 6%.


Author(s):  
R.M. Vilfand ◽  
◽  
K.A. Sumerova , ◽  
V.A. Tishchenko ◽  
V.M. Khan ◽  
...  

The main results of the analysis of the Northern Hemisphere large-scale atmospheric circulation features are presented for the 2020 summer. Skill scores of the consensus forecast for the 2020 Northern Eurasia summer are discussed in the context of analyzing the large-scale atmospheric circulation. The prognostic potential of the trend component in forecasting seasonal anomalies of air temperature and precipitation is noted. Keywords: air temperature, precipitation, forecast skill, trends, large-scale atmospheric circulation, sea surface temperature, NEACOF, circulation indices, Arctic ice


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