Based on the snowfall observations at 836 surface weather stations in China and the Daily Surface Climate Variables of China version 3.0 dataset for 1961–2013, capability of five methods with different objective crit...Based on the snowfall observations at 836 surface weather stations in China and the Daily Surface Climate Variables of China version 3.0 dataset for 1961–2013, capability of five methods with different objective criteria for identifying wintertime snowfall is evaluated, to provide reference for application of these methods in snowfall/rainfall discrimination. Methods Ⅰ, Ⅱ, Ⅲ, Ⅳ, and Ⅴuse the daily average surface air temperature(Ta), wet-bulb temperature(Tw), dynamic threshold Tw, 0-cm ground temperature, and 700–850-hPa thickness, respectively, to identify the snowfall. The results show that the climatological distribution of snowfall can be well produced by Methods Ⅰ, Ⅱ, and Ⅲ. Method Ⅳ underestimates the snowfall days in eastern Tibetan Plateau(ETP), and Method Ⅴ cannot yield the actual large numbers of snowfall days and amounts. Accordingly, the linear trends of snowfall days estimated from Methods Ⅰ, Ⅱ, and Ⅲ largely agree with the observations, while a discrepancy is found in the linear trend of snowfall amounts over southeastern China(SEC). For interannual and decadal variations of snowfall, Method Ⅴ shows the worst performance. It is more reasonable to use Tw to distinguish snowfall from rainfall instead of Ta, 0-cm ground temperature, and 700–850-hPa thickness;and the reference thresholds of Tw in northeastern China(NEC), northwestern China(NWC), ETP, and SEC are-1.5,-1.5,-0.4, and-0.3°C, respectively. The above results are beneficial to identifying snowfall in short-term climate prediction.展开更多
基金Supported by the National Key Research and Development Program of China(2016YFA0600702)National Natural Science Foundation of China(41625019)。
文摘Based on the snowfall observations at 836 surface weather stations in China and the Daily Surface Climate Variables of China version 3.0 dataset for 1961–2013, capability of five methods with different objective criteria for identifying wintertime snowfall is evaluated, to provide reference for application of these methods in snowfall/rainfall discrimination. Methods Ⅰ, Ⅱ, Ⅲ, Ⅳ, and Ⅴuse the daily average surface air temperature(Ta), wet-bulb temperature(Tw), dynamic threshold Tw, 0-cm ground temperature, and 700–850-hPa thickness, respectively, to identify the snowfall. The results show that the climatological distribution of snowfall can be well produced by Methods Ⅰ, Ⅱ, and Ⅲ. Method Ⅳ underestimates the snowfall days in eastern Tibetan Plateau(ETP), and Method Ⅴ cannot yield the actual large numbers of snowfall days and amounts. Accordingly, the linear trends of snowfall days estimated from Methods Ⅰ, Ⅱ, and Ⅲ largely agree with the observations, while a discrepancy is found in the linear trend of snowfall amounts over southeastern China(SEC). For interannual and decadal variations of snowfall, Method Ⅴ shows the worst performance. It is more reasonable to use Tw to distinguish snowfall from rainfall instead of Ta, 0-cm ground temperature, and 700–850-hPa thickness;and the reference thresholds of Tw in northeastern China(NEC), northwestern China(NWC), ETP, and SEC are-1.5,-1.5,-0.4, and-0.3°C, respectively. The above results are beneficial to identifying snowfall in short-term climate prediction.
