Interannual Variability of Snow Depth over the Tibetan Plateau and Its Associated Atmospheric Circulation Anomalies

Abstract

The interannual variability of wintertime snow depth over the Tibetan Plateau (TP) and related atmospheric circulation anomalies were investigated based on observed snow depth measurements and NCEP/NCAR reanalysis data. Empirical orthogonal function (EOF) analysis was applied to identify the spatio-temporal variability of wintertime TP snow depth. Snow depth anomalies were dominated by a monopole pattern over the TP and a dipole structure with opposite anomalies over the southeastern and northwestern TP. The atmospheric circulation conditions responsible for the interannual variability of TP snow depth were examined via regression analyses against the principal component of the most dominant EOF mode. In the upper troposphere, negative zonal wind anomalies over the TP with extensively positive anomalies to the south indicated that the southwestward shift of the westerly jet may favor the development of surface cyclones over the TP. An anomalous cyclone centered over the southeastern TP was associated with the anomalous westerly jet, which is conducive to heavier snowfall and results in positive snow depth anomalies. An anomalous cyclone was observed at 500 hPa over the TP, with an anomalous anticyclone immediately to the north, suggesting that the TP is frequently affected by surface cyclones. Regression analyses revealed that significant negative thickness anomalies exist around the TP from March to May, with a meridional dipole anomaly in March. The persistent negative anomalies due to more winter TP snow are not conducive to earlier reversal of the meridional temperature gradient, leading to a possible delay in the onset of the Asian summer monsoon. Keywords: Tibetan Plateau, snow depth, interannual variability, atmospheric circulation anomalies Citation: Mao, J.-Y., 2010: Interannual variability of snow depth over the Tibetan Plateau and its associated atmospheric circulation anomalies, Atmos. Oceanic Sci. Lett., 3,[213][214][215][216][217][218]

Tree-ring based February–April precipitation reconstruction for the lower reaches of the Yangtze River, southeastern China

“…The SST in the western Pacific in winter and spring negatively correlates with the WPSH anomaly (Fan and Liu, 2009). When the WPWP cools, the WPSH strengthens and its position shifts to the west and/or the north that increases spring rainfall in the mid-lower reaches of the Yangtze River (Jiang and Zhao, 2012;Deng and Luo, 2013).…”

Interdecadal Change in the Intensity of Interannual Variation of Spring Precipitation over Southern China and Possible Reasons

“…The variations of spring rainfall over southern China occur on multiple time scales, of which interannual variability is the primary one (Liu et al 2015;Li and Zhang 2013). Scientists have already done many studies to reveal the interannual variation of spring precipitation over southern China (Jiang and Zhao 2012;Liu et al 2015;Zhang and You 2010;Zuo and Zhang 2012). Li and Zhang (2013) used the power spectral analysis method to calculate the variance proportions of different time scale variations of spring precipitation over the middle and lower reaches of the Yangtze River valley and found that the interannual variation accounts for Corresponding author: Yunting Qiao, qiaoyt@mail.sysu.edu.cn 78.9% of the total variance.…”

“…Zuo and Zhang (2012) found that the interannual variability of spring rainfall is notable and becomes intensified after the late 1980s. Many scientists also revealed the characteristics of spring precipitation over southern China on the interdecadal time scale (Jiang and Zhao 2012;Zuo et al 2012a;Zhu et al 2014). Jiang and Zhao (2012) pointed out that the spring precipitation over southern China was less in the middle and late 1960s and greater in the middle 1970s to the early 1980s, compared with the climatological mean.…”

“…Many scientists also revealed the characteristics of spring precipitation over southern China on the interdecadal time scale (Jiang and Zhao 2012;Zuo et al 2012a;Zhu et al 2014). Jiang and Zhao (2012) pointed out that the spring precipitation over southern China was less in the middle and late 1960s and greater in the middle 1970s to the early 1980s, compared with the climatological mean. The spring precipitation began decreasing from the early 1990s again.…”

Spatiotemporal Variability and Change of the South China Spring Precipitation during 1961–2012

“…At the same time, a negative center to the east of the Tibetan Plateau appears, indicating a stronger low. From the basic dynamics, it can be inferred that such type of anomalous pressure gradient can lead to the strengthening of the southwesterly [19,20] at low levels. It is clear that the years of abundant (scarce) spring precipitation in the South China correspond to the strengthened (weakened) low-level southwesterly, which is also evident from the composite of the difference of the wind field at 850 hPa level between the abundant spring precipitation and scarce spring precipitation years ( Figure 10(b)).…”