Spring snow depth changes and feedback to surface air temperature across the Tibetan plateau from 1961 to 2013

Spring snow depth (SSD) in the Tibetan Plateau (TP) plays an essential role in snow water estimation, vegetation growth, and climate projections for Southwest China and the surrounding Asian countries. Previous studies have reported a decline in SSD that is associated with increasing surface air temperature (T-s) across the TP over the past decades. However, only a few studies have explored the potential feedback of SSD to T-s, which has hindered the elucidation of the vulnerability of snow cover in the TP against the backdrop of rapid climate change. Based on data from 69 meteorological stations in the central and eastern parts of the TP, this study analyses changes in SSD and its feedback to T-s from 1961 to 2013. Overall, a slightly negative trend in SSD was observed from 1961 to 2013, during which two contrasting trends were detected using a piecewise regression approach: an initial increase from 1961 to 1981 (0.12 cm decades(-1), p < .01) followed by a decrease from 1982 to 2013 (-0.36 cm decades(-1), p < .01). Sensitivity analysis revealed that the SSD decline was systematically correlated with a positive T-s anomaly, with sensitivities of -0.050 cm degrees C-1 (p < .01) and -0.069 cm degrees C-1 (p < .01) for 1961-2013 and 1982-2013, respectively. However, following the accelerated SSD decline during 1982-2013, its potential feedback to T-s was attenuated, with averaged feedback values from -1.328 degrees C cm(-1) during 1961-2013 to -0.936 degrees C cm(-1) during 1982-2013 in latitudes below 3,500 m, distributed in the Qaidam and Yellow River basins, and the upper reaches of the Yangtze River basin. The decrease in feedback from SSD to T-s may lead to changes in the mechanism controlling T-s dynamics across the TP, which should be considered in climate change projections in future studies.