Abstract

By using daily air temperature and precipitation data, and the weather phenomena data of daily snowfall from 98 meteorological stations over the Qinghai-Tibetan Plateau (QTP), this paper performs an “at-risk” evaluation on snowfall and accumulated snow over the QTP under current climate situation and future climate warming condition. When rainfall, snowfall, or accumulated snow weather phenomena occur, critical values are determined based on daily air temperature and precipitation for current climate conditions. Air temperature of 0°C is defined as the critical value of temperature for rainfall or snowfall, while 0°C air temperature and 4.0 mm (autumn) or 3.0 mm (spring) snowfall amounts are defined as the critical values for accumulated snowfall. Analyses based on the above critical values disclose that under current climate condition, stations with “at-risk” accumulated snow account for 33% and 36% of all stations, and the “at-risk” snowfall stations reach 78% and 81% in autumn and spring, respectively. Spatially, most stations with “at-risk” accumulated snow are located on the southern and eastern edge of the QTP, and stations with “at-risk” snowfall are also apparent at the northern edge. If the air temperature increases by 2.5°C in 2050, only the snowfall at a few “at-risk” snowfall stations will transform into rainfall, while most “at-risk” accumulated snow stations will face the problem that snowfall is hardly accumulated. Additionally, most stations will become “at-risk” accumulated snow stations, indicating that both the snow depth and the snow cover duration will decline in most areas of the QTP, including a delay of the start date and an advancing of the end date of snow cover. Ma, L., D. Qin, L. Bian, et al., 2011: Assessment of snow cover vulnerability over the Qinghai-Tibetan Plateau. Adv. Clim. Change Res., 2 (2), doi: 10.3724/SP.J.1248.2011.00093.

Abstract

Based on the number of snow cover days (NSCDs) and homogenized surface air temperature data for the period 1951–2004, this study performs the quantitative analysis on the sensitivity of NSCDs to surface air temperature over the Qinghai-Tibetan Plateau (QTP). Results show that both the extreme sensitivity and sensitivity under current climate are higher in the edge than in the central area of the QTP. There exists a strong negative correlation between station’s elevation and critical temperature, at which the sensitivity reaches extremum. The negative correlation between the elevation and the extreme sensitivity is not as strong as the former one. Currently, the climatological temperatures in quite a few stations do not reach the critical stage. The sensitivity at these stations will become greater under the current background of climate warming, which means NSCDs will be more sensitive to surface air temperature. Ma, L., D. Qin, L. Bian, et al., 2010: Sensitivity of the number of snow cover days to surface air temperature over the Qinghai-Tibetan Plateau. Adv. Clim. Change Res., 1, doi: 10.3724/SP.J.1248.2010.00076.